Synthesis of #alpha#-olefin by oligomerization of ethylene (part 5) post-treatemnt of catalysts

摘要

Post-treatment of ZrCl_4-EASC-TEA catalysts was studied after the oligomerization of ethylene.Three types of osttreatment were necessary for the industrial process,flashing to recover unreacted ethylene,inactivatio to inactivate thecatalyst,and deliming to remove the metalcatalyst.By-products were formed in the flashig by the insertion of interproducts were formed in the flashing by the insertion of intermediate #alpha#-olefin intothegrowing polymeric ethylene chain similar to the oligomerizationof ethylene,and the purity of the #alpha#-olefin was reduced,not by formationf inner olefins,but by formation of vinylidene-type olefins and branched-olefins.The decrease in #alpha#-olefin purity and the formationof organic chlorine compounds were suppressed by addition of organic chlorine compounds were supressed by additionof water to about 0.6 times molar ratio of the co-catalsyt alkyl aluminums.By-product organic chlorine compounds were formed int ehinactivation section by the addition reaction of HCl generated by inactivation of the catalyst.The rate f addition of HCl to #alpha#-olefin was constant,and independent of the carbon number of the #alpha#-olefin.The formation of organic chlorinecompounds was reduced to 1 ppm by using 20% aq.NH_3 as quencher,anaq.NH_3/solvent ratio greater than 0.06 and stirring power per unti volume greater than 0.5kW/m~3.Inactivation can be achieved at a relatively high temperature,so continuous operation could be achieved witihout the deposition of polymer.The deliming section also requires a ralatively high temperature at whichpolymer can be dissolved,because most metalcompounds of the catalyst are present in the by-product polymer formed by theoligomerization of ethylene.Metals could be almost completely removed from the products by deliming at a temperatue higher than 110degC,water/oil phase ratio higher than 0.2,and interfacialarea above 1*10~4 m~2/m~3.