Sciencemadness Discussion Board

Preparation of Acetaldehyde

khourygeo77 - 24-12-2017 at 05:44

Is it possible to prepare Acetaldehyde with little to no equipment and with easily accessible material?

Can it be found in particular places like markets or hardware stores etc.?

Thanks

[Edited on 24-12-2017 by khourygeo77]

JJay - 24-12-2017 at 06:55

It can be made from ethanol using various oxidizers, but that usually requires a distillation setup.

khourygeo77 - 24-12-2017 at 07:20

Quote: Originally posted by JJay  
It can be made from ethanol using various oxidizers, but that usually requires a distillation setup.



I have one

Any idea about the procedures?

NEMO-Chemistry - 24-12-2017 at 08:32

Just because it Christmas i will dismiss from my head any thoughts you want to do bad shit :D.

http://www.prepchem.com/synthesis-of-acetaldehyde/

khourygeo77 - 24-12-2017 at 09:38

Thanks. Cant get the chromate thing however

I have h2o2 and ethanol. I also have dilute hcl and vinegar and some acetic acid

From the readings I did, I need to mix h2o2 with ethanol and a dilute acid and I can get acetaldehyde. I'm not sure about the dilution, the pace of the reaction, and the final products however and which acid should I rather use as a catalyst?

myristicinaldehyde - 24-12-2017 at 10:16

https://www.sciencemadness.org/whisper/viewthread.php?tid=55

utfse

NEMO-Chemistry - 24-12-2017 at 10:16

Quote: Originally posted by khourygeo77  
Thanks. Cant get the chromate thing however

I have h2o2 and ethanol. I also have dilute hcl and vinegar and some acetic acid

From the readings I did, I need to mix h2o2 with ethanol and a dilute acid and I can get acetaldehyde. I'm not sure about the dilution, the pace of the reaction, and the final products however and which acid should I rather use as a catalyst?


I kind of gave you a warning above, i have also read the posts where you can use the chemicals you have. Unfortunately the sites these are on are for drug use. I kind of wanted you to NOT make it obvious what your upto, personally what you do is your business, but i am not being a part of it. Go ask where you saw the recipe.

You would have been better asking how to source the Diachromate 'thing' and sulphuric acid, FFS that would have at least made this look like a chemistry question. Now you gone and used up my Christmas good will!

JJay - 24-12-2017 at 10:43

You can make hexavalent chromium with household bleach or hydrogen peroxide and stainless steel flatware. You can actually use an equivalent amount potassium dichromate, available from pottery suppliers, in the prepchem procedure, but it won't dissolve until the solution gets hot. Some oxidizers could be used to oxidize ethanol directly, but for those that can't you might try a little bit of hexavalent chromium along with a larger amount of a strong oxidizer.

The basic procedure is to heat the oxidizer to above the boiling point of acetaldehyde but below the boiling point of ethanol and to drip ethanol into the solution as the acetaldehyde distills out. Immediately distilling out the acetaldehyde hopefully avoids a lot of over-oxidation to acetic acid.

I didn't think acetaldehyde was a very suspicious chemical. I'm sure it could probably be used to make drugs, but so could vinegar and distilled water.

khourygeo77 - 24-12-2017 at 10:46

I honestly searched for acetaldehyde. I came up with oxidation of ethanol. The common oxidant I use is H2O2. So I googled acetaldehyde + H2O2 and found something like that necessitating an acid and some places where sulfuric acid was used. I dont have sulfuric acid but have vinegar and hcl. I dont remember which pages I visited. I simply googled. There were also some other oxidants like metal and mineral salts but I dont have those either

JJay - 24-12-2017 at 11:09

This will probably work:

1. Dissolve some stainless steel in HCl.
2. Add a large excess of hydrogen peroxide and heat to 70 C or so.
3. Drip in ethanol slowly and distill out the acetaldehyde.

It's likely to be messy and would probably waste a lot of hydrogen peroxide, but I think it would work.

A more complicated scheme involving precipitating the metals as hydroxides and oxidizing the hydroxides with household bleach, filtering, and then adding HCl, heating, and dripping in the ethanol/distilling out acetaldehyde would almost certainly work.

NEMO-Chemistry - 24-12-2017 at 12:14

I only got arsey because cooks wont use Diachromate, so when you said you couldnt/wouldnt use it......

I am not anti drugs, each to there own, but i dont personally want anything to do with them. I suggest you go with JJay's method, otherwise it seriously starts to look like bad intentions.

Sulphuric acid i can understand as being hard to get, i have nightmares getting it. Recently because of the acid attacks the price has shot through the roof! I was paying £19 ltr for decent grade, its now £32 from the same place, plus you have to sign a declaration.

khourygeo77 - 24-12-2017 at 13:09

Quote: Originally posted by JJay  
This will probably work:

1. Dissolve some stainless steel in HCl.
2. Add a large excess of hydrogen peroxide and heat to 70 C or so.
3. Drip in ethanol slowly and distill out the acetaldehyde.

It's likely to be messy and would probably waste a lot of hydrogen peroxide, but I think it would work.

A more complicated scheme involving precipitating the metals as hydroxides and oxidizing the hydroxides with household bleach, filtering, and then adding HCl, heating, and dripping in the ethanol/distilling out acetaldehyde would almost certainly work.


Thank you.

Any idea about the yields and how much h2o2 may be wasted? What are also the proportions? Like how much should I put of each?

Assured Fish - 24-12-2017 at 14:42

I made a post in the acetaldehyde thread a few days ago and have been waiting for feedback, finally when someone asks about acetaldehyde though hes too much of an idiot to post it in the right thread.
Fucken typical.

As for the actual preparation of acetaldehyde, the dichromate method works however i absolutely must point some things out.

1. Do NOT use sulfuric acid, recycling the Cr2O3 afterwards will be impossible if you do, use HCl.

2. The acid dichromate mixture must be refluxing before you even begin adding the ethanol.

3. Use sodium dichromate not potassium dichromate, the low solubility of the potassium salt makes this reaction very difficult to control and with the risk of over oxidation being very high.
The less volume in the pot the better.

I have attempted this prep but i didn't follow my points, these points were what i learned as a result, however i doubt the yield will be particularly high and a large amount of dichromate is needed to oxidize a small amount of ethanol due to molecular weight differences.

This idea about using sulfuric acid and H2O2 sounds a little mad, H2SO5 or caros acid is perhaps one of the strongest oxidizers accessible to us amateurs, using this to selectively oxidize ethanol to the aldehyde would be impossible given that this stuff not only oxidizes to the carboxylic acid but would likely go all the way to CO2.

Using acetic acid will yeild peracetic acid, not sure how this would react with an alcohol.

Using HCl would in theory generate HClO or hypochlorous acid which would quickly disassociate producing chlorine gas, Im fairly confident this reaction doesn't take place this easily though.
Hypochlorous acid CAN oxidize alcohols to aldehydes, however nobody has succeeded in doing this on the forum.

Please though for the love of science go and read the fucken acetaldehyde thread and my recent post there.

JJay - 24-12-2017 at 15:55

Quote: Originally posted by khourygeo77  
Quote: Originally posted by JJay  
This will probably work:

1. Dissolve some stainless steel in HCl.
2. Add a large excess of hydrogen peroxide and heat to 70 C or so.
3. Drip in ethanol slowly and distill out the acetaldehyde.

It's likely to be messy and would probably waste a lot of hydrogen peroxide, but I think it would work.

A more complicated scheme involving precipitating the metals as hydroxides and oxidizing the hydroxides with household bleach, filtering, and then adding HCl, heating, and dripping in the ethanol/distilling out acetaldehyde would almost certainly work.


Thank you.

Any idea about the yields and how much h2o2 may be wasted? What are also the proportions? Like how much should I put of each?


It depends on the side reactions... I'm not sure, but a 1x molar excess might be a good place to start.