The Synthesis Of Oxime And New Hydrolysis Process For Preparing Hydroxylamine Hydrochloride

Hydroxylamine hydrochloride is an important chemical materials,mainly as a reducing agent and imaging agent,it is also widely used in organic synthesis. Currently the synthesis of hydroxylamine hydrochloride methods in the industrial mostly exist complicated processes, low yield, multi by-product,large waste emissions and other issues.Therefore,the market urgently needs a synthetic processes of hydroxylamine hydrochloride on energy efficient,high-quality products,environmentally friendly.In recent years,as ammoximation process proposed and widely used,ammoximation-oxime hydrolysis process as a new idea to produce hydroxylamine hydrochloride,the essence of the process is the NH3、H2O2、HC l as the basic raw material,intermediate oxime and ketone as internal circulation of materials,the process try to make the raw material is completely converted to the title product.The paper studied a series of substrates effects on ammoximation process,and to inspect the reaction mechanism has been controversial,through experiments and infrared spectroscopy,we verified that exist the hydroxylamine mechanism in the reaction processes.On the basis of ammoximation process,we researched and developmented the molecular sieve catalyst.This paper studied the influence of process conditions on the ammoximation oxime and hydrolysis process. Acetophenone as raw material in the reaction, the optimum conditions of ammoximation: n(NH3): n(H2O2): n(ketone) = 1:1.3:2.5, ammonia and hydrogen peroxide was added at the same time,the reaction temperature was 65℃,catalyst amount was 4%, the best solvent for the reaction was toluene or isopropanol,the amount of solvent was the same as ketone,the hydrogen peroxide concentration had no influence on the reaction.Under the optimum conditions,the conversion of ketones could reach 99.9%, oxime selectivity was more than 99%.Oxime hydrolysis conditions were: employ the way of reaction-distilled,ketone and hydrochloric acid mo lar ratio was 1 :1.1,the reaction temperature was about 110℃, reaction time was 90 min,the mass fraction of hydrochloric acid was 18%,the yield of hydroxylamine hydrochloride was 97%,the cecycle rate of ketone was 96%. Under the optimum conditions, the yield of hydroxylamine hydrochloride up to 96%,the recycle rate of ketone was 95%.The process achieved a high atom economy,with the advantage of low power consumption,green process,the moderate reaction temperature,less by-products and high yield compared to the traditional industrial routes,full compliance with national advocacy of green chemistry, clean production purposes.On the basis of small scale experiments,we carried out enlarging production and recycling process,to further validate and refine the process parameters o f small test,and to control quality requirements through verify the control program,design the process flow diagram of hydroxylamine hydrochloride,each section of process will be explained,and determine the basic requirements of major equipment,proposed the solutions of waste production problems.