GB467932A - Improvements relating to polymers of isobutylene - Google Patents

Abstract

Iso-butylene highly purified from poisons is polymerized below -40 DEG C. in the presence of a catalyst and of a suitable quantity of an added poison, viz. organic sulphur compounds, e.g. mercaptans, sulphides (including di- and polysulphides), ethyl thioether; hydrogen sulphide; sulphur; alkyl and hydrogen halides, e.g. fluorides, for instance tertiary-butyl fluoride, chlorides, hydrofluoric acid, hydrochloric acid; lubricating oils; aromatic hydrocarbons, e.g. benzene, toluene; normally liquid olefines; all used in quantities of up to 1 per cent; or n-butylenes or propylene, used in quantities of 10 to 25 per cent. Mixtures of poisons may be used, e.g. partially purified iso-butylene; cracked oils, especially the C4 cut therefrom which consists largely of butanes and butylenes with minor quantities of propane, propylene, pentane, and amylene). Iso-butylene substantially free from poisons is prepared by dehydration of tertiary- or iso-butyl alcohol, or by polymerizing the iso-butylene content of cracked light oils by sulphuric acid of 60 to 70 per cent strength, separating the polymer, and depolymerizing, e.g. by heat in the presence of depolymerization catalysts such as bauxite. The iso-butylene thus obtained may be distilled, washed with caustic soda, sodium plumbite, aqueous triethanolamine &c. to remove hydrogen sulphide and organic sulphur compounds. Polymerization of the purified isobutylene in the presence of the poison is preferably conducted in the presence of a diluent purified as described for iso-butylene or by hydrogenation: the diluent preferably consists of propane and/or butane with or without ethane or ethylene. The polymerization may be carried out in batch or continuously, using as catalysts, active halides, e.g. boron fluoride, aluminium chloride; sulphuric acid; or active clays. In an example, the iso-butylene content of a C4 cut is absorbed in 60 to 70 per cent sulphuric acid, the solution warmed, the polymers separated and depolymerized by activated clay. To one volume of this iso-butylene is added about 4 volumes of raw C4 cut and the mixture is polumerized below -40 DEG C. by boron fluoride. The polymers may be added to lubricating oils, gasoline, kerosene, gas oils, waxes, and greases. In further examples: polymers are referred to prepared in the presence of propane as diluent and of mercaptan (B.P. -30 DEG C.), ethyl thioether, and hydrogen sulphide, as poisons; there are added to lubricating oil polymers prepared in the presence of propane and of various quantities of C4 cut. Specifications 401,297, 432,310; and 437,934, [Group III], are referred to. The Specification as open to inspection under Sect. 91 comprises also the polymerization of iso-butylene only partially purified from poisons, no poison being added. In examples: impure iso-butylene is polymerized in the presence of propane, and the polymer added to lubricating oil; iso-butylene is polymerized in the presence of a crude refinery butane cut. This subject-matter does not appear in the Specification as accepted.ALSO:Iso-butylene highly purified from poisons is polymerized below -40 DEG C. in the presence of a catalyst and of a suitable quantity of an added poison, viz.: organic sulphur compounds, e.g. mercaptans, sulphides (including di- and poly-sulphides), ethyl thioether; hydrogen sulphide; sulphur; alkyl and hydrogen halides, e.g. fluorides, for instance tert-butyl fluoride, chlorides, hydrofluoric acid, hydrochloric acid; lubricating oils; aromatic hydrocarbons, e.g. benzene, toluene; normally liquid olefines; all used in quantities up to 1 per cent; or n-butylenes, propylene, used in quantities of 10--25 per cent. Mixtures of poisons may be used, e.g. partially purified iso-butylene; cracked oils especially the C4 cut therefrom (which consists largely of butanes and butylenes with minor quantities of propane, propylene pentane, and amylene). Polymerization is preferably conducted in the presence of a diluent purified from poisons, e.g. by hydrogenation: the diluent preferably consists of propane and/or butane with or without ethane and ethylene. The polymerization may be carried out in batch or continuously, using as catalysts active halides, e.g. boron fluoride, aluminium chloride; sulphuric acid; or active clays. In an example, the iso-butylene content of a C4 cut is absorbed in 60--70 per cent sulphuric acid, the solution warmed, the polymers separated and depolymerized by active clay. To one volume of this iso-butylene is added about 4 volumes of raw C4 cut and the mixture is polymerized below -40 DEG C. by boron fluoride. The polymers may be added to lubricating oils, gasoline, kerosene, gas oils, waxes, and greases. In further examples: polymers are referred to prepared in the presence of propane as diluent and of mercaptan (B.P.--30 DEG C.), ethyl thioether, and hydrogen sulphide, as poisons; there are added to lubricating oil polymers prepared in the presence of propane and of various quantities of C4 cut. Specifications 401,297, [Group IV], 432,310, and 437,934 are referred to. The Specification as open to inspection under Sect. 91 comprises also the polymerization of iso-butylene only partially purified from poisons, no poison being added. In examples: impure iso-butylene is polymerized in the presence of propane, and the polymer added to lubricating oil; iso-butylene is polymerized in the presence of a crude refinery butane cut. This subject-matter does not appear in the Specification as accepted.