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AssigneeHoechst Aktiengesellschaft
InventorsDieter Arnold, Jorg Bartels, Heinrich Lenzmann, Gunter Jacobsen, Heinz Wendt, Manfred Stoltenberg
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In this process for the preparation of ketene by the thermal, catalytic cracking of acetic acid under reduced pressure, the hot cracked gases are cooled to approx. 0.degree. to -10.degree. C. and, in the course thereof, water, unreacted acetic acid and acetic anhydride are condensed. The quantity of acetic acid employed for the thermal cracking reaction should be 0.5 to 2.5 t.times.hours.sup.-1 .times.m.sup.-3, relative to the volume V of a shell-and-tube heat exchanger through which the cracked gas is passed. The pressure drop in the tubular heat exchanger should be 50 to 150 mbars and the surface/volume ratio should be 60 to 120 m.sup.-1.
A process for the preparation of ketene by thermal, catalytic cracking of acetic acid under reduced pressure and by cooling the hot cracked gases to substantially 0.degree. C. to -10.degree. C., so that water, unreacted acetic acid and acetic anhydride are condensed, which process comprises passing the cracked gas through at least one shell-and-tube heat exchanger in tandem and having a volume V[m.sup.3 ], a pressure drop of 50 to 150 mbars and a surface/volume ratio of 60 to 120 m.sup.-1, and drawing off the condensate, wherein the quantity of acetic acid employed for the thermal cracking is at a rate of 0.5 to 2.5 tons per hour per cubic meter, for each cubic meter of the volume V of the at least one shell-and-tube heat exchanger.
Dependencies are inferred from the claim text.