Process for the structural isomerisation of n-alkenes, catalysts for carrying out this process and process for preparing this catalyst

摘要

n-Alkenes can be converted into the respective i-alkenes by structural isomerisation, by treating these n-alkenes or hydrocarbon streams containing such n-alkenes at a temperature from 300 to 550 DEG C and a pressure from 100 bar to 10 bar over a catalyst which consists of a gamma -Al2O3 having a purity of at least 99.5% by weight and an SiO2 doping of between 0.05 and 0.5% by weight, relative to the quantity of the undoped gamma -Al2O3. Hydrogen can be added to the hydrocarbon feedstream in an H2/n-alkenes molar ratio of 0.5-10 : 1. The catalyst can be prepared by treating a gamma -Al2O3 with a solution of a tetraalkyl orthosilicate, which can be decomposed at an elevated temperature, in an inert solvent, followed by evaporation of the solvent and thermal decomposition of the tetraalkyl orthosilicate.