Imperial Chemical Industries Limited

Richard R Cooper

Kenneth Stephenson Whiteley

David G Parker

A polyarylsulphone is prepared by the polycondensation of a bisphenol with an aryl dichloride, at least one of which contains a sulphone group, in the presence of a base and introducing into the reaction mixture less than 5% mole, relative to the aryl dichloride, of 4,4'-difluorodiphenylsulphone. The bisphenol and aryldichloride can be of 4,4'-dihydroxydiphenylsulphone and 4,4'-dichlorodiphenylsulphone respectively. The difluoro compound is added when the polymerisation is essentially complete. The polymer product if of improved quality.

Preparation of polyarylenesulfone from bis(chloroaryl) sulfone, dihydric

Ethylene is copolymerized in the gas phase, for example in a fluidized bed, using a gaseous mixture comprising ethylene, at least one olefine monomer containing at least 4 carbon atoms, an inert gaseous diluent and, optionally, hydrogen at a total absolute pressure of at least one MN/m.sup.2. The comonomer preferably contains 6 or 8 carbon atoms. The partial pressure of the comonomer may be in the range from 1 kN/m.sup.2 up to 550 kN/m.sup.2. The inert gaseous diluent typically has a partial pressure of at least 250 kN/m.sup.2 and forms 20% molar of the gaseous mixture. The inert gaseous diluent may be nitrogen and is preferably ethane.

Ethylene copolymerization using diluent gas

Ethylene is polymerised or copolymerised using a transition metal catalyst at a pressure in the range 300-1000 atmospheres and a temperature of at least 100.degree. C in the presence of a volatile inert diluent such as pentane, or at least one 1-olefine comonomer such as buten-1, or both. The catalyst can be a Ziegler type catalyst, an organo-compound of a transition metal such as a substituted silylmethyl, cyclopentadienyl, arene, norbornyl, .pi.-allyl or benzyl compound and may be supported on a suitable support such as silica, alumina, or magnesia. Other catalysts which may be used are supported chromium or molybdenum oxides. If a solid catalyst is used it is preferred to use a material which has been finely dispersed.

Ethylene polymerization

Ethylene is polymerized or copolymerized using a pressure of at least 300 kgm/cm.sup.2 and a multi-zone (i.e. two or more) reaction vessel wherein the feed to the first zone is fresh ethylene, which is preferably mixed with recycle gas from the low pressure hopper and into at least a subsequent zone there is introduced a feed containing return gas recycled from the separator. By this technique the composition of the gas feed to the various zones can be varied, for example the hydrogen content of the gas streams to the various zones can be varied and this can produce a polymer of broader molecular weight distribution.

Growing community of inventors

Cleveland, United Kingdom

Richard R Cooper