GB601202A - Improvements in and relating to the production of branched chain alkenes - Google Patents

Abstract

Alkenes are converted to more highly branched isomers by contact at 100-600 DEG C. and a pressure not exceeding 20 atm., in the presence of not less than an equal volume of a diluent, with an acid phosphate of copper or a mixture thereof with an acid phosphate of cadmium or of an alkaline earth metal. The catalysts may be prepared, for example, as described in Specifications 460,659 and 535,062, by partial neutralization of phosphoric acid with the metal carbonates or oxides or addition of phosphoric acid to the normal phosphates. They can be used in a dry, hard, porous state or on carriers such as active carbon or kieselguhr. Diluents include nitrogen, hydrogen, water vapour, methane, butane or other saturated hydrocarbon, generally in the ratio of diluent to alkene of 1 to 10 : 1, preferably 2 : 1, by volume under the reaction conditions. Where cracked alkene fractions are used as feedstock, saturated hydrocarbons within the range specified are generally present. Small amounts of water are preferably also added. A continuous vapour phase process is advantageous. Normal butene fractions may be treated to increase the isobutene content to, say, 10 per cent, followed by interpolymerization of the butenes, and further isomerization of the residue. In examples, normal butene with an equal volume of water vapour is passed over copper-cadmium or copper-calcium acid phosphate at about 300 DEG C. and atmospheric pressure while a normal butene fraction containing an excess of butanes over butenes is passed with water in a mass ratio to hydrocarbon of 0.9 or 0.1 over the same catalysts at 350 DEG C. and 80 p.s.i. Specification 496,676 also is referred to. The provisional Specifications refer to the use of acid phosphates of metals of Groups 1, 2, 3, 4, 6, 7 or 8 with or without normal phosphates.