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JacobM
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[*] posted on 8-1-2022 at 18:54


Yeah, I'll get that.

One more thing: can dilute (50-80%) H2SO4 be used to form butyl bromide from butanol?

I'm actually still only pretty young, but I have lots of chemicals and safety gear at my disposal. I also am on good terms with a university professor who I can contact for things like this. Trouble is, they take a long time to reply which doesn't surprise me and their replies usually focus on chemistry from papers that's probably small potatoes to them, but is like moving mountains for me.
I honestly have no intention of making massive amounts of (or any amount of) explosives or toxic gases or anything else that could be considered kewlism and I do take safety as seriously as possible with my conditions. I have a flammable cabinet. I only want to focus on reactions for their educational or novelty value.
For some reason, my mom doesn't want me using toluene or storing lots of concentrated sulfuric acid in bulk. Sulfuric acid is reasonable, but toluene? I don't think toluene is that bad. The cartridges in my respirator are BTX proof.
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[*] posted on 9-1-2022 at 02:04


Just want to add this to the list of reading material: Panten, Johannes; Surburg, Horst (Ed.): Common Fragrance and Flavor Materials. Preparation, Properties and Uses. 6th Ed. Weinheim: Wiley-VCH, 2016. Quite up to date and contains a shit ton of references for synthetic pathways.



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[*] posted on 9-1-2022 at 02:56


Yes, dawt, I also think this book is a good one because there is a good systematic approach. For example, it lists some alcohols having an interesting smell. Like 3-octanol. And now I am thinking about exploring esters of 3-octanol.

[Edited on 9-1-2022 by teodor]
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[*] posted on 9-1-2022 at 13:30


Amos - I bought methyl cinnamate from es-drei.de and the scent was very weak. Is there a way to make it stronger? I just sniffed directly from the bottle. Maybe grounding to very fine powder? Or heat it slightly? (Zimtsäuremethylester (min. 98%) 500g but it is now unavailable from their eshop).
teodor - I made allyl phenoxyacetate and allyl phenylacetate. First one is pineapple-flowers and second one honey. I was lazy to synthesize methyl and ethyl phenylacetates as I was able to buy them, both are honey scents. But too heavy and strong for me, I like the allyl phenylacetate much more. Maybe I should dilute methyl and ethyl phenylacetates. You already sniffed the compound Amos suggested (oxidizing piperine to piperonal) - that tiny vial with ground glass joint with a label Heliotropin, I told you that it is similar to Violet flowers (Viola odorata).
JacobM - acetophenone has very pleasant scent. Also good esters not yet mentioned are methyl anthranilate (grapes) and diethyl malonate (apples) - I tested both. You can also make apple scent fructone from ethyl acetoacetate with ethylene glycol.
Orange oil is very pleasant (D-limonene) and alfa pinene too (monoterpenes).
JacobM - you should react triflouroacetic acid or at least trichloroacetic acid with alfa pinene or d-limonene and then hydrolyze to alfa terpineol.
https://sci-hub.ee/http://dx.doi.org/10.1590/S0100-404220090...




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[*] posted on 9-1-2022 at 13:36


Methyl cinnamate doesn't have much scent as a solid- I find that sprinkling a bit on top of some warm water releases the scent. i think it's strawberry with artificial undertones, but most of my students couldn't actually identify it.



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JacobM
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[*] posted on 9-1-2022 at 14:56


I've read the same reference - but who has CF3CO2H? I don't, and I really don't want to work with it either.
I had a good idea- a first for this forum, and an easy one too. I'm not telling what it is, but look forward to it in the coming weeks.

Edit: I UTFSE'd to verify my claims.

[Edited on 9-1-2022 by JacobM]
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[*] posted on 10-1-2022 at 04:08


DraconicAcid - exactly, I almost did not feel any scent of methyl cinnamate.
JacobM the link I posted uses trichloroacetic acid. Also coumarin is very pleasant, but the reagents are not easy to obtain (salicylaldehyde + acetic anhydride + anhydrous Na acetate). In case of interest use the search engine here on forum to find it.




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[*] posted on 10-1-2022 at 05:50


Quote: Originally posted by Fery  

I was lazy to synthesize methyl and ethyl phenylacetates as I was able to buy them, both are honey scents. But too heavy and strong for me, I like the allyl phenylacetate much more. Maybe I should dilute methyl and ethyl phenylacetates. You already sniffed the compound Amos suggested (oxidizing piperine to piperonal) - that tiny vial with ground glass joint with a label Heliotropin, I told you that it is similar to Violet flowers (Viola odorata).


Even the allyl phenylacetate was too intrusive for me. Piperonal is great, it is one of my most valuable vials now.

I've got some success with the ester of menthol - menthyl acetate. It is a very great scent, also one of the main components of natural peppermint oil. But I used acetyl chloride. I think I will make write-up for the first version of the preparation soon - I didn't manage the vacuum distillation yet, so the preparation is not completed. There is a big difference in the density of vapors during the process compared to distillation under atmospheric pressure, I need to acquire some new skills to finish the process. But the crude ester has already a very delicious scent.
Generally I think terpene alcohols is an interesting field of exploration to an ester-maker.

[Edited on 10-1-2022 by teodor]
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[*] posted on 10-1-2022 at 08:33


Quote: Originally posted by JacobM  

One more thing: can dilute (50-80%) H2SO4 be used to form butyl bromide from butanol?

No form of sulfuric acid is a good way to make alkyl bromides because H2SO4 can oxidize HBr, and even a small amount of Br2 byproduct can make your life very unpleasant.

Keep in mind that volatile alkyl bromides are carcinogenic, and recommended exposure is less than 15 micrograms per day. They might not seem harmful, but if you haven't got appropriate safety equipment (at least one of fume hood/respirator and preferably both), you might want to target other things.

[Edited on 10-1-2022 by clearly_not_atara]




[Edited on 04-20-1969 by clearly_not_atara]
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[*] posted on 10-1-2022 at 08:50


teodor the menthol I gave you is natural, levomenthol, from India, from Mentha arvensis. Maybe also the acetyl ester you prepared is optically pure and the reaction itself or HCl or whatever did not cause racemization?
heliotropin I do not know whether natural or synthetical but it should not have optical isomers so it should not matter
optical isomers are sometimes very important in scents, e.g. I prepared L-carvone from D-limonene with nice minty scent, but its isomer D-carvone has a scent like cumin or caraway




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[*] posted on 10-1-2022 at 11:53


Fery, I didn't know it is natural & optical pure, thank you. I had a plan to collect 3 fractions and compare the smell, I also thought in the case of different optical isomers should be a difference, but I didn't expect much, so it is good to know that it could be a big difference.
My main concern was the presence of unreacted menthol in the ester because they have the same boiling point, so I planned to perform a saponification test.
But just by smell, there is not much menthol, the smell is completely changed but the ester still has the "coldness" effect of the menthol.

[Edited on 10-1-2022 by teodor]

Also, I created a separate thread for menthyl acetate, so I think we can discuss the rest there.

[Edited on 10-1-2022 by teodor]
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[*] posted on 10-1-2022 at 11:54


@ clearly_not_atara your claim above that sulphuric acid shouldn't be used to prepare alkyl bromides is dis-information, little more than urban myth!! I have used sulphuric acid in almost every alkyl bromide preparation I have ever run, I have posted very detailed procedures for bromination of such compounds as 1,4-butanediol to 1,4-dibromobutane on this site and referred to others. It clearly does work and my only caveat is that the total concentration of sulphuric acid in the aqueous phase should not exceed about 85%; this seems to be about the point where sulphuric starts to act as an oxidizing agent towards bromide ions/ hydrogen bromide. Iodide is another matter!
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[*] posted on 11-1-2022 at 11:45


If you like nutty coffee-type smells, give the Gutknecht pyrazine synthesis a go. It involves self-condensation of α-amino acetaldehyde, which you may have to prepare in situ.

A fun experiment I did in the second year of university involved isolating eugenol by steam-distilling oil of cloves, then isomerising it to isoeugenol, and oxidising it to vanillin with KMnO4.

ed: just realised that pyrazine precursor is the aldehyde form of glycine, so yes, you will definitely have to prepare it in situ.

[Edited on 11-1-2022 by Lionel Spanner]

[Edited on 11-1-2022 by Lionel Spanner]




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[*] posted on 14-1-2022 at 04:46


Fery: Piperonal has been on my list for a while...ozonolysis of piperine.

clearly_not_atara: That makes no sense. I've seen preps of alkyl bromides using sulfuric acid before.
Yes. I am aware of the hazards of 1-bromobutane, and have a respirator as well as a ventilated work area.

Lionel Spanner: Pyrazines have been on my radar before, specifically 2,5-dimethylpyrazine. The issues are that I don't have ether (not OTC in the US anymore) and that it takes a butt ton of stannous chloride (and ammonium persulfate) for the prep I found.

Edit: Terpene chem is definitely an interesting field, but one I haven't had much luck in. Terpin hydrate, terpineol and its esters, and pinene controlled aromatization have all just given me terrible smelling bullcrap.

I might make methyl salicylate. Nice smell, works OK with polyphosphoric acid, and other uses I'll demonstrate later.


[Edited on 14-1-2022 by JacobM]
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[*] posted on 30-1-2022 at 00:39


Quote: Originally posted by Fery  
Amos - I bought methyl cinnamate from es-drei.de and the scent was very weak. Is there a way to make it stronger? I just sniffed directly from the bottle. Maybe grounding to very fine powder? Or heat it slightly? (Zimtsäuremethylester (min. 98%) 500g but it is now unavailable from their eshop).
teodor - I made allyl phenoxyacetate and allyl phenylacetate. First one is pineapple-flowers and second one honey. I was lazy to synthesize methyl and ethyl phenylacetates as I was able to buy them, both are honey scents. But too heavy and strong for me, I like the allyl phenylacetate much more. Maybe I should dilute methyl and ethyl phenylacetates. You already sniffed the compound Amos suggested (oxidizing piperine to piperonal) - that tiny vial with ground glass joint with a label Heliotropin, I told you that it is similar to Violet flowers (Viola odorata).
JacobM - acetophenone has very pleasant scent. Also good esters not yet mentioned are methyl anthranilate (grapes) and diethyl malonate (apples) - I tested both. You can also make apple scent fructone from ethyl acetoacetate with ethylene glycol.
Orange oil is very pleasant (D-limonene) and alfa pinene too (monoterpenes).
JacobM - you should react triflouroacetic acid or at least trichloroacetic acid with alfa pinene or d-limonene and then hydrolyze to alfa terpineol.
https://sci-hub.ee/http://dx.doi.org/10.1590/S0100-404220090...


On the subject of scents and oranges I grabbed a few leaves off an orange tree recently and it was the exact smell of a box of froot loops.
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[*] posted on 30-1-2022 at 23:50


Quote: Originally posted by clearly_not_atara  
Quote: Originally posted by JacobM  

One more thing: can dilute (50-80%) H2SO4 be used to form butyl bromide from butanol?

No form of sulfuric acid is a good way to make alkyl bromides because H2SO4 can oxidize HBr, and even a small amount of Br2 byproduct can make your life very unpleasant.

Keep in mind that volatile alkyl bromides are carcinogenic, and recommended exposure is less than 15 micrograms per day. They might not seem harmful, but if you haven't got appropriate safety equipment (at least one of fume hood/respirator and preferably both), you might want to target other things.

[Edited on 10-1-2022 by clearly_not_atara]


H2SO4 was used for years in 1st year organic labs for this purpose.
(the more volatile ethyl bromide, no less)
Works fine as long as you don't dump it all in at once. A thiosulfate wash deals with any bromine traces before the final distillation.

Many schools had students doing this without fume hoods or respirators.

Feiser and Feiser's lab manual had them doing it with an old fashioned open drip tip on the condenser instead of one that spigots into the collection flask, which may be going a bit far when you've got a roomful of undergrads all doing it at once.

You probably use a fume hood and respirator when you peroxide your curly locks:D




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[*] posted on 31-1-2022 at 00:12


I made 2-naphthyl acetate, but haven't purified it from the starting naphthol enough to tell what it smells like.



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[*] posted on 31-1-2022 at 23:11


DraconicAcid - interesting, please let us know the scent of 2-naphthyl acetate. How did you prepare it? Fischer esterification?
So far I found only these good scenting compounds but they are different from your ester, alfa and beta acetonaphtones
http://www.thegoodscentscompany.com/data/rw1008371.html
http://www.thegoodscentscompany.com/data/rw1033571.html
Does anyone have an idea how to prepare them? I have acetylchloride, AlCl3, naphthalene at hand. Maybe alfa formed at low temperature and beta at high similarly as when sulfonating naphthalene? Of course acetylation in home lab at elevated temp is a nonsense. At very cold temperature preferably the alfa formed during acetylation?
Any idea how to prepare the beta isomer then?
Also 2-methoxynaphthalene and 2-ethoxynaphthalene have good scents but I did not have time to prepare them (from beta naphthol and methyl iodide / ethyl bromide)
http://www.thegoodscentscompany.com/data/rw1012112.html
http://www.thegoodscentscompany.com/data/rw1001632.html

edit:
I found how to prepare pure isomers by acetylation of naphthalene here:
https://patents.google.com/patent/US2487777A/en

also preparation of 2-methoxynaphthalene here, they used 2-naphthol+methanol+NaHSO4:
https://patents.google.com/patent/CN102285871A/en


Attachment: US2487777A.pdf (281kB)
This file has been downloaded 64 times

[Edited on 1-2-2022 by Fery]




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[*] posted on 1-2-2022 at 11:20


I haven't looked into acylations much (I don't have anhydrous aluminum chloride, nor do I have any acid halides or thionyl chloride)- I thought I'd read that acid anhydrides could be used, but haven't found many preps involving them.

The reaction of naphthoxide with ethyl bromide works pretty well, as long as the KOH dissolves in the alcohol to start with. For some reason, that step decided it just didn't want to go last time the class did the lab, and yields were low (but I recovered a LOT of unreacted naphthol from the waste). Extrapolating this to ethylating vanillin or salicaldehyde has been utterly fruitless so far.

Reaction of 2-naphthol with 1-bromobutane gave a hard-to-purify compound (low melting point), and apparently, it smelled like raspberries, but I was the only one who couldn't smell it.

[Edited on 1-2-2022 by DraconicAcid]




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[*] posted on 1-2-2022 at 22:56


DraconicAcid - interesting idea, you are right, it should be raspberry:
http://www.thegoodscentscompany.com/data/rw1413311.html
Also isobutyl seems to be promising:
http://www.thegoodscentscompany.com/data/rw1020171.html
I did not find info about n-propyl, n-amyl and isoamyl ethers of 2-naphthol, I wonder what are they scents like.




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[*] posted on 5-2-2022 at 10:36


I've purified the 2-naphthyl acetate, and I can't smell a damned thing from it.



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[*] posted on 5-2-2022 at 13:38


How about Draconic Acid?

Although he's far too modest to mention it, he is reputed to have a sweet floral odor.:P




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[*] posted on 14-2-2022 at 06:21


I've found a good one - you can synthesise corylone (sweet/spicy coffee-like smell) from diethyl adipate in three steps, namely:

1. Dieckmann condensation, with additional methyl iodide to methylate the enolate;
2. α-chlorination of the ketone with chlorine or NCS;
3. Dilute hydrochloric + acetic acid, to remove the remaining ester.

I'm not sure about the mechanism for the last step, but all three steps are relatively simple.




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[*] posted on 18-2-2022 at 15:01


Another good one is making coumarin from malic acid and phenol in a Pechmann condensation. When mixed with conc. sulphuric acid and heated to 100 °C, malic acid decarboxylates and oxidises to form formylacetic acid, which reacts with phenol to form coumarin. Aluminium chloride may or may not be required.



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[*] posted on 19-2-2022 at 09:26


Hi Lionel Spanner, coumarin has very nice scent. I prepared it from salicylaldehyde + acetic anhydride + anhydrous Na acetate:
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...




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