Study On Catalytic System For Beckmann Rearrangement In Green Medium

The conversion of ketoximes to corresponding amides, under acidic catalysts, known as the Beckmann rearrangement. Beckmann rearrangement is an common method used in organic chemistry. It could identify the structure of originally ketoximes by the resultant amides of the Beckmann rearrangement and hydrolysate of amides and could also synthesize economically a series of organic products.Beckmann rearrangement is usually used in Lewis acid catalyst, such catalysts because of their strong acid, strong oxidizing and strong corrosion resistance, toxicity and other factors, makes the complexity of the response operation, after dealing with red tape, and some also have a large number of by-products and even respond to equipment corrosion and environmental pollution and safety issues.Today, with the development of atom-economy and environment-economy, chemists are trying to develope an environment-friendly catalyst system, therefore, searching for a new catalyst of Beckmann rearrangement reaction is an interest topic.This paper studied the catalyst PEG-supported sulfonic acid (PEG-OSO3H) and a relatively friendly environment for the Lewis acid (PTSA, ClSO3H) catalyst system to catalytic Beckmann rearrangement. These catalytic reaction system not only high, operation is simple and small environmental pollution, catalyst and solvent reuse can be recycled, a green catalytic reaction is a new attempt.This article is divided into the following four chapters:Chapter I: First of all, on the Beckmann rearrangement reaction mechanism of the history and made a brief introduction, the highlights in recent years for the Beckmann rearrangement of new catalysts and new methods, at the same time in recent years as a polyethylene glycol Green reaction media in organic reactions has done a brief introduction.Chapter II: The return of mixing conditions, the use of PEG-supported sulfonic acid catalyst to a series of Ketoxime the Beckmann rearrangement, the reaction has a higher yield, the experimental operation and post-processing is simple, easy catalyst separation and can be Recycling is an ideal catalyst for Beckmann rearrangement. Under the same conditions, PEG-supported sulfonic acid catalyzed aldehyde oxime can also generate the corresponding nitrile dehydration.Chapter III: In this chapter the use of PEG-400 as the solvent, the use of p-toluenesulfonic acid as a catalyst for a series of oxime to Beckmann rearrangement studies. 115℃in the conditions, the PEG-400 as the solvent, p-toluenesulfonic acid catalysis can effectively generate the corresponding oxime amide. Good selectivity of the reaction system, a product of easy separation, and no environmental pollution. In the same conditions, p-toluenesulfonic acid catalyzed aldehyde oxime can also generate the corresponding nitrile dehydration.Chapter IV: This chapter studies the PEG-400 / chlorosulfonic acid system catalyzed Beckmann rearrangement. In the oil bath temperature of 110℃conditions, PEG-400 as the solvent, a variety of chlorosulfonic acid oxime catalytic Beckmann rearrangement took place to generate the corresponding amide; in the same conditions, the chlorosulfonic acid can be catalyzed by aldehyde oxime dehydration to generate the corresponding nitriles. The catalyst system of high reactivity, easy separation of products, environmental pollution and small, is a highly efficient catalyst system.