The first step, ketoxime synthesis: 5 kg of Ti-MWW molecular sieve, 36 kg of butanone, and 100 kg of water were added to the reactor together, heated to 60 °C in a water bath, and then 75 kg of ammonia water and 68 kg of hydrogen peroxide were added to the reactor. The uniform rate was added to the reactor within 90 minutes, keeping the water bath temperature and stirring speed unchanged throughout the process. After the reaction was completed, the unreacted ammonia was absorbed under reduced pressure. The butanone oxime is extracted, and the obtained butanone oxime is mixed with the oil phase to obtain a crude butanone oxime.
The second step, the preparation of hydroxylamine hydrochloride: take 45 kilograms of water, add 13.5 kilograms of ammonium chloride, add 43 kilograms of crude butanone oxime obtained in the first step, heat it to 70 ° C to make it react, depressurize to a vacuum degree of 100KPa and absorb the reaction to generate The ammonia and methyl ethyl ketone were kept at 70°C for 6 hours, and after cooling to 0°C, the lower water phase was released with a separating funnel after standing, and the unreacted butanone oxime was extracted with ether, and the obtained aqueous phase was Hydroxylamine hydrochloride aqueous solution. The hydroxylamine hydrochloride aqueous solution is frozen and precipitated at -10°C, filtered and suctioned to obtain hydroxylamine hydrochloride crystals, and then the filtrate is evaporated and concentrated under negative pressure, and then subjected to cold precipitation, repeated several times, and the obtained hydroxylamine hydrochloride crystals are weighed together. 16 kg of hydroxylamine hydrochloride crystals, the yield is 92% based on ammonium chloride.
The unreacted ammonia gas absorbed in the first step under reduced pressure, the ammonia gas and butanone generated by the reaction under reduced pressure absorption in the second step can be reused in the first step. In the second step, the diethyl ether extract was evaporated to remove diethyl ether, and then combined with the upper oil as unreacted crude butanone oxime for reuse in the second step.
A green synthesis process for preparing hydroxylamine hydrochloride without solvent, taking 0.36g of Ti-MWW catalyst, 8.35g of ammonia water (28wt.%), and 4.5g of butanone in a reaction flask, and controlling the temperature at 65° C.; Then, 21.25 g of hydrogen peroxide (concentration of 10%) was dropped into the flask with a peristaltic pump, and the residence time was controlled at 2 h. Subsequently, the reaction solution is passed through the membrane filter, and the catalyst mother liquor and the crude product are separated, and the catalyst mother liquor is recycled by using a circulating pump. 36%) to the reaction device, the mol ratio of hydrochloric acid and butanone is 1.2:1, the butanone obtained by hydrolysis is recycled to the amidoxime chemical section through distillation to continue the reaction, and the reaction mother liquor is concentrated and crystallized to obtain hydroxylamine hydrochloride product. The conversion rate of butanone=99.1%, the selectivity of butanone oxime reaches 100%, the recovery rate of butanone=95%, the yield of hydroxylamine hydrochloride=96%, and the product purity=99.3%.