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 process is described for isomerizing pentenenitrile in a reactant stream, wherein the isomerization is effected over a heterogeneous catalyst in a distillation column in such a way that, during the isomerization of the isomerization reactant, it is distillatively depleted in relation to the isomerization product in the reaction column of the distillation column.
Abstract:
Preparation of nickel(0)-phosphorus ligand complexes (Q) containing at least a nickel(0) as central atom and at least a ligand containing phosphorus comprises reacting a nickel(II) compound with a reducing agent in the presence of the ligand to obtain a reaction mixture and extracting the obtained reaction mixture by adding at least a dinitrile, at least a hydrocarbon and at least two immiscible phases. Preparation of nickel(0)-phosphorus ligand complexes (Q) containing at least a nickel(0) as central atom and at least a ligand containing phosphorus comprises reacting a nickel(II) compound with a reducing agent in the presence of the ligand to obtain a reaction mixture, and extracting the obtained reaction mixture by adding at least a dinitrile, at least a hydrocarbon and at least two immiscible phases, where: the amount of nickel(0) content in the reaction mixture is at most 1.3 wt.%; the molar ratio of: the reducing agent to the nickel(II) compound is 1:1-1000:1, which is calculated as the molar ratio of the redox equivalent, and the ligand containing phosphorus to the nickel(II) compound is at most 30:1, which is calculated as the molar ratio of phosphorus and nickel atoms. Independent claims are included for: (1) a mixture comprising (Q), obtained by the above process; and (2) a method for the isomerization of unsaturated nitrile to linear unsaturated nitrile using (Q) as catalyst, which is regenerated by circulation method.
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:
Procedimiento para la separación por extracción de catalizadores disueltos, homogéneos, a partir de una descarga de la reacción de una hidrocianuración de mononitrilos insaturados para dar dinitrilos, mediante extracción con ayuda de un hidrocarburo K, caracterizado porque a) se concentra por evaporación la descarga de la reacción como paso previo a la etapa b) mediante destilación a presiones comprendidas entre 0,1 y 5.000 mbares y a temperaturas comprendidas entre 10 y 150ºC, b) se aporta un hidrocarburo K a la descarga de la reacción, concentrada por evaporación, con lo que se obtiene una corriente I, y c) se alimenta la corriente I, sin separación previa de las fases líquidas, en un dispositivo de extracción y se extrae a una temperatura T con el hidrocarburo K, obteniéndose una corriente II que contiene el hidrocarburo K enriquecido con el catalizador, y una corriente III pobre en catalizador.
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.