GB479657A - A process for the polymerisation of olefines - Google Patents

Abstract

Normally gaseous hydrocarbons containing tertiary and non-tertiary olefines of 4 and/or 5 carbon atoms are contacted at elevated temperature with a polymerization catalyst under such conditions that the tertiary olefines are predominantly polymerized to form gasoline-type polymers the residual gases then being subjected to thermal non-catalytic polymerization. Acid-acting catalysts, if desired in the form of solid complex compounds or incorporated in solid carriers, may be used. Such catalysts are mineral oxy-acids, e.g. phosphoric, phosphorous, sulphuric, and arsenic acids, phosphorus acid anhydrides, acid salts, and oxy-halides, inorganic halides, e.g. chlorides of Al, Zn, Mg, Fe, Ni, Be, Sn, and Ti, and fluorides of B, Be, As, and P, or their complex compounds with nitro-hydrocarbons, acids, ethers, or other metal halides, and acid-acting salts such as ZnSO4, CdSO4, PbSO4, BiOCl, and Cd3(PO4)2. Calcined mixtures of phosphoric acids and siliceous materials are particularly suitable. Metals, e.g. Zn, Al, and Group 8 metals, and hydroxy compounds, e.g. water and alcohol, may be used in conjunction with the catalysts. The olefine-containing gases may be treated with an absorption oil to remove C3 or C2 hydrocarbons and heavier, the oil then being fractionated to obtain a C3 or C2, C3 fraction, and a C4 and heavier fraction. This latter fraction is heated to 250--425 DEG F. and passed over the catalyst, the product then being fractionated to separate the polymer and residual gases which, if desired after addition of the previously separated C3 or C2, C3 fraction, are heated to above 900, preferably above 1100 DEG F., and passed through a reactor in which time is allowed for polymerization. Superatmospheric pressures may be employed. The product is quenched, e.g. with polymer gasoline produced in the process, to cool it below about 800 DEG F. and is fractionated to separate tar and heavy polymers, and residual gas from the gasoline-like polymers which are largely aromatic. This residual gas may be returned to the oil absorption stage or part mixed with the residual gases from the catalytic polymerization. By the use in the catalytic polymerization of a temperature of about 300--425 DEG F., and preferably below 400 DEG F., and by limiting the time so that the ratio of tertiary to total olefines polymerized is not less than about 0.5, a gasoline of high octane number and lead response, particularly after hydrogenation, is obtained. If the catalytically treated reaction mixture contains free acid it may be neutralized prior to further treatment.