Purification of crude hydrogen chloride
First Claim
1. A process for the purification of a crude hydrogen chloride gas by-product, which is obtained in the production of chloroacetic acids by the catalytic chlorination of acetic acid with chlorine gas in contact with acetic anhydride and/or acetyl chloride, and continues to be contaminated, even after having been prepurified, with about 0.6 up to 3 % by volume of acetyl chloride and optionally with some minor proportion of chloroacetyl chloride, which comprises:
- introducing the crude hydrogen chloride gas into the base portion of a scrubbing zone and scrubbing it countercurrently therein with about 0.5 up to 20 liter, per normal cubic meter (S.T.P.) of hydrogen chloride gas, of a cooled scrubbing liquid under circulation and consisting substantially of about 20 up to 80 weight % of concentrated H2 SO4, about 15 up to 60 weight % of acetic acid, and about 5 up to 50 weight % of water;
introducing the resulting purified moist hydrogen chloride gas issuing at the head of the scrubbing zone into the base portion of a drying zone and drying it therein by scrubbing it countercurrently with precooled sulfuric acid under circulation, the sulfuric acid being used at a rate of about 0.5 up to 20 liter, per normal cubic meter of hydrogen chloride; and
removing dry hydrogen chloride near the head of the drying zone.
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Abstract
Crude hydrogen chloride gas obtained as a by-product in the production of chloroacetic acids by the catalytic chlorination of acetic acid with chlorine gas in contact with acetic anhydride and/or acetyl chloride, and contaminated with about 0.6 up to 3 % by volume of acetyl chloride is purified. To this end, crude hydrogen chloride gas is introduced into the base portion of a scrubbing zone and scrubbed countercurrently therein with 0.5 up to 20 liter, per normal cubic meter (S.T.P) of hydrogen chloride gas, of a cooled scrubbing liquid under circulation, consisting substantially of 20-80 weight % of concentrated H2 SO4, 15-60 weight % of acetic acid, and 5-50 weight % of water. The resulting purified moist hydrogen chloride gas issuing at the head of the scrubbing zone is introduced into the base portion of a drying zone and scrubbed countercurrently with precooled sulfuric acid under circulation.
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Citations
11 Claims
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1. A process for the purification of a crude hydrogen chloride gas by-product, which is obtained in the production of chloroacetic acids by the catalytic chlorination of acetic acid with chlorine gas in contact with acetic anhydride and/or acetyl chloride, and continues to be contaminated, even after having been prepurified, with about 0.6 up to 3 % by volume of acetyl chloride and optionally with some minor proportion of chloroacetyl chloride, which comprises:
- introducing the crude hydrogen chloride gas into the base portion of a scrubbing zone and scrubbing it countercurrently therein with about 0.5 up to 20 liter, per normal cubic meter (S.T.P.) of hydrogen chloride gas, of a cooled scrubbing liquid under circulation and consisting substantially of about 20 up to 80 weight % of concentrated H2 SO4, about 15 up to 60 weight % of acetic acid, and about 5 up to 50 weight % of water;
introducing the resulting purified moist hydrogen chloride gas issuing at the head of the scrubbing zone into the base portion of a drying zone and drying it therein by scrubbing it countercurrently with precooled sulfuric acid under circulation, the sulfuric acid being used at a rate of about 0.5 up to 20 liter, per normal cubic meter of hydrogen chloride; and
removing dry hydrogen chloride near the head of the drying zone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- introducing the crude hydrogen chloride gas into the base portion of a scrubbing zone and scrubbing it countercurrently therein with about 0.5 up to 20 liter, per normal cubic meter (S.T.P.) of hydrogen chloride gas, of a cooled scrubbing liquid under circulation and consisting substantially of about 20 up to 80 weight % of concentrated H2 SO4, about 15 up to 60 weight % of acetic acid, and about 5 up to 50 weight % of water;
Specification