Study On Modification Of Zeolite Molecular Sieve And Their Catalytic Performance In Alkylation Of Benzene With Methanol

Toluene as an important intermediate and product of chemical industry,it is widely used in chemical industry,medicine,textile,printing and dyeing.At present,the main production methods of toluene are coal tar fractionation and petroleum aromatization.With the rapid development of coal chemical industry in our country,the market of benzene is relative excess supply,methanol market well supplied,using toluene,benzene alkylation reaction and methanol production is a new kind of toluene production way.The rate of conversion of reactants and the yield of toluene in the methanol alkylation of benzene and methanol has become the focus of researchers in this field.In response to the above problems,a highly efficient,economical and environment-friendly catalyst is what the researchers have been pursuing.This thesis mainly studies the ZSM-5 zeolite and modified mordenite zeolite,by XRD,BET,Py-IR analysis means such as the structure,morphology,acid and other properties of the catalysts were characterized,and the objective product selectivity and yield of toluene to evaluate the performance of the catalytic system.The following four aspects are mainly discussed:?1?By means of equal volume impregnation method,Nd and Ce were used to modify HZSM-5,and the Nd/HZSM and Ce/HZSM-5 load molecular sieve catalysts were prepared.Using the ion exchange method,the zeolite zeolite was modified by using formic acid and citric acid to obtain the catalyst of H-MOR₁ and H-MOR₂molecular sieve.?2?By means of XRD,BET and Py-IR,FT-IR,SEM,NH₃-TPD,TG,icp-aes characterization methods of rare earth modified HZSM-5 and formic acid modified mordenite zeolite test,discusses the structure of the above two kinds of molecular sieve catalyst,morphology and the change of the channel change,thermal stability and acid.?3?Thecatalyticperformancewasevaluatedbyasingle-waytube reactor.Explores the Ce/HZSM 5 molecular sieve catalyst in benzene,methanol mole ratio of 1:1,reaction pressure 1.5 MPa,the temperature of 400?,the reaction time of3.5 h,quality airspeed 2.5 h^-1,Ce load mass fraction 4%,catalyst loading quantity of2.5 g,it is concluded that the conversion of benzene is 73.72%,the selectivity and yield of toluene was 56.77%,41.85%,respectively.?4?explores the formic acid modified mordenite zeolite catalysts?H-MOR₁?in3.0h reaction time,reaction pressure to atmospheric pressure condition,WHSV=2.0h^-1,the reaction temperature 400?,the molar ratio of benzene/methanol 1:1,formic acid capacity of 1 mol/L.In this reaction,the conversion rate of benzene was 48.44%,and the selectivity and yield of toluene were 89.31%and 43.26%,respectively.