Sciencemadness Discussion Board

Wonderful aromatic compound identification

Adipocerex - 10-8-2016 at 07:08

Hey SM!
In an experiment yesterday i made some Sodium Ethoxide (i presume) from adding small chunks of Na to anhydrous ethanol which was dried on calcium chloride. (A bit of the calcium chloride stayed in solution) The ethanol might contain butanone still as well

CH3CH2OH + Na = CH3CH2NaO + H2


Just for the thrill of it i added about 1 drop of H2SO4 to the aqueous solution and a white precipitate crashed out. I have vacuum dried the chrystals which crashed out from solution. And both the solution & the chrystals have a wonderful sweet smell of raspberry.

What on earth have i made? :D Is cannot be an aromatic Ester?.
CH3CH2NaO + H2SO4 + CH3CH2OH = ?

Ethanol + Calcium Chloride(s) + Na(s) + H2SO4 = ?

Metacelsus - 10-8-2016 at 10:31

How much butanone? It's possible you made some aldol condensation products.

Adipocerex - 10-8-2016 at 10:39

Percentage wise it there is maybe <2% of the weight of the ethanol solution. The weight of the solution is about 8 grams. So it is really not much

Endo - 10-8-2016 at 11:25

Calcium chloride is considered incompatible for use drying alcohols because it facilitates condensation product formation. It also often has small amounts of hydroxides present (Ca(OH)2) which can increase the pH of the solution and cause side reactions in addition to drying. So it all depends on how long your ethanol was drying, how pure your CaCl2 was, and what species formed before you started your experiment.

Details on CaCl2 as a drying agent:

http://www.chem.ucla.edu/~bacher/Specialtopics/Drying%20Agen...

https://www.erowid.org/archive/rhodium/chemistry/equipment/d...

Etaoin Shrdlu - 11-8-2016 at 09:54

I assume this is a typo, but just to be sure, you didn't really add sulfuric acid to the aqueous solution?

Of note, of course, is that sodium sulfate is white and insoluble in ethanol. I don't know what the raspberry smell would be.

stoichiometric_steve - 11-8-2016 at 10:16

Calcium Sulfate.

froot - 11-8-2016 at 11:17

Side reaction producing acetaldehyde?

Adipocerex - 12-8-2016 at 02:16

Have i just accidentally created a new method of producing raspberry aroma?

Side note: I forgot that it was not only H2SO4 but a weak piranha solution.

And it is highly likely Calcium Sulfate the white precipitate and maybe the raspberry smell is some analogue of 4-(4-hydroxyphenyl)butan-2-one)) or ethyl formate?

http://www.compoundchem.com/2014/09/18/raspberries/

Adipocerex - 15-8-2016 at 14:53

Nobody? Nobody can tell me which the aromatic compound is? Butanone, Sodium, H2O2, Sodium Ethoxide, Ethanol, H2SO4, CaCl2 forms?

PHILOU Zrealone - 16-8-2016 at 05:20

Maybe CH3-CH2-CO-CH=C(-CH3)-CH2-CH3 or higher condensation products or oxydation products due to H2O2 --> epoxyde or gem-diol.

Texium - 16-8-2016 at 08:06

Quote: Originally posted by Adipocerex  
Nobody? Nobody can tell me which the aromatic compound is? Butanone, Sodium, H2O2, Sodium Ethoxide, Ethanol, H2SO4, CaCl2 forms?
No, because frankly that isn't a chemical reaction, that's throwing a bunch of crap in a flask. All that anyone can do is speculate vaguely. Also, it's very misleading the way that you keep throwing around the word "aromatic." I hope that you aren't implying that you believe this compound exhibits aromaticity, and are just referring to the way it smells.

Start over, and do it in a more controlled way. Measure the amounts of everything that you use. Know for certain how pure your reagents are. Then describe exactly what you did, clearly.

PHILOU Zrealone - 16-8-2016 at 11:26

In fact aromatic compounds (benzen family) are intitially called aromatic because many such compounds where extracted/isolated from natural source used as seasonings/spices for cooking or for perfumery and in french (famous for cooking, perfumery and chemistry at that time) seasonings are called "aromates" (giving an aroma to food or displaying a good aroma). The adjective is "aromatic" thus what displays such particularity of giving an aroma recalling seasonings or natural perfumes.

So thymol from thyme, vanillin from vanilla, carvacrol from oregano, toluen from tolu balm, safrole from sasafras, estragole from basil, anethole from anis, ....but also terpenic compounds belongs to the aromatic following the french definition and remains in the perfumery, cooking language...aswel as (al)chemical one for long...but this is of course misleading if one is refering to the conjugated cyclohexatriene structure...


[Edited on 16-8-2016 by PHILOU Zrealone]

Texium - 16-8-2016 at 11:46

Yes, I'm aware of the origins of the term, and it's still fine to use it in a non-scientific setting, but in modern scientific discourse, the use of the word "aromatic" to describe the odor of a compound should be avoided. Just my two cents on that matter. The main problem the OP has is still the lack of a definite procedure and any controls, but if he/she were to try again in a more controlled way, we could have something to work with.

j_sum1 - 16-8-2016 at 15:05

@P-Z
cyclohexatriene – That's not a word you hear every day. :)

I agree with zts. Try again while controlling your variables.
It is these kind of serendipitous observations that propel science in new directions. (Yesterday I read about extracting gold using cornstarch - a process discovered by accident.)
But it is the skill of a scientist to make careful initial observations (well done) ask the right questions (also well done) and perform a carefully-controlled investigation to determine what the hell is going on.

We can of course speculate on the source of the raspberry smell and may even have a chance of being correct. But from this distance there is no way of knowing. OTOH, if you were to replicate with known concentrations and then post your procedure -- it is likely that we will get better answers.

If I was to guess, I would say some kind of ester had been formed. But, as with many aromas, it is likely to be a mixture of compounds -- especially likely in this case where there are a large number of reagents and the smell probably comes from assorted side reactions involving impurities.

Keep us informed.

thanos thanatos - 16-8-2016 at 20:33

I also agree with zts16. This is a chemistry forum, so aromatic means something quite specific here that has nothing to do with how a compound smells.

However, PHILOU's post would make you think that saying a molecule is aromatic means it has a phenyl group in it. Aromaticity is a much more general property. Aromaticity is a property of cyclic organic molecules (either all carbon or heterocyclic) with alternating single and double bonds. These molecules have resonance structures that distribute the electron density more evenly around the ring, thus stabilizing the molecule. Benzene and phenyl groups are just the most well known example of aromatic molecules.

PHILOU Zrealone - 17-8-2016 at 06:36

Quote: Originally posted by thanos thanatos  
I also agree with zts16. This is a chemistry forum, so aromatic means something quite specific here that has nothing to do with how a compound smells.

However, PHILOU's post would make you think that saying a molecule is aromatic means it has a phenyl group in it. Aromaticity is a much more general property. Aromaticity is a property of cyclic organic molecules (either all carbon or heterocyclic) with alternating single and double bonds. These molecules have resonance structures that distribute the electron density more evenly around the ring, thus stabilizing the molecule. Benzene and phenyl groups are just the most well known example of aromatic molecules.

The OP wrote "smell" and "aromatic ester" ... by definition noze can hardly be a detector or sp2 aromaticity...it is subjective description used by perfumers! ;):)

If you read carefully my comment:
"In fact aromatic compounds (benzen family) are intitially called aromatic because many such compounds were extracted/isolated from natural source"
You will notice the history signification of my explanation.:D
The term aromatic was first introduced in early 1855 by August Wilhelm von Hofmann while the Erich Huckel rules dates from 1930 (defined pyrole and thiophen as being aromatic) and later on based on Hückel's those from Woodward–Hoffmann's work from 1965...thus a century later!
:P:cool:

I know what aromaticity is...I have worked and synthesized PHEHAT ligand (= 1,10-phenanthroline[5,6-b]-1,4,5,8,9,12-hexaazatriphenylene) a fully polycyclic-heteroaromatic-extended system of 7 fuzed benzen rings. :cool::);):P

Many of my posts and drawings into this forum illustrate my understanding of it :);):cool::P

thanos thanatos - 18-8-2016 at 06:20

Quote: Originally posted by PHILOU Zrealone  
Quote: Originally posted by thanos thanatos  
I also agree with zts16. This is a chemistry forum, so aromatic means something quite specific here that has nothing to do with how a compound smells.

However, PHILOU's post would make you think that saying a molecule is aromatic means it has a phenyl group in it. Aromaticity is a much more general property. Aromaticity is a property of cyclic organic molecules (either all carbon or heterocyclic) with alternating single and double bonds. These molecules have resonance structures that distribute the electron density more evenly around the ring, thus stabilizing the molecule. Benzene and phenyl groups are just the most well known example of aromatic molecules.

The OP wrote "smell" and "aromatic ester" ... by definition noze can hardly be a detector or sp2 aromaticity...it is subjective description used by perfumers! ;):)

If you read carefully my comment:
"In fact aromatic compounds (benzen family) are intitially called aromatic because many such compounds were extracted/isolated from natural source"
You will notice the history signification of my explanation.:D
The term aromatic was first introduced in early 1855 by August Wilhelm von Hofmann while the Erich Huckel rules dates from 1930 (defined pyrole and thiophen as being aromatic) and later on based on Hückel's those from Woodward–Hoffmann's work from 1965...thus a century later!
:P:cool:

I know what aromaticity is...I have worked and synthesized PHEHAT ligand (= 1,10-phenanthroline[5,6-b]-1,4,5,8,9,12-hexaazatriphenylene) a fully polycyclic-heteroaromatic-extended system of 7 fuzed benzen rings. :cool::);):P

Many of my posts and drawings into this forum illustrate my understanding of it :);):cool::P


You are quite right on the history of the term aromatic as it applies to chemistry, and I think it's naturally confusing when the term means two very different things, depending on context. Generally, the context in this forum is chemistry.

I didn't mean to imply that you didn't know what aromaticity was. It's just that your post gave the impression that aromaticity, in the chemical sense, was "refering to the conjugated cyclohexatriene structure...", which doesn't really capture what aromaticity, in the chemical sense of the word, really means. After all, benzene is not 1,3,5-cyclohexatriene.

PHILOU Zrealone - 18-8-2016 at 09:01

Benzene is 1,3,5- and 2,4,6-cyclohexatriene at the same time ;) (thus 1,2,3,4,5,6-cyclohexatriene) :P:D:)

Live with that chemistry has its roots into alchemistry...so you will always have some sticky sulfurous ambiguous names because of the perpetuation of those into less scientific fields (cooking, perfumery, potery, grocery, pharmacy, naturopathy, alchemistry, homeopathy, ...).

I used to like to know where this or that chemical name came from and why...it is very instructive.

Etaoin Shrdlu - 30-8-2016 at 03:20

FYI, modern terminology for this use of "aromatic compound" is "aroma compound." Less confusing.

Melgar - 30-8-2016 at 17:12

Because other people are being unnecessarily mean, I'll try and do the opposite. Lots of discoveries have been made by throwing a bunch of crap together and then noticing that the crap behaved in interesting, unexpected ways. Plenty of famous chemists have made discoveries this way. It's how they discovered that vanillin could be synthesized from wood pulp, (vats of lignin dissolved in NaOH would start smelling like vanilla after a few days) and a former waste product became the source of something that was formerly extremely valuable and expensive. The key now is to try and replicate it. Figure out what parts react, and in what order. If it has a fruity smell to it, it's probably an ester, so we can narrow it down that way. The key now, is to do actual science, and learn something new using the scientific method. Good luck!