Abstract: Polyisocyanate composition containing (A) at least one polyisocyanate obtainable by reacting at least one monomeric isocyanate, (B) at least one solvent containing a mixture of C7-C14 aromatic hydrocarbons, (C) optionally at least one further solvent, (D) optionally at least one Lewis-acidic organic metal compound capable of accelerating the reaction of isocyanate groups with isocyanate-reactive groups, (E) optionally other coatings additives, wherein the amount of cumene in component (B) is less than 1 wt %, preferably less than 0.7 wt %.

Abstract: The present invention relates to a new process for preparing polyisocyanates containing isocyanurate groups and being flocculation-stable in solvents from (cyclo)aliphatic diisocyanates.

Abstract: The present invention relates to a novel process for preparing isocyanurate-comprising polyisocyanates of (cyclo)aliphatic diisocyanates that are especially stable to color drift in solvents.

Abstract: The present invention relates to a new process for preparing polyisocyanates containing isocyanurate groups and being flocculation-stable in solvents from (cyclo)aliphatic diisocyanates.

Abstract: The present invention relates to a novel process for preparing isocyanurate-comprising polyisocyanates of (cyclo)aliphatic diisocyanates that are especially stable to color drift in solvents.

Abstract: A process is described for preparing 3-pentenenitrile, characterized by the following process steps: (a) isomerizing a reactant stream which comprises 2-methyl-3-butenenitrile over at least one dissolved or dispersed isomerization catalyst to give a stream 1 which comprises the at least one isomerization catalyst, 2-methyl-3-butenenitrile, 3-pentenenitrile and (Z)-2-methyl-2-butenenitrile, (b) distilling stream 1 to obtain a stream 2 as the top product which comprises 2-methyl-3-butenenitrile, 3-pentenenitrile and (Z)-2-methyl-2-butenenitrile, and a stream 3 as the bottom product which comprises the at least one isomerization catalyst, (c) distilling stream 2 to obtain a stream 4 as the top product which, compared to stream 2, is enriched in (Z)-2-methyl-2-butenenitrile, based on the sum of all pentenenitriles in stream 2, and a stream 5 as the bottom product which, compared to stream 2, is enriched in 3-pentenenitrile and 2-methyl-3-butenenitrile, based on the sum of all pentenenitriles in stream 2, (d) dis

Abstract: A process is described for preparing 3-pentenenitrile, characterized by the following process steps: (a) isomerizing a reactant stream which comprises 2-methyl-3-butenenitrile over at least one dissolved or dispersed isomerization catalyst to give a stream 1 which comprises the at least one isomerization catalyst, 2-methyl-3-butenenitrile, 3-pentenenitrile and (Z)-2-methyl-2-butenenitrile, (b) distilling stream 1 to obtain a stream 2 as the top product which comprises 2-methyl-3-butenenitrile, 3-pentenenitrile and (Z)-2-methyl-2-butenenitrile, and a stream 3 as the bottom product which comprises the at least one isomerization catalyst, (c) distilling stream 2 to obtain a stream 4 as the top product which, compared to stream 2, is enriched in (Z)-2-methyl-2-butenenitrile, based on the sum of all pentenenitriles in stream 2, and a stream 5 as the bottom product which, compared to stream 2, is enriched in 3-pentenenitrile and 2-methyl-3-butenenitrile, based on the sum of all pentenenitriles in stream 2, (d) dis

Abstract: Process for working up an exhaust gas from a system for producing hydroxylamine or hydroxylammonium salts by catalytic reduction of nitrogen monoxide with hydrogen, the exhaust gas containing nitrogen monoxide, hydrogen, dinitrogen monoxide, nitrogen and ammonia. At least some of the hydrogen present in the exhaust gas is separated off from the exhaust gas by means of a gas-tight membrane-electrode assembly which comprises at least one selectively proton-conducting membrane, a retentate side, a permeate side, and, on each side of the membrane, at least one electrode catalyst, wherein, on the retentate side of the membrane, at least some of the hydrogen is oxidized to protons at the anode catalyst and the protons, after crossing the membrane, are, on the permeate side, at the cathode catalyst according to (I) reduced to hydrogen and/or (II) reacted with oxygen to form water, the oxygen originating from an oxygen-containing stream which is contacted with the permeate side.

Abstract: A process for long-term operation of a continuous heterogeneously catalyzed partial dehydrogenation of a hydrocarbon to be dehydrogenated, in which a reaction gas mixture stream comprising the hydrocarbon to be dehydrogenated in a molar starting amount KW is conducted through an overall catalyst bed comprising the total amount M of dehydrogenation catalyst and the deactivation of the overall catalyst bed is counteracted in such a way that, with increasing operating time, the contribution to the conversion in the first third of the total amount M of dehydrogenation catalyst in flow direction decreases, the contribution to the conversion in the last third of the total amount M of dehydrogenation catalyst in flow direction increases, and the contribution to the conversion in the second third of the total amount M of dehydrogenation catalyst in flow direction passes through a maximum.

Abstract: A process for working up an exhaust gas A from a system for producing hydroxylamine or hydroxylammonium salts by catalytic reduction of nitrogen monoxide with hydrogen, wherein the exhaust gas A comprises nitrogen monoxide, hydrogen, dinitrogen monoxide, nitrogen and ammonia, and at least some of the hydrogen present in the exhaust gas A is separated off from the exhaust gas A by means of a gas-tight membrane-electrode assembly which comprises at least one selectively proton-conducting membrane, a retentate side, a permeate side, and, on each side of the membrane, at least one electrode catalyst, wherein, on the retentate side of the membrane, at least some of the hydrogen is oxidized to protons at the anode catalyst and the protons, after crossing the membrane, are, on the permeate side, at the cathode catalyst according to I reduced to hydrogen and/or II reacted with oxygen to form water, wherein the oxygen originates from an oxygen-comprising stream O which is contacted with the permeate side.

Abstract: A method for producing 3-pentenenitrile is provided that includes: (a) isomerizing an educt stream containing 2-methyl-3-butenenitrile on at least one dissolved or dispersed isomerization catalyst to form a stream (1), which contains the isomerization catalyst(s), 2-methyl-3-butenenitrile, 3-pentenenitrile and (Z)-2-methyl-2-butenenitrile; (b) distilling the stream (1) to obtain a stream (2) as the overhead product, which contains 2-methyl-3-butenenitrile, 3-pentenenitrile and (Z)-2-methyl-2-butenenitrile and a stream (3) as the bottom product, which contains the isomerization catalyst(s); (c) distilling the stream (2) to obtain a stream (4) as the overhead product, which is enriched with (Z)-2-methyl-2-butenenitrile in comparison to stream (2), and a stream (5) as the bottom product, which is enriched with 3-pentenenitrile and 2-methyl-3-butenenitrile in comparison to stream (2); (d) distilling stream (5) to obtain a stream (6) as the bottom product, which contains 3-pentenenitrile and a stream (7) as the he

Abstract: A process is described for separating mixtures of isomeric pentenenitriles, in which at least one isomer is removed from the mixture, wherein the separation of the substance mixtures of isomeric pentenenitriles is effected distillatively under reduced pressure.

Abstract: A method for producing 3-pentenenitrile is provided that includes: (a) isomerizing an educt stream containing 2-methyl-3-butenenitrile on at least one dissolved or dispersed isomerisation catalyst to form a stream (1), which contains the isomerisation catalyst(s), 2-methyl-3-butenenitrile, 3-pentenenitrile and (Z)-2-methyl-2-butenenitrile; (b) distilling the stream (1) to obtain a stream (2) as the overhead product, which contains 2-methyl-3-butenenitrile, 3-pentenenitrile and (Z)-2-methyl-2-butenenitrile and a stream (3) as the bottom product, which contains the isomerisation catalyst(s); (c) distilling the stream (2) to obtain a stream (4) as the overhead product, which is enriched with (Z)-2-methyl-2-butenenitrile in comparison to stream (2), and a stream (5) as the bottom product, which is enriched with 3-pentenenitrile and 2-methyl-3-butenenitrile in comparison to stream (2); (d) distilling stream (5) to obtain a stream (6) as the bottom product, which contains 3-pentenenitrile and a stream (7) as the he

Abstract: An process for preparing 3-pentenenitrile by hydrocyanating 1,3-butadiene, in which the process yield with regard to recycled 1,3-butadiene is maximized.

Abstract: A process is described for separating mixtures of isomeric pentenenitriles, in which at least one isomer is removed from the mixture, wherein the separation of the substance mixtures of isomeric pentenenitriles is effected distillatively under reduced pressure.

Abstract: A process for extractively removing homogeneously dissolved catalysts from a reaction effluent of a hydrocyanation of unsaturated mononitriles to dinitriles with a hydrocarbon H, including performing the steps of a) concentrating the reaction effluent before step b) by distillation at pressures of from 0.1 to 5000 mbar and temperatures of from 10 to 150° C., b) adding a hydrocarbon H to the concentrated reaction effluent to obtain a stream I, and c) feeding stream I, without prior separation of the liquid phases, into an extraction apparatus and extracting it at a temperature T with the hydrocarbon H to obtain a stream II comprising the hydrocarbon H enriched with the catalyst and a stream III having a low catalyst content.

Abstract: Method of producing compounds of the general formula XPR2(OR1)??Ia where X is chlorine, bromine or iodine and R1 is an organic radical, by reacting compounds of the general formula X2PR2??II, in which X has the meaning given above and R2 is an organic radical, with compounds of the general formula R1OH??III, in which R1 has the meaning given above, to give a mixture IV, in that a) the postreaction is carried out at a temperature of from 50 to 240° C. and a pressure of from 0.001 to 0.9 bar, b) from the mixture IV the compounds Ia are separated off from the compounds PR2(OR1)2??Ib and, if appropriate, the compounds II and c) compounds Ib and, if appropriate, unreacted compounds II are returned to the synthesis stage.

Abstract: An adiponitrile/methylglutaronitrile preparation process includes distilling a reaction stream to obtain stream 3 depleted in pentenenitriles (bottom product) and stream 4 enriched in pentenenitriles (top product); extracting stream 3 obtaining stream 6 enriched with extractant (top product) and stream 7 depleted in extractant (bottom product); distilling stream 6 obtaining stream 8 comprising the catalyst (bottom product) and stream 9 comprising the extractant (top product); distilling stream 7 obtaining stream 10 (bottom product) and stream 11 comprising the extractant (top product); distilling stream 10 obtaining stream 12 comprising catalyst degradation products, at least one promotor, adiponitrile and methylglutaronitrile (bottom product) and stream 13 comprising pentenenitriles (top product); distilling stream 12 obtaining stream 14 comprising catalyst degradation products and the promotor(s) (bottom product) and stream 15 comprising adiponitrile and methylglutaronitrile (top product); distilling stream

Abstract: A process is described for preparing 3-pentenenitrile by hydrocyanating 1,3-butadiene, wherein 1,3-butadiene is reacted with hydrogen cyanide in the presence of at least one catalyst and the stream resulting therefrom is purified distillatively, the bottom temperature during the distillation not exceeding 140° C.

Abstract: A process for preparing biphenols of the general formula I by reaction of monophenols of the general formula II where the radicals R1, R2 and R3 are each, independently of one another, hydrogen, alkyl, aryl or arylalkyl having from 1 to 10 carbon atoms, in the presence of an oxidant in a reactor, wherein a) the reactor comprises no stationary internals which act as baffles, b) a total of not more than 0.6 mol of oxidant is used per one mol of monophenol, and c) the oxidant is introduced either continuously or discontinuously in a plurality of portions over a period of from 10 minutes to 24 hours, with the amount of oxidant introduced per unit time not being constant over the total period of time but instead being varied.