Study Of Methyl Tert-Butyl Ether Decomposition For Isobutene

Isobutene is an important basic organic chemical material; it is also one of the important monomers of synthesized rubber. The main use of isobutene is to product butyl rubber, poly-isobutene, MMA, isoprene, tert-butylamine and other chemical products. Now the market requirements is more than 20 million t/a.The most widely used technical way to produce isobutene is through MTBE decomposition. The technics can be divided into gas phase decomposition and liquid phase reaction-distillation.The method that through MTBE decomposition to produce isobutene was studied in this dissertation.Firstly, by using the macro porous strongly acidic styrene type cation exchange resin(H) as catalyst, the intrinsic reaction kinetics of MTBE liquid phase decomposition was studied. Kinetic parameters, k and E_a, were fitted according to the experimental data.Secondly, the catalyst used in MTBE gas phase decomposition was mainly studied in this article. On the basic study of sulfate/γ-Al₂O₃ catalysts, we know that the catalytic activity and property were strongly related to total acid value, Bronsted acid value and Lewis acid value of the catalyst. After we knew this principle, a new kind of MTBE decomposition catalyst was developed. It was bisulfate load on carrier. Carrier used here can be γ-Al₂O₃, SiO₂, molecular sieve or activated carbon, γ-Al₂O₃ was the first choice. The effects of drying temperature, dipping amount, dipping time and reaction conditions on the catalytic performance had been studied.It was proved that the said catalyst was an excellent solid acid catalyst. The MTBE conversion, methanol selectivity and isobutene selectivity are respectively 97.7%, 98.7% and 99.8% under the condition of 170℃, 0.1MPa, LHSV=2h^-1 on the micro-pilot.The surface acid property of the said catalysts were studied in this article. The surface acid include Bronsted acid and Lewis acid. After the dipping of bisulfate, Bronsted acid value was obviously promoted. The high value of B/L is good for MTBE conversion and methanol selectivity.