Integrated process for preparing isocyanates
First Claim
1. A process for preparing organic isocyanates, which comprises the steps (a) making available a first partial amount of chlorine, with the chlorine of this first partial amount having a content of free and bound bromine and iodine of <
- 400 ppm;
(b) making available a second partial amount of chlorine;
(c) reacting the first and second partial amounts of chlorine with carbon monoxide to form phosgene;
(d) reacting the phosgene from step (c) with one or more primary amines to form the corresponding isocyanates and hydrogen chloride;
(e) separating off and, if necessary, purifying the isocyanates formed in step (d);
(f) separating off and, if necessary, purifying the hydrogen chloride formed in step (d);
(g) catalytically oxidizing at least part of the hydrogen chloride separated off in step (e) by means of oxygen to form chlorine;
(h) separating off the chlorine formed in step (g) and using at least a partial amount of the chlorine which has been separated off as second partial amount of chlorine in step (b).
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Accused Products
Abstract
Process for preparing organic isocyanates, which comprises the steps
(a) making available a first partial amount of chlorine, with the chlorine of this first partial amount having a content of free and bound bromine and iodine of <400 ppm;
(b) making available a second partial amount of chlorine;
(c) reacting the first and second partial amounts of chlorine with carbon monoxide to form phosgene;
(d) reacting the phosgene from step (c) with one or more primary amines to form the corresponding isocyanates and hydrogen chloride;
(e) separating off and, if necessary, purifying the isocyanates formed in step (d);
(f) separating off and, if necessary, purifying the hydrogen chloride formed in step (d);
(g) catalytically oxidizing at least part of the hydrogen chloride separated off in step (e) by means of oxygen to form chlorine;
(h) separating off the chlorine formed in step (g) and using at least a partial amount of the chlorine which has been separated off as second partial amount of chlorine in step (b).
84 Citations
10 Claims
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1. A process for preparing organic isocyanates, which comprises the steps
(a) making available a first partial amount of chlorine, with the chlorine of this first partial amount having a content of free and bound bromine and iodine of < - 400 ppm;
(b) making available a second partial amount of chlorine;
(c) reacting the first and second partial amounts of chlorine with carbon monoxide to form phosgene;
(d) reacting the phosgene from step (c) with one or more primary amines to form the corresponding isocyanates and hydrogen chloride;
(e) separating off and, if necessary, purifying the isocyanates formed in step (d);
(f) separating off and, if necessary, purifying the hydrogen chloride formed in step (d);
(g) catalytically oxidizing at least part of the hydrogen chloride separated off in step (e) by means of oxygen to form chlorine;
(h) separating off the chlorine formed in step (g) and using at least a partial amount of the chlorine which has been separated off as second partial amount of chlorine in step (b). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- 400 ppm;
Specification