QUICK SYNTHESIS OF ZSM-48 BY DIRECT TiO_2 ADDITION IN A SOLID REACTION MIXTURE SYSTEM

IntroductionZeoliteZSM-48wasfirstsuccessfullypreparedfromthehydrothermalanddouble-aminenoneque0ussysteminl980sl'2].Rccently,ithasbeensynthesizedinapuresolidsysteml3].Comparedwlththcpreviousmcthods,synthesisofZSM-48inapuresolidsystem,orsolidreactionmixturesystem,cangreatlyincreasetheyteldofproductsperunitvolume,sirnplifythesynthesisproceduresanddecreasetheenvironmentalpollution.However,ittakesmoretimetocompletecrystalIiZationthantheOthersdo.Therefore,itisnecessarytostudyhowthecrystallizati…

QUICK SYNTHESIS OF ZSM-48 BY DIRECT TiO2 ADDITION IN A SOLID REACTION MIXTURE SYSTEM

zeolite ZSM-48 has been successfully synthsized by using secondarily and thirdly added solid materials when the nuclei centers just formed in the original reation mixture or the crystallization completed. A small amount of mother liquor in an autoclave can be made full use. It is the basis of continuous prepartion of zeolites. The catalytic property of the catalyst using as-synthesized ZSM-48 as the support in the reaction of CO hydrogenation to light olefins is nearly the same as tha of ZSM-48 prepared by using originally added materials. The TiO2 dispesiveness in the ZSM-48 made by direct adding TiO2 into the srpthesis mixture is higher than that made by calcining the mixture of TiO2 and ZSM-48. Introduction of different amounts of TiO2 in the experimental range does not have strong influences on crystallization rate, but it affects fine structure of zeolites.TiO2 also alters the reducibility and adsorbaility of ZSM-48, and the introduction of a suitable amount of TiO2 into ZSM-48 can give high CO conversion and C2~C4 selectivity.