Catalytic Etherification Performance Of High Stability Modified β Molecular Sieve

Because of the unique porous system with three-dimensionaltwelve-membered ring, β zeolite molecular sieve has good ion exchange,selective absorption and catalytic performance. Its structure andproperty can be modified. It is also wildly used in some fields, such aspetroleum chemical industry and Environmental protection. Especiallyin etherification reaction, zeolite molecular sieve gradually becomes themost potential etherification catalyst.Pickling to take off the aluminum was used to modify β zeolitemolecular sieve in this paper. The catalytic performance ofβ(hydrochloric acid), β(citric acid) and β zeolite molecular sieve wascompared with ethanol and tertiary butanol as the raw materials, D-06resin catalyst as reference under different process conditions(mole ratioof ethanol and tertiary butanol, space velocity, reaction temperature,acid concentration, temperature and time of acid treatment). Theexperimental results show that the reaction activity of β (HCl) zeolitemolecular sieve is better than resin, β(citric acid) and β zeolitemolecular sieve, and the yield of ETBE can be41.30%.The useful life of β(hydrochloric acid), β(citric acid) and β zeolitemolecular sieve was investigated with D-06resin catalyst as referenceunder the optimum process conditions. The experimental results showthat the useful life of D-06resin catalyst is the longest, the useful life ofβ zeolite molecular sieve is70h which is the shortest, the useful life ofβ(hydrochloric acid) zeolite molecular sieve is105h, and the useful lifeof β(citric acid) zeolite molecular sieve is115h.β zeolite molecular sieve was characterized by fourier infraredchromatography, X-ray diffraction and N2adsorption-desorption technology. The experimental results show: no matter the β zeolitemolecular sieve modified by hydrochloric acid or citric acid, nonframework aluminum and transition state aluminum are taken off first,and then the framework aluminum. The deprivation degree of β zeolitemolecular sieve modified by hydrochloric acid is more obvious than βzeolite molecular sieve modified by citric acid. In addition, whenmodified by citric acid, adding aluminum effect also exists.