The Study On Synthesis Of Hydroxylamine Hydrochloride By Reaction-Extraction Technology

Hydroxylamine hydrochloride is an important reducing agent, an analytical reagent and one kind of intermediate products of most organic synthetic processes, so it is widely used in chemical and pharmaceutical industries. At present, the process routes of hydroxylamine hydrochloride mainly are nitrofication of natural gas, acetone oxime method and NO catalytic reduction. However these processes do have many shortcomings, such as strict reaction conditions, high capital outlay and low product yield.Reaction-extraction, as one of branches of reaction separation technology, has overcome limitations brought about by the balance of reversible reaction and has a high superiority to the point of enhancing product yield, selectivity and separation efficiency. Recently, reaction-extraction technology has been developed and extensively used.This thesis presents a novel process for hydroxylamine hydrochloride production using reaction-extraction technology and methylbenzene as an extractant. Using this extractant, the by-product of cyclohexanone oxime-hydrochloric acid reaction is obtained from the aqueous phase in order to decrease the concentration of cyclohexanone and increase the rate of production of hydroxylamine hydrochloride. It is shown in this paper that there are many operating parameters at play, such as reaction temperature, concentration of cyclohexanone oxime, concentration of hydrochloric acid and aqueous-organic volume ratio. These parameters affect the concentration of hydroxylamine hydrochloride and must be controlled before the optimum reaction conditions in the first stage to produce hydroxylamine hydrochloride is decided upon. At the same time, the experiments have compared the cross-current process with countercurrent operation, and the results show that cross-current fits the reaction well. Under the condition of cross-current operation, a lot of experiments were also done to reveal in detail the effects of the number of stages and other operating parameters in order to obtain the optimum number of stages and the reaction conditions.This novel process has been used in some pilot plant of China Petrochemical Stock Company and the results of pilot-scale study were in accordance with those of lab-scale study, the concentration of hydroxylamine hydrochloride was122.04g/L.