Patent GB-823194-A (GB)
Title: Improvements in or relating to olefine polymerisation processes
Inventor: SZEWSKI WLADYSLAW HENRY SKORO
IPC: C08F10/00
Filed: 1958-06-13
Abstract: A catalyst for polymerization of olefines (particularly ethylene, but higher olefines and olefinic mixtures are not excluded) is formed by mixing (1) a reducing metal of Groups I, II or III, preferably Al, but also e.g. alkali metals such as Na or K, as well as Mg, Zr, Cd, Hg, Ga, In, TI; (2) a compound of a metal, which is in its normal maximum valency state, of Groups IVA, VA, VIA, VIIA or VIII; and (3) a separately prepared compound of a metal, in a lower than normal maximum valency state, of Groups IVA, VA, VIA, VIIA or VIII.  It is preferred that the metals of compounds (2) and (3) are identical and that the said compounds are inorganic, particularly halides, especially chlorides; the metal of compounds (2) and (3) is then preferably Ti (said compounds being especially (a) TiCl4 plus (b) TiCl3 or TiCl2 or mixture thereof), but may also be, e.g. Zr, V, Hf, Th, Ch, Ta, Cr, Mo, W, U, Fe, Co, Ni, Mn.  The said reducing metal is preferably in the form of "flitters," i.e. platelets of surface area exceeding 600 cm2/gm. but at least 75% do not pass a 100 mesh sieve; more preferably it is in the form of "fine flitters," i.e. platelets of surface area exceeding 1000 cm2/gm. with the aforementioned sieve requirement.  The catalyst components are preferably mixed in an inert solvent, e.g. pentane, hexane, isobutane, isooctane, benzene, toluene or a light petroleum distillate b.p. 90-110 DEG  C. In polymerization, the catalyst is preferably suspended in an inert hydrocarbon medium which is preferably a essentially non-aromatic solvent such as isooctane, n-hexane or a light petroleum fraction but may also be e.g. o-dichlorobenzene.  In the example, the ingredients are TiCl3 (by interaction of TiCl4 and ClAl(C2H5)2), TiCl4, Al "fire flitters" and a hydrocarbon solvent, boiling between 90 DEG  and 110 DEG  C. and of aromatic content about 10% by weight.ALSO:Olefines, particularly ethylene but also possibly higher olefines and olefinic mixtures, are polymerized by use of a catalytic mixture of (1) a reducing metal of Group I, II or III; (2) a compound of a metal in its normal maximum valency state of Groups IVa, Va, VIa, VIIa or VIII; and (3) a separately prepared compound of a metal in a lower than normal maximum valency state of Groups IVa, Va, VIa, VIIa or VIII; the preferred catalyst comprises Al, TiCl4 and TiCl3, the latter being prepared, preferably, by TiCl4(C2H5)2AlCl interaction. Polymerization may be continuous or batchwise and polymerization conditions preferred are: 60-220 DEG  and below 500 atm.  Preferably the polymer is isolated by first removing free solvent, then treating with, e.g., methanolic or aqueous HCl, particularly with heating; then washing with, say, 1% aqueous acid, then with aqueous alkali until the polymer is slightly alkaline and finally with alcohol.  The ethylene used should preferably contain less than 30 p.p.m. by weight of all impurities (disregarding hydrogen and saturated hydrocarbon), as e.g. acetylene 1 p.p.m., oxygen 15 p.p.m. and carbon monoxide 5 p.p.m,; purification of ethylene may be carried out, for example, with ammoniacal cuprous chloride, acetone, catalytic hydrogenation, or Al triethyl in iso-octane.  The polymer's molecular weight may be controlled by the presence of an alcohol.  In polymerization, the catalyst is preferably suspended in an inert hydrocarbon medium, preferably an essentially non-aromatic solvent such as isooctane, n-hexane or a light petroleum fraction, but o-dichlorobenzene, for example, may also be used (in the example, the hydrocarbon solvent boils between 90 DEG  and 110 DEG  C. and is of about 10% by weight aromatic content).  Said medium should also be pure; thus e.g. the isooctane or light petroleum distillate can be purified by washing with concentrated H2SO4, water, aqueous alkali and water again, and distillation over sodium in a nitrogen atmosphere.