Abstract:
A process for the preparation of caprolactam is provided, wherein a) a mixture (I) containing 6-aminocapronitrile and water is reacted in the gas phase, in the presence of a catalyst, to give a mixture (II) containing caprolactam, ammonia, water, high-boiling components and low-boiling components, b) ammonia is then removed from the mixture (II) to give a mixture (III) containing caprolactam, water, high-boiling components and low-boiling components, c) water is then removed from the mixture (III) to give a mixture (IV) containing caprolactam, high-boiling components and low-boiling components, and d) a solid (V) containing caprolactam is then obtained from the mixture (IV) by crystallization, the proportion by weight of caprolactam in the solid (V) being greater than in the mixture (IV).
Abstract:
A process for the preparation of caprolactam is provided, wherein a) a mixture (I) containing 6-aminocapronitrile and water is reacted in the liquid phase, in the presence of a catalyst, to give a mixture (II) containing caprolactam, ammonia, water, high-boiling components and low-boiling components, b) ammonia is then removed from the mixture (II) to give a mixture (III) containing caprolactam, water, high-boiling components and low-boiling components, c) water is then removed from the mixture (III) to give a mixture (IV) containing caprolactam, high-boiling components and low-boiling components, and d) a solid (V) containing caprolactam is then obtained from the mixture (IV) by crystallization, the proportion by weight of caprolactam in the solid (V) being greater than in the mixture (IV).
Abstract:
Shaped materials useful as catalyst for preparing cyclic lactams by reacting aminocarbonitriles with water in the liquid phase in a fixed bed reactor and which have no soluble constituents under the reaction conditions, comprising pyrogenic titanium dioxide as essential constituent, these compositions being obtainable by shaping the pyrogenic titanium dioxide into shaped articles and, before or after the shaping, treating the pyrogenic titanium dioxide with from 0.1 to 30% by weight, based on the pyrogenic titanium dioxide, of an acid in which pyrogenic titanium dioxide is sparingly soluble.
Abstract:
The invention relates to a process for preparing lactams by cyclizing hydrolysis of amino nitriles with water in the gas phase on catalysts which comprise oxides or mixed oxides of the metals of groups 3, 4, 5, 13 and/or 14 of the Periodic Table, where appropriate in addition a metal oxide of groups 6, 7, 8, 9 and/or 10, and further comprise a phosphate, carbonate, silicate, arsenite, arsenate, antimonite, antimonate and/or nitrate of said metals and/or, if metal oxides of groups 6, 7, 8, 9 or 10 are present, a sulfate of the abovementioned metals.
Abstract:
Process for preparing an aqueous mixture of null-caprolactam and 6-aminocaproic acid and/or 6-aminocaproamide which involves, as the reductive amination step, contacting 5-formylvaleric acid and/or an alkyl 5-formylvalerate in water as solvent with hydrogen and an excess of ammonia in the presence of a ruthenium on carrier, as a catalyst, wherein the carrier is titanium oxide, zirconium oxide, graphite or carbon and the catalyst also contains at least one of the metals of group 8-11, or a compound of these metals. The aqueous mixture can be used to prepare null-caprolactam.
Abstract:
A process of producing an aliphatic aldehyde-acid (e.g., adipaldehyde-acid) and/or an aliphatic dicarboxylic acid (e.g., adipic acid) comprising oxidizing a cyclic ketone (e.g., cyclohexanone) with molecular oxygen in the presence of a fixed catalyst which comprises a composite of a carrier and at least one metal element belonging to the groups 4 to 11 of the Periodic Table supported on the carrier and has an acid amount of 0.06 mmol/g or more per unit weight of the carrier.
Abstract:
Cyclic lactams are prepared by reacting aminocarbonitriles with water in the liquid phase in a fixed bed reactor in the presence of a catalyst which comprises a catalytically active oxide, which has no soluble constituents under the reaction conditions and which consists of shaped articles obtainable by shaping the oxide into shaped articles and, before or after said shaping, treating the oxide with from 0.1 to 30% by weight, based on the oxide, of an acid in which the oxide is sparingly soluble.
Abstract:
Process to separate &egr;-caprolactam from an aqueous mixture containing &egr;-caprolactam and at least 0.5 wt % oligomers, wherein the separation is performed by extraction using an organic extraction agent. The aqueous mixture may be obtained in a process to prepare &egr;-caprolactam starting from 6-aminocapronitrile or in a process to prepare &egr;-caprolactam starting from 6-aminocaproic acid.
Abstract:
A process for the preparation of five-membered or six-membered ring lactams from aliphatic .alpha.,.omega.-dinitriles has been developed. In the process an aliphatic .alpha.,.omega.-dinitrile is first converted to an ammonium salt of an .omega.-nitrilecarboxylic acid in aqueous solution using a catalyst having an aliphatic nitrilase (EC 3.5.5.7) activity, or a combination of nitrile hydratase (EC 4.2.1.84) and amidase (EC 3.5.1.4) activities. The ammonium salt of the .omega.-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate .omega.-nitrilecarboxylic acid or .omega.-aminocarboxylic acid. When the aliphatic .alpha.,.omega.-dinitrile is also unsymmetrically substituted at the .alpha.-carbon atom, the nitrilase produces the .omega.-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the .omega.-nitrile group with greater than 98% regioselectivity, thereby producing only one of the two possible lactam products during the subsequent hydrogenation. A heat-treatment process to select for desirable regioselective nitrilase or nitrile hydratase activities while destroying undesirable activities is also provided.
Abstract:
A process for the preparation of five-membered or six-membered ring lactams from aliphatic .alpha.,.omega.-dinitriles has been developed. In the process an aliphatic .alpha.,.omega.-dinitrile is first converted to an ammonium salt of an .omega.-nitrile-carboxylic acid in aqueous solution using a catalyst having an aliphatic nitrilase (EC 3.5.5.7) activity, or a combination of nitrile hydratase (EC 4.2.1.84) and arnidase (EC 3.5.1.4) activities. The ammonium salt of the .omega.-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate .omega.-nitrilecarboxylic acid or .omega.-aminocarboxylic acid. When the aliphatic .alpha.,.omega.-dinitrile is also unsymmetrically substituted at the .alpha.-carbon atom, the nitrilase produces the .omega.-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the .omega.-nitrile group with greater than 98% regioselectivity, thereby producing only one of the two possible lactam products during the subsequent hydrogenation. A heat-treatment process to select for desirable regioselective nitrilase or nitrile hydratase activities while destroying undesirable activities is also provided.