June 04, 2020, 02:03:29 AM
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Topic: Produce a low-freezing rocket fuel  (Read 22127 times)

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Offline Enthalpy

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Re: Produce a low-freezing rocket fuel
« Reply #45 on: April 15, 2019, 11:09:27 AM »
The usual process to separate H2 from CO, N2 and others after partial oxidation seems to be pressure swing adsorption (PSA). Looks simple and efficient. It can separate CO from N2 too, or maybe it's better to remove N2 from O2 prior to partial oxidation.

I've not found how quickly Ocotea caparrapi grows. Just "large tree (25m)" or "20m de altura". "Humid area surrounding the town of Caparrapi" suggests a fast growth under the equator.
https://es.wikipedia.org/wiki/Ocotea_caparrapi
https://www.academia.edu/15574491/Bandoni_LOS_RECURSOS_VEGETALES_AROM%C3%81TICOS_EN_LATINOAM%C3%89RICA_
https://pubs.acs.org/doi/pdf/10.1021/np960012r

Offline Enthalpy

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Re: Produce a low-freezing rocket fuel
« Reply #46 on: May 30, 2019, 06:44:56 PM »
Turpentine and other paper by-products make decent fuels, possibly separated as beta-pinene, alpha-pinene, carene, optionally saturated. But their big ring brings no or little heat of formation, loses two hydrogen atoms, and makes a stiffer molecule more prone to freeze. Due to C10, the flash point could be higher.

Maybe metathesis affords better molecules. Ethylene would make a C12, uneasily flammable. The flexible, open and very unsymmetric backbone should be harder to freeze. As is, it might be a (component of) jet fuel, or a Diesel fuel since the C3 chain eases autoignition. After saturation with hydrogen, it could be a rocket fuel, not magic but easily produced.

Beta-pinene, which has other uses, wouldn't fit as its double bond isn't in the ring. Carene I suppose neither because its big ring is unstrained. But alpha-pinene, otherwise little useful, has a double bond in its strained ring, which should help the metathesis.

The product has one very accessible double bond and may readily dimerize. I hope the strain in alpha-pinene lets the useful reaction outpace the unwanted one.

Comments please?
Marc Schaefer, aka Enthalpy

Offline Enthalpy

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Re: Produce a low-freezing rocket fuel
« Reply #47 on: June 02, 2019, 06:30:39 PM »
It goes without saying, but maybe better if I say it: longer alkenes can react with alpha-pinene to produce bigger molecules.

Symmetric alkenes like 2-butene would remain identical if reacting among themselves, but I suppose the double bond of alpha-pinene is too crowded for them.

Longer straight 1-alkenes (cheap propene, butene...) would increase the boiling and flash points of the product and ease its autoignition, while branched ones make autoignition harder if any useful. In a jet engine, a broader spectrum of boiling points stabilizes the flame, while in a Diesel engine, more uniform properties reduce sooting. This holds for metathesis products alone (synthetic fuels are a known solution to Diesel sooting), which can already be a mix, and holds also for mixes with biofuels or fossil fuels.

The longer metathesis products, having no fully exposed double bond, should be less prone to further metathesis.

Saturating the double bonds would improve the energy per mass unit of a jet fuel. If the alkene is obtained from methane of from C3 and C4 fractions, hydrogen is available.

Offline Enthalpy

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Re: Produce a low-freezing rocket fuel
« Reply #48 on: January 22, 2020, 07:02:14 AM »
More about uses at wind music instruments.

Most woodwinds assemble several joints with corks for airtightness. The corks are greased to glide and be more airtight. Here in rich Europe, I got 15g of cork grease for 5€ at the store, and over the Web, shipping makes the same sum. That's 300€/kg at retail for a petrol derivate, wow. The grease isn't as refined as are some paraffins. It stinks, and the manufacturer adds a strong smell to conceal it. Yamaha produces already a synthetic grease that sells for twice as much. Room for profit!

Light oil lubricates the keyworks of woodwinds. It's standard mechanical oil from what I've seen, and it dries in months, while professionals let overhaul their instrument every second year, amateurs less often, and sometimes an instrument idles for decades but shouldn't corrode. Slower evaporation would bring much, as a corrosion protection and as a lubricant. But the temperature range is tiny, the contact pressure and the shear number too, so true lubricating oils are not needed. Many compounds could beat mechanical oils here, maybe squalane (used in cosmetics) or a longer version of farnesane.

Marc Schaefer, aka Enthalpy

Offline Enthalpy

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Re: Produce a low-freezing rocket fuel
« Reply #49 on: January 26, 2020, 05:51:05 PM »
No exotic synthetic molecules mandatory as grease and oil for wind instruments: triglycerides should suffice. They are cheap, and their bigger molecules evaporate slower than squalane.

Tallow served for centuries as an excellent cork grease, but its ill-defined animal origin has drawbacks for Jews, Hindus, Muslims, vegans and the many people who find it disgusting. It may also stink and deteriorate at air. Similar palm oil (a solid) improves much. As sold for cooking, it's already refined, bleached and deodorized
https://en.wikipedia.org/wiki/Palm_oil
Further treatment can stabilize its properties for a long time: hydrogenation, fractionation... It's done for industrial pastry. Heating once in a pan at the user's home, possibly under limited air,  would remove humidity and volatiles.

Palm kernel oil is generally liquid despite being strongly saturated, thanks to its shorter fatty acids
https://en.wikipedia.org/wiki/Palm_kernel_oil
and while other cooking oils serve as lubricants, at chainsaws for instance, palm kernel oil is reportedly stable over longer time. Here too, products reaching rich consumers are already well processed, but further simple treatments like hydrogenation and fractionation would make a long-lived keyworks lubricant. Removing free acids and C4 acids seems important.

Make simple treatments on palm oil, sell for 300€/kg, that sounds good.
Marc Schaefer, aka Enthalpy

Offline Enthalpy

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Re: Produce a low-freezing rocket fuel
« Reply #50 on: January 30, 2020, 06:42:46 PM »
I've bought for 1.5€ 1kg of allegedly edible palm oil, and as a lubricating grease it's fabulous for music instruments, extremely effective. Tallow must have been that good.

Zero odour, vegan, no known allergies, should fit many faiths. Share the 150 cents among 60 musicians if you wish. One year indicative shelf life is fine for cork grease that we replenish more often.

Any reason to improve the grease before repackaging it in 15g units and selling each for 5€? Time will tell if it smells unpleasantly after years. And while this palm+canola solid mix is easily rubbed on corks, musicians are used to softer pastes. So maybe palm oil and a lighter triglyceride like palm kernel oil could be hydrogenated, fractionated, then mixed or interesterified, de-acidified and well dried, for use at varied temperatures and for very long service.

Marc Schaefer, aka Enthalpy

Offline Enthalpy

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Re: Produce a low-freezing rocket fuel
« Reply #51 on: March 01, 2020, 03:40:36 PM »
Depending the alkyls, the trialkylamines of February 18, 2020 can have varied uses.
https://www.chemicalforums.com/index.php?topic=103039.msg362089#msg362089

It may not be as hydrophobic as hydrocarbons. I ignore if its combustion produces more NOx than a hydrocarbon. Slightly more efficient than an alkane, and if burnt with air, the engine power increases a bit but the consumption too. Mass-poduction is easy and efficient, the product is accurate.

From propene and n-butene, C+N~11.5 make a good rocket fuel and a jet fuel probably, with a good liquid range, flash point and self-ignition. Presently the C3-C4 fraction is torched at gas and oil wells, so using it as a fuel would reduce the CO2 emissions. The complete fraction could be fed to the reactor, the alkenes would react, the alkanes at the output easily separated and pyrolysed to reinject alkenes.

Gas and oil wells have no chemical processing presently. Using this fraction would need an ammonia and hydroamination unit at the well, or on a boat that collects the stored fraction, or onshore, or to transport the fraction overseas which isn't done up to now as butane is too cheap. Refineries have already an ammonia and hydroamination unit, propene is available but it serves, butene can be obtained from ethylene.

Ethylene and propene would target gasoline's molar mass but not the octane number. Isobutene might achieve a good octane number (or not, due to the amine) but with C+N=13, the upper end for gasoline. Maybe ethylene and isobutene achieve both. Alkylation is a cheap competitor.

n-alkenes around hexene would make a synthetic Diesel fuel emitting no fine particles hopefully, thanks to uniform autoignition temperature, lack of aromatics, high H/C ratio, and clean amine flame. Hexene is typically obtained from ethylene at refineries, so the fuel needs more processing than presently.

Marc Schaefer, aka Enthalpy

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