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NNadir

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Current location: New Jersey
Member since: 2002
Number of posts: 22,539

Journal Archives

Understanding the Relationship Between Chemical Feedstocks and Dangerous Fossil Fuels.

Recently in this space, I posted a very esoteric piece - so esoteric that it understandably provoked no comment - on the preparation of p-xylene from dimethylfuran, a chemical that is accessible from biomass such as straw.

The Conversion of Cellulosic Biomass Into Aromatic Compounds.

In so doing, I failed to apply a lesson I often - albeit with very limited success - try to evoke whenever one hears these "feel good/sound good" bits of environmental wishful thinking - which is to think about scale. For instance, the scale of world energy consumption as of 2016 was 576 exajoules per year - fraction of which that is derived from dangerous fossil fuels has been rising not falling throughout the 21st century - and all of the endless hype about the solar industry's "percent" growth is merely an attempt to bury the issue of scale. Wind and solar energy combined, despite all the cheering, did not produce 10 exajoules of energy in 2016 and thus has been insignificant, is insignificant, and always will be insignificant.

A recent publication in one of my favorite journals Environmental Science and Technology has served for my inattention to issues of scale in referencing a lab scale process as significant; there's a long way between "there" - "there" being significance - and "here," "here" being a world in which the collapse of the planetary atmosphere is accelerating and not as popularly imagined, even remotely being addressed. The paper is this one, about the role that dangerous fossil fuels play in the chemical industry, the chemical industry being at the very core of and essential to our way of life, pretty much involved in everything a modern bourgeois person - such as I am - does. Here is the paper: Mapping Global Flows of Chemicals: From Fossil Fuel Feedstocks to Chemical Products (Levi and Cullen, Environ. Sci. Technol., 2018, 52 (4), pp 1725–1734)

This graphic from the paper shows pretty much everything you need to know about it:



(Similar types of flow diagrams for energy are widely available from the Lawrence Livermore Laboratory and other places. I sometimes post a particular version here and there showing the energy flow diagram for Denmark, that offshore oil and gas hellhole showing how trivial its much ballyhooed and hyped wind industry is.)

Anyway.

From this diagram, one can discern the world requirement for "BTX" (Benzene, Toluene and Xylenes) is on the order of 80 million tons, of which roughly 70 million tons is carbon. This compares to the average annual average amount of carbon dioxide that is routinely dumped into the atmosphere while we wait for the grand super duper renewable energy nirvana that never comes, roughly 35 billion tons of CO2, corresponding to about 15 billion tons of carbon.

70 million tons may be accessible via "waste" biomass. Over on another website where I was banned for telling the truth, I roughly calculated from available references that the total carbon content of all the straw in China is roughly 267 million tons.

This of course does not account for transporting and processing all the straw in China, of course, just so I'm not encouraging false optimism.

According to the cited paper, the world chemical industry's contribution to climate change from direct by products of the chemicals themselves as carbon dioxide, is relatively small, 267 million tons, or less than 1%. More serious is the release of methane, and probably less serious, but significant all the same, is the contribution to climate change from nitrous oxide, a side product of the ammonia industry on which our food supply depends:



However this ignores the energy input of chemical processing, which is far more significant.

From the opening text of the paper we have these remarks from the authors:

Industrial chemicals and their derivatives pervade modern society. Although often diffuse in their application (e.g., pharmaceuticals), the bulk outputs of the chemical and petrochemical sector, (also referred to here as "the chemical sector" ), are deployed in huge volumes to make millions of tonnes per year (Mt yr–1) of chemical products, such as fertilizers and plastics. Our industrialized economy is dependent on chemicals.

In performing this pivotal role, the chemical sector exerts a large environmental burden. It is responsible for approximately 7% of global anthropogenic global greenhouse gas (GHG) emissions, and 5.5% when only counting CO2 emissions.(1) The sector’s final energy consumption is the largest among industrial sectors: 42.5 EJ in 2014, of which 25 EJ is feedstock energy.(2) Other sources of emissions include those stemming directly from the chemical transformations mobilized in reactors (process emissions), and from energy conversion in the transformation sector (indirect emissions). In addition to these gaseous emissions, chemical products can spawn pernicious aqueous discharges. The oft-publicised problem of fertilizer runoff contributing to hypertrophication,(3) and the more recent exposition of plastic waste ending up in the world’s oceans(4, 5) and organisms(6) are notable examples.


Returning to the issue of the ammonia industry, it is worth noting that 55 million tons, graphically it seems to be on the order of 1/3 of the total, comes from coal, the most dangerous of the three dangerous fossil fuels. Coal is often reported as being "dead," which is nonsense; reports of its death are greatly exaggerated, to steal a Twainism. Between 2000 and 2016 coal was the fastest growing source of primary energy on this planet, increasing by 2/3 of the amount used in 2000 (roughly 90 exajoules worth) by 60 additional exajoules. The contribution that coal makes to ammonia synthesis may be trivial in comparison to its use in the energy and steel industry, but it is real and significant.

I found this paper thought provoking, and it served for a useful refocusing on the realities of our increasingly dire environmental situation.

If we want to be serious - and there's no way that we are even remotely so in any country or even in any political party in any country - scale is the most important thing of which we can think.

I hope you're having a pleasant weekend.

Nature Climate and Atmospheric Science: Dramatic declines in snowpack in the western US

According to this open sourced paper in Nature Climate and Atmospheric Sci, the Western US Mountains Can't Hold Snow; the West Can't Get Water: Dramatic declines in snowpack in the western US (Mote, et al npj Climate and Atmospheric Sciencevolume 1, Article number: 2 (2018)

This is not a short term event. It's a trend.

California’s recent multi-year drought (2011–16) and its extension into Oregon and Washington has shown that warming can create drought simply by preventing the accumulation of mountain snowpack. The year 2015, for instance, set the record low 1 April snow water equivalent (SWE) at over 80% of sites west of 117° longitude,1 a result of high winter temperatures rather than low precipitation.2,3,4

More than a decade ago, we showed that spring snowpack had declined at a large majority of locations in the mountainous western US, and corroborated the observations with hydrologic modeling that reached broadly similar conclusions.5 We also noted that computing an area-averaged snowpack value from observations is challenging because the locations of long-term monitoring sites are usually chosen to favor a certain type of terrain and elevational range, with temperature-sensitive locations undersampled early in the record in some states.6 Methodological choices (e.g., about record length) can therefore strongly influence results and must be carefully evaluated. In contrast, model-based estimates provide a basis for estimating long-term SWE changes across the entire Western U.S. domain.

Since our earlier work, several papers have further explored the relationships between mountain snowpack, variability and trends in precipitation and temperature, and geographically important factors. Stoelinga et al. (ref. 7) derived a snowpack index for the Cascades from streamflow measurements, from which they estimated that the spring snowpack declined 23% between 1930 and 2007. Pierce et al. (ref. 8) using a hydrologic model forced by observations and by two 1600-year climate model runs to estimate natural internal climate variability, attributed declines in snowpack (specifically SWE divided by accumulation-season precipitation) across the western US to anthropogenic warming...


The article is, again, open sourced and there's not a whole lot of need to go over or quote the rest of it. It's pretty clear.

It seems to be involved with something called "climate change." A lot of whiny people have been carrying on about it, but fortunately we've successfully been able to completely and totally ignore them.

Don't worry; be happy.

California has lots of wind turbines and lots of solar cells and therefore all of our problems will shortly be solved, because they, and the natural gas on which they depend most of the time, are clean and green.

Have a nice Friday.

The Conversion of Cellulosic Biomass Into Aromatic Compounds.

Most of the chemicals utilized in the preparation of polymers are currently derived from petroleum, and to the extent they are degraded either by combustion or other means, the represent a climate risk.

Since we have, in our times, spectacularly failed to address climate change, offering in lieu of things that actually work truckloads of wishful thinking (solar and wind) future generations will need to clean up our mess, the biggest mess being the planetary atmosphere and the oceans with which they are in a shifting equilibrium.

Although plastics represent a huge environmental problem, the problem would be mitigated to the extent that they were obtained from air rather than from petroleum, since in the former case, they would represent sequestered carbon.

Some years back, there was a lot of talk about converting cellulosic materials into ethanol via fermentation schemes of various types. All of these efforts have more or less commercially failed, probably because, among other things, they were water and energy intensive.

However, the chemical dehydration of cellulosic materials, generally with acid and heat, is known to produce compounds in a class known as furans, five membered unsaturated rings, generally with one or two single carbon side chains. (Historically almost all the furan in the world was made from oat hulls, until petrochemicals replaced them via a route from butadiene obtained from dangerous fossil fuels.)

Here, for example is the structure of dimethylfuran:



A problem with biomass to chemicals conversion has been, however, the low production of aromatic compounds like benzene, toluene and the xylenes, one of which p-xylene, aka as 1,4-dimethylbenzene is an important precursor to common plastics like PET, polyethylene terephthalate, a polymer used in bottles and in clothing. Xylenes are also important constituents of cleaners, fuels, paints and varnishes, especially those requiring special properties such as in works of art.

It is thus with interest I came across the following paper published by Chinese scientists in the scientific literature: One-Step Conversion of Biomass-Derived Furanics into Aromatics by Brønsted Acid Ionic Liquids at Room Temperature (Zhang et al, ACS Sustainable Chem. Eng., 2018, 6 (2), pp 2541–2551)

The introduction covers what I just said.

Aromatics are elementary commodity products from petroleum resources. For example, p-xylene (PX) is a fundamental aromatic hydrocarbon and serves as the feedstock for the production of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), coatings, dyes, and so on.1−3 With a research octane number of 127 and low toxicity, PX is regarded as an excellent octane booster while the price has limited its application.4 Since the last century, fossil resources have constituted the main feedstocks for the production of most fuels, chemicals, and materials, but the environmental concerns together with diminishing fossil reserves result in a global challenge. Efficient processes that enable the production of valuable products from renewable feedstocks with high yields must be developed to reduce global warming while satisfying the growing energy demands...


The authors express their goal and what they have accomplished a little further on:

one-step synthetic route at mild conditions with high selectivity would be a significant advance in the conversion of furanics into aromatics. Herein, we report a novel process to efficiently obtain PX and 2,5-methylbenzoic acid (2,5-DMBA) by acidic ionic liquids from biobased DMF and acrylic acid which can be produced by oxidative dehydration of the side-product from biodiesel production (i.e., glycerol).34,35 The reaction including Diels−Alder cycloaddition, dehydration, and decarboxylation could be accomplished conveniently at room temperature and atmospheric pressure as shown in Scheme 1c. The predominant success of this efficient conversion relies on the unique properties of ionic liquids (ILs) used as solvents and acidic catalysts to suppress the retro Diels−Alder reactions and side-reactions. For further understanding of the reaction mechanism, isotopic labeling and computational study were used. We also highlighted the generality of this catalytic system with a series of related furanic compounds and dienophiles; then, moderate aromatic yields were obtained, and the influence of different substituents of the reactants are also described.


Reference 35, on dehydrating and oxidizing glycerol to give acrylic acid is this one from the same journal: Highly Selective Production of Acrylic Acid from Glycerol via Two Steps Using Au/CeO2 Catalysts

The "ionic liquids" are salts, usually with one or two organic species, that are liquid at or near room temperature. Most of those used in the paper are of the alkylimidazole type, albeit mostly with inorganic counterions like sulfates or phosphates.

Some pictures from the paper:



The picture shows a tree as the source, but this is unnecessary, straw and things like corn cobs would work quite as well, if not better. Wood, by the way, is a source of aromatic compounds, from the lignin they contain in addition to cellulose, but in general they are phenolic, having one or more acidic -OH moieties on the aromatic ring.

Here the authors compare their work, (c), with those of previous authors working on the same idea, furans to aromatics:



Here is some graphics showing the yields and selectivity under several conditions:



The caption:

Figure 1. (a) Conversion of DMF and yield and selectivity of aromatics as a function of time at 25 °C. (b) Effect of temperature on DMF conversion and aromatic yield. (c) Effect of temperature on aromatic selectivity. Reaction conditions: 1 mmol of DMF, 6.9 mmol of acrylic acid, 2 mmol of [Bmim]HSO4, (b, c) 60 min (10, 25 °C), 30 min (40, 55, 70 °C).


PX is paraxylene, 2,5 DMBA is 2,5 dimethyl benzoic acid.

Reaction parameters:



The caption:

Figure 2. (a) Kinetics of the reaction between DMF and acrylic acid at different temperatures. Reaction conditions: 1 mmol of DMF, 6.9 mmol of acrylic acid, 2 mmol of [Bmim]HSO4. (b) Arrhenius plot for the conversion of DMF catalyzed by [Bmim]HSO4 from 10 to 70 °C.


Reaction mechanisms leading to the two main aromatic products:



Note the role of the inorganic anions.

The free energy diagram associated with this mechanism:



The authors thus conclude:

In summary, the one-step conversion of biobased furanics into aromatics via a synthetic route including Diels−Alder, dehydration, and decarboxylation reactions can be efficiently catalyzed by acidic ILs at mild conditions. [Bmim]HSO4 gave high yield of PX and 2,5-DMBA from DMF and acrylic acid with up to 89% aromatic selectivity in a single step at room temperature. The reaction mechanism supported by computational simulation and isotopic tracing was studied, and the energy barriers of every elementary step were presented. With application of [BSO3HMIm]HSO4 to the reactions using different dienes and dienophiles, moderate yields of various aromatics were obtained, which suggested the great potential to obtain excellent yield of renewable aromatics by tuning the structure and properties of ILs, particularly the acidity. It was also proven that the electron-donating methyl groups on the furan ring could significantly benefit the dehydration and decarboxylation processes.


Interesting I think, esoteric but interesting.

Have a pleasant Tuesday tomorrow.

Charles Ball describing being taken from his mother forever.

Recently in this space, I was describing the pain of reading the book The Half Has Never Been Told about the relationship between the origins of all American wealth, past and present, and human slavery:

I can only read this book in short spurts until the pain becomes too great. Read it, I must.

The early chapter makes considerable reference to the autobiographical work of the escaped slave Charles Ball, Slavery in the United States: a narrative of the life and adventures of Charles Ball, a black man, who lived forty years in Maryland, South Carolina and Georgia, as a slave,

Yesterday during my library research into other topics connected with my scientific work, I paused to download an electronic version of Ball's book, which begins with a description of being taken from his mother.

I reproduce a portion here:

My story is a true one, and I shall tell it in a simple style. It will be merely a recital of my life as a slave in the Southern States of the Union—a description of negro slavery in the “model Republic.”

My grandfather was brought from Africa and sold as a slave in Calvert county, in Maryland. I never understood the name of the ship in which he was imported, nor the name of the planter who bought him on his arrival, but at the time I knew him he was a slave in a family called Maud, who resided near Leonardtown. My father was a slave in a family named Hauty, living near the same place. My mother was the slave of a tobacco planter, who died when [Page 10] I was about four years old. My mother had several children, and they were sold upon master’s death to separate purchasers. She was sold, my father told me, to a Georgia trader. I, of all her children, was the only one left in Maryland. When sold I was naked, never having had on clothes in my life, but my new master gave me a child’s frock, belonging to one of his own children. After he had purchased me, he dressed me in this garment, took me before him on his horse, and started home; but my poor mother, when she saw me leaving her for the last time, ran after me, took me down from the horse, clasped me in her arms, and wept loudly and bitterly over me. My master seemed to pity her; and endeavored to soothe her distress by telling her that he would be a good master to me, and that I should not want anything. She then, still holding me in her arms, walked along the road beside the horse as he moved slowly, and earnestly and imploringly besought my master to buy her and the rest ofher children, and not permit them to be carried away by the negro buyers; but whilst thus entreating him to save her and her family, the slave-driver, who had first bought her, came running in pursuit of her with a raw-hide in his hand. When he overtook us, he told her he was her master now, and ordered her to give that little negro to its owner, and come back with him. [Page 11]

My mother then turned to him and cried, “Oh, master, do not take me from my child!” Without making any reply, he gave her two or three heavy blows on the shoulders with his raw-hide, snatched me from her arms, handed me to my master, and seizing her by one arm, dragged her back towards the place of sale. My master then quickened the pace of his horse; and as we advanced, the cries of my poor parent became more and more indistinct—at length they died away in the distance, and I never again heard the voice of my poor mother. Young as I was, the horrors of that day sank deeply into my heart, and even at this time, though half a century has elapsed, the terrors of the scene return with painful vividness upon my memory. Frightened at the sight of the cruelties inflicted upon my poor mother, I forgot my own sorrows at parting from her and clung to my new master, as an angel and a saviour, when compared with the hardened fiend into whose power she had fallen. She had been a kind and good mother to me; had warmed me in her bosom in the cold nights of winter; and had often divided the scanty pittance of food allowed her by her mistress, between my brothers, and sisters, and me, and gone supperless to bed herself. Whatever victuals she could obtain beyond the coarse food, salt fish and corn bread, allowed to slaves on the Patuxent and Potomac rivers, she carefully, distributed [Page 12] among her children, and treated us with all the tenderness which her own miserable condition would permit. I have no doubt that she was chained and driven to Carolina, and toiled out the residue of a forlorn and famished existence in the rice swamps, or indigo fields of the South.

My father never recovered from the effects of the shock, which this sudden and overwhelming ruin of his family gave him...


Unbelievable, absolutely unbelievable...

Lest we forget, this is who we are.

Cogenerating Thermochemical Hydrogen While Recovering Waste Copper.

The paper from the primary scientific literature to which I'll refer is this one:

Co-production of Hydrogen and Copper from Copper Waste Using a Thermochemical Cu–Cl Cycle (Farrukh Khalid* , Ibrahim Dincer, and Marc A. Rosen, Energy and Fuels, 2018, 32 (2), pp 2137–2144)

There are many hydrogen cycles known, water splitting thermal cycles. The CuCl2 cycle is just one of them, other examples include the much studied sulfur-iodine cycle and variations, various cerium cycles (which include carbon dioxide splitting options), zinc cycles...etc...etc.

I've dreamt up a few variations on my own, although I have no idea whether they would actually work.

In general, they all feature the possibility of high thermal efficiency, since they are easily coupled to thermal processes for electricity generation, the generation of heat for chemical processing, and the production of pure oxygen that may be utilized for closed combustion systems that will not involve smokestacks and will, to the extent that oxygen is used to combust biomass, allow for the recovery of carbon dioxide from the atmosphere for its removal.

One limitation of these cycles involves materials science, although we have in recent decades developed some spectacularly refractory materials and others are clearly on the horizon.

One of the problems that humanity faces however is the depletion of important elements in the periodic table, including some in the popular, but spectacularly failed, so called "renewable energy" industry, which is in fact, is neither "renewable" nor sustainable for precisely this reason.

When elements are distributed, as in "distributed energy" their recovery involves energy, and the more diffuse they are, the more distributed they are, the more energy is required to reconcentrate them into a recoverable and useful form. This is a consequence of the second law of thermodynamics, which cannot be repealed by the legislature of California (where such repeal is often proposed, albeit usually "by 'such and such' a date, when conveniently, the people voting on the repeal will be either out of office or dead) or by any other legislature or even by any ersatz or real dictator, orange or otherwise.

The dilution of elements or molecules is known as "the entropy of mixing."

An essential element in our modern life is copper, which is ever more critical particularly because of the sloppy ways we use it, in low capacity utilization systems such as wind turbines, which, since they require redundancy as well as the use of large mass collection systems, and when these systems turn into landfill, the recovery of copper in them will require energy.

That's why this paper is of interest.

From the introduction:

The use of energy plays an important part in the progress of any country. With increasing populations and rising living standards in many countries, the demand for energy is growing. The present dependence upon fossil fuels to meet most of this energy demand and the challenges associated with fossil fuels has led to research around the world to develop environmentally benign energy sources, such as renewable and nuclear. During the past decade, there has been an increasing interest in the development of large-scale non-fossil hydrogen production technologies, particularly coupled with renewable and nuclear process heat/waste heat, which leads to clean hydrogen production with almost negligible life cycle emissions and, hence, minimized environmental impact. In this regard, thermochemical and/or electrochemical processes with a renewable or nuclear option offer an environmentally friendly option.(1-5)


I agree with part of the last statement. Nuclear energy is environmentally friendly, but in my oft expressed opinion, so called "renewable energy" is not.

Hydrogen is not an acceptable fuel, but it an extremely useful captive intermediate where it can be utilized to make sustainable fuels - my personal favorite being dimethyl ether, DME - via the hydrogenation of carbon dioxide (or monoxide).

The introduction continues:

A number of thermochemical cycles have been investigated(6-8) to produce hydrogen from water. However, most of these cycles operate at over 800°C. The relatively lower temperature (550 °C) requirement and use of inexpensive chemicals make the copper–chlorine (Cu–Cl) thermochemical cycle a promising process for hydrogen production. To build large-scale hydrogen production facilities based on this cycle, some challenges need to be resolved. First, the difficulty in separation of CuCl and CuCl2 from the spent anolyte in the electrolytic step needs to be addressed. Second, some copper crossover is observed in the electrolyzer membrane, resulting in degradation of the electrolyzer performance. One of the possible ways to achieve better kinetics and integration is the introduction of a high-temperature electrolysis step in the Cu–Cl cycle. Such a high-temperature electrolysis step needs to be thoroughly examined in terms of feasibility and practical viability.

Copper is one of the most widely used metals in the world, with applications including energy technologies, electronic devices, electricity transport, and coin production. With advances in electrical and electronic technology and decreases in prices, the use of such equipment has increased.(9, 10) This has led to increases in copper waste, especially in the industrial world,(11) posing a worldwide challenge for safe disposal.(12, 13) There are numerous methods available to recycle copper from copper waste, such as pyrometallurgy and hydrometallurgy.(14-17) However, each process has drawbacks. For instance, the energy consumption is very high and the temperature requirement is high (more than 1273 K) in pyrometallurgy...


Here, from the paper, is a schematic of the particular copper chloride cycle the authors envision. Note that their cycle requires an electrical input, but not all cycles, not even all copper chloride cycles, do:



Their purpose in including electricity is to reduce the temperatures required. With advances in materials science, this may not be necessary.

Their particular cycle relies on the oxidation of chlorine gas at 950K with water (steam) to give HCl gas and oxygen, and the HCl gas is reacted with copper wastes to generate hydrogen and cuprous chloride (copper (I) chloride) and hydrogen at around 770K, a temperature at which the cuprous chloride is a liquid, simplifying mass transfer. This liquid is electrochemically disproportionated into copper metal and cupric chloride (CuCl2 - copper (II) chloride) and the latter is thermochemically decomposed at 883 K to give chlorine gas and copper metal.

Here's a schematic of the electrochemical step:



Here's a photograph of the actual lab scale operating system:



I used to love putting stuff together that looked like that when I was in the lab. It makes one feel all "sciency." (Sometimes modern instrumentation can look too clean to be fun.)

There's a nice discussion of the thermodynamics in the paper, as well as a simple graphic that shows the story:



The caption:

Figure 6. Specific exergy destruction and exergy efficency of the various steps of the proposed Cu–Cl cycle.


A number of other graphics in the paper discuss optimization of the temperatures for each step. The interested reader may refer to the original either by subscription or by traveling to a good scientific library.

Note that the electrochemical portion may not be strictly necessary, depending on process parameters, and indeed on chemistry. A well known variant of copper based thermochemical cycles is the copper bromide cycle, and indeed iodide cycles also are possible.

Usually at this point someone will mention cost, usually in the context of declaring that "nuclear energy is too expensive" among other distorted views by which anti-nukes morph into Ayn Rand type Laissez Faire capitalists, usually with a healthy dollop of selective attention.

So called "renewable energy" is not cheap unless it is isolated from the environmentally questionable necessity for redundant back up whenever the sun isn't shining - sunlight is widely reported to disappear for various amounts of time depending on latitude and season - and the wind isn't blowing.

The reality is that the back up - despite all the horseshit about Elon Musk's (and other) unsustainable batteries - is dangerous natural gas, also reported as being "cheap."

It's "cheap" only if someone other than the user pays for cleaning up the trash it leaves behind, for example, carbon dioxide, radioactive flowback water, permanently leaching spent fields, etc.

The people consigned to pay for these clean ups are not the users; it is rather all future generations, our children, our grandchildren, their children, their great grandchildren etc.

The fact is that the dangerous fossil fuel industry is simply allowed to dump its waste directly into the planetary atmosphere without restriction, and without cost, while cleaner forms of energy, notably nuclear energy, are required to show that they can contain all by products indefinitely, over as long a period as stupid people can imagine, even though nuclear materials have a spectacular record of not killing many people, while fossil fuel waste kills millions upon millions of people year after year after year after year with little comment.

Because of this situation, so called "natural gas" is described as being "cheap" even though it is no such thing.

In recent weeks I've been reading about the history of human slavery in this country; a horrible story that is very difficult to read. Sometimes I have to put the books I'm reading down weeping; they're too painful to read but innocent people were required to live these events.

It is hard not to express profound disgust at the generations of white Americans of those times in which human slavery was legal in this country, and the twisted mentality that sought to perpetuate this great crime for many unimaginably cruel generations.

And then I think about how future generations might regard our generation, and I'm not comforted by the thought.

Since all current schemes to stop dumping the dangerous fossil fuel waste carbon dioxide into our favorite waste dump, the planetary atmosphere, have all failed, future generations will be required to clean up our garbage, this while having fewer resources than our generation enjoyed - and squandered - with complete disregard for them.

To get resources, they'll have to dig through our garbage, and probably face huge health risks in doing so. It's hard to think they'll think kindly on us any more than I think kindly on the purveyors of human slavery in the United States.

Maybe processes described in this paper might help a little, but irrespective of leaving them with the paltry record of such unscaled experiments they will be totally in their rights, in my view, to view us with as much or more disgust as I - more than a century later - view the slaveholders and their enablers, North, South, and everywhere else.

Have a pleasant Sunday tomorrow.

Highly sensitive, uranium based UV detectors.

I am fascinated by the remarkable chemistry of the actinide elements because of the interesting chemistry of the 5f orbitals.

(One of the "actinides," thorium, strictly has limited or no 5f chemistry, although its considered an actinide nonetheless, for convenience.)

One of the interesting things about the actinides, all of which are radioactive, is that they are excellent shielding materials for high energy radiation, owing to the fact that they have so many electrons - uranium, for example has 92 - making it possible for them to have many electronic transitions, and because they are massive, their inner electrons can absorb very high energy radiation to emit "Auger electrons."

Thus I was fascinated by a paper published recently in the wonderful - if overly dense - journal ACS Appl. Mater. Interfaces, specifically, this one: Highly Sensitive Detection of UV Radiation Using a Uranium Coordination Polymer, published by scientists at the Key State Laboratory of Radiation Medicine and Protection and the School for Radiological and Interdisciplinary Sciences and a few other institutions in Sozhou, China. (Wang et al, ACS Appl. Mater. Interfaces, 2018, 10 (5), pp 4844–4850)

(The Chinese government doesn't hate science quite as much as our government hates it, which is why they are going to eat us alive in the 21st century.)

Here's the introductory text from the paper:

Ultraviolet radiation is widely used in chemical industries, such as curing and photolithography, sterilization, surface modification technique, and so forth,1−3 but can exhibit either positive or negative impacts on human health. For instance, UV radiation is crucial for assisting human skin to produce vitamin D that is necessary in physiological processes.4 Excessive doses of UV radiation, however, impose great damage on the human body and may result in the development of cutaneous malignant melanoma (CMM) and non-melanoma skin cancer (NMSC),5 leading to premature skin-aging and eye disorders. 6,7 Besides these physical impacts, developing efficient UV photodetectors is also highly desirable in automotive, aerospace, environmental, and biological researches.7 Currently, various techniques have been developed to detect UV radiation both qualitatively and quantitatively. The most developed semiconductor photodetectors, including metal−semiconductor− metal (MSM) detectors,8 PIN photodiodes detectors,9 p− n junction diodes,10 and Schottky barrier detectors,11 often suffer from several disadvantages, such as sophisticated synthesis and manufacturing procedure, not being able to measure the accumulated UV dosage as well as high defect density in the material. The latter greatly lowers the detection sensitivity and efficiency.12


The authors propose a uranium based detector for the following reasons:

Uranium, the most critical 5f element in the nuclear fuel cycle, is chosen in this work as the metal center based on the following considerations. First, depleted uranium is an abundant long-half-life radioactive byproduct of the nuclear power industry that receives limited studies in luminescent coordination polymer systems compared with other metals. Second, uranyl luminescence originating from the HOMO− LUMO transition of hybridized molecular orbitals often exhibits brighter emission and more efficient absorption of UV light than trivalent lanthanides owing to the non Laporte forbidden nature which greatly extends the detection limit.34 Third, given the 5f/6d orbitals of uranyl are deeply involved in coordination, the luminescence is highly sensitive to the coordination environment, which affords more opportunities for developing detection ability (i.e., more efficient energy transfer).35


LUMO here refers to the "lowest unoccupied molecular orbital" and HOMO to the "lowest occupied molecular orbital." Transitions between molecular orbitals (or in some cases atomic orbitals), defined by quantum mechanics, determine the properties of radiation absorption and emission, not only at high energy levels such as those observed for UV, X-rays, and gamma radiation, but also in the visible range: Color is a function of these effects.

The authors synthesize a "MOF" - a "metal organic framework" - a class of materials that has been the subject of vast amounts of research in recent years. This particular framework is built from uranium atoms, nitroisophtalic acid and dimethylformamide.

Here's a graphic describing the structure of this framework:



The caption:

Figure 1. Crystal structure depictions of 1, where hydrogen atoms are omitted for clarity: (a) coordination environment of uranium(VI); (b) asymmetric unit of [UO2(L)(DMF)]; (c) 1D metal–organic chain of 1 composed of 5-nitroisophthalic acid linked asymmetric units; (d) pseudolayered structure comprising 1D chains coalescing due to π···π interactions. Atom colors: U = green, O = red, C = black, N = blue


Although the molecules luminescence nicely, after long term irradiation, the intensity of the luminescence fades:



The caption:

Figure 2. (a) UV dosage dependent luminescence spectra of 1 performed on a single crystal to show the quenching effect under 365 nm UV light. (b) Correlation between the quenching ratio and radiation dosage. Inset is the correlation between D/[(I0 – I)/I0 %] and the UV dosage. (c) is the corresponding luminescence photographs of a single crystal after receiving continuous UV radiation.


Surprisingly however, this effect seems not to relate to structural degradation of the molecular organic framework, which demonstrates remarkable structural integrity even upon irradiation with higher energy wavelengths, to wit, x-rays and gamma rays, as is shown in the XRD (X-ray diffraction pattern) graphics shown:



The caption:

Figure 3. (a) PXRD patterns for samples irradiated with UV, 100 Gy X-ray and 100 kGy γ-ray radiation. (b) EPR spectra of 1 before and after UV, 100 Gy X-ray, 100 kGy γ-ray radiations.


The EPR (Electron Paramagnetic Resonance) spectra clearly shows the persistence of free radicals, thought to reside on the dimethylformamide ligand:



The caption:

Figure 4. (a) Optimized geometry structure and bond parameters of ground state DMF molecule. (b) Optimized geometry structure, bond parameters (left), and net spin density (right) of triplet DMF· radical. (c, d) Simulated radical-free and radical-bearing coordination structures of the fragment, named as uranyl-5-NIPA-DMF and uranyl-5-NIPA-DMF·, respectively. Bond parameters are labeled below each structure.


I love this last graphic, because one doesn't get to look at electron density diagrams of molecular orbitals resulting from the mixing of f orbitals all that much:



The caption:

Figure 5. Density of states (DOS) of (a) the isolated uranyl molecule, (b) the uranyl-5-NIPA-DMF complex, and (c) the uranyl-5-NIPA-DMF· complex. The gray-filled and empty areas below DOS curves indicate the occupied and unoccupied states, respectively. For each DOS, the lowest unoccupied U(5f) orbital is normalized at 0 eV for convenience.


The authors thus conclude:

In summary, a highly stable uranium coordination polymer was successfully synthesized through solvothermal method that exhibits superior sensing property. The intrinsic luminescence of 1 could be quenched by UV which makes it suitable for monitoring UV radiation. The radical-induced quenching mechanism confirmed by EPR, X-ray crystallography, and DFT calculations studies corroborates this property of 1...

... This work provides us new opportunity for searching powerful UV responsive materials by taking advantage of efficient UV light asbsorber (uranyl) as metal center. We further noticed that many other uranyl hybrid materials constructed from different types of ligands and solvents may exhibit similar properties, which can be therefore fine-tuned by varying uranyl coordiation enviorments, crystal structures, and chemical constituents (e.g., light sensitizer), and the systematic investigations are in progress. We also believe this work offers new insight into methods in which depleted uranium may be reused for beneficial purposes.


It's a fine paper, but I will note that my preferred use for depleted uranium is as a precursor to plutonium as a nuclear fuel.

The interesting thing for me about this paper is the stability of this framework in a high radiation field. This suggests it's use as a "breathable" nuclear fuel, albeit one that would operate in a thermal spectrum, thus of use in thorium derived U-233 systems as opposed to plutonium breeding systems.

An interesting paper I think.

Have a nice weekend.

Can we eliminate the emissions of the greenhouse and ozone depleting gas N2O from nylon manufacture?

Nitrous oxide, N2O, aka "laughing gas" is no laughing matter.

Other than carbon dioxide, it is the atmospheric pollutant that most troubles me, not just because it is a profound greenhouse gas with a climate forcing potential 120 times as large as carbon dioxide, but also because it is an ozone depleting agent.

There is no really great way to eliminate human emissions - like carbon dioxide it has always been a natural component of the atmosphere, but anthrogenic emissions have swamped natural emissions - because the emission of nitrous oxide is an inevitable consequence of fertilizing soil for agriculture, without which a huge fraction of the planet's population would literally need to starve to death.

However, going through some scientific literature I collected a few years back but never properly filed in my computer's filing system, I was surprised to learn that between 5 to 8% of nitrous oxide emissions are an industrial side product of nylon manufacture.

The paper to which I refer is here: One-pot room-temperature conversion of cyclohexane to adipic acid by ozone and UV light (Kuo Chu Hwang*, Arunachalam Sagadevan, Science 19 Dec 2014:
Vol. 346, Issue 6216, pp. 1495-1498)

A key intermediate in the manufacture of the nylon polymer is the diacid adipic acid which has the following structure:



Nylon 66 has this structure:



Adipic acid is made from a constituent of the dangerous fossil fuel petroleum, cyclohexane, by oxidation with pressurized oxygen at 125C over a manganese and cobalt catalyst to give a mixture of cyclohexanol and cyclohexanone. These are passed over ammonium vanadate and cupric catalysts in the presence of 65% nitric acid (itself made by oxidation of ammonia prepared using dangerous natural gas) to give adipic acid.

During this process, the reductant is nitric acid, which is converted to N2O, which is then dumped into our favorite waste dump, the planetary atmosphere.

World production of adipic acid is on the order of a billion kg.

Some brief excerpts from the text:

Adipic acid is a precursor for the synthesis of the nylon-6,6 polymer and, as such, is one of the most important industrial chemical intermediates. More than 3.5 million metric tons of adipic acid were produced in 2013, reflecting a ~5% growth rate per year over the past 5 years (1, 2). Nearly 95% of the worldwide industrial production of adipic acid employed the nitric acid oxidation method (3). The first step is air oxidation of cyclohexane under high temperatures (125° to 165°C) and high pressure (8 to 15 atm) to produce KA oil (i.e., a mixture of cyclohexanone and cyclohexanol) with 4 to 11% conversion and ~85% selectivity (4, 5). In the second step, nitric acid is applied as an oxidant: the conversion is ~100%, and the selectivity for adipic acid is 93 to 95% with some other short-chain acids as side products (see Fig. 1A). The process requires the nitric acid–to–KA oil ratio to be maintained at 40:1. Disadvantages of the current industrial process include low overall product yield; corrosion of reaction vessels by nitric acid; emission of the ozone-depleting greenhouse gas N2O; and high energy consumption. It was estimated that ~0.3 kg of N2O gas is formed per kilogram of adipic acid produced (6, 7)...

...Inspired by literature reports that ozone and ultraviolet (UV) irradiation are primarily responsible for oxidative degradation of most hydrocarbons in the atmosphere, we sought to investigate whether both treatments in combination could oxidize cyclohexane, which exclusively contains unactivated sp3 C-H bonds. In a simple experiment, ozone gas was bubbled through neat cyclohexane with concurrent UV irradiation at room temperature. No metal catalyst or solvent was used. After 2 to 8 hours, a solid product gradually precipitated to the bottom of the reaction vessel (see Fig. 1B and fig. S1 for reaction scheme and pictures, respectively). A portion of the liquid cyclohexane evaporated due to the O3 gas bubbling. The solid oxidation product of cyclohexane was subjected to 1H nuclear magnetic resonance (NMR) and 13C NMR analysis (in deuterated chloroform) for structure characterization and proven to be adipic acid.


UV radiation can be continuously supplied by exposing BaF2, barium fluoride, to a gamma emitting radioactive substance, these being available in large quantities from used nuclear fuel. There are many ways to generate ozone, although the usual method is to generate it electrochemically.

I have no idea if there has been any effort to industrialize this most interesting bench chemistry, but this is a beautiful, if esoteric environmental idea.

I can't believe I overlooked this very beautiful paper for a couple of years.

Have a very pleasant weekend.











Lead Free Perovskite Solar Cells Predicted.

The paper to which the title of this post refers is this one: Predicted Lead-Free Perovskites for Solar Cells (Roshan Ali, Guo-Jiao Hou, Zhen-Gang Zhu, Qing-Bo Yan, Qing-Rong Zheng, and Gang Su,*Chem. Mater., 2018, 30 (3), pp 718–728) Excerpts and graphics from the paper "predicting" lead free perovskite solar cells will be below.

First though, I love the title, "...Predicted."

During my whole adult life - I'm not young - I've heard wonderful predictions about solar energy.

This one, from 1976 is my favorite:

In June 1976 the Institute considered that with a conservation program far more modest than that contemplated in this article, the likely range of U.S. primary energy demand in the year 2000 would be about 100-126 quads, with the lower end of the range more probable and end-use energy being about 60-65 quads. And, at the further end of the spectrum, projections for 2000 being considered by the "Demand Panel" of a major U.S. National Research Council study, as of mid-1976, ranged as low as about 54 quads of fuels (plus 16 of solar energy)


(Source: Amory Lovins, Energy Strategy, The Road Not Taken? Foreign Affairs,, October, 1976 pp. 65-95, excerpt on page 76.)

It's my favorite because there is no reference to the report of "The Institute," they are merely evoked. (The Institute in question was the "Institute of Energy Analysis," which I believe was headed by Alvin Weinberg, the chief developer of the Pressurized Water Nuclear Reactor that Amory Lovins has spent a career despising. Lovins has since had a wonderful career "consulting" for companies like SunCor, which is not a solar company but is rather a Canadian Oil Sands company, which (since it pays Lovins) can tout itself as a "sutainable" oil sands company and which is only one of the greasy fossil fuel companies for which the "green" anti-nuke Lovins consults.

The age of doublespeak is hardly limited to that other asshole Trump.

Lovins also predicted in 1980 that nuclear energy would die by 2000 (or else there would be a nuclear war) but that's another story.

Anyway, a "Quad" is quite nearly an exajoule (EJ) - there's 1.055 EJ to a Quad. Lovins was, without citation, claiming that a little birdie told him that he was free to imply that "by 2000" the US would be consuming 54 quads plus, 16 of solar energy, a total of 70 exajoules.

Current US energy consumption is near his predicted lower end in his first unreferenced assertion, roughly 100 exajoules. However the world as a whole, added another 126 exajoules of consumption since 2000 (it's now widely reported to be 2018) to reach a total of 576 exajoules (as of 2016, the last year for which data's been compiled by the International Energy Agency.)

On the entire planet, as of 2016, the commercial solar industry was not producing 10 exajoules of solar energy, never mind 16 in the United States. In fact, solar and wind combined did not, as of 2016 produce 10 exajoules.

The fastest growing source of energy worldwide from 2000 to 2016 was coal, which increased by more than 60 exajoules to 157 exajoules total.

As a result, the concentration of the dangerous fossil fuel waste carbon dioxide has averaged annual increases of just under 2.2 ppm all through the 21st century, after averaging less than roughly 1.3 ppm in the 20th century, beginning with measurements in 1958.

In 1976, when Lovins wrote this appalling garbage, mean carbon dioxide concentrations were 332.04 ppm; in 2017 they were 406.53 ppm.

A prediction: No one now living will ever see a value for the concentration of the dangerous fossil fuel waste carbon dioxide below 400 ppm, and the reason is that there is little hope that any of us will stop lying to ourselves.

Solar energy is the predicted future, and, regrettably, the future will be the same as the past.

So much for "predictions."

Solar energy is also "clean" and "green," except when it's not.

The most efficient solar materials - generating just tons of excitement in the primary scientific literature - is the "perovskite" structured materials.



Let's turn to the cited paper about the latest "solar breakthrough" du jour, and I'm speaking as an old man who used to get excited by "solar breakthroughs" day after day, going back to the time I was thin and had hair, back in the days when Amory Lovins was declared "a genius." - a long time ago

The authors write in the introduction:

The discovery of organic–inorganic halide perovskites, especially, methylammonium lead triiodide, CH3NH3PbI3 (MAPbI3), and formamidinium lead triiodide, HC(NH2)2PbI3 (FAPbI3), as light absorbers has brought a rapid development in photovoltaics (PV) technology.(1-11) These perovskites contain earth-abundant essential elements, making them highly promising for low-cost and large-scale PV applications. In 2009, Kojima et al.(1) for the first time investigated a MAPbI3-based solar cell with power conversion efficiency of 3.8%. Later, Lee et al.(12) and Kim et al.(3) improved the efficiencies remarkably up to 10.9% and 9.7%, respectively. These works arouse a great passion of studying these materials and the techniques to promote the performance and efficiency. The record efficiency for perovskite solar cells now stands at 22.1%,(13) which is somehow comparable to the crystalline silicon, today’s leading PV technology (25.3%)...

...MAPbI3 is a direct-gap semiconductor, with experimental bandgap of 1.55 eV.(18) It has strong and very sharp absorption, almost 25 times higher than that of Si yet better than GaAs.(19-21) They have long-lived photogenerated electrons and holes and have long charge diffusion length.(22-25) Due to the small electron–hole effective masses, the ambipolar transport is high.(26) In MAPbI3, dissipationless absorption and emission of photons were observed, which enable photons to recycle, leading to utilization of photons within the active layer.(27)


We're saved.

Or maybe not. In solar papers it's rare (though less and less unknown) to wonder about how "green" this technology really is. The authors continue:

Another important and serious issue is the presence of lead in these solar cell materials. As PV panels are normally placed in open field or on the roof of houses, their exposure to rainfall is unavoidable. In the presence of rain and moisture, PbI2 degrades as a substance that may cause severe health problems, i.e., from cardiovascular and developmental diseases to neurological and reproductive damages, increasing oxidative stress.(35) Furthermore, lead pollution has serious impacts on soil and water resources, greenhouse gas emissions, and abundance of material inputs.(36-38) To remove the toxicity of Pb in solar cells, one may either develop an effective method of encapsulation and recycling all components of the PV panels at the end of their lifetime or replace Pb by other nontoxic elements in halide perovskites. For the latter one, the Pb-free perovskites should have excellent absorption, having suitable and direct band gaps comparable to MAPbI3. Also the alternative Pb-free perovskite must exist in the range of tolerance factor (0.81–1.11)(39, 40) to ensure the structural stability of the perovskite solar cell.


The authors begin then to evaluate cogeners and other materials that might replace lead.

This is a computational paper utilizing computer modeling to predict what might replace lead, which is proposed to replace among others, the toxic element cadmium, now in use (as a compound with the toxic elements selenium or tellurium) is some "green" and "distributed" solar cells.

Some pretty pictures from the paper, beginning with the evocative opening "eye catcher" graphic:




The lead perovskite structure along with the structures of some computationally evaluated putative perovskite structures:




The caption:

Figure 1. Supercell structure of MAPbI3 is shown from a front view in (a) and a side view in (b). Supercells are shown for MA(Ca0.125Si0.875)I3 in (c), for MA(Ca0.375Si0.625)I3 in (d), and MA(Ca0.5Si0.5)I3 in (e).


One of the issue with these wonderful perovskite solar cells that will save the world someday (we predict) is that they are structurally unstable, as alluded to in the previous text. One of the powerful things that computational chemistry can do is to predict structure, based on thermodynamic parameters such as the enthalpy or free energy. This kind of data has been incorporated into a factor denoted as the "tolerance factor."

It's plotted here:




The caption:

Figure 2. Tolerance factor (t), black in color, represents the perovskite phase stability for all mono- and mixed-replaced materials. The two dotted black lines represent the tolerance factor range. The red curve represents our calculated formation enthalpy. The blue and magenta color triangles represent the previous calculated enthalpy formation values, while the green square represents the experimental formation enthalpy for MAPbI3. Materials below the horizontal red-dotted line show thermodynamic stability.


Next we have a periodic table talking about the elements in the "predicted" solar cells.



The caption:


Figure 3. Pb-replaced (12 in total), unreplaced (due to smaller ionic radii; 17 in total), metallic (30 in total), highly toxic (12 in total), and mixed (Ca/Si, Zn/Si) Pb-replaced elements are tabulated in the periodic table.


A note on this periodic table. Two of the elements identified here as "toxic" are already found in commercial solar cells; they are cadmium and arsenic. Two of the "replacement" elements are also found in solar cells, gallium (Ga) and germanium (Ge). Both of these latter elements are considered "critical elements" meaning that their long term supply is not guaranteed for future generations.

This calls into question the use of the term "renewable" to describe this stuff.

Another element included in solar cells is probably the most threatened element in the periodic table, indium.

Indium, which is an impurity in zinc (and a few other) ores is a constituent of a semiceramic material known as ITO (Indium Tin Oxide) which has the unique property of being both an electric conductor and being transparent. It is widely utilized in all touch screen devices, including (the major use, since the solar industry remains trivial) cell phones.

The following graphic shows that the perovskite solar cells as designed (and modeled here) contain ITO. So much for "renewable," at least so far as these cells are concerned.



The caption:

Figure 4. (a) Schematic structure of the simulated device, with a single layer perovskite. (b) The dielectric function ϵ2 and (c) the absorption efficiency of the simulated device with the active Pb-free perovskite layer of MAPbI3, MAGeI3, and MASnI3.


Some technical stuff, the bandgap width:



Figure 5. Bandgap values of our mixed study MA(Ca/Si)X3 and MA(Zn/Si)X3(where X= I, Br, Cl). The red dotted line (1.3 eV) shows the ideal band gap for a single-junction solar cell according to the Shockley-Queisser theory. The blue dash-dot line (1.8 eV) shows the ideal band gap for the top-cell in tandem solar cells.


Schockley, for a little bit of history, holds the record for being the most racist Nobel Laureate ever, although he is in a three way tie with Phillip Lennard and Johannes Stark for this dubious distinction, with the (dis)honorable runner up being James Watson.

Now the punchline, the "imaginary" part of the diaelectric function:



The caption:

Figure 6. (a) Imaginary part of dielectric function (ε2) and (b) Total device absorption efficiencies (single layer) for methylammonium Pb-free triiodides, MACa0.125Si0.875I3, MACa0.375Si0.625I3, MACa0.5Si0.5I3, and MAZn0.5Si0.5I3 in comparison to MAPbI3. The device architecture of solar cell is the same as in Figure 3a.


The imaginary part...

This "imaginary" of course refers to the fact that the function is a complex function, a type of function that appears quite a bit in mathematical physics and mathematical physical chemistry, most notably in quantum mechanics but also in places like cubic equations of state, like for example, the very widely utilized Peng-Robinson equation for real gases. "Imaginary" here refers of course to the square root of -1, which does not exist except that it does exist as an essential mathematical construct for understanding the universe.

But in the solar case, I also insist - although this is not what people want to hear, although I think it is what they should here if they actually give a rat's ass about climate change, not that anyone, right or left actually does - the imaginary part has a deeper meaning.

The solar industry did not work to arrest climate change; it is not working; and it will not work, and the reason is energy to mass ratios.

And these ratios, the requirement for distribution in what will surely prove an irretrievable way is why so called "renewable energy" will never be as clean, as safe nor as sustainable as nuclear energy. There is not enough matter on the planet, and in particular non-toxic matter to make the solar scheme work, and I haven't even touched the other magic touchstone so often evoked with it, the chemistry of chemical batteries.

I suppose on Valentine's day evening, one should expect to hear what one wants to hear, but I'm not a good guy.

I hope you had a pleasant evening nonetheless.

Mass Spectrometry of DNA Adducts: Resolving the Mechanism of How Air Pollution Induces Cancer.

Leafing through my files today, I came across a review article that I'm sure I read, or partially read, in the past, but which is a pleasure to read again.

It is here: Mass Spectrometry of Structurally Modified DNA (Natalia Tretyakova, Peter W. Villalta, and Srikanth Kotapati, Chem. Rev., 2013, 113 (4), pp 2395–2436)

Although this is basically a scientific post, it is on a political website and it is therefore worth noting that all three authors of this paper then (and perhaps still) working at the University of Minnesota are immigrants, one from Canada, one from India, and one from Russia.

This is worth noting in the time of Hair Fuhrer, the uneducated nepotist criminal unintelligent moronic nativist bankruptcy king who lounges in the White House trying to destroy his country with the help his Spokesperson Paul Ryan working in the House, and his equally stupid bigoted apologist in the Senate, Mitch McConnell. All three of these puerile, horrible fools are far worse traitors to both the spirit, promise, and legal structures of this country than these three fine scientists could ever be. The self declared "Real Genius" in the White House would be barely qualified to wash glassware in these people's lab, not that stupid people should be allowed in labs at all in any capacity.

Sorry, I couldn't resist.

The science:

As an advocate of the rapid expansion of nuclear power, I am often confronted with people who want to prattle on about Fukushima (or Chernobyl) as if they were the worst energy disasters of all time. I point out that this is absurd since, for example, the Banqiao dam disaster killed close to 200,000 people, possibly even more in 1976 in a matter of days, not that anyone gives a shit about these deaths. (The death toll varies depending on where you read about it, and the real number will almost certainly never be known.) But the Banqiao dam disaster, is still not the greatest energy disaster of all time, not at least in my book.

The greatest energy disaster of all time is the on going and continuous disaster of air pollution, which as I often point out using the following link, kills approximately 7 million people a year, every year:

A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010 (Lancet 2012, 380, 2224–60: For air pollution mortality figures see Table 3, page 2238 and the text on page 2240.)

This does not include deaths owing to the other effect of air pollution, climate change.

Air pollution kills in a variety of ways: A large fraction of the deaths take place in children under the age of 5, because of their poorly developed respiratory systems coupled with other environmental insults to their physiology, but the DALY (disability adjusted lost years) of life also involves lung cancer among the adult lives lost to air pollution, which develops over a number of years, and before killing its victims, seriously disables them and leaves them in great pain.

The scientific review article cited above explains how air pollutants cause cancer, that it, it explores the analytical chemistry elucidating the mechanism by which air pollutants are carcinogenic.

The mechanism is basically this: Many air pollutants are fairly flat molecules that fit into the grooves (minor and major) that characterize the famous helical structure of DNA. Once there, they are in a position to chemically bond directly to the functional groups associated with DNA molecules. This is in contrast to the epigenetic modification of DNA (and RNA) which is the natural biochemical modification of the 5 nucleobases that make up these molecules for purposes of affecting cellular biology.

In their introduction the authors briefly describe epigenetic modifications:

Epigenetic DNA modifications such as 5-methylcytosine (MeC) are important regulators of cell function that influence chromatin structure and control the levels of gene expression. DNA methyltransferases (DMTs) catalyze the addition of the C-5 methyl group to cytosine nucleobases.(1) DMTs preferentially recognize hypomethylated 5′-CG-3′ sequences, producing epigenetic modifications which preserve DNA methylation patterns. C-5 cytosine methylation controls gene expression by mediating the binding of specific proteins (methyl-CpG binding proteins) to MeCG sites, followed by the recruitment of histone-modifying enzymes that promote chromatin remodeling.(2) Recent studies have discovered additional cytosine modifications, e.g., 5-hydroxymethyl-C, 5-formyl-C, and 5-carboxyl-C; these modifications have been hypothesized to be demethylation intermediates or they may have their own unique epigenetic functions within cells.(3-5)


Continuing they then describe the difference between normal epigenetic modifications of nucleobases to describe the odious effects of air pollution:

In contrast to epigenetic modifications, chemical DNA damage including nucleobase alkylation, oxidation, deamination, and cross-linking occurs at a variety of sites, including the N-7, O-6, C-8, and N-2 of guanine; the N-1, N-3, and N-7 of adenine; the O-2 and O-4 of thymine; and the O-2 and N-4 of cytosine (Scheme 1 and Chart 1).(6) Some carcinogens are inherently reactive toward DNA, while others must first be metabolically activated to electrophilic intermediates (e.g., epoxides, quinone methides, diazonium ions, and nitrenium ions), which subsequently bind to DNA, producing nucleobase adducts (Figure 1).(6) All living cells contain extensive DNA repair systems responsible for removing nucleobase lesions. If structurally modified DNA bases escape repair, they may induce base mispairing during DNA replication; in this case, the chemical damage is converted into permanent genetic damage (mutations).(6) Accumulation of mutations in genes controlling cell growth, proliferation, programmed cell death, and cell differentiation is likely to cause cancer.(7-10)


The bold is mine.

Here, from the paper, is a graphic describing sites where the nucleobases are subject to modification.



(Uracil, desmethyl cytosine, associated with RNA is not shown here.)


They immediately show some of the adducts they will discuss in the paper:



Chart 1. Structures of Representative DNA Adductsa
a1,N6-etheno-2′-deoxyadenosine (εAdo); 3,N4-etheno-2′-deoxycytosine (εdCyd); O6-methyl-2′-deoxyguanosine (O6-Me-dG); N7-methylguanine (N7-Me-G); 8-oxo-7,8-dihydro-2′deoxyguanosine (8-oxo-dG); 8-oxo-7,8-dihydro-2′deoxyadenosine (8-oxo-dA); N7-ethylguanine (N7-ethyl-G); 1, 1,N6-(1-hydroxymethyl-2-hydroxypropan-1,3-diyl)-2′-deoxyadenosine (1,N6 -αHMHP-dA); 1,N6-(2-hydroxy-3-hydroxymethyl-propan-1,3-diyl)-2′-deoxyadenosine (1,N6 -γHMHP-dA).


Then there's a little cartoon about how this all works:



The caption:

Figure 1. Central role of DNA adducts in chemical carcinogenesis. Adapted with permission from Reference 55. Copyright 2011 American Chemical Society.


The point made here is that sometimes, probably most of the time cells with damaged DNA either repair the DNA or die, which is a usually a good thing. However sometimes the cells survive, and, particularly if the damaged DNA is involved in the regulation of cell division, mutate into cancer cells. Reference 55 is here: Quantitation of DNA Adducts by Stable Isotope Dilution Mass Spectrometry (Natalia Tretyakova, Melissa Goggin, Dewakar Sangaraju, and Gregory Janis, Chem. Res. Toxicol., 2012, 25 (10), pp 2007–2035)

Further down they give an even broader picture of DNA modified by air pollutants, a picture that is rather scary actually:



The caption:

Chart 4. Structures of DNA Adducts Highlighted in Section 5.5a
aN7-(2′-Hydroxyethyl)guanine (N7-HEG); 5-hydroxymethyl-2′-deoxyuridine (HmdU); 3,N4-ethenocytosine (εCyt); 7-(1′,2′-dihydroxyheptyl)-3H-imidozo(2,1-i)purine (DHH- εAde); 1,N6-ethenoadenine (εAde); N2,3-ethenoguanine (N2,3-εGua); 1,N2-ethenoguanine (1,N2- εGua); 4-hydroxyestrogen-1-N3-adenine (4-OH-E-1-N3Ade); 1,N6-etheno-2′-deoxyadenosine (εdAdo); 3,N4-etheno-2′-deoxycytidine (εdCyt); 1,N2- etheno-2′-deoxyguanosine (1,N2- εdGuo); O2-ethylthymidine (O2-edT); O4-ethylthymidine (O4-edT); 1-(guan-7-yl)-4-(aden-1-yl)-2,3-butanediol (N7G-N1A-BD); 1,4-bis-(guan-7-yl)-2,3-butanediol (bis-N7G-BD); N2-hydroxymethyl-2′-deoxyguanosine (N2-HOMe-dG); N7-ethylguanine (N7-Ethyl-G); N-(deoxyguanosin-8-yl)-PhIP (C8-dG-PhIP); 10-(deoxyguanosin-N2-yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene (dG-N2-B[a]P); 7-(deoxyadenosin-N6-yl)aristolactam I (dA-AL-I); 7-deoxyguanosin-N2-yl aristolactam I (dG-AL-I).


To be fair to people who don't give a shit about the worst energy disaster of all time, air pollution, but would rather engage in the use of electricity that almost certainly involves the combustion of dangerous fossil fuels to go on their computers to whine about Fukushima and Chernobyl, it does seem to me that a few of these adducts probably derive from pollutants other than air pollutants. For example, dG-C8–4-ABP probably derives from a water pollutant like a partially dehalogenated PCB. Others are almost certainly derived from air pollutants, for example dG-AI-I looks like it comes from a lignin derived combustion product of that wonderful "renewable" fuel wood, which is a large participant (along with straw) in about half of the 7 million air pollution deaths that take place each year, mostly among poor people, although wood burning is very popular, and, as Valentine's day approaches, considered very "romantic" in the first world.

Cigarette smoking is the combustion of biomass, just saying...

The review article is of interest to the analytical chemist, and there's a very nice overview of various types of mass spectrometry instruments, triple quads, orbitraps, Q-traps, TOF instruments etc, etc, as well as wonderful descriptions of sample preparation.

The mass spectrometer is clearly one of the most important tools ever invented for investigating the world, whether the topic is carcinogenisis, therapeutics, air and water pollution, extraterrestrial chemistry, what have you. It is very unlikely that J.J. Thompson, genius that he was, could imagine where the discovery of the electron would take science.

Unbelievable.

In any case, this paper should represent a subtle warning to anyone who actually cares about environmental science about what is clearly - if not to everyone else, at least to me - the worst energy disaster of all time, air pollution. This disaster has been taking place for a long time, and it will not stop until we clear our minds and think anew, until we pay attention..

Not so long I had an unpleasant discussion on the internet with one of those "FUKUSHIMA!!! FUKUSHIMA!!! FUKUSHIMA!!!" assholes who insist on contemplating their navels while the planet dies.

This person, who informed me that he or she was a "heavy ion physicist" (as opposed to a nuclear physicist, since "nuclear" is apparently a bad word) said that Fukushima was the worst disaster of the 21st century because, to paraphrase, "one could calculate the excess cancers from it."

He or she felt qualified to inform me of this fact because he or she claimed to have a Ph.D. As someone who has met thousands of Ph.D's, if not tens of thousands, over a long life, I have a perspective on what that degree qualifies one to say or do on any variety of subjects, but no matter, famously:



Happily for me, I will never interact with this person again.

Nevertheless, I, for example, could be a greeter at a Walmart who never graduated from elementary school, but it has no bearing whatsoever on the truth or falsity of any of the above.

To Wit: Donald Trump was awarded an MBA from the Wharton School of Business, but apparently that only qualifies him to drive businesses, and apparently whole countries into bankruptcy.

Having a Ph.D. doesn't prevent you from being an asshole, even an ignorant asshole.

Some simple arithmetic with some very basic assumptions:

If Fukushima were to cause 10,000 "eventual" cancers - it won't but if it did - and if only 10% of the 7 million air pollution deaths involved lung (or other) cancer, then the total cancer loss from Fukushima would be on the order of about 5 or 6 days worth of air pollution cancer deaths.

Fukushima is the result of a massive earthquake which by the way also killed 20,000 people, not from radiation, but because they happened to live in a coastal city not that anyone is interested in banning coastal cities.

Air pollution, by contrast to the reactor failures at Fukushima, does not require an earthquake to kill people. It kills people when its primary source, dangerous fossil fuel and biomass combustion operates normally.

This bears repeating. If we pay only selective attention to energy disasters as opposed to full attention involving risk/benefit calculations - because no decision of any kind will ever lead to risk free situations - we subject ourselves to the greater risk doing great harm to the future of humanity, and not just humanity, but to the very beautiful world to which we have had the good fortune to see.

I wish you a pleasant Sunday afternoon.



Radiolytic degradation of CFCs.

In one of the rare successes of an environmental treaty, the CFC's, chlorofluorocarbons, were banned internationally by the 1987 protocol because of their potential for depleting ozone.

However these species, which are also greenhouse gases, are long lived in the atmosphere, and many remain in old refrigerators, air conditioners and even spray cans. Thus they are still present in the atmosphere.

They degrade by termination of chain reactions, induced in the upper atmosphere, primarily by interaction with UV, X-ray, and gamma radiation associated with outer space and the high ionosphere.

High energy radiation is of course, available in the lower atmosphere either by the use of accelerators - from a radiochemical perspective the most often utilized energy consuming tool in this regard is the electron beam - or from the decay of radioactive materials, most commonly in the lab either Co-60 made by bombarding natural cobalt with neutrons in a nuclear reactor, or by use of the fission product cesium-137, which is available on a macroscopic scale.

Most often when I look for literature on this subject, I am mostly concerned with halogenated species in water, for example the famous PCB's which continue to pollute the Hudson River, but while going through such literature today, I came across a study on the degradation of CFC's.

The paper is here: Chain reaction on de-halogenation of 1,2-dibromotetrafluoroethane and 1,1,2-trichlorotrifluoroethane induced by irradiation in alcohols (Nakagawa, Radiation Physics and Chemistry Volume 108, March 2015, Pages 29-32

It's a brief but interesting paper.

Some brief excerpts:

Chloro-fluoro aliphatic carbons (CFC) and bromo-fluoro aliphatic carbons (Halon) are considered environmental pollutants. Some techniques have been studied to decompose halogenated carbons. Irradiation with gamma-rays or high-energy electrons in alkaline 2-propanol solution seems to be one of the effective methods for degradation of chlorinated carbons, not only CFCs but also polychlorinated aromatic carbons, such as polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated biphenyls (PCB), polychlorinated phenols (PCP), polychlorinated benzenes (PCBz), and so on. There are many reports on the degradation of chlorinated carbons, and the reaction mechanisms have been well studied (Mucka et al., 1997; Schmid et al., 1997; Schmelling et al., 1998; Yamamoto and Tagawa, 1999; Hirota et al., 2000; Nakagawa and Shimokawa, 2002). On the contrary, few studies on the decomposition of brominated carbons exist. Though also investigated the degradation of 1,2-dibromotetrafluoroethane (Halon2402) in alkaline 2-propanol solution, they could not observe the product Halon2401, produced from the substitution of one of the bromine atoms in Halon2402 with a hydrogen atom. It is suspected that the mechanism for decomposition of Halon2402 in 2-propanol solution is entirely the same as that of chlorinated carbons.

In this report, the degradation of Halon2402 induced by irradiation in 2-propanol and methanol was studied in detail with careful de-oxygenation, and the charge transfer from an alcohol radical to Halon2402 was found to be the trigger of the chain reaction in pure alcohol


In this paper both Co-60 and Cs-137 were utilized.

It was found that in both methanol and isopropanol (rubbing alcohol) both bromo and chloro fluorocarbons were dechlorinated and or debrominated. However methanol was less efficient and detectable amounts of the probably inert (but still a greenhouse gas) tetrafluoroethylene was formed from the halon 2402 gave measurable yields (by Gas Chromatography) tetrafluoroethylene aka 1,1,2,2-tetrafluoroethene.

The halides formed were measured by old fashioned chemistry, a Mohr's titration, and so it is not clear the extent to which defluorination took place, since Mohr's titrations do not really distinguish between halides, if I recall their chemistry well.

Defluorination is a tougher not than dechlorination or debromination, but not actually impossible, at least with gamma radiation, particularly where gaseous or liquid water is available.

These reactions were conducted in alcoholic solvents in the absence of catalysts like titanium dioxide.

Thus as a practical matter, they are only applicable to the destruction of isolated CFC's.

Of course, the same chemistry as takes place in the upper atmosphere would also work at ground level. Ozone is essential in the upper atmosphere, but at ground level it is a serious air pollutant with huge health consequences. Irradiation of air, therefore, containing CFC's - as all air now does - would therefore destroy ozone. Further, owing to the Maxwell-Boltzmann distribution, CFC's, being relatively heavy molecules in comparison to air - which has a density very close to that of pure nitrogen - is far more concentrated at ground level than in the upper atmosphere.

The storage of radioactive materials in highly polluted cities would therefore mitigate these health issues significantly. However, realistically, there is too much fear and ignorance surrounding nuclear materials for that wise decision ever to happen, but well, the supposition that ignorance is not good for health is not a new concept and is well established and regrettably, widely observed.

I wish you a pleasant Sunday.
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