Imperial Chemical Industries Limited

Michael S Spencer

Thomas V Whittam

Glyn D Short

Dennis Albert Dowden

Ian Robertson Shannon

A solution of a di-alkyl carbonate, e.g. dimethyl carbonate, in the corresponding alcohol, e.g. methanol, is concentrated by contacting the solution with a hydrophobic zeolite e.g. silicalite. The di-alkyl carbonate is absorbed preferentially. Where the solution also contains water, e.g. as in the case of the products from certain di-alkyl carbonate synthesis reactions, the water can be removed using a hydrophilic zeolite prior to recycle of the alcohol.

Carbonate production

A feedstock comprising a hydrocarbon containing 2 or more carbon atoms in the molecule and/or a hydrocarbon derivative containing hydrogen-carbon links is converted to olefins over the zeolite NU-3. When in particular the feedstock is methanol or dimethyl ether olefins are formed with high selectivity against formation of aromatics.

Olefins

A catalyst for hydrocarbon conversion contains a silica-containing material having a plate or sheet morphology, for example 'FU-1' and a material having catalytic activity for hydrocarbon conversion, for example rare-earth exchanged zeolite Y. The catalyst is especially suitable for cracking heavy fractions to naphtha-type products, apparently because the plate or sheet material provides channels by which large molecules can gain access to active centers in the catalyst.

Hydrocarbon conversion

Olefins are produced by reacting a feedstock containing a hydrocarbon containing 2 or more carbon atoms in the molecule and/or a hydrocarbon derivative containing hydrogen-carbon links over a catalyst comprising 'FU-1,' which is a zeolite-like silica-containing material characterized inter alia by chemical composition and X-ray diffraction pattern. The feedstock is preferably methanol or dimethyl ether. The predominant olefin product can be controlled according to the reaction conditions used. Conversion to aromatics is very low.

Hydrocarbon catalytic reactions (including isomerization, cyclization, aromatization, disproportionation, alkylation, de-alkylation, reforming, hydrcracking) are effected over a catalyst comprising a crystalline solid solution of two or more irreducible compounds differing in the valency of their cations and/or their anions. The catalysts may be made by heating together the components of the crystalline solid solution or compounds thermally decomposable thereto. Some of the catalysts contain one or more additional acidic materials which act as co-catalysts, and are new compositions of matter.

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Stockton-on-Tees, United Kingdom

Michael S Spencer