Process for preparing hydroxylamine salt by continuous hydrolysis of oxime

Abstract

The invention belongs to the field of hydroxylamine salt preparation, and particularly relates to a continuous preparation process of a hydroxylamine salt. According to the process, ketoxime and hydrochloric acid (sulfuric acid) are used as raw materials and are subjected to continuous hydrolysis to prepare a hydroxylamine salt; and the process comprises: preparing a hydrolysis stock solution fromketoxime and hydrochloric acid (sulfuric acid), pumping the hydrolysis stock solution into a hydrolysis kettle, continuously producing a hydrolysis completion liquid from the hydrolysis kettle, decolorizing the hydrolysis completion liquid by active carbon, feeding into a concentration device, continuously cooling and crystallizing the concentrated completion liquid, feeding into a centrifugal machine, returning centrifugal mother liquor to a decolorizing liquid tank, and drying the centrifugal product to obtain a finished product hydroxylamine salt. According to the hydrolysis process, continuous operation of hydrolysis, decoloration and crystallization is realized, the equipment utilization rate is greatly improved, the hydrolysis efficiency is improved, the retention time of a hydrolysis stock solution is short, and excessive side reactions are avoided. The product purity is high, the superior product requirements are met, and the cost can be effectively reduced.

Description

technical field [0001] The invention belongs to the field of preparation of hydroxylamine salts, and in particular relates to a new preparation process of hydroxylamine salts. Background technique [0002] As an important chemical raw material, hydroxylamine salt is mainly used as a reducing agent and imaging agent. It is mainly used to prepare oximes in organic synthesis, and is also used to synthesize anticancer drugs (hydroxyurea), sulfa drugs (sulfamethoxazole) and Raw material of pesticide (methomyl). It is used as a depolarizer in electroanalysis and as a non-coloring short-term stopper in the synthetic rubber industry. The pharmaceutical industry is used as an intermediate of sulfamethoxazole. Synthetic dye industry is used as isatin intermediate preparation. In the oil industry, it is used as an anti-aging agent and antioxidant for fatty acids and soaps. In analytical chemistry, it is used as a reducing agent for the analysis of formaldehyde, furfural, camphor an...

AI Technical Summary

Problems solved by technology

Although the occurrence of side reactions is reduced, the hydrolysis temperature is low, which inhibits the hydrolysis balance, and will cause a large amount of unreacted oxime to remain in the hydrolyzed solution. The decompression dehydration of the hydrolyzed solution will cause a large amount of oxime loss, and the product needs to be refined by ethanol , the introduction of organic solvents

Some patents also use low-temperature hydrolysis, adding a titanium-silicon molecular sieve catalyst to catalyze the hydrolysis, the interstitial hydrolysis time is longer, the strong acid system is likely to cause catalyst deactivation, and there are problems with catalyst separation, activation and regeneration

[0005] The above hydrolysis methods have problems such as low selectivity, refined products, many by-products, and serious environmental pollution.

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