US 5,470,925 A · Process for the production of alkene polymers

Abstract

An ethylene stream which contains ethane as an impurity or a propylene stream which contains propane as an impurity is contacted with a polymerization catalyst thereby producing a polymer product containing unreacted ethylene or propylene and the corresponding alkane. A gas mixture containing ethylene or propylene and the corresponding alkane is separated from the polymer product and subjected to adsorption at a temperature of 50.degree. to 200.degree. C. in a bed of adsorbent which selectively adsorbs alkenes, thereby adsorbing substantially all of the propylene or ethylene from the gas mixture. The ethylene or propylene is desorbed from the adsorbent and recycled to the polymerization zone. The process is operated on a low per pass conversion with recycle of unreacted monomer. In the system of the invention the adsorption unit may be upstream or downstream of the polymerization reactor.

Claims43

Dependent claims

A process for the production of a propylene polymer comprising the steps:

(a) contacting a propylene-propane mixture with a polymerization catalyst in a reaction zone under conditions which result in the production of a product containing a propylene polymer, unreacted propylene and propane;
(b) separating a gas mixture comprising unreacted propylene and propane from said product;
(c) selectively adsorbing propylene from said gas mixture by passing said gas mixture through an adsorption zone containing an adsorbent which selectively adsorbs propylene;
(d) regenerating said adsorbent, thereby producing a propylene-enriched gas stream;
and
(e) recycling at least part of said propylene-enriched gas stream to said reaction zone.

3 more elements

Dependencies are inferred from the claim text.

Process for the production of alkene polymers

Life of this patent

Process for the production of alkene polymers

Life of this patent

Abstract

Claims43