Method for preparing acetaldoxime

Abstract

The invention discloses a method for preparing acetaldoxime. The method is characterized by carrying out a high-selectivity acetaldoxime combination reaction on acetaldehyde, ammonia and an alcohol solvent in a liquid phase by taking titanium silicate molecular sieve as a catalyst and taking hydrogen peroxide as an oxidant, and distilling and purifying the reaction solution to acquire the acetaldoxime, wherein the mass ratio of the acetaldehyde, the ammonia, the alcohol solvent and the catalyst is 1: (0.38-0.78): (2-10): (0.05-0.68). Compared with the prior art, the method for preparing the acetaldoxime has the advantages of high conversion rate of acetaldehyde, good selectivity and high utilization rate of hydrogen peroxide; the reaction process is simple and is environment-friendly and pollutions to the environment are reduced; the industrial production is facilitated; and the development of green chemistry is promoted.

Description

technical field [0001] The invention relates to the technical field of organic chemical synthesis, in particular to a method for preparing acetaldehyde oxime. Background technique [0002] Acetaldoxime is a less toxic reducing agent and an important reagent in organic synthesis and analysis. In the 1990s, acetaldehyde oxime replaced the highly toxic hydrazine as a boiler water oxygen scavenger, and its oxygen scavenging effect was much higher than that of hydrazine, so it was widely used. Acetaldoxime is an important intermediate for the synthesis of pesticides methomyl and thiodicarb. These two pesticides are good broad-spectrum insecticides. With the continuous growth of production, the market demand for acetaldehyde oxime also increases . [0003] At present, acetaldehyde oxime is generally produced by the aminoxime compound method of sulfuric acid (hydrochloride) hydroxylamine and acetaldehyde. The main disadvantages of this production process are: complex process, lon...

AI Technical Summary

Problems solved by technology

[0003] At present, acetaldehyde oxime is generally produced by the aminoxime compound method of sulfuric acid (hydrochloride) hydroxylamine and acetaldehyde. The main disadvantages of this production process are: complex process, long reaction process, large amount of hydroxylamine salt, and need to add alkali to adjust The pH of the reaction system, and by-products are generated, which is not friendly to the environment

[0004] Titanium-silicon molecular sieves are new heteroatom molecular sieves developed in the early 1980s. Currently, the titanium-silicon molecular sieves with microporous structures include TS-1, Ti-Beta, Ti-MOR, Ti-MWW, etc. Titanium-silicon molecular sieves with pore structure include Ti-MCM-41, Ti-MCM-48 and Ti-SBA-15, etc. Because molecular sieves have a porous and orderly structure, they have excellent type selection functions and will have a transition of valence characteristics. Metal titanium is introduced into the molecular sieve framework structure to form oxidation-reduction catalysis, which has been widely used in the ammoximation of aldehydes and ketones, such as Chinese patent: CN 1683323A discloses the preparation of cyclohexanone oxime, CN 1651405A, CN 101318912A discloses the preparation of methyl ethyl ketone oxime with TS-1 and CN 1022416605A discloses the preparation of citronellaldoxime with TS-1, but there is no patent or literature report to prepare acetaldehyde oxime with titanium silicon molecular sieve,