Patent ID: 6262314
Filing Date: 2001-07-17
Classification: B01D,C07C,Y02P,Y10S

Abstract:
A process for preparing ethers, comprising the steps of:providing a feedstock containing iso-olefins selected from the group consisting of C5 iso-olefins, C6 iso-olefins and mixtures thereof,;mixing said feedstock with alkyl alcohol so as to provide a reaction feedstock,feeding said reaction feedstock to a reactor zone in the presence of a first etherification catalyst whereby said alkyl alcohol reacts with said iso-olefins to form alkyl-tert-alkyl ethers so as to provide an intermediate feedstock containing said ethers and unreacted iso-olefins and alkyl alcohol;feeding said intermediate feedstock to a catalytic distillation column having a second etherification catalyst defining a catalytic zone;mixing additional alkyl alcohol to said intermediate feedstock upstream of said catalytic zone wherein said step of feeding said intermediate feedstock and said mixing steps are carried out so as to provide a molar ratio of total alkyl alcohol to said unreacted iso-olefins of between about 2.5 and 6.0 so as to form azeotropes of said alkyl alcohol with said unreacted iso-olefins without forming azeotropes of said alkyl alcohol with said ethers whereby said azeotropes of said alkyl alcohol with said unreacted iso-olefins flow to said catalytic zone and said ethers are removed as bottoms from said catalytic distillation column wherein said catalytic zone is substantially free of said ethers and wherein said unreacted iso-olefins in said catalytic zone react with said additional alkyl alcohol in said catalytic zone to form additional alkyl-tert-alkyl ethers which are removed as bottoms.