Sciencemadness Discussion Board

Performic Acid Oxidation Solvents...

stoichiometric_steve - 29-8-2007 at 12:58

reading about this in the rhodium mirrors, it seems that DCM is the solvent of choice, as it limits the reaction temperature.

does anybody have experience with this kind of reaction and could thus tell me if it is possible to substitute tert-butyl-methyl-ether (TBME...not MTBE ;)) for DCM for environmental reasons?

leu - 30-8-2007 at 16:11

Ethers can be oxidized by peracids to glycols and/or oxiranes so using ethers as a solvent for Swern oxidations is unproductive and can be even possibly quite hazardous in the case proposed :P



[Edited on 31-8-2007 by leu]

Related Reference Information (Good Reading )

solo - 31-8-2007 at 02:17

Execution of a Performic Acid Oxidation on Multikilogram Scale
David H. Brown Ripin,* Gerald A. Weisenburger,* David J. am Ende, David R. Bill, Pamela J. Clifford, Clifford N. Meltz, and James E. Phillips
Organic Process Research & Development 2007, 11, 762−765


Abstract:
In order to run a peracid oxidation on multikilogram scale in
a pilot plant facility with an acceptable level of risk, an extensive
study of the thermal characteristics of the reaction, reactants,
and quench was undertaken. A number of features were
engineered into the process in order to confidently run the
process without the potential for a thermal or pressure excursion
on scale.

Attachment: Execution of a Performic Acid Oxidation on Multikilogram Scale .pdf (141kB)
This file has been downloaded 1585 times

roamingnome - 31-8-2007 at 06:55

Quote:

DCM for environmental reasons


well if the enviroment is the concern, get a deicated solvent recorvey still for DCM

i think the montra around here these days is... try it and tell us the results

DCM works, is available, and is choice during workup....


just dont go out for a cigarette break when you think the addition part is threw and come back to find it all bubbled up threw the condensor...

leu - 31-8-2007 at 12:00

Quote:
there is no way you could possible oxidize TBME to a glycol or an oxirane. and the oxidation mentioned is no Swern oxidation, either...are you drunk?


No, but apparently you are ignorant of the dangers of mixing an alkyl ether with a peracid :o Organic peroxides are rather hazardous, if you want to try it on a small scale please do it in a manner that won't kill you so you let the forum know that you survived your folly :P

leu - 31-8-2007 at 12:44

Quote:
TBME does not form peroxides.



The chemist who wrote the wikipedia article actually said this:

In chemistry

Being an ether, MTBE is a Lewis base. However, unlike other ethers such as diethyl ether or THF, it does not coordinate well enough with magnesium to be used for making Grignard reagents. The tert-butyl group is easily cleaved off under strongly acidic conditions (forming a moderately stable carbocation), particularly if heated (isobutylene is lost), something which can limit the use of MTBE as a solvent. However it possesses one distinct advantage over most ethers- it has a much lower tendency to form explosive organic peroxides than most ethers. Opened bottles of diethyl ether or THF can build up dangerous levels of these peroxides in months, whereas samples of MTBE are usually safe for years (but they should still be tested periodically).

The author said that MTBE can form peroxides but didn't contemplate anyone being foolish enough to add a peroxide former to MTBE and then use it a solvent in an organic reaction :o In your first post in this thread you said:
Quote:
does anybody have experience with this kind of reaction and could thus tell me if it is possible to substitute tert-butyl-methyl-ether (TBME...not MTBE ;)) for DCM for environmental reasons?


which demonstrates your lack of understanding of the nomenclature of ethers, and more importantly the dangers implicit in handling them :P Please use plenty of sandbags when you conduct your first experiment as without them you aren't likely to be able to tell the forum about your folly :D

S.C. Wack - 1-9-2007 at 03:39

Quote:
Originally posted by stoichiometric_steve

are gonna post more off topic BS? it's you who is not familiar the nomeclature of organic compounds. but i will explain, so your folly has an end:

(tert) is not included in defining the order of the substituents, and (B)utyl comes way before (M)ethyl in the alphabet, which is what IUPAC says. so the correct nomenclature is tert-Butyl-Methylether. Hence, TBME.


OK then, let's talk about who is familiar with IUPAC nomenclature: Not you. Try 2-methoxy-2-methylpropane.

Even the most cursory search of the web shows that MTBE is clearly the preferred name in the literature, reference books, and suppliers, though TBME (spelled out) gets a good showing at ACS with 35% of the total.

The acidic hydrolysis and oxidation with various oxidizers to t-butanol is not a secret. Nor is its reaction with H2O2 and acid to form peroxides: US6225510. But then they call the ether MTBE in that patent, so maybe they have it in for you.

Why leu is worried about you and your other_aliases getting blown up, I don't know. He's a nice guy, maybe too nice.

[Edited on 1-9-2007 by S.C. Wack]

Sergei_Eisenstein - 1-9-2007 at 11:48

You rule. Now try to order a few barrels of TBME using the correct name.
There are so many non-IUPAC conforming names and chemists know what they are. As such, every chemist knows what MTBE stands for, and starting to use TBME instead is just asking trouble. It's the same as demanding to use hydrogen oxide instead of water.

MTBE does form peroxides, but much slower then diethyl ether. It is generally resistant against hydrogen peroxide, but it is not against hydroxyl radical.

leu - 1-9-2007 at 13:49

An alternative to halogenated solvents that actually works is used in this procedure from Organic Syntheses, note the authors of the referenced citations:

Attachment: CV7P0126.pdf (155kB)
This file has been downloaded 1682 times

stoichiometric_steve - 1-9-2007 at 23:46

Quote:
Originally posted by leu
An alternative to halogenated solvents that actually works is used in this procedure from Organic Syntheses


that is the first and only useful reply to my initial question.

leu, YOU RULE :)

WizardX - 4-9-2007 at 02:17

SYNTHESIS OF EPOXIDES USING DIMETHYLDIOXIRANE: trans-STILBENE OXIDE
http://www.orgsyn.org/orgsyn/prep.asp?prep=cv9p0288