Patent ID: 8153838
Filing Date: 2012-04-10
Classification: C07C,C25B

Abstract:
1. A process for the production of an isocyanate comprising: (a) reacting chlorine with carbon monoxide to produce phosgene, (b) reacting the phosgene formed in (a) with at least one organic amine to form an isocyanate and hydrogen chloride, (c) separating the isocyanate from the hydrogen chloride, (d) optionally, purifying the hydrogen chloride, (e) preparing an aqueous solution of the hydrogen chloride, (f) purifying the aqueous solution of hydrogen chloride to a content of organic solvents of a maximum of 0.05 wt. %, wherein the purification is carried out by stripping the aqueous hydrogen chloride solution with steam, (g) subjecting at least a portion of the aqueous hydrogen chloride solution to electrochemical oxidation to form chlorine, and (h) returning at least a portion of the chlorine produced in (g) to (a).