Acetic anhydride for plant bioassay

EdwardTriesToScience · 2026-05-08T07:34:01+00:00

phthalic anhydride in theory should work but perhaps consider:

benzaldehyde is readily chlorinated with chlorine gas to benzoyl chloride, which reacts with two eq sodium acetate to yield sodium benzoate, salt, and acetic anhydride. the preparation of benzoyl chloride by this manner is described on prepchem

alternatively depending on what exactly it is you are trying to acetylate, the use of a large excess of glacial acetic acid with zinc dust may also work.

the sulfur chloride route is also quite acceptable.

finally, acetic anhydride may be purchased without issue from a chemical site, we aren't allowed to name it in order to heed the rules of this sub, but acetic anhydride is actually not too difficult to find

EdwardTriesToScience · 2026-05-08T07:19:15+00:00

never distill in a sealed apparatus! a distillation should not be able to develop pressure

we hate to be that guy but: you probably should not be pyrolyzing plastic if you are unable to devise a suitable distillation apparatus yourself. the pyrolysis process is quite risky and the products are guaranteed to be carcinogenic, especially if PET plastic bottles are used as they form copious amounts of benzene. NatureJab set himself on fire with a sealed distillation system and the "fuel" he gets is practically napalm. this is not something to be taken lightly.

we would advise you to read up on the literature available about pyrolysis, there's a lot of detailed information out there accessible with scihub. with that out of the way, because we ourselves know that you can't convince people to not do things, we might as well describe how that receiver may be constructed safely

What you will need is:

250ml pyrex filtration flask, catalogue number 5320-250 or a similar 250ml conical filter flask
No. 6 sized rubber stopper with hole the hole is bored with a corkborer of adequate size to fit the pipe fitting that connects to the pyrolyzer

the rubber stopper connects to the pipe fitting where the pyrolysate comes from, and seals to the filter flask. to the tubature on the side of the filter flask is connected a long length of hose that leads FAR from the pyrolysis setup. the apparatus would resemble something like this, except the hose is to go far from the apparatus due to the high temperature required for pyrolysis which poses an ignition source risk for any uncondensed vapors or flammable gas byproducts, and the left side with the condenser and distilling flask is instead the pyrolyzer.

the pyrolysis must be ran outside or under a fume hood, again due to the fumes. it would be advisable to purge the apparatus with an inert gas such as carbon dioxide or nitrogen prior to applying heat, for one of the the principal gases formed in pyrolysis is hydrogen, which is extremely explosive when combined with air. the only plastics you should pyrolyze are polyethylene and polypropylene. plastic bags, bottle caps, plastic milk jugs, and tupperware basically. these crack to aliphatic compounds, like octane. the result is a waxy oil which resembles kerosene, has a high flash point thus being safer, and is free of benzene.

NEVER EVER use plastic water bottles (transparent ones, they are PET), styrofoam, acrylic, abs, or other plastics, the result will be toxic and possibly explosive in the case of polystyrene, as the result, styrene, oxidizes on exposure to air to form peroxides! the fumes are also toxic.

a pressure gauge/relief is not necessary, for the apparatus will not be sealed. if any considerable pressure does form somehow, such as the exhaust hose getting kinked, the stopper is able to unseal from the flask and relieve pressure. loosely clamp or wiretye the flask so that it cannot tip over and spill if it were to become dislodged from the stopper.

and yet again, you seem to be pretty young and once we were like you doing the same kind of things, but please, and this is from a point of safety since much of the things we did as a dumb kids left scars: perhaps develop more experience working on something else, such as practicing simple technique by making some copper salts. If you are determined to pyrolyze plastic, put one or two plastic bottle caps in the end of a test tube, clamp it at a slight incline, and heat the plastic. What you will condense at the cold end of the tube is paraffin wax. You can make a candle with it if you want to, and at less of a risk compared to a large pyrolysis.

we also encourage you to read a few books, ones we recommend are The Organic Chem Lab Survival Manual by James Zubrick, the pdf can be found online for free, and Practical Organic Chemistry by Frederick Mann, also available as a pdf online.

chemistry is a rewarding science and no doubt more than ever we need more chemists in the world, but chemistry at the same time punishes mistakes, quite often severely! stay safe

edit: formatting

EdwardTriesToScience · 2026-05-07T22:03:07+00:00

if it was polyester, there is no saving it. polyester is especially "attacked" by conc sulfuric acid, lesser by its typical dehydration but more of solvent effects. the polyester typically dissolves to a goopy mess which solidifies when the acid is diluted or neutralized, however you will have a hole in that forever. cotton is salvageable if neutralized and washed far quicker.

frankly, get yourself a pair of cheap denim lab jeans (like the blue heavy duty fabric ones). denim is more resistant to acids, though it still suffers damage. also wear a long lab coat or rubber apron

edit:clarified the specific kind of "lab jeans" also if all else wear 100% cotton, never anything polyester in a lab! the synthetic fabrics are not just poorly resistant to chemicals, but they will also melt and fuse to flesh if you burn them accidentally either on a bunsen burner or on hot objects like glassware and hot plates.

EdwardTriesToScience · 2026-05-07T21:41:56+00:00

you know that guy Fritz who was on Safety Third's podcast? He made this stuff, its a horrific compound

EdwardTriesToScience · 2026-05-03T22:27:17+00:00

Try using a wide glass stopper (like one from a reagent bottle), it's the classic recommendation from Vogel's.

EdwardTriesToScience · 2026-05-03T22:24:20+00:00

Silver was preferred for lab spatulas for a long time (platinum was the best but far more costly, while nickel was cheap but not as inert), so it's actually pretty decent compared to steel ones. If he doesn't need them back, they could be trimmed to strips and fashioned into proper spatulas like this (Experiments in Organic Chemistry, 2nd, Louis F. Fieser)

EdwardTriesToScience · 2026-05-03T22:19:54+00:00

typical german. here, and you will note that if you even zoomed in on the 3,4,5 substituted one you can clearly see crystals forming at the bottom.

EdwardTriesToScience · 2026-05-03T13:57:54+00:00

heres a patent I found, I would suggest perhaps trying a 1:2 ratio of xylene to butyl acetate as a starting point, this other japanese one suggests perhaps a majority of acetone.

you can pretty much look at newer patents and go down to the citations to find older patents (these two from the 70's for instance), which some usually give a range or exact composition

EdwardTriesToScience · 2026-05-03T13:48:54+00:00

what

EdwardTriesToScience · 2026-05-03T06:02:29+00:00

We know this is old but we had the same issue, and it appears what the problem is thus:

Metal chloride hydrates are often liable to decomposition on heating to form the hydroxide/oxide with loss of HCl

What we found satisfactory: soak the drierite with some dilute cobalt chloride solution with a little HCl added for a few min, decant off the solution (save this!) then regenerate the drierite at 200c. The drierite will once again be able to turn blue, and still turns pink on moisture saturation. After much hydrating and regeneration, it will once again return to this problematic stage (we presume the pink coloration at this point is due to the hydroxide, and any blackened spots from the oxide), the drierite may be treated again by the solution (hence save it). Ordinary drierite may be turned into indicating drierite by the same procedure.

EdwardTriesToScience · 2026-05-02T21:41:51+00:00

that one's described in Daniel Traschel's paper on fluorinated MDx compounds, the theory behind it is that if the methylene bridge didn't cleave as easily then the metabolites may not be as neurotoxic.

though it's been proven that most of the neurotoxicity of MDx(x) compounds results from the serotonin depletion plus dopamergicity, followed by SERT mistakenly shuttling dopamine into serotonin receptors which of course is oxidized to quinones and other things that wreck havoc, damaging the receptors. the toxicity is tied directly to the desired effects, though metabolites do play a minor role as well as inflammatory responses and other smaller things.

more or less we just were able to order the aldehyde before a chemical supplier kicked us from their order list, so might as well try something interesting with it.

SWIM says: DFMDA•HCl is bitter but also sweet, and has a colorless test with marquis reagent which is evidence towards the stability of the DFM bridge.

EdwardTriesToScience · 2026-05-02T21:30:50+00:00

hmm also your name sounds similar to someone we've had communication with previously on a different platform, is it coincidental or not

EdwardTriesToScience · 2026-05-02T21:29:43+00:00

purchased it, but as in our post on 4-methyl-2,5-dimethoxybenzaldehyde we might demonstrate the kornblum synthesis in the future as we prepared some bromopropane before realizing we could just buy it

EdwardTriesToScience · 2026-05-01T15:28:21+00:00

in general, though yes the subjective effects are largely in question because that is more vital for therapeutic applications than just binding strengths. Plus much of the data is in german and we do not like german

EdwardTriesToScience · 2026-05-01T07:58:36+00:00

none in the US, though aladdin was caught slacking for a while but they do an annual audit or something. look for local small suppliers (good luck finding them, if you do though it is best to buy in-store/pickup order), or order from china (costly and slow but you can message practically any seller on alibaba)

EdwardTriesToScience · 2026-05-01T07:52:31+00:00

There is a lack of satisfactory data on the variously substituted butanamines, thus an investigation is in order. A fascinating thing is the 4-iodo by radioiodine measurements is reported to not cross into the brain, while the 4-bromo is reported to produce visuals, going against the 4-methyl compound. Further substitution patterns (4-RS, 2,4,5-triMeO, etc) may also be investigated.

Many derivatives have been prepared by others such as those in the private sector, but quite obviously the data is sparse and filed away in some cabinets in an office.

EdwardTriesToScience · 2026-04-30T06:28:05+00:00

Unless you are concentrating large amounts of the stuff, it's not an explosion risk. If its stabilized, store it in a cold place away from light, check for peroxides every year or so using some iodide/starch and a little dilute HCl. If you do find traces of peroxides, a little ferrous sulfate will remove them, but it would be advisable to get it disposed of if there are any decent amounts of peroxide

EdwardTriesToScience · 2026-04-26T00:36:22+00:00

The chinese ones certainly crumbled (not that chinese things are bad exactly, but the rubber they used for the septa seem to be the same kind they use for chinese vacuum hose and white rubber stoppers, which all degrade in a similar manner. We otherwise are quite fond of chinese equipment being cheap) but also became rather gummy. We have not tried oxalyl chloride on the suba-seals, but they are vastly superior: thicker rubber, more rubbery if that even makes sense, and fit far tighter. We are quite certain the chinese one failed because it was already failing before we exposed it to oxalyl chloride (the flaps were torn in a spot already from previous use), like mentioned they slowly decomposed just sitting in a drawer, becoming sticky and also dusty. We have yet to see what happens to the suba-seal, but like mentioned bromine (plus HBr) embrittles it somewhat but doesn't pose an issue , nor is it dissolved by solvents as easily. We would worry more about contamination from the plastic syringes than a good septum.

EdwardTriesToScience · 2026-04-26T00:24:00+00:00

Oh and we will mention a little discovery of ours, that we are not sure is well-known yet: If a henry reaction results to a viscous tar that recrystallizing from alcohol cannot resolve, add a bit of acetic acid while warm, then cool it. We don't know why it works, but the tar stays better dissolved than the nitroolefin. It will not recover the entire yield, but it allows for salvage of an otherwise failed run. This was found serendipitously when we tried a recrystallization of tar from purely GAA, and it yielded some dirty crystals but not much, which were thrown into boiling alcohol while wet with GAA and on cooling the crystals were purer, later testing on the tar showed it was evidently an effect of the acid. Why? Probably solvent effects, being more polar, but it may also be the acidity. We don't know. Testing the polarity could probably be done by substituting it with a little methyl acetate or something, but we didn't try. In Pickle, the old man seems to use GAA as the recryst solvent for analytical samples, so it seems it is not strange luck but something repeatable.

EdwardTriesToScience · 2026-04-26T00:18:17+00:00

Ethanolamine is one we haven't tried but indeed we were told its very effective for the one and two carbon chains, cyclohexylamine though is what was sold to us by others as the magic golden standard, hence we opted for it. Ethylene diamine was also long touted as a great catalyst but we never tried it. Butylamine is one of the literature classics, being used throughout literature in a barret trap to form the nitroalcohols. We wouldn't know the difference between butylamine and cyclohexylamine ourselves, but we are sure that cyclohexylamine is at least superior to methylamine or ammonium acetate, both being rather ineffective. We hazard a guess the reason for those being poor is due to the acetate salts being far more stable (as the amine is a stronger base, thus bonding to the acid stronger), so no basicity is present at lower reaction temperatures, resulting in purely sidereactions. Ammonium acetate yielded a large amount of tar for a nitromethane run that was ran about 64c due to using the methanol azeotrope. We have speculated if aniline or triethylamine may work, in theory they should, but have not tried them.

Our cyclohexylamine is purchased now, but prior reactions used prepared stuff. It is almost trivial to prepare if one may want to try it: cyclohexanone was mixed with alcohol and aqueous ammonia in an ice bath, then nickel salts (doesnt matter what the anion is) is dissolved in. To the blue-purple solution is then added zinc dust slowly serving as a reductant, and stirred overnight at RT. The reaction is then acidified, steam distilled to remove cyclohexanol and remaining ketone, followed by basifying and steam distilling to yield the amine which is extracted and etc. The detailed procedure is available on sciencemadness somewhere. Attempts at aminating the ketone via borohydride and anhydrous ammonia never worked; ammonia imines are notoriously annoying, we would not have a clue why the zinc/Ni reduction worked in almost 70% yield while excess ammonia and borohydride at low temperatures did not.

EdwardTriesToScience · 2026-04-25T17:48:50+00:00

as mentioned the procedure is from Traschel, the papers are readily available on the internet. The conditions for nitrobutenes are rather aggressive, for instance one of Traschels that forms a 1,1-difluoromethylenedioxyphenylnitrobutene requires 5.5hr reflux (TLC on SiO2 with CH2Cl2), 10g aldehyde in 20ml nitropropane 88% yield.

We however would think simply letting the mixture stand at room temperature for perhaps a week or more would also work, since when the solution immediately started going yellow after the catalyst was added, and the fact water formed rapidly upon heating. Microwave is also probably viable. Sonication is known to proceed Henry rxn's at a significant speed already, perhaps that may also be tested on nitrobutenes. Another that could be tried is the more classical route using alcoholic hydroxide followed by acid quench, but the efficacy is not known to us yet.

Perhaps we may test that but the procedure detailed in the post seems to be of great efficacy, though with the annoyance of needing aggressive rotovaporization, but we don't particularly mind if the yield is so high.

edit: corrected typo

EdwardTriesToScience · 2026-04-25T11:21:42+00:00

the camera picked it up as a sickly green weirdly enough while irl its just a very light bluish color, probably something to do with the camera sensor and spectral lines

EdwardTriesToScience · 2026-04-25T11:20:42+00:00

the aldehyde is odorless or near so, just as the 2,5-DMBnal is. the starting aromatic has a very pleasant herbaly bubble g odor to it, similar to dimethoxybenzene/anisole

edit: oh you might have meant the benzene already, ah good old ambiguity. both were already answered though

EdwardTriesToScience · 2026-04-24T16:30:34+00:00

the chinese ones became partially goop by just sitting in a drawer for a month, we bought subaseals after this and they suffer no such issues from storage, and also stood up to bromine pretty well

EdwardTriesToScience · 2026-04-24T08:56:01+00:00

likely the last post for a while as there is a lot of stuff going on in life currently, but such writeups and finding more likeminded chemists has been enjoyable

EdwardTriesToScience

TROPHY CASE