Monthly Archives: August 2022

Simple PFAS Destruction Process Disclosed

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An article titled Low-temperature mineralization of perfluorocarboxylic acids, Dichtel and Houk, et al., Science, 18 August 2022, Vol 377, Issue 6608, pp. 839-845, DOI: 10.1126/science.abm8868, came out yesterday with a method for defluorination and chain scission of per- and polyfluoroalkyl substances (PFAS). Blessedly, the article is available without charge.

The article describes the mineralization of reactive perfluorocarboxylic anions with NaOH in water and dimethylsulfoxide, DMSO, at 80 to 120 C and ambient pressure.

Ok. If the prefixes “per” and “poly” are unknown to you, read below, otherwise skip ahead.

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First, some clarification of the name “PFAS” for you non-chemists out there. The “P” in PFAS stands for either prefix “poly” or “per”. Both prefixes appear in common use. The prefix “per” is used to abbreviate the name when some atom or fragment is attached at every possible alkyl (see below) carbon connection point in a molecule or specified fragment of the molecule. The much lengthier proper name would have a number of the position of each separate fluorine atom on the molecule. “Per” and “poly” saves everyone from having to trip over a great many tongue-twisting syllables.

Hydrocarbons consist of only hydrogen atoms on a carbon skeleton. Hydrocarbon carbon atoms can have 0 to 3 hydrogen atoms attached to each skeleton atom. The exception would be methane, CH4, which has 4 hydrogen atoms attached. “Alkyl” refers to a subclass of hydrocarbon fragments or molecules that are absent multiple bonds between atoms of a carbon skeleton. A molecule with a carbon skeleton having no multiple bonds between carbon atoms and linked to hydrogen atoms only is called an “alkane”. An alkane fragment that is connected to something else is called an “alkyl” group.

Gasp! So, a perfluoroalkyl molecule or fragment would have 2 or more of its hydrogen atoms replaced with 2 or more fluorine atoms on a given carbon atom (see definition below).

From Wikipedia “According to the Organisation for Economic Co-operation and Development (OECD): “PFASs are defined as fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e. with a few noted exceptions, any chemical with at least a perfluorinated methyl group (–CF3) or a perfluorinated methylene group (–CF2–) is a PFAS.“

The prefix “poly” is much simpler. It is meant to indicate that the word it is attached to has many units of something, as in polyfluoroalkyl, which means many fluorine atoms attached to alkyl carbon atoms. Or it could refer to a string of repeating units as in a polymer.

Outside of the narrow PFAS world, the prefix per in “perfluoroalkyl” would indicate in common usage that the alkyl fragment is completely saturated with fluorine atoms.

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If we were at the bar during happy hour slamming well drinks after a long day of shaking separatory funnels, washing glassware and trying to vacuum distill something useful out of tar, someone might have groused that the PFAS destruction process is simply a process where you heat the piss out of a DMSO/water mixture of NaOH and PFAS to destruction. Ok, the word they used is “mineralization” rather than the more chaotic sounding words “destruction” or “digestion”. Everyone has thermally decomposed a reaction mixture in the past. We would pause for a moment, shrug our shoulders and say “well, of course that works”. DMSO is a highly polar, high-boiling solvent which supports the formation of ionic decomposition products at elevated temperature. Kendall Houk even did some snazzy DFT calculations on decomposition mechanisms. Now, that is how to develop a new approach to decomposition! Get out the big stick of quantum mechanical computing power and swing it around! The rascals Dichtel and Houk worked it out first so we’d raise our glasses and drink in their honor. Here’s to you, boys and girls!

As we stagger out to the Uber for the ride home, somebody mutters “I wonder how far along the patent application is and who will be the assignee?”

Prey

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I watched the latest Predator action movie “Prey” on Hulu recently. The Predator franchise is at it’s core a SciFi-alien-slasher series. While slasher films are not my first choice of entertainment, I do enjoy a good SciFi story. The story takes place in 1719 North American Comanche country. The exact geography is not revealed. The cast is predominantly Native American and there is considerable spoken Comanche. French trappers make an appearance in the story and speak in French.

In the beginning the Predator is dropped off a space ship, by friends I assume, and left to have a grand ole time slaughtering the local wildlife. No camping gear or supplies, just weapons that are strapped on and nasty looking jaws.

A common flaw with stories set in the past or the future is anachronistic language. Vocabulary or contemporary cultural references slipping in from a different time can interfere with the disbelief that you’re trying hard to set aside. For example, the current SciFi series Star Trek: Strange New Worlds, while entertaining, serves as a terrible example of lazy and shameless anachronisms. In Prey I didn’t notice much in the way of this. But, my knowledge of Comanche history and culture is vanishingly small.

If you want more background and details on the movie, I’d recommend the review in Vulture or IMDB. Or, just watch it. Earlier I said that Prey is a slasher film. Yes, there is plenty of slashing in a way that only the Predator can manage. There are white hats and black hats in the story and well as an appealing protagonist. Plenty of conflict to go around. One nasty bear has a particularly bad day. And the trappers? Well you’ll just have to watch it.

New oil refining capacity set for 2023

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Since 2019, the US has lost over 1 million barrels per day of oil refining capacity, according to Energy Intelligence. On top of this, 2023 will see an additional loss of 268,000 barrels per day refining capacity with the closure of the LyondellBasell refinery in Houston, TX. Loss of oil refining capacity translates directly into greater scarcity of fuel distillates, which exerts upward pressure on retail fuel prices.

But, there is good news as well. In 2023 there will be a combined 505,000 barrel per day uptick in refinery capacity according to Energy Intelligence. ExxonMobil will see an increase in capacity at its Beaumont, TX, refinery. Valero Energy will be adding two coker and sulfur recovery trains to increase their heavy sour crude oil throughput to provide a 55,000 barrel per day increase in fuels output at their Port Arthur, TX, plant.

The controversial Limetree Bay refinery in St. Croix in the US Virgin Islands, now owned by West Indies Petroleum Limited and Port Hamilton Refining and Transportation, LLLP, is scheduled to reopen, but information is scarce. Formerly the Hovensa facility, a joint venture of Hess Corp. and Petroleos de Venezuela SA, this refinery processed Libyan and Venezuelan crude and has supplied much of the US gulf coast. According to Energy Intelligence, the refinery is thought to be able to restart and produce 200,000 barrels per day. However, the former Hovensa facility has a recent history of losses, Clean Air Act violations and a bankruptcy sale. It doesn’t sound like the situation has fully played out yet.

Yellow Gold and Black Gold in the Ground

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Some years back I visited the large CC&V open pit gold mine by Cripple Creek, Colorado. Standing at the bottom of the pit we could see haul trucks busily transferring ore to a staging site. Suspecting that it might be overburden, I asked what they were doing. Our guide, a geologist, said that this ore would be staged as unrefined until the price of gold rose to a certain higher value. The whole ore body had been mapped 3-dimensionally so at any given location and level where they blast, they have a rough idea of how much gold is present. At the time, ~10 years back, the geologist said that each large haul truck was typically carrying about $10,000 worth of gold. I don’t know how accurate that is, but there you have it.

The Cripple Creek gold load was discovered about 1893 and occurs in the throat of an extinct volcano. The ore contains gold and calaverite, AuTe2, a gold telluride mineral. The gold and AuTe2 is so finely dispersed that most people who work at the mine have never actually seen the gold. The recovery method they use is cyanide extraction. Unfortunately, tellurium interferes with this extraction process and unavoidably some of the gold as the telluride is left in the tailings. The ore is said to contain about 1 gram of recoverable gold per ton.

What prompted this essay was a moment of clarity I had reading a notice from the Energy Information Administration, EIA. It is common to hear about oil reserves. One might suppose that this refers to the total proven reserves in the ground. But this article referred to “economically recoverable oil resources”. When oil reserves are expressed in this way, the recoverable oil then becomes a function of the current oil prices. If oil prices are low, then the reserves are considered smaller than when oil prices are high. It seems so obvious but I never gave it a thought before. As with gold, the lesson is to pay attention to the type of reserves being discussed.

Top Gun: Maverick

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History. I’m preparing myself for the upcoming May 27th release of Top Gun: Maverick. To be blunt, I’m still disappointed by the first movie which was released in 1986, so I’m bracing to be disappointed again. Make no mistake, I am an aviation enthusiast and I did really enjoy the flying action scenes with the F-14’s in the first movie. The flying shots were well thought out and captured on film. So, what’s not to like? Well … the rest of the story. The content that is left over when you take out the aircraft and the flying. Roger Ebert of the Chicago Sun-Times said it best, “”Movies like Top Gun are hard to review because the good parts are so good and the bad parts are so relentless.”

Current. On to the recent release, Top Gun: Maverick. As before the flying sequences were quite good. But again it was against the backdrop of, well, a dumb story. As before the story is written to feature studly macho bravado against the lone-wolf instinct on the part of Maverick. The strenuously independent behavior of Maverick flies in the face of military discipline and is where I part company with the story.

The old timer, Maverick, is finally brought in to lead a group of Top Gun fighter jocks to bomb a highly defended hard target in what looks like a deep crater with impossibly steep walls. Among the best of the best, Maverick is regarded by old timers to be the very best despite his undisciplined ways. Of course, the new generation of fighter pilots are skeptical.

A lot happens … yada, yada, … love interest … yada, yada … guilt trip …. etc, etc … steal a fighter from the enemy … resolve to overcome adversity one more time … zip, zing, zowie … triumph!!

A movie is entertainment that requires you to set aside disbelief. Very often I can do it. But this time I couldn’t.

Cracker Barrel vs Cry Babies

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I have nothing constructive to add here, but it’s just too funny to leave alone. A scandal has hit the news. Cracker Barrel has announced they are offering a new plant-based sausage on their menu. It has resulted in an flood of outrage on the interwebs. Here in the land of the free and the home of the brave, indignant customers are venting their outrage over an optional menu item as a menacing sign of what is to come.

The US Navy may be adding it to their menu, sparking righteous indignation from our very own pistol packin’ Rep. Lauren Boebert (R-CO). It was proposed for the 2023 defense budget. Boebert cried out that it is “liberal woke garbage”. It’s a new food choice for our sailors, Lauren. You are crying wolf again.

According to a source that I don’t trust and never quote, the New York Post, Tejas Rep. Chip Roy (R-TX) voted against it in 2021. In a Twitter thread, he exclaimed

“A woke military that drafts our daughters, wastes resources on Green New Deal garbage, holds no one accountable for Afghanistan disaster, and prioritizes playing leftist politics over destroying our enemies,” he wrote in the thread. “Rep. Roy voted no.”

Oh! The horror of it! A vegan meat substitute is an example of wokeness, they rage. To be woke is to be aware of social injustice and to tolerate the choices of other people. But to the lunatic fringe, it is a crime against MAGA land.

It will be interesting to see what the restaurant does about this, if anything. It is an amusing tempest in a teapot.

LyondellBasell to Produce Pyrolysis Oils from Plastic

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According to Reuters, LyondellBasell is considering converting it’s Houston refinery to the production of pyrolysis oils. The Houston crude oil refinery is scheduled to close at the end of 2023. The new operation would recycle plastic waste by pyrolysis and convert it to a stream of hydrocarbons referred to as pyrolysis oil. The company announced that hydrotreaters on the current plant site could be used to upgrade the pyrolysis oil. ICIS reports that they will use a selective catalyst in the process to produce a pyrolysis oil that is said to be similar to naphtha.

ICIS reports that the pyrolysis oil could be transferred to a nearby Channelview cracker by pipeline to crack the pyrolysis oils into a into undisclosed products.

LyondellBasell announced in May of 2021 from Wesseling, Germany, that it has been making steps toward a circular economy by converting polymer waste to virgin quality polymer. It was reported that they intend to produce ethylene and propylene monomer from their process. Virgin quality polymer would open the food contact market to the product. Details are limited.

Polymer waste contains a good deal of potential energy locked in the hydrocarbon chains. Conversion to liquid fuels would represent a type of energy recovery. I have not seen thermodynamic calculations revealing the energy efficiency in converting polymer waste to fuel.

Most synthetic organic polymers are substantially hydrocarbon in composition and can be thermally depolymerized or otherwise cracked to produce valuable liquid chemical feedstocks. Some companies are now realizing the value locked into polymer waste.

LyondellBasell has pledged to reduce CO2 emissions 15 % per ton of product worldwide.