Sciencemadness Discussion Board

synthesis of a primary alcohol

Magpie - 20-12-2007 at 11:28

I have been wanting to synthesize isoamyl alcohol, a primary alcohol. Classic theory uses formaldehyde in a Grignard reaction to make a primary alcohol. But I have never seen an actual procedure for doing this.

It's obvious that formalin could not be used. Assuming this can be done, could trioxane or paraformaldehyde serve as the source of the formaldehyde?

Or, how is this normally done?

12AX7 - 20-12-2007 at 11:34

From what substrate?

In lab we did a hydroboration to make 1-octanol from 1-octene.

Tim

garage chemist - 20-12-2007 at 11:42

The Organikum gives a procedure to make anhydrous formaldehyde gas for use in grignards.
Paraformaldehyde is first dried in vacuum over P2O5 for a long time and then depolymerised by heating in a flask with a drop of H2SO4. The gas is directly led into the grignard solution through a short and wide tube.

The synthesis of primary alcohols this way usually gives bad yields. I would not bother with this.
What do you want the isoamyl alcohol for?

solo - 20-12-2007 at 12:11

Reference Information


A 13C Nuclear Magnetic Resonance Investigation of the Metabolism of Leucine to Isoamyl Alcohol in Saccharomyces cerevisiae
J. Richard Dickinson, Margaret M. Lanterman, Dean J. Danner, Bruce M. Pearson

Attachment: A 13C Nuclear Magnetic Resonance Investigation of the Metabolism of Leucine to Isoamyl Alcohol in Saccharomyces cerevis (428kB)
This file has been downloaded 598 times

Magpie - 20-12-2007 at 12:49

Tim, the substrate I had in mind was isobutyl bromide.
Quote:

The synthesis of primary alcohols this way usually gives bad yields. I would not bother with this.


Thanks, gc, I suspected as much. That's likely why I've never run across a procedure. The reason I want it is to fill my lab with the smells of pineapple by making isoamyl acetate. ;)

Thanks also to Solo, I will take a close look at that article.

Sandmeyer - 18-1-2008 at 17:52

Ah, another let's-make-cheap-OTC-product-in-impractical-nonOTC-way thread. ;)

Magpie - 18-1-2008 at 20:48

It's not that I can't buy isoamyl alcohol cheaply. It just seemed like a fun way to investigate that technology. ;)

vulture - 19-1-2008 at 06:31

If you have isobutylbromide, just hydrolyze with hot water. But it would be a shame to waste it just to make the alcohol.

Magpie - 19-1-2008 at 09:23

Vulture, that would give me isobutyl alcohol. I need to add a carbon to get isoamyl alcohol. For this I need dry formaldehyde.

I'm interested in technology to build primary alcohols. Now using ethylene oxide would alllow one to build primary alcohols 2 carbons at a time. But making EtO seems risky, and since it is an evil chemical you can't just buy a lecture bottle of it like an institution would do.

JohnWW - 19-1-2008 at 19:46

Quote:
Originally posted by vulture
If you have isobutylbromide, just hydrolyze with hot water. But it would be a shame to waste it just to make the alcohol.

That makes one wonder whether he wants to drink the stuff! (Toxic in fair amounts, although it occurs in trace amounts in booze).

MagicJigPipe - 19-1-2008 at 20:24

They use EtO at hospitals to sterilize surgical euipment. If only you knew someone on the inside. Actually, last time I was in a hospital the "DANGER: ETHYLENE OXIDE" room was unlocked. Stealing is wrong, however. Seriously.

[Edited on 19-1-2008 by MagicJigPipe]

Magpie - 19-1-2008 at 20:38

EtO is horribly expensive. Over $1000 for 227g! And there seems to be only one supplier: Pfaltz and Bauer. I don't see how hospitals can afford to use it unless nothing else will do the job.

When I took my exams for organic chemistry (a long time ago) it seems like I could always make the synthesis go with EtO. Of course, this was just on paper. But the professors always accepted it as it was legitimate no matter how impractical. Also, EtO was probably a lot cheaper then. Before we learned how carcinogenic (and evil) it is.

MagicJigPipe - 19-1-2008 at 21:57

I'm pretty sure they don't use ACS grade or whatever but I wasn't hallucinating. My Mom works at the hospital and she confirms this. From what I read ethylene oxide is commonly used for this. I'm sure it doesn't take much and I'm sure they use the lowest grade they can get by with. I will take a picture of the sign and maybe even the container tomorrow.

These are the first few hits on google.

http://www.tpub.com/content/medical/14274/css/14274_147.htm

http://www.infectioncontroltoday.com/articles/061feat4.html

http://www.sterigenics.com/services/medical_sterilization/co...

In fact, the first thing the google toolbar finished my sentence with when I typed in ethylene oxide was "sterilization".

Guess we should get back on topic, eh?

[Edited on 20-1-2008 by MagicJigPipe]

smuv - 19-1-2008 at 22:51

@ Magpie, you are mistaken.

Ethylene oxide is a high volume chemical and is therefore pretty cheep. Although old numbers the spot price of ethylene oxide in 1968 was 15.5 cents per pound. The industrial product is very high purity usually >99.7%, which is more than suitable for sterilization.

If you do not have much faith in my old statistics keep in mind the price of ethylene oxide must be less than the price of ethylene glycol(s), ethanolamine(s), glycol ethers and acrylonitrile as all these products are produced from ethylene oxide. I would recommend doing some research about ethylene oxide as you may be very interested by the importance of this chemical feedstock.

spot prices from: Miller, Ethylene and industrial derivatives

[Edited on 19-1-2008 by smuv]

not_important - 19-1-2008 at 23:10

Medical sterilization grade EO is more expensive, roughly 50 cents US per cc, as is lab reagent grade.

Oxetane acts similar to ethylene oxide, although more slowly, yielding R-CH2-CH2-CH2OH from RMgBr

smuv - 19-1-2008 at 23:22

I am very surprised to hear this astronomical price.

Still ethylene oxide seems conceptually easy to make from ethylene via ethylene chlorohydrin. Additionally the product would be very pure (often even more so than the ethylene used to produce it). I plan to make ethylene oxide one of these days, however the health hazards have been on my mind as of late.

MagicJigPipe - 20-1-2008 at 00:28

As am I. Surely the hospital would not use something that is so prohibitively expensive. Seems like it would be cheaper to use a huge autoclave. And I know hospitals are ALL about cutting costs, especially the one I mentioned earlier.

not_important - 20-1-2008 at 00:50

Ethylene oxide is used to sterilize items that can't tolerate heat or water. Many plastics aren't going to tolerate the 120+ C saturated steam very well, especially plastics with the needed properties for their end use. Dry heat uses 160 to 180 C for a much longer time. Electronics are also not too likely to welcome 120 C steam, either, and are given EO treatment.
Quote:
Ethylene Oxide Sterilization
Materials such as suction tubing, handpieces, radiographic film holders, and prosthetic appliances may be sterilized without adverse effects.

Why Hospitals Choose EO for Low-Temperature Sterilization

First, they can get the best possible Sterility Assurance Level with EO. Side-by-side studies (EO blends vs. pure EO vs. hydrogen peroxide plasma) show higher safety margins offered by EO with the best SALs achieved by the EO blend sterilizers.4-5 EO sterilizers use an overkill cycle to achieve an SAL of 10-6, which operators confirm by a BI challenge in a barrier pack in every sterilizer load.

Secondly, those who use the blend sterilizers rely on a "workhorse" process where there are almost no material limits, almost no device configuration limits, no size limits, high load limits (for chamber sizes up to 70 cubic feet), and for large chambers, the highest per cycle through-put with the greatest variety of devices.


http://www.tpub.com/content/medical/14274/css/14274_147.htm
http://www.infectioncontroltoday.com/articles/061feat4.html

MagicJigPipe - 20-1-2008 at 01:14

Thanks for that info. Has anyone found any realistic costs for sterilization grade EtO? Surely it can't be $.50 a mL. I mean, it would cost $500 a liter. That's like the gas equivalent of platinum. Around ... $250 a gram? I suppose if it was that much they would HAVE to reuse it.

I know it's possible. I just... well, I can't fathom that much money I suppose.

Maybe it only takes a very small amount?

not_important - 20-1-2008 at 01:43

That's a ml of the liquid, BP ~10 C at 1 atmosphere, in pre-measured amounts under pressure in dispensing containers. Appears that 5 to 10 ml of liquid EO is needed for a counter-top unit, perhaps as a small clinic might use.