Study On The Catalyst And Technology Of The Synthesis Of Diisopropylbenzene

p-diisopropylbenzene(p-DIPB) is an important organic intermediate,there are two main ways of preparation of DIPB,one way is the alkylation of benzene or cumene with propylene or isopropyl alcohol;another way is the cumene disproportionation.In this paper,the alkylation of cumene with isopropyl alcohol and cumene disproportionation for preparing p-DIPB on Hβzeolite was studied.However,in those two ways there are disadvantage such as low selectivity of primary reaction,low conversion and equal selection fore m-DIPB and p-DIPB.To eliminate these problems,much attention has been paid to the development of solid catalysts.In this paper,alkylation of cumene with isopropyl alcohol for preparing p-DIPB on Hβzeolite was studied in autoclave and the catalystic performances of cumene disproportionation were evaluated by a fixed-bed micro-reactor operated under medium pressure.Several factors such as the deposition amount of silica and phosphor,the calcinating atmosphere, modification numbers and so on,which affect the effect of modification have been investigated.The means of XRD,FT-IR,NH3-TPD,BET etc.were used to characterize the catalysts,and these results were related to catalytic performance.Some conclusions were obtained.(1) When zeolite Hβused as the catalyst for alkylation of cumene with isopropyl alcohol, the optimal reaction conditions are that the decalin is the best solvent,and the mole ratio of isopropyl alcohol to cumene is 5:1,catalyst dosage is 10w%,reaction temperature is 240°C, and reaction time is 8 hrs.Under optimal reaction conditions,the conversion of cumene can reach 40.92%,the selective of p-DIPB can reach 45.73%.(2)The deposited modifier reacted with silanol groups and framework silanol groups on the external surface of zeolite under the heated condition and formed the silicon oxides;acidic sites on the surface of zeolite were passivated by SiO2 deposition.The acidic property on the external and internal surface of zeolite could be adjusted by choosing the modifier with different molecular volume.The conversion rate of cumene on modified zeolite catalyst down to 8.49%,and the selective of p-DIPB reach 63.00%.(3)As for modification of Hβzeolite,we attempt some metal surfactant such as P,Cu,B.Result show,cupric nitrate,ammonium dihydrogen phosphate and boric acid were ideal surfactant.These zeolite were modified by metal can able to increase the conversion rate of cumene.(4)In this paper,the shape-selective disproportionation of cumene was studied,the optimal conditions were selected as follws:temperature is 220~240℃;initial pressure is 1.0~1.5 MPa;1.0~2.5 of molar ratio of H2/cumene;WHSV is 1.5~2.0.In this condition, the conversion of cumene can reach 40.92%,the selective of p-DIPB can reach 45.73%,the study of reaction indicated that relatively low reaction temperature and low WHSV favored the increasing of the yield of p-DIPB and the catalyst has good stability.