Patent GB-790195-A (GB)
Title: Improvements in or relating to polymerization of olefins
IPC: C08F2/00
Filed: 1954-01-15
Abstract: Olefines are polymerized at a temperature up to approximately 450 DEG F. in the presence of a catalyst comprising chromium oxide, at least a portion of the chromium being in the hexavalent form, and at least one member of the group consisting of silica, alumina, and silica-alumina composites.  Ethylene, propylene, 1- and 2-butenes, 1- and 2-pentenes, 1- and 2-hexenes, 1-and 2-hexenes, 1- and 2-octenes, 1-dodecene, isobutylene, 2 - methyl - 1 - butene, 3 - methyl - 1 - butene, 4 - methyl - 1 - pentene, 4 - vinylcyclohexene, a -methyl-2-butene, cyclohexene, butadiene and isoprene are mentioned. 1-Olefines having a maximum of 8 carbon atoms and no branching nearer the double bond that the 4-position, yield tacky, semi-solid and/or solid polymers. Diluents such as propane, isobutane, n- and iso-pentane, and iso-octane may be present and polymerization effected at a pressure, e.g. 100 to 500 p.s.i.g., sufficient to maintain the diluent in the liquid state at a temperature within the range 150 DEG  to 450 DEG  F., preferably 275 DEG  to 375 DEG  F. for ethylene, 170 DEG  to 245 DEG  F. for propylene and 150 DEG  to 350 DEG  F. for higher 1-olefines. The catalysts may be prepared as described in 790,196, [Group III], and may be used in a fixed or moving bed as a suspension. Polymers or copolymers prepared by this method have a major proportion of their double bonds present in the form of transinternal and/or vinyl groups and branched vinyl groups are substantially absent.  The tacky products may be used in pressure-sensitive tapes, sealing compounds, laminated and tracing papers, hydraulic fluids, electrical capacitors, surface coatings and rubber extenders or may be blended with lubricating oils as viscosity index improvers.  Specification 619,231 also is referred to.ALSO:Lubricating oils, or viscosity index improvers, for lubricating oils, comprise polymers of olefines prepared by polymerization at a temperature up to approximately 450 DEG  F. using a catalyst comprising chromium oxide, at least a portion of which is in the hexavalent form, and at least one member of the group consisting of silica, alumina and silica-alumina composites (see Group IV (a)).  Examples of the use of polymers of propylene, 1-butene, 1-pentene, 1-hexene and 4-methyl-1-pentene and copolymers of 1-hexene with 4-methyl-1-pentene and 1-butene with propylene are given.  The addition of the polymers, as viscosity index improvers, to SAE10 or SAE 20 lubricating oil is described. Specifications 619,231 and 790,196 are referred to.ALSO:Olefines are polymerized, at a temperature up to approximately 450 DEG  F., in the presence of a catalyst comprising chromium oxide, at least a portion of the chromium being in the hexavalent form, and at least one member of the group consisting of silica, alumina and silica-alumina composites. Ethylene, propylene, 1- and 2-butenes, 1- and 2-pentenes, 1- and 2-hexenes, 1- and 2-octenes, 1-dodecene, isobutylene, 2-methyl - 1 - butene, 3 - methyl - 1 - butene, 4-methyl - 1 - pentene, 4 - vinylcyclohexene, 2-methyl-2-butene, cyclohexene, butadiene and isoprene and mentioned.  1-Olefines having a maximum of 8 carbon atoms and no branching nearer the double bond than the 4-position, yield tacky, semi-solid and/or solid polymers.  Diluents such as propane, isobutane, n- and iso-pentane, and iso-octane may be present and polymerization effected at a pressure, e.g. 100 to 500 p.s.i.g., sufficient to maintain the diluent in the liquid state at a temperature within the range 150 DEG  to 450 DEG  F., preferably 275 DEG  to 375 DEG  F. for ethylene, 170 DEG  to 245 DEG  F. for propylene and 150 DEG  to 350 DEG  F. for higher 1-olefines.  The catalysts may be prepared as described in Specification 790,196 (see Group III) and may be used in a fixed or moving bed as a suspension. In an example propylene is polymerized in the presence of chromium oxide deposited on a major proportion of a silica-alumina support, at a temperature of from 150 DEG  to 300 DEG  F., preferably from 170 DEG  to 245 DEG  F., under a pressure of at least 300 p.s.i.g., to give a tacky, semi-solid product which may be (a) extracted with pentane to yield a solid polymer, and the pentane soluble fraction extracted with methyl isobutyl ketone to yield an oily and tacky polymer; or (b) fractionated under vacuum to produce a liquid overhead fraction, and a bottoms fraction from which the tacky polymer is extracted with methyl isobutyl ketone leaving the solid polymer.  In a modification propylene is dimerized with a nickel oxide-silica-alumina catalyst to a mixture of 4-methyl-1-pentene, 4-methyl-2-pentene, 2-methyl-2-pentene and 1-, 2-, 3-hexenes which are isomerized to a mixture of 4-methyl-1-pentene and 1-hexene, which is polymerized or admixed or separated, at a temperature of 100 DEG to 300 DEG  F. to a tacky semi-solid polymer.  Polymers or copolymers of olefines prepared by this method have a major proportion of their double bonds present in the form of trans-internal and/or vinyl groups and branched vinyl groups are substantially absent. Polyethylene of this type has an average molecular weight of 5,000 to 30,000, a melting point of 235 DEG  F. to 260 DEG  F. and a density of 0.92 to 0.97, and polypropylene an average molecular weight, based on viscosity, of 500 to 20,000 and may comprise a liquid fraction boiling in the range 400 DEG  to 900 DEG  F., a tacky fraction boiling above 900 DEG  F. of molecular weight 500 to 5000, soluble in pentane and methyl isobutyl ketone, and a solid fraction of M.P. 240 DEG  to 300 DEG  F. and a density of 0.90 to 0.95.  The tacky product may be used in pressure-sensitive adhesive tapes, sealing compounds, laminated and tracing papers, hydraulic fluids, electrical capacitors, surface coatings and rubber extenders or blended with lubricating oils as the viscosity index improvers.  Specification 619,231 also is referred to.