Patent GB-487166-A (GB)
Title: A process for the production of polymerisation products of tertiary olefines
IPC: C07C2/14
Filed: 1936-12-15
Abstract: Polymerized tertiary olefines of high anti-knock value are produced by contacting the olefines with an aqueous mineral acid of less than 50 per cent concentration at a temperature above 100 DEG  C. and at a superatmospheric pressure at which conversion to a dimer thereof takes place at a practical rate.  Pure tertiary olefines, or mixtures thereof, or mixtures with paraffins and/or other compounds such as other olefines which may or may not undergo interpolymerization, may be treated.  Specified other p  olefines are ethylene, propylene, 1-butene, 2-butene, 1-pentene, 2-pentene, 3-methyl-1-butene. Olefinic mixtures consisting of hydrocarbons containing the same number of carbon atoms to the molecule are advantageously used. Reference is made to the production of dimers of 2-methyl propene and/or 2-methyl-1-butene and/or 2-methyl-2-butene, and polymers of the tertiary hexylenes. The process is particularly described with reference to the production of di-isobutylene.ALSO:Tertiary olefines are polymerized by contact with an aqueous mineral acid of less than 50 per cent concentration at a temperature above 100 DEG  C. and at a superatmospheric pressure at which conversion of the olefine to a dimer thereof takes place at a practical rate.  Pure tertiary olefines, or mixtures thereof, or mixtures with paraffins and/or other compounds such as other olefines which may or may not undergo interpolymerization, may be treated.  Specified other olefines are ethylene, propylene, 1-butene, 2-butene, 1-pentene, 2-pentene, 3-methyl-1-butene. Suitable sources of the tertiary olefines are hydrocarbons derived from mineral and shale oils, natural gas, or from coal, peat, &c., animal or vegetable oils, fats and waxes.  The olefines may result from dehydrogenation, distilling, cracking, &c. They may also be obtained by dehydrating alcohols.  Olefine mixtures consisting of hydrocarbons containing the same number of carbon atoms to the molecule are advantageously used.  Reference is made to the production of dimers of 2-methyl propene and/or 2-methyl-1-butene and/or 2-methyl-2-butene, and polymers of the tertiary hexylenes. Suitable mineral acids are phosphoric and sulphuric acids.  Other agents such as the corresponding salt of a nitrogen base may be present.  A lower acid concentration limit of 0,5 per cent, and an upper temperature limit of about 350 DEG  C. are specified.  A temperature of 200-250 DEG  C. is suitable for the selective polymerization of isobutylene in the presence of secondary butylenes. The pressure employed ranges between that corresponding to the vapour pressure of water at the operating temperature and 700 atmos.  The olefine treated may be in the gaseous, liquid or both phases.  The process is particularly described with reference to the production of di-isobutylene. Isobutylene, or a butane-butylene fraction of cracked petroleum oil containing it, is passed under pressure through aqueous sulphuric acid, preferably together with part of the totally condensed effluent material from the polymerizer.  The feed material is preheated by countercurrent with the effluent, and then brought to the reaction temperature in a second preheater. Water removed from the system is replaced, preferably by direct introduction into the polymerizer, but water or steam may be added at other points.  The feed is preferably introduced near the bottom of the polymerizer. The reaction products and water vapour are totally condensed, and the effluent is run to a separator maintained at the vapour pressure of the liquid.  The whole of the separated aqueous layer is returned to the polymerizer, whilst the polymer layer is fractionated to separate unconverted isobutylenes and tertiary butyl alcohol, which may be added to the polymerizer feed.  Tertiary butyl alcohol may, however, be recovered as a bye product.  A table is given showing the results obtained under different working conditions.  The polymerized olefines are of high anti-knock value and may be used as or in fuels.