Other

Bayer Corporation

Bayer Materialscience Ag

Bayer Materialscience, LLC

Guenther Weymans

Berthold Keggenhoff

Bill L Brady, Jr

Friedhelm Steffens

High boiling contaminants such as chloro-aromatic compounds are removed from a gas by compressing the gas containing the contaminant, cooling the compressed gas to reduce the temperature of the gas to at least 20&#xb0; C. above the outlet temperature of a second cooling stage but above the freezing point of the highest melting compound in the first cooling stage, further cooling the gas in a second cooling stage to at least &#x2212;20&#xb0; C., returning cooled gas from the second cooling stage to the first cooling stage, and recovering condensate streams which contain the contaminant compound from the first and second cooling stages. An apparatus suitable for carrying out this process is also disclosed. The process of the present invention is particularly useful for removing chloro-aromatic compounds from anhydrous hydrogen chloride gas.

Process for purification of anhydrous hydrogen chloride gas

High boiling contaminants such as chloro-aromatic compounds are removed from a gas by compressing the gas containing the contaminant, cooling the compressed gas to reduce the temperature of the gas to at least 20&deg; C. above the outlet temperature of a second cooling stage but above the freezing point of the highest melting compound in the first cooling stage, further cooling the gas in a second cooling stage to at least &minus;20&deg; C., returning cooled gas from the second cooling stage to the first cooling stage, and recovering condensate streams which contain the contaminant compound from the first and second cooling stages. An apparatus suitable for carrying out this process is also disclosed. The process of the present invention is particularly useful for removing chloro-aromatic compounds from anhydrous hydrogen chloride gas.

A mixture of materials having different boiling points is separated into fractions having different boiling points. The separated fraction containing the desired product is stripped using the vapors of a lower boiling fraction. The process of the present invention is particularly useful for recovering a desired isomer or isomer mixture from a technical mixture obtained during production of an aromatic amine such as toluenediamine. Little or no unwanted isomer or by-product is present in the isomer or isomer mixture product of this process.

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Kuerten-Bechen, Germany

Guenther Weymans