The Dow Chemical Company

Dow Deutschland Inc.

Jeff H Stultz

Pradeep Jain

David A Eversdyk

Che I Kao

Gary A Camp

Bernd Wottawa

R Bruce Combs

Heinz Rorup

Greg A Winter

Siegfried Unger

Edmund R Nettersheim

A solution polymerization system for polymerizing a olefin monomer by reacting the monomer with catalyst and solvent has been invented. The system in one aspect including a flow loop with a product polymer outlet, the flow loop forming a recycling reactor, a catalyst inlet on the flow loop through which catalyst and solvent flow into the flow loop, a monomer inlet on the flow loop through which monomer and solvent flow into the flow loop and, with the catalyst, form a reactant materials stream, a first heat exchanger on the flow loop for receiving the reactant materials stream and any formed polymer and for removing heat of reaction or polymerization from the flow loop, and pump apparatus for pumping the reactant materials stream and formed polymer in the flow loop and from the first heat exchanger to the product polymer outlet. In one aspect, the system includes at least one additional heat exchanger on the flow loop for receiving the reactant materials stream and formed polymer and for removing heat of reaction or polymerization from the flow loop, the pump apparatus pumping formed polymer and remaining reactant materials to the product polymer outlet, and a portion of the formed polymer and remaining reactant materials flowing out from the product polymer outlet and the remainder recycling through the flow loop. In one aspect systems and methods according to the present invention are used to make polyethylene.

Non-adiabatic olefin solution polymerization

Aqueous hydrochloric acid of very high purity can be obtained in a process for purifying crude aqueous 5 to 20 wt. % hydrochloric acid. In the purification, process water or a water/HCl mixture is evaporated from the crude aqueous hydrochloric acid at a pressure of from 0.01 to 1.0 bar and a temperature of from 10.degree. to 100.degree. C. until a crude, azeotropic mixture of water and HCl is obtained. The crude, azeotropic mixture of water and HCl is distilled in a distillation apparatus at a pressure of from 0.1 to 1.5 bar and a temperature of from 50.degree. to 110.degree. C. A purified gaseous, azeotropic mixture of water and HCl is recovered from the head of the distillation apparatus and a liquid mixture is left at the bottom of the distillation apparatus. The liquid mixture which is left at the bottom of the distillation apparatus is distilled at a pressure of from 0.5 to 2.5 bar and a temperature of from 80.degree. to 130.degree. C.

Process for purifying crude hydrochloric acid

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Freeport, TX, United States of America

Jeff H Stultz