E.i. Dupont De Nemours and Company

Kung H Lee

Domenic J Barsotti

Edward Kaoru Sakata

Earl M Clark

A process is disclosed for separating components of an azeotropic or azeotrope-like mixture containing only organic compounds at least one of which compound is a halocarbon comprising contacting said azeotropic or azeotrope-like mixture with a semipermeable membrane to form at least one exit stream having an increased concentration of at least one component and at least one other exit stream having an increased concentration of at least one other component of the azeotropic or azeotrope-like mixture and, thereafter, recovering at least one exit stream.

Process for separating and recovering halocarbons from mixtures thereof

A process for separating and recovering an organic phase (e.g., fluorocarbons such as chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons and perfluorocarbons) from a feed stream of a mixture of fluorocarbons and hydrogen fluoride, wherein the mixture is characterized as forming at least one azeotrope or azeotrope-like composition involving at least one fluorocarbon and hydrogen fluoride, by passing the fluorocarbon/HF mixture feed stream through the feed side of a semipermeable membrane unit and then further separating a fluorocarbon-depleted hydrogen fluoride permeate stream and a fluorocarbon enriched residual stream exiting the membrane unit by conventional distillation. An essentially pure fluorocarbon phase and hydrogen fluoride phase are recovered from the distillation with the azeotrope or azeotrope-like distillate being recycled to the inlet of the semipermeable membrane unit.

Process for separating and recovering fluorocarbons and hydrogen

A process for separating and recovering organic vapors (e.g., chlorofluorocarbons) from a feed stream of organic vapors and air wherein organic vapors are present in the 'window concentration' range being too high for conventional carbon adsorption and too low for efficient compression/condensation recovery. By passing the organic vapor and air feed stream through the feed side of a semipermeable membrane unit, a vapor depleted stream exiting the membrane unit can then be processed by conventional carbon adsorption while a vapor enriched stream from the membrane unit can be processed by conventional compression and condensation.

Process for recovering organic vapors from air

An improved process for separating and removing non-condensible gaseous contaminants (e.g., nitrogen, oxygen and the like) from a conventional halocarbon vapor compression refrigeration system by withdrawing a vapor stream above liquified refrigerant exiting the condenser on the high pressure side of the expansion valve and then processing this vapor by use of a second compression step, followed by condensation into a receiver. The liquid halocarbon from the receiver is returned to the evaporator while the vapor phase is sent to a semipermeable membrane separation unit. The halocarbon enriched effluent from the semipermeable membrane unit is recycled to the inlet side of the second compressor while the non-condensible contaminant enriched stream is vented from the refrigeration system. Such a high pressure purge loop is useful in selectively removing non-condensible gaseous with minimum halocarbon refrigerant loss.

Method and apparatus for removal of gas from refrigeration system

A process is disclosed for the manufacture of chloroform by partial chlorination of methyl chloride-methylene chloride mixtures to produce a chlorinated product mixture containing chloroform, methyl chloride, methylene chloride and little or no carbon tetrachloride, the amount of methylene chloride being substantially equal to the amount employed in the initial feed mixture and the amount of carbon tetrachloride corresponding to less than 0.1 mole of chloroform in the product.

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Chadds Ford, PA, United States of America

Kung H Lee