Author Topic: Possible Peracetic Revision  (Read 17439 times)

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Rhodium

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Re: Peracetic Information
« Reply #60 on: March 04, 2002, 02:04:00 PM »
Can a cinnamic alcohol epoxide (3-phenyl-2,3-epoxypropanol) be turned into someting useful? I feel that it should be possible, but I don't really know how.

foxy2

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Re: Peracetic Information
« Reply #61 on: March 04, 2002, 02:12:00 PM »
German Percarboxylic Acid Epoxidation Patent
A German Speakering Bee(hest) could scan thru here and see if there is anything interesting, I can't tell.

Patent DE19849527



Abstract
The invention relates to a method of epoxidizing olefins with percarboxylic acid in a reaction mixture consisting of an aqueous phase and an organic phase. According to said method, the percarboxylic acid in the aqueous phase is formed in situ from hydrogen peroxide and a carboxylic acid or a carboxylic acid anhydride and the olefins in the organic phase are dissolved in an organic solvent. The epoxidation is carried out in several steps. Each step is carried out with a fresh aqueous phase each and after each step the aqueous phase is removed.

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Rhodium

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Re: Peracetic Information
« Reply #62 on: March 04, 2002, 03:05:00 PM »
Multiple stage peracid oxidation of alkenes (DE 19849527)

They state that the total reaction time is considerably shortened from overnight stirring to a few hours. The yield of epoxide is also increased, as the two-phase reaction and shorter reaction time reduces the incidence of acid-catalyzed ring-opening and other side reactions. The discarded aqueous phases still contain excess HCOOH/H2O2, and this should be recycled. By choosing toluene as the non-polar reaction solvent, the water and formic acid forms azeotropes with the solvent, and are thus removed first by simple distillation, leaving only an anhydrous toluene solution of the epoxide, which can be further purified by vacuum distillation. The same is also true using xylene or dichloromethane. The concentration of the hydrogen peroxide is not so critical, but use no less than 25% peroxide, calculated from the total water content of the acid and the peroxide solution.

Example 1

In a 2000ml RBF, 336g 1-dodecene (2 mol) and 46g 99% formic acid (1 mol) was dissolved in 800g toluene and heated to 90°C. To the vigorously stirred mixture was added 136g 50% hydrogen peroxide (2 mol) during 20 minutes, and after that the mixture was stirred for a further 20 minutes,  and the aqueous phase was then discarded.

For step 2-4, the designated amount of formic acid is added in one portion, and the designated amount of hydrogen peroxide (same concentrations and temperatures as above) is added during five minutes, followed by 20 minutes of stirring and dicarding of the lower aqueous layer. In step 2, use 0.5 mole formic acid and 0.5 mole 50% H2O2, and for step 3-4, use 0.3 moles of each.

The crude product was analyzed with GC to reveal the following composition:

93.2% 1,2-Epoxydodecane
 1.1% 1-dodecene
 2.1% 1,2-dodecanediol
 1.6% 1,2-dodecanediol monoformate
 1.6% 1,2-dodecanediol diformate