Acetone Ammoximation Over Titanosilicate Zeolite

Acetone oxime is an important fine chemical product, with low toxicity, environmental friendly and high reducibility performance. With these advantages, acetone oxime can replace the highly toxic N2H4as a large-scale boiler deaerator inhibitors, and can be used as intermediates in organic synthesis and so on. Usually, the traditional crafts of acetone oxime synthesis is depend on hydroxylamine method, but there are serious environmental pollution, low production efficiency, low atomic economy and other shortcomings. Therefore, developing new process of green synthesis way of acetoxime is necessary. Titanium silicalite/H2O2system used in catalytic synthesizing of acetone oxime is a new process, which is environmental friendly, is a green chemical process.This paper investigates the basic law of the process of acetone oxime synthesis catalytic in titanium silicalite/H2O2system, and gets some constructive results which can good for acetone oxime industrial production.1. Titanium Silicalite Ti-MWW is an efficient catalyst for catalytic synthesis of acetone oxime in acetone ammoximation. Studies have shown that, Ti-MWW is high active and high selectivity in synthesis of acetone oxime.The optimal conditions are that reaction temperature is333K, solvent is pure water, the amount of catalyst is0.50g (for50mmol acetone), reaction time is2h, ammonia and acetone molar ratio is1.6, hydrogen peroxide and acetone molar ratio is1.2. Catalytic effect of the catalyst is that the conversion rate of acetone and selectivity of acetone oxime are99%or more, and the catalyst can be reused more than10times.2. Titanium silicalite TS-1can also achieve desired reaction results, but is requires harsh reaction conditions relatively. The best condition are that, reaction temperature is333K, tert-butanol and water are co-solvents, which the tert-butyl alcohol is12g, water is13g, catalyst is0.7g (for50mmol acetone), reaction time is2h, hydrogen peroxide and acetone molar ratio is1.2, ammonia and acetone molar ratio is4.0or more.3. Experimental results show that in titanium silicalite/H2O2system, the acetone ammoximation process is due to hydroxylamine mechanism. First step of this mechanism is reaction made on the active sites of titanium silicalite catalyst, ammonia and hydrogen peroxide are got reacting, which product is hydroxylamine. The second step is hydroxylamine and acetone getting non-catalytic reaction to generate acetone oxime.4. In the titanium silicalite/H2O2system acetone ammoximation process, excessive ammonia can be partly replaced by organic base, such as Tetrapropylammonium hydroxide (TPAOH).