Patent GB-798592-A (GB)
Title: Improvements in or relating to polymerization of olefins
IPC: C08F4/14
Filed: 1956-04-23
Abstract: A catalyst for polymerizing olefines consists of a boron hydride or lower boron alkyl in admixture with an oxide of a metal of Group 5A or Group 6A of the Periodic Table.  Diborane is preferred, but BH3, B5H9, B6H10 or B10H14 may be used.  Oxides specified are of vanadium, niobium, tantalum, chromium, molybdenum, tungsten and uranium, and may be made by calcining the salts of oxy-acids, e.g. vanadates and molybdates.  In addition, other metal oxides may be present, e.g. of copper, tin, zinc, nickel, cobalt, titanium and zirconium. The oxide may be supported on active carbon, alumina, kaolin and similar compounds; low surface area supports, e.g. tabular alumina, silicon carbide, on metals e.g. anodized aluminium, slightly oxidized steel sheet; or on fluorides of alkali metals, alkaline earth metals, aluminium, gallium or indium.  A Group 5A or 6A metal oxide precipitated on aluminium fluoride as support is preferred, and may then be formed into powder, granules, or other shapes, or used as a coating on the reactor wall.  The content of boron hydride may be minimised by partially reducing the oxide component with hydrogen, hydrogen sulphide, sulphur dioxide, carbon monoxide, water, gas, or by hydrocarbons yielding hydrogen, e.g. paraffins, aromatics, and polyethylenes, using temperatures of 450 DEG  to 850 DEG  C. Olefines polymerized are preferably normally gaseous alkenes, but may contain more than one double-bond and also substituting groups, e.g. halogen and cyanogen.  Examples are butadiene, styrene, tetrafluorethylene and perfluorvinyl chloride.  The polymerizing reaction may be controlled by adding acetylene or carbon monoxide, which affects the molecular weight range of solid crystalline polymers produced. Diluents may be present, e.g. aliphatic and cyclo-diphatic hydrocarbons, aromatic or hydrogenated aromatic hydrocarbons. The diluent should be freed from catalyst poisons, and the polymerization reactants freed from water, oxygen, carbon dioxide and sulphur compounds.  In examples the catalysts used consist of vanadium, mobium, tungsten, molybdenum, or chromium oxide supported on alumina or zirconia admixed with di- or penta-borane, boron trimethyl or boron tri-n-butyl.  The polymers produced may be blended with lower molecular weight poly-ethylenes, or with waxes and hydrocarbon oils, e.g. lubricating oils, or they may be treated with halogens, sulphuryl chloride, or irradiated with high energy radiations.ALSO:Olefinic hydrocarbons, preferably normally gaseous alkenes such as ethylene, propylene, isobutylene, 1-butene, alone, in admixture or with monomers such as t-butylethylene, butadiene, isoprene, styrene, aralkyl styrene, tetra-fluoroethylene, and per-fluorovinyl chloride are polymerized in the presence of a catalyst consisting of a boron hydride or lower boron alkyl in admixture with an oxide of a metal of Group 5a or 6a of the Periodic Table.  Diborane is preferred but BH3, B5H9, B6H10, B10H14, boron tri-methyl or boron tri-n-butyl may be used.  Oxides specified are of vanadium, niobium, tantalium, chromium, molybdenum, tungsten, and uranium, and may be made by calcining the salts of oxy-acids, e.g. vanadates and molybdates.  In addition, other metal oxides may be present, e.g. of copper, tin, zinc, nickel, cobalt, titanium, and zirconium.  The oxide may be supported on active carbon, alumina, kaolin; tabular alumina, silicon carbide; or on metals, e.g. anodized aluminium, slightly oxidized steel sheet; or on fluorides of alkali or alkaline earth metals, aluminium, gallium or indium.  A Group 5A or 6A metal oxide precipitated on aluminium fluoride is preferred, and may then be formed into powder, granules, or other shapes, or used as a coating on the reactor wall.  The oxide/support may first be partially reduced with hydrogen, hydrogen sulphide, sulphur dioxide, carbon monoxide, water gas, or by hydrocarbons yielding hydrogen, e.g. paraffins, aromatics, and poly-ethylenes using temperatures of 450 DEG  to 850 DEG  C.  Olefines treated are preferably normally gaseous alkenes and may contain more than one double bond, and also substituents, e.g. halogens and cyanogen. Examples are: styrene, butadiene, isobutylene, tetrafluoroethylene, and perfluorvinyl chloride.  The polymerization may be controlled by adding acetylene or carbon monoxide which affects the molecular weight range of the solid crystalline polymers produced.  Diluents may be present, e.g. aliphatic or aromatic hydrocarbons, cycloaliphatic or hydrogenated aromatic hydrocarbons.  The diluent should be freed from catalyst poisons, and the reactants freed from oxygen, water, carbon dioxide and sulphur compounds.  The polymers produced may be blended with other polymers, or with waxes or lubricating oil, or they may be treated with halogens, sulphuryl chloride, or irradiated with high energy radiations.