Purification and polymerization processes

摘要

The purification of hydrocarbons for use and/or which have been used as diluents in the polymerization of a -olefins is effected by distilling with an alkali metal hydroxide or alkoxide and passing the distillate through an adsorbent. The hydrocarbon may be pentane, hexane, heptane, n- or iso-octane, high molecular weight liquid paraffin mixtures, naphtha, mineral spirits, cyclohexane, methyl cyclohexane, tetra- or deca-hydronaphthalene, benzene, toluene, xylene, ethylbenzene, n- or iso-propylbenzene, ethyl-toluene, diethylbenzene or mono- or di-alkyl naphthalenes. The purification can be applied to diluents used in polymerization processes using a Group 6a metal oxide catalyst or to Ziegler-type catalyst comprising a mixture of a transition metal compound and a metal or metal hydride, or organometallic compound. The olefins polymerized may be ethylene, propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, 1-octene, 1-decene, or styrene. The copolymerization of ethylene and propylene, and ethylene and 1-hexene are exemplified.ALSO:The purification of hydrocarbons for use and/or which have been used as diluents in the polymerization of a -olefins is effected by distilling with an alkali metal hydroxide or alkoxide and passing the distillate through an adsorbent. The hydrocarbon may be pentane, hexane, heptane, n- or iso-octane, high molecular weight liquid paraffin mixtures, naphtha, mineral spirits, cyclohexane, methyl cyclohexane, tetra- or deca-hydronaphthalene, benzene, toluene, xylene, ethylbenzene, n- or iso-propylbenzene, ethyltoluene, diethylbenzene or mono- or di-alkyl naphthalenes. The purification can be applied to diluents used in polymerization processes using a Group 6A metal oxide catalyst or an ionic catalyst comprising a mixture of a transition metal compound and a metal or organometallic compound. The alkali metal compound is preferably sodium hydroxide methoxide, ethoxide, propoxide, isopropoxide, butoxide or isobutoxide or a similar compound of potassium or lithium used in an amount of 0.4-5 pounds per 1000 gallons of diluent and the mixture is preferably refluxed for 0.5-15 hours before distilling. The distillate is then contacted with silica gel, activated carbon, activated alumina, fuller's earth, bauxite, acid-treated clays or magnesia using a space velocity of about 1 vol./vol./hr. The adsorbent is regenerated, whenever carbonyl compounds appear in the effluent by blowing through it a hot inert gas, e.g. methane, preferably containing 10-25% of steam at 150-250 DEG C. and preferably at or above the boiling point of the diluent.