Basf Se Corporation

Byoung-Yeon Kim

Gerhard Olbert

Heiner Schelling

Eckhard Stroefer

Wolfgang Gerlinger

Jon S Speier

Kai Thiele

Hans-Juergen Pallasch

A reactor () for preparing phosgene by gas-phase reaction of carbon monoxide and chlorine in the presence of a solid-state catalyst, which is provided in a plurality of catalyst tubes () which are arranged parallel to one another in the longitudinal direction of the reactor () and are welded at each of their two ends into a tube plate (), with introduction of the starting materials at the upper end of the catalyst tubes () and discharge of the gaseous reaction mixture at the lower end of the catalyst tubes (), in each case via a cap, and also with introduction and discharge facilities for a liquid heat transfer medium () in the space () between the catalyst tubes () within the shell, where the flow of the heat transfer medium () in the space () between the catalyst tubes () within the shell is meandering as a result of deflection plates (), each alternative deflection plate () leaves two openings () having the shape of a segment of a circle free on opposite sides at the interior wall of the reactor and the immediately subsequent deflection plate leaves a central opening () which is bounded by two straight lines which are parallel to and equidistant from one another and a reactor diameter free and the reactor () has no tubes in the region of the openings () having the shape of a segment of a circle and in the region of the central openings (), wherein the many catalyst tubes () aligned parallel to one another in the longitudinal direction of the reactor () are arranged in two bundles of identical catalyst tubes () which are separated from one another by a region which is free of catalyst tubes () and extends to both sides along a reactor diameter and the heat transfer coefficients at the interface between the catalyst tubes () and the heat transfer medium () are equalized over each reactor cross section by the flow paths of the heat transfer medium () in each reactor cross section, in each case measured from the first to last catalyst tube () in the flow direction of the heat transfer medium (), being matched to one another by means of an altered arrangement of the catalyst tubes (), is proposed.

Reactor and process for preparing phosgene

A process for preparing phosgene by reaction of a feed stream () obtained by combining and mixing a chlorine feed stream () and a carbon monoxide feed stream (), with the carbon monoxide being introduced in a stoichiometric excess over chlorine, in catalyst tubes filled with beds of activated carbon in a reactor R having a bundle of catalyst tubes, to give a product gas mixture () which is separated into a liquid, phosgene-comprising product stream () and an offgas stream () comprising carbon monoxide which is discharged via a pressure-regulating valve, where the reaction of the feed stream () in the reactor R and the separation of the product gas mixture () are carried out under a pressure in the range fromtobar gauge pressure, wherein the excess of carbon monoxide in the feed stream () to the reactor R is regulated by continuously measuring the flow and the concentration of carbon monoxide in the offgas stream (), calculating the actual value of the excess of carbon monoxide in the feed stream () to the reactor R from these measurements in combination with the continuously measured values for the flow of the carbon monoxide feed stream () and the flow of and the chlorine concentration in the chlorine feed stream () and matching this to the intended value of the excess of carbon monoxide in the feed stream () to the reactor R by adapting the flow of the carbon monoxide feed stream (), is proposed.

Method for producing phosgene

The present invention accordingly provides a process for preparing light-colored polyphenylene-polymethylene polyisocyanates comprising the steps (a) providing an amount of chlorine, (b) separating the chlorine provided in the step (a) to obtain a first chlorine fraction having a content of free and bound bromine and iodine of &#x3c;50 ppm and a second chlorine fraction having an increased content of free and bound bromine and iodine that depends on the original amount of bromine and iodine in the chlorine provided in step (a) and the separation split, (c) reacting carbon monoxide with at least a portion of the first chlorine fraction to form a first phosgene fraction, (d) reacting carbon monoxide with at least a part of the second chlorine fraction to form a second phosgene fraction, (e) reacting at least a portion of a first phosgene fraction with at least one amine of the diphenylmethane diamine series (MDA) to form the corresponding polyphenylene-polymethylene polyisocyanate (PMDI), and (f) reacting at least a portion of the second phosgene fraction with at least one primary amine with the exception of mono- and polyphenylene-polymethylene polyamines to form an at least one isocyanate-containing reaction solution.

Process for the preparation of light-colored iocyanates of a diphenylmethanediisocyanate series

The present invention relates to a process for preparing light-colored polyphenylene-polymethylene-polyisocyanate (PMDI), comprising the steps (a) providing carbon monoxide and chlorine, (b) reacting carbon monoxide with chlorine to form phosgene, (c) reacting the phosgene from step (b) with at least one primary amine with the exception of mono- and polyphenylene-polymethylene polyamines with an excess of phosgene to form an at least one isocyanate containing reaction solution, and hydrogen chloride, (d) separating excess phosgene from the isocyanate-containing reaction solution obtained in step (c), (e) providing at least one polyphenylene-polymethylene polyamine, and (f) reacting at least a portion of the phosgene separated in step (d) with the at least one polyphenylene-polymethylene polyamine to form the light-colored polyphenylene-polymethylene polyisocyanate.

Process for preparing light-coloured isocyanates of the diphenylmethane series

A reactor () for preparing phosgene by gas-phase reaction of carbon monoxide and chlorine in the presence of a solid-state catalyst, which is provided in the catalyst tubes () of a bundle of catalyst tubes () which are arranged parallel to one another in the longitudinal direction of the reactor () and are welded at each of their two ends into a tube plate (), with introduction of the starting materials at the upper end of the catalyst tubes () and discharge of the gaseous reaction mixture at the lower end of the catalyst tubes (), in each case via a cap, and also with introduction and discharge facilities for a liquid heat transfer medium () in the intermediate space () between the catalyst tubes () , where the flow of the heat transfer medium () in the space () between the catalyst tubes () is guided by deflection plates (), which leave alternating openings () free on opposite sides at the interior wall of the reactor, in which openings the deflection plates () have cutouts having the shape of a segment of a circle, and the reactor () has no tubes in the region of the openings (), wherein the heat transfer coefficients at the interface between the catalyst tubes () and the heat transfer medium () are equalized over each reactor cross section by the flow paths of the heat transfer medium () in each reactor cross section, in each case measured from the first to last catalyst tube () in the flow direction of the heat transfer medium (), being matched to one another by means of an altered arrangement of the catalyst tubes (), is proposed.

Growing community of inventors

Baton Rouge, LA, United States of America

Byoung-Yeon Kim