NNadir

NNadir's Journal

September 30, 2020

Un Cadeau des Dieux

September 29, 2020

My wife got laid off from her University job today.

We kind of knew the University was on its last legs; as many private universities are.

Small private liberal arts focused universities are dying rapidly. Her university is still alive, but going down fast in the days of Covid.

Years ago, for the one and only time, I got fired, and I ran into an acquaintance, and told her I'd just lost my job, and she said, "That's great! This is a tremendous opportunity!"

I was polite about it, and didn't say the "Fuck you Lady!" that was going through my head.

But she was right. I left a wing of the industry which was dying - API manufacturing - because of Indian and Chinese competition, and went into another side where I learned so much more than I ever knew. Getting fired was just great for me. My life would have sucked if it didn't happen.

We are NOT watching the debates tonight. It's not like it matters; we're all Biden all they way for all the time and have no interest in watching that old senile drooling, drug addict in the White House try to take down someone who knows something he will never know; what it is to be decent, intelligent, and worthy of ones life.

Tonight we'll be watching Blade Runner 2049, celebrating that we are still alive, and yes, drinking a bit.

Life is beautiful and then you die.

Tears in rain.

September 29, 2020

Palestinian refugee receives Spanish citizenship after discovering Jewish Sephardic roots

As a U.K.-based academic who was born in Dubai to a Palestinian father and Lebanese mother, Heba Nabil Iskandarani had plenty of potential national identities.

What she lacked, however, was a passport.

A 26-year-old lecturer in architecture at Birmingham City University, Iskandarani has been stateless for most of her life, possessing only a Lebanese travel document that defines her as a Palestinian refugee.

But after discovering that her Palestinian father had Jewish roots going back to Spain, Iskandarani was able to claim Spanish citizenship thanks to a 2015 law that promised to naturalize anyone whose Jewish ancestors fled the Spanish Inquisition.

In an interview with the Jewish Telegraphic Agency, Iskandarani attributed her quest for citizenship as rooted in both an emotional search for an identity and as a practical remedy to the bureaucratic complications that resulted from her lack of national citizenship.

“This deep addiction for belonging made me look deeper into my family history,” Iskandarani wrote in a Sept. 12 Facebook post. “I wanted to find a solution to break the cycle of shame, the feeling of being less than all. I needed an identity a country to fall back too [sic]...”

Palestinian refugee receives Spanish citizenship after discovering Jewish Sephardic roots

September 27, 2020

Daily new Covid cases in New Jersey have jumped from September 12 to September 25,...

...from 297 cases per day, to 750 cases per day.

Not good...

My wife keeps talking about things like Christmas and next summer.

I'm not entirely sure I'm going to live that long. I'm clearly high risk, fat, old, borderline diabetic, with type A blood and male.

I think we get our ballots the first week in October. I'm filling out mine immediately and bringing it down to the County Board of Elections. I do hope to see that piece of shit dragged out of the White House if necessary, but failing that, I want to do my part to make it happen.

September 27, 2020

Screening Study of Different Amine-Based Solutions as Sorbents for Direct CO2 Capture from Air

The paper I'll discuss in this post is this one: Screening Study of Different Amine-Based Solutions as Sorbents for Direct CO2 Capture from Air (Francesco Barzagli, Claudia Giorgi, Fabrizio Mani, and Maurizio Peruzzini ACS Sustainable Chemistry & Engineering 2020 8 (37), 14013-14021).

Let me start this commentary by repeating myself: We will be damned for all time in history for leaving future generations the task of picking through our garbage dumps to survive. We will not be forgiven and we should not be forgiven.

Of course, we already have people picking through landfills to survive, but in my view, the most egregious dump of them all is precisely the one which almost no higher living thing can escape, our atmosphere.

Some years back, there was a moderately prominent energy website on the internet - it apparently operated from 2005 to 2013 -The Oil Drum which was built around the idea advanced by James Kunstler a journalist, once at Rolling Stone, in his book, The Long Emergency, that the world was experiencing "Peak Oil" and that we were all going to die when oil ran out.

(I could offer my standard joke that one cannot get a degree in journalism if one has passed a college level science course, but it appears that Kunstler does not have a degree in journalism; and certainly doesn't have one in a scientific discipline either.)

Personally, although I was certainly known to ridicule Kunstler despite that he was inexplicably popular among many of us on the left - the same people who opposed the two Iraq wars which were about claims of the essential nature of petroleum, also embraced Kunstler's fetishizing that pernicious substance - but I wish he'd been partly right, that oil was running out, if not about everyone dying without it. Regrettably it hasn't run out, even though the destruction we wrought to get at it is increasingly odious.

As of 2018, according to the 2019 Edition of the World Energy Outlook, dangerous petroleum was the largest single source of primary energy on this planet, producing 184.34 exajoules of energy out of 599.34 exajoules. It was the third fastest growing source of energy in the 21st century, after dangerous coal and dangerous natural gas; together they made up 81% of the world energy supply in 2018, as compared to 80% in the year 2000.

Things are getting worse, not better, but thank you Germany for pretending to care, even if pretending to care has been expressed by an embrace of stupidity. You're excused Germany, inasmuch as we live in the age of stupidity, and the stupidity of the German Energy Policy is simply an embrace of our times.

Eventually though, irrespective of the fate of Kunstler's mentality over the short term, the world will run out of oil, at least if we don't drown in its waste. I personally hope it is sooner rather than later.

This said, if we are ever to have any hope of reaching human development goals, which were first succinctly codified in Article 25, section 1 of the largely ignored 1948 Universal Declaration of Human Rights, an industrial society will require sources of carbon for essential chemicals and materials. Even though we live in the pyritic age of stupidity, we also live in the Golden Age of Chemistry, and an obvious source for carbon, the source in fact utilized by living things, is the otherwise dangerous fossil fuel waste carbon dioxide.

This paper is about the much discussed concept of "Direct Air Capture," often abbreviated in the scientific literature as "DAC," of carbon dioxide. This is an energetically expensive proposition, because in a purely thermodynamic sense, one must overcome the Entropy of Mixing, said entropy having contributed to the dubious embrace of dangerous fossil fuels by providing an efficiency kick. Sophisticated arguments have been advanced about why it might work; other sophisticated arguments have been advanced stating why it won't work. I come in on the side of saying it is feasible, not easy, but feasible, but only if no carbon dependent energy source (with the possible exception to a limited extent of bioenergy) is utilized to address overcoming the entropy that we, and all generations before us beginning in the 19th century, have dumped on future generations. From my perspective it is obviously feasible, since plants and algae do it all the time, albeit from the agency of providing a huge surface area via the self replicating function of life.

I personally think that a better industrial choice for capturing carbon dioxide from the air is indirect air capture, utilizing seawater, but that's another topic entirely.

Even I concede however that under limited circumstances, there are circumstances under which direct air capture might be viable, as a side product.

This involves my view of the wisest approach to what I'll call - since it involves a massive electrical circuit, the grid - capacitance, although I'm not a fan of the sometimes discussed idea of massive "super capacitors," designed to store electricity on a grand scale in the same way as it is stored, for example, in cell phones, or TV's in a short term fashion.

Capacitance is a refined word for energy storage. Energy storage is widely discussed as a scheme to make so called "renewable energy" a practical source of energy, by throwing good money after bad: So called "renewable energy" is an expensive failure, and attempts to store it to make its availability fit better into energy demand are misguided because they will certainly fail, just as so called "renewable energy" has failed to address climate change, particularly because what would be required would be the storage of electrical energy for a very long time in many circumstances. The mass requirements of doing so, and the toxicological and carbon associated with accumulating that mass, would surely be incredibly destructive and expensive.

Nevertheless, on an electrical grid, short term capacitance is a necessary feature. Here is the CAISO graphic for electricity demand in California during the recent extreme heat wave, accessed on September 6, 2020 at 3:05 pm Pacific Coast Daylight time:

Note that the distance between the forecasted peak power on that date, 45,168 MW, and the minimum at around 6:45 am on the same date, looks to be, from the graph, about 26,000 MW is roughly 20,000 MW. There are two ways to address this discrepancy, one being to build redundant power plants to cover these exigencies. This is extremely wasteful and therefore environmentally and economically unattractive, and it represents the reason that the highest electricity prices in the OECD are found in Germany and in Denmark. The other is capacitance, but this need not - in my opinion should not - involve the storage of electricity itself either in batteries or in massive super capacitors since this approach will clearly be environmentally odious. A better option would be to store the energy as heat, as in a phase change material, or as compressed air, or perhaps both.

For the purposes of this discussion, I will only discuss compressed air. Compressing air generates heat according to - on the simplest level - Charles Law, although vastly more sophisticated gas laws are obviously well known and widely used. It follows that gases cool when they expand adiabatically, that is, without heat being added. However, if one adds heat, in particular waste heat, one can under the right circumstances increase the exergy derived from the heat, where exergy is the usable energy extracted from the system.

If the air is compressed over a solution containing a carbon capture agent, similar to the amines discussed here, or - more to my personal liking - metal hydroxides, one can remove carbon dioxide from the air as a side product of the effort.

Another possibility is to use air as the working fluid in a Brayton cycle, during which the air is continuously cycled over carbon capture agents. This is certainly possible; all jet engines are Brayton cycle heat engines, and all use air as the working fluid.

If the air is superheated after compression, say to temperatures approaching 1000° or even higher, this will have the effect of combusting the greenhouse gas methane as well as carbon particulate matter, the latter a serious health risk, the former a potent greenhouse gas. If the heat transfer medium is highly radioactive it will have the effect of destroying the ozone depleting greenhouse gas nitrous oxide, residual CFC's, HFC's, sulfur hexaflouride, carbon tetrafluoride.

Although unlike the hyped up energy charlatan Amory Lovins, I am aware of Jevon's Paradox, I still think that high efficiency is desirable, particularly if we consider human development goals of justice and opportunity and health for all of humanity, not just those of us who live in wealthy countries. A very high temperature Brayton cycle, or a series of them, coupled to a Rankine cycle and perhaps even a Stirling cycle offers a number of opportunities, including the opportunity of providing sensible heat for chemical processing and, in fact, carbon dioxide recovery and reduction into useful products.

From the paper's introduction:

The recent climate conference COP21 (Paris, 2015) underlined the need to take actions by most of the world’s countries to mitigate climate change and keep the global temperature rise well below 2 °C above preindustrial levels.(1) In addition to the reduction of the combustion of fossil fuels and the improvement of the CO2 capture from large-point sources, the so-called carbon capture and sequestration (CCS) technology,(2,3) a strategy that is emerging as crucial for achieving the ambitious Paris’ target, is the development of negative emission technologies (NETs).(4) NETs relate to CO2 removal from the atmosphere through techniques such as the chemical CO2 capture from ambient air, called direct air capture (DAC).(5) DAC is a developing technology with the potential to contrast the dispersed emissions coming from transport and residential heating, which cannot be captured at their sparse sources and represent approximately half of the annual anthropogenic CO2 emissions.(6,7) In the DAC process, large air-absorbent contactors equipped with many fans blow the air to the absorber, where the ultradiluted CO2 (approximately 410 ppm) is selectively removed and the “clean” air is returned to the atmosphere. Afterward, the sorbent is regenerated and the captured CO2 is released for disposal or, more interestingly, for direct utilization, as, for example, in the catalytic methanation.(8) Moreover, DAC systems benefit from their inherent flexibility of placement, and careful location planning can favor the use of renewable energy and can reduce the cost of CO2 transportation from the capture site to the storage or utilization sites.(9) An ideal DAC process should combine a quick and efficient CO2 capture with low-energy inputs for air handling, sorbent regeneration, and CO2 release. Although DAC processes were considered prohibitively expensive until a few years ago, with costs in the range 200–1000 $/ton of CO2 (10 times higher than conventional capture from flue gas), the most recent economic analyses suggest that with the latest improvements (mainly engineering) the DAC technology is approaching commercial viability, with capturing costs that can be reduced to less than 100 $/ton of CO2.(10?12) In particular, several studies demonstrated that an air–liquid cross-flow scheme, which reduces the pressure drop, can dramatically lower the capture cost...(9)

The "approximately 410 ppm" remark is bitterly amusing to anyone who pays attention to carbon dioxide concentrations in the air. I am certainly such a person, as I monitor these levels closely on a weekly basis. I note that it was only a few years ago that scientific papers were talking about "approximately 390 ppm."

Depending on this year's carbon dioxide minimum, which will probably occur this week, measured at Mauna Loa we may never see a level as low as 410 ppm again, so dramatic is our failure to address climate change. In the last 52 weeks, going back to the week beginning of the week of September 29, there have been six where the concentration at Mauna Loa was lower than 410 ppm. That week, represented the annual minimum. We have not, as of this year, seen a value as low as 410 ppm: The last data point, the week beginning September 20, 2020, reported a concentration of 411.27 ppm. If values fall this year to 410 ppm - I doubt they will - it will be the last time in the lifetime of anyone now living that it will do so. (This year's maximum was 417.43 ppm, measured in the week beginning May 24, 2020, during worldwide Covid shutdowns.)

So there's that.

Later the introduction continues:

So far, the main potential technologies involve chemisorbent materials; (6) in particular, many researchers have focused on the development of solid-based sorbent systems, especially immobilized amine/silica sorbents or hollow fiber sorbents.(13?18) Alkaline liquid sorbents have also been taken into consideration for their fast and efficient CO2 capture in continuous (not batch) processes; (6) however, their development has so far been limited due to the high costs of regeneration. Aqueous solutions of sodium and potassium hydroxide have been extensively studied as sorbents for DAC processes for their strong alkalinity and their high reaction rate even with ultradiluted CO2.(19,20) Despite a good capture efficiency, the process is energy intensive: the sorbent regeneration is based on the formation of CaCO3 by adding Ca(OH)2, and the subsequent calcination of CaCO3 to release pure CO2 requires very high temperatures (900 °C), which entail high energy costs, up to 180 kJ/mol CO2.(9,10,19)

With the aim of developing new liquid sorbents for the efficient capture of ultradiluted aerial CO2 with a lower regeneration energy compared to KOH and NaOH solutions, we decided to investigate the performance of several amine-based sorbents in DAC systems. Aqueous amines are well-known (and widely investigated) sorbents for the efficient CO2 capture from large-scale emission points (CO2 12–15% v/v), which can be regenerated at T = 100–120 °C, a temperature well below that required for the CaCO3 calcination.(21,22) Currently, many researchers are working to develop innovative amine-based absorbents able to combine the most efficient CO2 capture with the lowest heat of CO2 desorption,(23?26) an important parameter for assessing the regeneration energy (the opposite of the heat of CO2 absorption, usually lower than 90 kJ/mol CO2 for all of the most studied aqueous amines).(22,27)

For various reasons, I'm not quite sanguine about giving up on alkali metal hydroxides, although - despite it's limited availability - for various reasons I won't discuss presently, I favor cesium or at least rubidium hydroxides. I note that alkali hydroxides can be made into continuous systems by the expedient of drizzling in saturated solutions of group 2 hydroxides, those of calcium, strontium or barium. The authors are nonetheless focused on reducing the regeneration heat and energy required, as they state above, and study various amines.

The amines tested and their structures are shown in a table in the text:

Here is a photograph of their equipment, accompanied by a schematic:

The caption:

Figure 1. Apparatus for the determination of the percentage of CO2 absorbed and its schematic flow diagram. Blue lines refer to air and black lines to the liquid sorbent.

Carbon dioxide captured by amines, including the commercial carbon capture amine, monoethanolamine, is generally in the form of carbamates, structures in which a carbon dioxide is loosely bound to a amine nitrogen.

Some tables of results:

The formation of carbamates tracked by NMR:

The caption:

Figure 2. 13C NMR spectra of aqueous MEA, 2A1B, AMP, and AMPD at the end of the absorption experiment. The numbers indicate the carbon atoms referred to both free and protonated amine fast exchanging in the NMR scale. Asterisks denote the chemical shifts of carbon backbones of amine carbamate. C indicates the carbonyl atoms of amine carbamate, while b/c refers to the signal of fast exchanging bicarbonate/carbonate ions. The intensity of the signals at 163–167 ppm is not in scale.

The authors explore the use of non-aqueous solvents. This table gives results.

In some cases the carbamates react with the alcoholic functions in the nonaqueous solvents having them to produce alkylcarbonates by the proposed mechanism:

The caption:

Figure 4. Scheme of the proposed two-step reaction mechanism for the formation of alkyl carbonate in nonaqueous EMEA solutions, including (A) the initial formation of the carbamate of the amine and (B) its subsequent reaction with an alcohol.

Excerpts from the conclusion:

With the aim of identifying the most crucial chemical peculiarities for the development of new liquid absorbents for DAC processes, we carried out a screening study on the performance of different aqueous alkanolamine solutions, under the same operating conditions: their ability to absorb CO2 from an air stream was correlated with their chemical structure and with the species formed by the absorption reaction, and useful information on the reaction mechanism has been obtained. As a general finding, aqueous unhindered primary amines are the most suitable sorbents for DAC processes, as they are as efficient as aqueous alkali hydroxides but with a potential energy saving due to the lower temperatures required for sorbent regeneration. The formation of a high yield of amine carbamate seems to be the decisive factor for an efficient CO2 capture, but the formation of an appreciable amount of carbonate/bicarbonate because of the strong basicity of some amines (EMEA, BUMEA) can contribute to attain a high percentage of CO2 absorbed. The amines that are unable to form carbamate have provided poor absorption values...

...These findings highlighted the differences of DAC processes compared to conventional CCS processes and, consequently, the best CCS absorbents cannot be the best choice for the DAC process. The obtained results also showed that aqueous amines are more efficient than the same amines in organic diluents. MEA and DGA in EG/PrOH display slightly lower abs% compared to the aqueous solution by virtue of the high percentage of carbamate formed...

This is a fine paper; I like it, although I'm not sure I agree with the idea of amine carbon capture reagents, in particular because in the case of a commercial example MEA, monoethylamine, the stability of the amine proves to be a long term problem. Another is the recognition that the air is hardly clean, and besides the formation of sulfates, there is a considerable amount of nitrogen oxides in the air. A recently discovered problem in the pharmaceutical and, albeit to a lesser extent, the food industries is the formation of highly carcinogenic and genotoxic nitrosoamines. At the scale of air capture - we're talking billions of tons here - this may be problematic for these amines, even if they are designed to be used in closed systems.

I wish you a pleasant and safe Sunday.

September 27, 2020

Los Angeles, 2019.

I watched the "Final Cut" of Blade Runner today, which begins with the title, "Los Angeles, 2019."

Flying cars, lots of rain...um...um...

Los Angeles looks a little different than expected in 1982, I think.

There are no replicants in Los Angeles, from what I can tell, but I may be missing something.

I especially liked the part where they get kind of "sciency," when Tyrell tells Batty why he can't live. It was less silly than some things you see in science fiction.

It was though, I think, a pretty good movie, if you like that sort of science fiction sort of thing. I'm not, in general, a science fiction fan, but I liked this one.

September 26, 2020

A Rare-Earth Samarium Oxide Catalyst for Electrocatalytic Nitrogen Reduction to Ammonia

The paper I'll discuss in this post is this one: A Rare-Earth Samarium Oxide Catalyst for Electrocatalytic Nitrogen Reduction to Ammonia (Yonghua Cheng, Haifeng Nan, Qingqing Li, Yaojing Luo, and Ke Chu
ACS Sustainable Chemistry & Engineering 2020 8 (37), 13908-13914).

I often reflect on Stuart Kaufmann's remark, which has stuck in my mind for nearly two decades, in his fabulous book The Origins of Order that life can be considered, "An Eddy in Thermodynamics." I once spent part of an afternoon with Freeman Dyson - one of the best afternoons of my life - and he approved of that description as well.

The nitrogen-nitrogen triple bond is one of the strongest, and thus one of the most thermodynamically stable, bonds there is, 9.79 ev/bond. This means that it is very, very, very difficult to break. Worse, the activation energy of breaking it is also enormous, 3.5 ev/bond. Yet, for life to exist, breaking this bond is essential because of the impossible to understate role of nitrogen in biochemistry, where it plays a huge role in proteomics and nucleic acids, as well as in amino sugars, the role of which is very critical in immunology, the science at the forefront of the world's current crisis.

Before the development of the Haber-Bosch process, which is brilliantly discussed by one of my favorite thinkers, Vaclav Smil, in his wonderful "down to Earth" popular science book, Enriching the Earth, almost all of the fixed nitrogen on Earth was formed via the agency of a molybdenum/iron metalloenzyme, nitrogenase.

Here is the structure of the metal center of nitrogenase:

The caption:

Fig. 2. (A) Schematic representation of the FeMo-cofactor model. Y represents the bridging ligand with relatively light electron density. (B) Stereoview of the FeMo-cofactor and surrounding protein environment

Kim and Rees Science Vol. 257, Issue 5077, pp. 1677-1682 (1992)

I once had the privilege of attending one of Emily Carter's lectures in connection with the publication of this paper:

Prediction of a low-temperature N2 dissociation catalyst exploiting near-IR–to–visible light nanoplasmonics (Martirez and Carter, Science Advances (2017) Vol. 3, no. 12, eaao4710).

I asked her kind of rhetorically, "What is it about molybdenum, anyway?" and she laughed and made a sort of noncommittal remark about orbitals, a subject about which she knows more than I have ever known or ever will know.

I am, by the way, convinced that the best way to replace the dependence of the world on dangerous natural gas - and in some places even coal - for the production of ammonia, which is said to consume about 2% of the world energy supply, does not involve photochemical bond activation, or, for that matter, the electrochemistry under discussion in this paper on Samarium. I think the Haber-Bosch Process is acceptable if the heat energy required comes from process intensification of the thermal downgrade of thermochemical hydrogen production using nuclear energy as the primary energy source.

As I often remark, electricity is a thermodynamically degraded form of energy, and it is only acceptable to use it for chemical processes in the case where it is waste electricity.

Dealing with the environmental - in particular atmospheric - consequences of the Haber-Bosch process, on which the world's food supply depends, is another issue entirely.

From the introduction:

Ammonia (NH3), as a pivotal nitrogen building block and a carbon-free hydrogen fuel carrier, is widely applied in the agricultural, clinical, environmental, and biomedical fields, along with many other fields.(1) Electrochemical dinitrogen reduction via nitrogen reduction reaction (NRR) provides a promising route for green NH3 synthesis.(2) Nonetheless, developing efficient electrocatalysts to boost the NRR and impede the hydrogen evolution reaction (HER) is highly imperative. To this end, extensive efforts, both theoretical and experimental, have been dedicated to exploring effective NRR catalysts, involving precious metals,(3?5) nonprecious compounds,(6?20) and metal-free materials.(21?23)

Lanthanide rare-earth compounds have gained a noticeable popularity in various applications of batteries, sensors, catalysis, and supercapacitors,(24) owing to their unique electron configurations, high surface chemical activity, and robust structure. Recent studies have identified CeO2,(25?27) DyF,(28) and La2O3(29) as promising rare-earth NRR catalysts. As a typical lanthanide oxide, Sm2O3 has recently attracted considerable interest in photocatalysis and electrocatalysis. For instance, Sm2O3 could act as an effective catalyst for the oxidative coupling of methane with high activity, selectivity, and durability.(30) Wang et al. prove that Sm2O3 can catalyze oxygen reduction actively and selectively and with high stability.(31)
Here, we first demonstrate Sm2O3 to be an effective and stable NRR electrocatalyst. Theoretical computations uncover that Sm2O3 can facilitate the NRR and hinder the HER. On the basis of the theoretical results, we synthesized Sm2O3 nanoparticles (NPs) which delivered an appealing NRR performance as well as robust stability.

The authors here did similar computational work to that reported by Carter, but went a step further into the experimental realm:

Density functional theory (DFT) computations are first performed to authenticate the NRR feasibility of Sm2O3. The dominant (222) facet is considered for building the Sm2O3 model. As shown in Figure 1a, the Sm2O3 (222) comprises abundant surface-exposed Sm atoms with a positive charge of +1.01 |e|, which provides the catalytic opportunity for polarizing and activating the negatively charged N2 molecules.(32) Initially, upon N2 adsorption (Figure 1b), the *N2 prefers an end-on adsorption configuration and gains ?0.02 |e| from an active Sm atom, resulting in an N–N bond elongation of 1.12 Å. Remarkably, for *N2 ? *NNH (Figure 1c), two N atoms in *NNH gain a large amount of charge (?0.57 |e|), and the N–N bond is dramatically elongated to 1.215 Å, indicating that Sm atoms enable the effective N2 protonation to catalyze the NRR.

Some pictures from the text:

The caption:

Figure 1. (a) Schematic of NRR on Sm2O3 (222). (b, c) Optimized models of (b) *N2 and (c) *NNH on active Sm atom: N1 and N2 represent the distal-N and nearest-N, respectively. (d) PDOS of *NNH on Sm atom. (e) Free energy profiles of reaction pathway on Sm2O3 (222) at zero and applied energy of ?0.92 V (inset: free energies of various species on Sm2O3 (222).

The caption:

Figure 2. Characterizations of Sm2O3 NPs: (a) XRD, (b) unit cell of Sm2O3, (c) TEM, (d) HRTEM, (e) SAED, (f) lattice measurement, (g) atomic configuration of Sm2O3 (222) facet (side view), (h) XPS Sm 3d spectra, and (i) O 1s spectra.

The caption:

Figure 3. (a) LSV curves of Sm2O3 NPs. (b) Time-dependent current density curves of Sm2O3 NPs for 2 h at various potentials and (c) corresponding UV–vis absorption data of resultant electrolytes and (d) obtained NH3 yields and FEs. (e) UV–vis spectra of the electrolytes after 2 h of electrolysis on Sm2O3 NPs at various potentials. (f) NH3 yields of Sm2O3 NPs, Sm2O3/RGO, and bare RGO at ?0.6 V.

The caption:

Figure 4. (a) UV–vis absorption spectra of the electrolytes after 2 h of electrolysis over Sm2O3 NPs at ?0.6 V at different conditions. (b) 1H NMR measurement. (c) Cycling test. (d) Chronoamperometry test for 20 h.

From the succinct conclusion of the paper:

In summary, the combined computational and experimental results validate Sm2O3 to be a high-performance rare-earth electrocatalyst for the NRR. Theoretical calculations unveil that the active Sm centers could favorably boost the NRR and impede the HER. The prepared Sm2O3 NPs show an appealing NRR activity along with high stability. This work may provide a new pathway for the rational design of rare-earth catalysts for electroreduction of N2 to NH3.

Again, I basically am less than supportive, despite the fine science demonstrated in this paper, to electrochemical reduction of ammonia, except in the case where there is waste electricity.

However, it is environmentally and economically wise to avoid waste electricity, and the idea of storing it in batteries is about as environmentally odious as one can get in my opinion.

Continuous processes are always desirable, as opposed to batch or interrupted processes, in an environmental and economic senses - because these senses depend on thermodynamics.

This fact - facts matter - is why so called "renewable energy" will continue to fail to address environmental issues while simultaneously failing to address the ethical issues associated with human development goals.

I trust you will have a pleasant and safe weekend.

September 26, 2020

At the Purchaser's Option...

September 26, 2020

Everything I got is done and pawned.

September 24, 2020

Utilizing the 21 Tesla Magnet at the National High Magnetic Field Lab to Characterize Asphaltenes.

The papers I'll discuss in this post are the two parts of papers appearing recently in the scientific journal Energy and Fuels.

They are: Probing Aggregation Tendencies in Asphaltenes by Gel Permeation Chromatography. Part 1: Online Inductively Coupled Plasma Mass Spectrometry and Offline Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (Marshall et al., Energy and Fuels, Energy Fuels 2020, 34, 7, 8308–8315)...

...and...

Probing Aggregation Tendencies in Asphaltenes by Gel Permeation Chromatography. Part 2: Online Detection by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and Inductively Coupled Plasma Mass Spectrometry (Marshall et al., Energy and Fuels, Energy Fuels 2020, 34, 9, 10915–10925).

This journal's papers are generally overwhelmingly about dangerous fossil fuels. Anyone with a passive knowledge of my often turgid writings will be aware that I oppose the use of all dangerous fossil fuels and believe they must be phased out as quickly as possible on an emergency basis. I nonetheless regularly read this journal for several reasons. One is that while I favor largely doing away with the car CULTure - something of a hard sell I freely admit - there are certain materials, including to be perfectly honest, fuels, that cannot be ethically banned while respecting human development goals, that are obtained from dangerous fossil fuels. Thus to maintain access to these materials while simultaneously banning the mining of dangerous fossil fuels, we must understand what these materials are and how they can be either manufactured or replaced without the use of dangerous fossil fuels themselves. Of particular importance are "cokes" which are carbonaceous materials used widely in the reduction of metal ores, either in thermal settings (as in Bessamer furnaces in the steel industry) or as electrodes in Hall Heroult and FFC processes. The second reason is that many papers, especially those in the (generally smaller) section related to biomass offer insights to the now necessary goal of removing carbon dioxide from the air. A third reason is that there is generally a section in this journal connected with the capture of carbon dioxide. Although these are largely addressed to the quixotic idea of giant underground dangerous fossil fuel waste dumps (aka "sequestering" ) they are also relevant to more sane means of addressing climate change. A final reason is that often these papers just contain good science.

The papers under discussion here are largely directed to problems in the dangerous fossil fuel industry, in particular, the dangerous petroleum industry, but they are relevant actually to many of the reasons I gave above. For example, in the case of removing carbon dioxide from the air: In the high temperature reformation of biomass, it is often the case that "tars" are formed; these are in fact, asphaltenes, close to those found in dangerous crude petroleum. Although asphaltenes are problematic - very problematic - in industrial equipment, they are widely used as the familiar product asphalt, generally an aggregate of sand and asphaltenes. Thus, were we to pave roads, bicycle paths and walkways with asphaltenes obtained from the reformation of biomass, we would be removing carbon dioxide from the air and effectively sequestering in an economically viable manner. Indeed, as we will see below, asphaltenes can be regarded, in part, as fragmented graphene, and a deeper understanding of their chemistry can lead to new insights in materials science. Finally this paper utilizes one of the tremendous resources built in an era when the US government was more committed to science rather than racism, corruption, lies, hypocrisy, the subjugation and denigration of women, power grabbing and the spreading of diseases as it is today in the Senate and Administration. The National High Magnetic Field Laboratory at Florida State University is a tremendous scientific resource.

The introduction of Part 1 of the two part series:

Asphaltenes are one of the most complex and problematic components of petroleum crude oils. Across(1) the entire production chain, asphaltenes pose potential complications.(2) Upstream, on the oil recovery side, asphaltene deposits can block pipelines, often requiring production shutdowns to remedy, resulting in massive losses. Downstream, on the upgrading and refining side, crude oils with high asphaltene concentrations typically have lower yields and higher maintenance costs. Defined purely on the basis of insolubility in an n-alkane solution (typically n-pentane or n-heptane), asphaltenes are not a well-defined (or well-understood) chemical compound class.(3) Compared to their parent crude oils, asphaltenes are typically more aromatic with greater heteroatom content.(4?6) Thus, historically it has long been hypothesized that ?–? stacking and hydrogen bonding between polar compounds drive asphaltene nanoaggregation, which leads to precipitation and eventual deposition. However, asphaltenes are extremely difficult to analyze due to their tendency to aggregate, resulting in very poor ionization efficiency in mass spectrometry analysis.
Linking molecular structure to aggregation potential requires detailed molecular level information. On a bulk scale, asphaltenes are more aromatic and contain more polar compounds than their parent crude oils. However, recent works have started to illuminate the importance of wax-like interactions between more aliphatic compounds that may contribute to asphaltene aggregation. Unstable asphaltenes have also been shown to have higher binding capacities for alkanes and waxes.(7) Berrueco et al. observed a correlation between decreases in fluorescence intensity and UV absorbance in the largest, excluded molecular weight regime of GPC fractions from asphaltenes, petroleum pitch, and coal-derived materials.(8?10) They hypothesized that compounds in the largest, excluded GPC peak may be larger and more aliphatic.(10) Characterization by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) for GPC aggregate fractions collected from a typical atmospheric residue revealed a surprisingly strong correlation between nanoaggregation potential and decreased aromaticity.(11) Large, very aliphatic compounds with extremely low ionization efficiencies comprised the largest, most aggregated fractions...

... Trace metals present in crude oils also complicate refinery processes by potentially deactivating hydrotreatment and hydrocracking catalysts. Vanadium, nickel, and iron are typically the most abundant metals found in petroleum products. Structurally, these metals are incorporated into heterocyclic macrocycles with four modified pyrrole subunits, known as porphyrins.(17,18) The forces driving asphaltene aggregation are not well understood: although metal-containing petroporphyrins are greatly enriched in precipitated asphaltenes, the nature of their involvement is unknown.(19) To probe the forces driving asphaltene aggregation in a laboratory, gel permeation chromatography (GPC) acts as a proxy for real-world aggregation. However, it is not entirely clear how well on-column nanoaggregation mimics that of asphaltene aggregation in the field.

Inductively coupled plasma mass spectrometry (ICP-MS) coupled with GPC yields quantitative chromatograms, commonly called size distributions or size profiles, for individual elements. For porphyrinic metals like vanadium and nickel, GPC chromatograms generally yield trimodal/multimodal aggregate size profiles sufficiently unique to act as “fingerprints” for petroleum samples.(20,21)...

Two of the most important analytical tools in chemistry, NMR and mass spectrometry, depend on magnetic fields. The absolute most sensitive mass spectrometers in the world, those with the highest mass resolution, are Fourier Transform Ion Cyclotron Resonance Mass Spectrometers, and a major manufacturer of these is Bruker, which is the company that built the 21 Tesla magnet at the Lab. The use of this magnet in mass spectrometry allows for the most sensitive analysis ever conducted anywhere.

The authors continue:

Four GPC fractions corresponding to various aggregate sizes were collected from an Arabian heavy crude oil and its corresponding purified asphaltenes for further analysis by 9.4 T Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). For petroleum product and complex mixtures, differences in ionization efficiency and aggregation tendency between compounds result in the preferential detection of the most easily ionized species. Although ionization bias can be partially overcome by chromatographic separations,(27,28) the choice of ionization method is still critical. Here, we chose positive-ion atmospheric pressure photoionization ((+)APPI), which is believed to be the most suitable method for characterization of asphaltenes.(29?31) Although APPI is well known to preferentially ionize aromatic compounds, ionization is more uniform than electrospray.(29,32) This work is the first part of a two-part study investigating the molecular composition of the PetroPhase 2017 asphaltene sample across a GPC elution profile. Here, we focus on the results from offline fraction collection and direct infusion and highlight some of the challenges we faced with that approach. In part 2, we shall examine the benefits of coupling the GPC method with online detection by 21T FT-ICR-MS, which reveals a more comprehensive molecular characterization.

Aromaticity in chemistry refers to a quantum chemical effect in which a ring system contains (2n+2) "pi" electrons where n is an integer including zero. Aromatic rings are stabilized when compared to non aromatic systems of carbon atoms, the latter being termed "aliphatic" above. (The size of the ring also contributes to aromaticity: An eight membered ring with 2 pi electrons is not aromatic, a three membered ring with two pi electrons is aromatic.) The degree to which a ring system is aromatic can be crudely examined (for very complex systems like asphaltenes) by considering "double bond equivalents" herein called "DBEs."

Besides carbon, asphaltenes also contain quantities of sulfur, nitrogen and oxygen. Under certain circumstances these atoms can donate electrons to a ring system, inducing a degree of aromaticity. For instance, furan, a five membered ring containing an oxygen, derivatives of which has been the subject of considerable attention in connection with biofuels made from non-food biomaterials, has a measurable degree aromaticity.

The asphaltenes were solvated in xylene, aromatic molecules which are a mixture of dimethylbenzenes, and subject to gel permeation chromatography (GPC) a chromatographic technique which separates molecules (somewhat crudely) on the basis of their molecular size, which generally correlates closely with molecular weight. The elution through the chromatograph columns utilized THF, tetrahydrofuran, which is made by hydrogenating furan, mentioned above, or by condensation of a product of the dangerous fossil fuel industry, butadiene. A small portion of the eluted asphaltenes were diverted to a commercial high resolution inductively coupled plasma (ICP) high resolution mass spectrometer designed to measure "heteroatoms," those atoms which are not carbon or hydrogen. These were used to monitor sulfur, using the isotope with a mass of 32, the most common sulfur isotope, presumably in such a way as to break up interfering O2 molecules, vanadium-51, the only stable isotope of this element, (natural vanadium is very slightly radioactive owing to the very rare radioactive isotope vanadium-50), and Nickel-58. It does not seem iron was monitored.

A word on why these metals are important in studying aggregation: Metals are known to complex with certain aromatic rings, in particular cyclopentadiene anions, but also with the molecules described above as porphyrins. The presence of porphyrins is definitely an artifact of the fact that the origin of most dangerous fossil fuels was from biomass; dangerous fossil fuels are stored solar energy. Porphyrins are very common in biological systems, two metal coordinating porphyrins are generally known by the general public. Chlorophyll contains a porphyrin structure coordinating magnesium, and hemoglobulin a porphyrin coordinating iron. (There are many other examples.) The authors remark that the fractions that are highly aggregated often contain metals, and part of their effort is to explore why this is.

Some pictures from the text of Part 1:

Sulfur, Vanadium and Nickel:

The caption:

Figure 1. Sulfur (top), vanadium (middle), and nickel (bottom) GPC ICP mass chromatograms. Intensities for the Petrophase 2017 purified asphaltenes are plotted in blue, and parent whole crude oil’s intensities are in red. High, medium, and low molecular weight (HMW, MMW, and LMW) and tailing fraction elution ranges are indicated at the top.

In general, the heaviest molecules elute first in GCP.

The distribution and ratios of hetero atoms, sulfur, nitrogen and oxygen in the various fractions:

The caption:

Figure 2. Heteroatom class distributions from (+) APPI 9.4 T FT-ICR mass spectral analysis for the PetroPhase 2017 purified asphaltenes and its corresponding GPC fractions. Heteroatom classes represent the most abundant heteroatom classes for the purified asphaltenes prior to fractionation.

The lower the ratio of hydrogen to carbon, the more aromatic character a molecule is likely to have:

The caption:

Figure 3. Average H/C ratios for the heteroatom class groups from the purified asphaltenes and its corresponding GPC aggregate fractions.

In general, asphaltenes, especially given their aromatic character, are difficult to ionize. A typical ionization technique - for which a Nobel Prize was awarded, is ESI - electrospray ionization - but in this case, another method, more suitable to the ionization of aromatics, APPI - atmospheric pressure photoionization by which the ionization is achieved by the use of very high energy ultraviolet radiation was utilized, owing the expected aromatic nature of asphaltenes. The ionization efficiency was obtained by recording the number of ions collected as a function of time:

The caption:

Figure 4. (Right) Monomer ion yields for the Arabian whole crude oil and its fractions. (Left) Monomer ion yields for the purified asphaltenes and its fractions. Ionization efficiencies were calculated from the inverse of the ion accumulation periods used to collect the FT-ICR mass spectra (see text). Those values were then normalized to the tailing fraction from the whole crude oil. Both the whole crude oil and the purified asphaltenes show an inverse relationship between ionization efficiency and aggregate size.

It is important to note the different scales on the y axes in the graphic above.

In the next series of graphics, the double bond equivalents within molecules within the fractions are represented. The closer this distribution - these in effect a three dimensional graphics where the third dimension is represented by color - lies to the red line in each graphic, the more highly aromatic these asphaltenes are:

The caption:

Figure 5. Positive-ion APPI-derived isoabundance-contoured plots of double-bond equivalents vs carbon number for the S1 class (top) and S2 class (bottom) for the asphaltenes and its corresponding GPC fractions. Red dashed lines represent the polycyclic aromatic hydrocarbon planar limit.(47,48)

The caption:

Figure 6. Positive ion APPI-derived isoabundance-contoured plots of double-bond equivalents vs carbon number for the O1S1 class (top) and O1S2 class (bottom) for the asphaltenes and its corresponding GPC fractions. Red dashed lines represent the polycyclic aromatic hydrocarbon planar limit.

To some extent, this data is a function of the analytical method.

The authors write:

The high-MW fraction has the lowest average DBE and the greatest average carbon number for both classes. The compositional range corresponds to compounds that are the most aliphatic, and the distribution becomes less aromatic as aggregate size increases. The most abundant species likely have ?2–4 aromatic rings, as nonaromatics ionize very poorly by APPI, and likely contain very long alkyl chains. It is interesting to note that compounds with DBE 6 and 50 carbons are likely entrained material that coprecipitated with the purified asphaltenes, because they should be soluble in heptane on their own. As shown in Figure 6, the same observations discussed above were also made for the O1S1 and O1S2 heteroatom classes, which were among the most abundant heteroatom classes in the whole asphaltene prior to fractionation. The average composition shifts to larger, more aliphatic compounds as aggregate size increases.

In this case, the samples were collected by fractionation and analyzed by direct infusion. In part 2, the limitations of this procedure are addressed by the use of in line LC/MS/MS using the 21 Tesla magnet.

The conclusion of part 1:

Monomer ion yield and aggregation state were strongly correlated in both the crude oil and the asphaltenes. The monomer ion yields of the two largest aggregate GPC fractions (high MW and medium MW) from the asphaltenes were ?1000 times lower than that of the least aggregated, tailing fraction from the whole crude. Due to the extremely low monomer ion yields in these fractions, analysis was limited to only the most abundant heteroatom classes in the asphaltenes. Note that it is difficult, if not impossible, to determine the extent to which the observed heteroatom classes represent the actual composition of the high- and medium-MW GPC fractions; it is entirely possible that additional heteroatom classes are present but ionize so poorly due to their aggregation state that they are not observed. However, for all of the heteroatom classes that we were able to characterize, both in the whole crude oil and in the purified asphaltenes, we observed a strong correlation between aggregation tendency and more aliphatic compounds. As aggregate size decreased, the composition shifted toward more condensed aromatics. No clear evidence of polar functionalities driving aggregation during the GPC separation was observed. A follow-up study will utilize online GPC with detection by 21 T FT-ICR-MS to overcome the limitations associated with fraction collection and direct infusion experiments.

Part 2 begins thus:

Notoriously one of the most problematic components of crude oils—asphaltenes—can complicate every stage of the production chain.(1) On the recovery side, asphaltene deposition in pipelines can require production shutdowns to remove the blockage. On the refinery side, high asphaltene concentrations typically decrease a crude oil’s yield and, simultaneously, increase maintenance costs. Asphaltenes are also possibly the most polydisperse and compositionally complex mixture in the world.(2?6) Unfortunately, asphaltenes are not a well-understood chemical compound class partly due to their poor definition: insolubility in an n-alkane solution, typically n-pentane or n-heptane.(7) Based on bulk properties, asphaltenes typically contain higher concentrations of polar heteroatoms and are more aromatic than their parent crude oils.(8?10) On the basis of these typical characteristics, it has long been believed that asphaltene nanoaggregation is driven primarily by ?–? stacking and hydrogen bonding between polar compounds. However, linking chemical functionalities to aggregation potential requires detailed molecular-level information, and the tendency of asphaltenes to aggregate results in very poor ionization efficiency and makes them extremely difficult to analyze.
Despite the challenges associated with the analysis of asphaltenes, recent work has begun to reveal that waxlike interactions between more aliphatic compounds may play a more important role in asphaltene aggregation than previously known...

...Gel permeation chromatography (GPC) can help probe the forces driving asphaltene aggregation by acting as a proxy for studying aggregation in a laboratory. GPC is often coupled online with detection by inductively coupled plasma mass spectrometry (ICP MS), thereby enabling the quantitative determination of individual elements. GPC ICP MS chromatograms are commonly termed size distributions or size profiles. Most commonly, sulfur is monitored along with the most abundant heavy metals in petroleum products (vanadium, nickel, and iron). Heavy metals are of interest due to their potential to deactivate hydrotreatment and hydrocracking catalysts during upgrading and refinery processes. Vanadium, nickel, and iron exist structurally in petroleum as porphyrins (heterocyclic macrocycles with four modified pyrrole subunits).(20,21) Metal-containing petroporphyrins are enriched in precipitated asphaltenes, but their exact role in asphaltene aggregation is unknown.(22) GPC ICP MS chromatograms for porphyrinic metals typically exhibit multimodal/trimodal aggregate size distributions that provide “fingerprints” for petroleum samples.(23,24)...

...In the analysis of complex mixtures, especially asphaltenes, ionization biases arise from differences in ionization efficiencies and aggregation tendencies, resulting in the preferential detection of the species that ionize most efficiently. Chromatographic separations help to overcome ionization biases by simplifying the sample matrix,(2,30) but just as important is the choice of ionization method. Positive-ion atmospheric pressure photoionization ((+)APPI) is widely thought to be the most compatible method for asphaltenes.(5,31,32) Despite the well-known ionization biases of aromatic compounds, APPI ionizes more uniformly compared to electrospray, which is why it was selected for this study,(5,33) which is the second installment of a study that investigates the aggregation tendencies and molecular composition of the PetroPhase 2017 asphaltene sample by use of GPC. In part 1, GPC aggregate fractions were collected from the PetroPhase 2017 asphaltene sample and analyzed by direct infusion.(34) Monomer ion yields and aggregation state were strongly correlated. The asphaltene fractions that were most aggregated ionized ?1000 times less efficiently than the least aggregated fractions in the whole crude oil...

And a rationale for the improvement at 21 Tesla:

...Very few previous reports have combined chromatographic methods with online detection by FT-ICR MS to characterize petroleum products and/or asphaltenes.(36) Several close mass differences are critical to resolve in the analysis of petroleum products. Two particularly important mass differences are the 3.4 mDa (S1H4 vs C3) and 1.1 mDa (13C1H332S1 vs C4). These close mass differences make online detection by high-resolution MS difficult on a chromatographic time scale. Often, long transients are required to obtain high mass resolving power, and coaddition of time-domain transients is required to increase signal-to-noise ratio to maintain sufficient dynamic range. For that reason, many studies with online detection by high-resolution MS resemble fraction collection and analysis by direct infusion...

From the experimental section, the mass resolution that would make any mass spectrometrist weep with envy:

The APPI source (ThermoFisher Scientific, San Jose, CA) was set to a vaporization temperature of 350 °C, and N2 was used for the sheath gas (50 psi) and the auxiliary gas (32 mL/min) to avoid sample oxidation. Experiments were performed with a custom-built hybrid dual ion-trap 21 T FT-ICR mass spectrometer described previously.(41,42) Excitation and detection were performed with a Predator data station.(43) Online detection by 21 T FT-ICR MS yields a mass resolving power of 3400000 at m/z 400 for an adsorption-mode mass spectrum (6.2 s transient duration), yielding 6451 unique assigned molecular formulas (120 ppb RMS error).(36) A 3.1 s transient often maximizes sensitivity and improves scan rate, while maintaining sufficient resolving power to separate the 1.1 mDa mass split out to ?m/z 700. In this study we expected to observe species with molecular weights as great as ?1000 Da, so we chose a 4.5 s transient to maintain resolution of the 1.1 mDa mass split. All spectra were phase-corrected for a mass resolving power of ?2500000 at m/z 400

Resolution envy is a terrible vice.

This mass resolution is basically an order of magnitude greater than the very best common commercial instruments.

Some pictures from the text:

The caption:

Figure 1. GPC total ion chromatogram (TIC) from (+)APPI 21 T FT-ICR mass spectral analysis of the PetroPhase 2017 asphaltenes plotted in black on the primary axis. Sulfur (blue) and vanadium (red) GPC ICP-MS chromatograms are plotted on the secondary axis on the right.

The caption:

Figure 2. GPC TIC (black) and extracted ion chromatogram (XIC) for the N4O151V1 heteroatom class (blue) from the (+)APPI mass spectral analysis of purified Athabasca Bitumen asphaltenes plotted on the left axes. The vanadium (red) GPC ICP-MS chromatogram is plotted on the secondary axis on the right.

TIC is "total ion current" a measure of the number of ions being recorded in a unit of elution time. The N4 focus is particularly important to represent porphyrins, which are macrocyclic rings with 4 internal rings, each of which contains one nitrogen.

More N4 related stuff:

The caption:

Figure 3. XIC and (+)APPI derived isoabundance color-contoured plots of double-bond equivalents (DBE) vs carbon number shown in order of elution from left to right for the N4O151V1 heteroatom class (top) from the analysis of the PetroPhase 2017 asphaltenes. The inverted chromatogram shows the XIC’s average H/C ratio (bottom).

Some data on the presence of sulfur, and an unexpected finding with respect to ?–? stacking:

The caption:

Figure 4. GPC FT-ICR MS extracted ion chromatograms for the hydrocarbon and sulfur heteroatom classes (center). Positive APPI-derived isoabundance contour plots of DBE vs carbon number for the HC class (top), S1 class (middle), and S2 class (bottom) with short retention times (left) and long retention times (right). As aggregation decreases, the compositional range for each class moves from more aliphatic species on the left toward condensed polycyclic aromatics on the right.

Some more along these lines:

The caption:

Figure 5. Extracted ion chromatograms and plots of DBE vs carbon number shown in order of elution from left to right for the N1O2S1 (top) and N1O2S2 (bottom) heteroatom classes from the PetroPhase 2017 asphaltenes. As aggregation decreases, the compositional range shifts toward more condensed aromatics in the high DBE range, and the abundance of lower DBE species increases, possibly indicating a shift in structural motifs (i.e., from thiophenic to sulfidic sulfur).

The caption:

Figure 6. Extracted ion chromatograms and plots of DBE vs carbon number shown in order of elution from left to right for the O1S1 (top) and O1S2 (bottom) heteroatom classes from the PetroPhase 2017 asphaltenes.

The caption:

Figure 7. Extracted ion chromatograms and plots of DBE vs carbon number shown in order of elution from left to right for the O1S1 (top) and O2S1 (bottom) heteroatom classes from the PetroPhase 2017 asphaltenes.

Some commentary from the paper in connection with figure 8:

The first major advantage with online detection is the ability to track compositional changes for heteroatom classes not observable by direct infusion, making it well suited for analysis of samples with low ionization efficiencies. The second major advantage is the increased chromatographic resolution afforded by online detection. For the N1O1S1 and N1O1S2 heteroatom classes shown in Figure 8, we observe the same global trends as previously discussed. The XICs for the N1O1S1 (black) and N1O1S2 (red) heteroatom exhibit a bimodal distribution with a smaller, narrow peak eluting near the total exclusion limit from ?25–30 min and a second, broader, later-eluting hump from ?34–55 min. The isoabundance-contoured plots of DBE vs carbon number on the top correspond to the N1O1S1 class, whereas those on the bottom correspond to the N1O1S2 heteroatom class. The plots of DBE vs carbon number directly above and below the XICs show the composition of large elution periods of ?7 min. The longer elution periods reveal the same global trends discussed previously at length. If we were able to successfully track compositional changes for those heteroatom classes by direct infusion (which we were not able to do), we would expect to observe similar global trends. The most aliphatic species elute earliest in the largest aggregates, and aromaticity increases as aggregation lessens at longer elution times.

This suggests that the bigger asphaltenes are not actually graphene like fragments.

Figure 8:

The caption:

Figure 8. Extracted ion chromatograms and plots of DBE vs carbon number for the PetroPhase 2017 asphaltenes shown in order of elution from left to right for the N1O1S1 (top) and N1O1S2 (bottom) heteroatom classes. The composition for the most aggregated species exhibits a bimodal distribution. Online detection enables the small overlaid plots to show three discrete segments of that region. The shorter time windows reveal that the first species to elute are actually more aromatic, with DBE ? 20–25. Those species are followed closely by more alkylated compounds in much higher relative abundance.

The caption:

Figure 9. Extracted ion chromatograms and plots of DBE vs carbon number for the PetroPhase 2017 asphaltenes shown in order of elution from left to right for the N1 (top) and N2 (bottom) heteroatom classes.

The caption:

Figure 10. Extracted ion chromatograms and plots of DBE vs carbon number for the PetroPhase 2017 asphaltenes shown in order of elution from left to right for the N1O1 (top) and N1O2 (bottom) heteroatom classes.

The following is the cartoon from the abstract page that kind of "rubs it in" about the incredible mass resolution observed with this instrument.

The overall conclusion from this two part work:

GPC coupled with online detection successfully overcomes the challenges associated with fraction collection and analysis by direct infusion and reveals that for all heteroatom classes in the PetroPhase 2017 asphaltene sample aggregate size and aromaticity are inversely correlated. The largest aggregate region is composed of the most alkylated species, and the composition shifts toward more aromatic compounds as aggregation decreases. In addition to the ability to characterize samples with extremely low ionization efficiencies, online coupling improves the chromatographic resolution, which enables a closer examination of the most aggregated region. Smaller time segments revealed a local trend in the largest aggregates that opposed the global trend. The very first species to elute in the largest aggregates are actually more aromatic, and more alkylated compounds eluted shortly thereafter in greater relative abundance. Even disregarding the limitations associated with fraction collection and direct infusion, it would be difficult (and certainly impractical) to collect a sufficient number of fractions with short enough time intervals to reveal this local trend in the largest aggregates.

Sigh...

I have to admit that as much as I hate dangerous fuels and want them banned as quickly as is humanly and humanely possible, I certainly took pleasure in reading this paper about a problem in the dangerous fossil fuel industry, and, in any case, as noted in the turgid and highly esoteric text above, I see asphaltenes as a potential means to sequester carbon dioxide removed from the air via biomass.

It is important to note that this very powerful instrument can do many incredible things other than to address problems in the dangerous fossil fuel industry. The National High Magnetic Field Laboratory can serve to solve many intractable biological problems, in particular those associated with human disease, as well as addressing many severe environmental problems.

In these times of public insanity, it is wonderful to take a break and recognize that great scientific tools still exist and have yet to be wrecked along with our Constitution and our Country.

Have a nice evening.

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