Abstract:
The invention concerns the manufacture of a hydrogenation catalyst by the reduction of platinum from an oxidation state of not less than two with a reducing agent in an aqueous medium in the presence of a carbon-containing support following partial poisoning, the method using a compound of general formula (I) in which X, Y and Z, which may be the same or different, are hydrogen, C1-C18 alkyl, C5-C10 cycloalkyl, halogen, hydroxyl, C1-C6 alkoxy or-NR'R'', whereby R, R' and R'', which may by the same or different, are hydrogen, C1-C18 alkyl or C5-C10 cycloalkyl. The invention also concerns a hydrogenation catalyst manufactured by this method, its use in the production of hydroxylammonium salts, a method of producing hydroxylammonium salts and a method of regenerating platinum-based hydrogenation catalysts of this kind.
Abstract:
Vorgeschlagen wird ein Verfahren zur Aufarbeitung des Abgases aus einer Anlage zur Herstellung von Hydroxylamin oder Hydroxylammonium-Salzen durch katalytische Reduktion von Stickstoffmonoxid mit Wasserstoff zwecks Verwertung zumindest eines Teils des im Abgas enthaltenen Stickstoffmonoxids und gegebenenfalls Wasserstoff zur Herstellung von Hydroxylamin oder Hydrolxylammonium-Salzen, das dadurch gekennzeichnet ist, dass aus dem Abgas der Anlage zur Herstellung von Hydroxylamin oder Hydroxylammonium- Salzen in einer ersten Trennstufe Stickstoffmonoxid selektiv abgetrennt wird.
Abstract:
In a process for producing n-butyraldehyde and/or n-butanol, (a) 1,3-butadiene is reacted with an alcohol having the formula ROH, in which the residue R stands for a non-substituted C2-C20-alkyl or alkenyl group that may also be substituted by 1 or 2 C1-C10-alkoxy or hydroxy groups, a C6-C10-aryl or C7-C11-aralkyl group or the methyl group, at a higher temperature and pressure in the presence of a Brönsted acid or in the presence of a compound of an element from groups IB, VIIb or VIIIb of the periodic table of elements with phosphoric or nitrogenated ligands, so as to produce a mixture of addition compounds having the formulas (II) and (III); (b) the addition compound III is isomerised into the addition compound II; (c) the addition compound II is isomerised in the presence of a homogeneous or heterogeneous transition metal element catalyst in liquid phase or in the presence of a heterogeneous transition metal element-containing catalyst in gaseous phase, so as to produce an enol ether having the formula (IV); and (d) n-butyraldehyde and/or n-butanol are generated by reacting said enol ether IV with hydrogen and water or with water in the presence of a homogeneous or heterogeneous transition metal element catalyst in the liquid phase or in the presence of a heterogeneous transition metal element-containing catalyst in the gaseous phase. The alcohol ROH released is recycled into the partial reaction (a).
Abstract:
The invention relates to a hydrogenation catalyst by the reduction from platinum in the stage of oxidation of +4 (Pt (IV)) with a selective reducing agent in an acidic aqueous medium in the presence of a carbon-containing carrier to platinum in the stage of oxidation +2 (Pt (II)), subsequent poisoning of the platinum thus obtained with a sulphur-containing selective reducing agent, and subsequent reduction of the platinum thus partially poisoned to form metallic platinum (Pt(0)) and subsequent processing as known per se in that (a) Pt (II) is partially poisoned with a sulphur-containing selective reducing agent, wherein the sulphur-containing selective reduction agent is used in an amount which corresponds to from 15 to 70 mol % of the amount of the sulphur-containing selective reducing agent which might be needed to reduce Pt(IV) to Pt (II), provided that the amount of Pt (IV) corresponds to the amount of Pt (II) used and to be poisoned, and subsequently the partially poisoned Pt (II) is reduced with an alkali metal formate to Pt (0); or (b) platinum in the stage of oxidation of greater than +2 is partially poisoned and subsequently or simultaneously reduced with an alkali metal formate to Pt (0). The invention also relates to a hydrogenation catalyst, use of the hydrogenation catalyst for preparing hydroxylammonium salts, a process for the preparation of hydroxylammonium salts, and a process for regenerating platinum-containing hydrogenation catalysts.
Abstract:
The proposed process for producing n-butyraldehyde and/or n-butanol involves the following steps: (a) 1,3-butadiene is allowed to react with an amine of formula (I) R R NH, in which the groups independently of one another represent hydrogen, optionally substituted aliphatic or cyclo-aliphatic groups, or aryl or aralkyl groups, or are connected to a bridging unit which can contain heteroatoms, at high temperature and pressure and in the presence of a compound of a group VIIIb element, in the presence of an alkali metal amide, or in the presence of a basic metal oxide, to form a mixture of addition compounds of formula (II) and (III); (b) addition compound (III) is isomerised to addition compound (II); (c) addition compound (II) is isomerised in the presence of a homogeneous or heterogeneous transition metal catalyst in liquid phase or in the presence of a heterogeneous catalyst containing transition metal in the gas phase to produce enamine of formula (IV); and (d) the enamine (IV) is converted, by reaction with hydrogen and water, or water, in the presence of a homogeneous or heterogeneous transition metal catalyst in liquid phase, in the presence of a heterogenous catalyst containing transition metal in the gas phase, in the presence of an acid or in the presence of one of the above mentioned catalysts and of an acid, to n-butyraldehyde and/or n-butanol, the amine (I) being released and the released amine (I) being led back into sub-reaction (a).
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:
Verfahren zur Aufarbeitung eines Abgases (A) aus einer Anlage zur Herstellung von Hydroxylamin oder Hydroxylammonium-Salzen durch katalytische Reduktion von Stickstoffmonoxid mit Wasserstoff, wobei das Abgas (A) Stickstoffmonoxid, Wasserstoff, Distickstoffmonoxid, Stickstoff und Ammoniak enthält und mindestens ein Teil des im Abgas (A) enthaltenen Wasserstoffs aus dem Abgas (A) mittels einer gasdichten Membran-Elektroden-Assembly abgetrennt wird, die mindestens eine selektiv protonenleitende Membran, eine Retentatseite, eine Permeatseite und auf jeder Seite der Membran mindestens einen Elektrodenkatalysator aufweist, wobei auf der Retentatseite der Membran mindestens ein Teil des Wasserstoffs an dem Anodenkatalysator zu Protonen oxidiert wird und die Protonen nach Durchqueren der Membran auf der Permeatseite an dem Kathodenkatalysator gemäß; (I) zu Wasserstoff reduziert werden, und/oder (II) mit Sauerstoff zu Wasser umgesetzt werden, wobei der Sauerstoff aus einem Sauerstoff enthaltenden Strom (O) stammt, der mit der Permeatseite in Kontakt gebracht wird.
Abstract:
A carbon-containing catalyst support is prepared by treating the carbon-containing catalyst support with a compound of the formula I M(OR)mXn I where M is Ti or Zr, X is Cl or Br, and R is C1-C20-alkyl, and m and n are integers from zero to four, where the sum of m and n is equal to four.