Alexander Jeff Harris

US Patent:

42150787, Jul 29, 1980

Filed:

Apr 2, 1979

Appl. No.:

6/026202

Inventors:

Chester A. Hargreaves - Wilmington DE
Alexander T. Harris - Metairie LA
Robert A. Schulze - Wilmington DE

Assignee:

E. I. Du Pont de Nemours and Company - Wilmington DE

International Classification:

C07C 2120

US Classification:

260655

Abstract:

An improved process for the production of chloroprene, which is the critical monomer constituent of neoprene rubbers, and of 2,3-dichlorobutadiene-1,3, which often is copolymerized with chloroprene to provide better low temperature properties of the resulting elastomer, involves dehydrochlorination of a chlorinated hydrocarbon such as 3,4-dichlorobutene-1, 2,3,4-trichlorobutene-1, or 1,2,3,4-tetrachlorobutane, with an aqueous mixture of sodium hydroxide and sodium chloride having the composition of chlor/alkali cell liquor; separation of the organic phase from which the desired product, chloroprene or 2,3-dichlorobutadiene-1,3, is recovered by distillation; and recirculation of the aqueous (brine) phase to the electrolysis apparatus, from which the sodium hydroxide-sodium chloride liquor is returned to the dehydrochlorination step. This process saves energy in that it does not require cell liquor concentration to isolate pure sodium hydroxide, and it is environmentally desirable because it avoids problems associated with brine disposal.