Abstract:
The invention relates to a process for hydrogenating an aromatic amine that has at least one amino group bound to an aromatic nucleus with hydrogen in the presence of a supported catalyst that contains at least ruthenium as active metal. The catalyst support has a BET surface area in the range from greater than 30 m2/g to less than 70 m2/g and more than 50% of the pore volume of the catalyst support is formed by macropores having a pore diameter of greater than 50 nm and less than 50% are mesopores having a pore diameter of 2 to 50 nm.
Abstract:
An impeller for a delivery pump in which profiled section (14) comprising webs (15) is located on the outer periphery of an impeller (4) for a feed pump (2) that is configured as a side channel pump. The webs (15) are arranged at an ascending incline, viewed in the rotational direction of the impeller (4) from the designated pressure side to the designated intake side. This permits flow losses between the radial external region of the impeller (4) and the housing parts (6, 7) of the feed pump (2) to be maintained at a particularly low level.
Abstract:
Carrier-bound ruthenium catalysts are used to produce alcohols by the catalytic hydrogenation of aldehydes and ketones. The problem of deactivation of the catalyst is solved by the use of a ruthenium catalyst on an oxide carrier of the series TiO2, SiO2, ZrO2, MgO, mixed oxides thereof and silicates thereof. In particular, Ru on TiO2 or SiO2 results in a long service life of the catalyst.
Abstract:
&bgr;-Hydroxyaldehydes are produced by a method in which 1,2-oxiranes are reacted with carbon monoxide and hydrogen in the presence of transitional metal compounds which are modified with phosphorus-oxygen ligands or nitrogen-oxygen ligands and which act as a catalyst.
Abstract:
In a process for the epoxidation of propene, comprising the steps: reacting propene with hydrogen peroxide in the presence of a titanium silicalite catalyst and a methanol solvent; separating non-reacted propene and propene oxide from the resulting reaction mixture to provide a solvent mixture comprising methanol and water in a combined amount of at least 90% by weight; and feeding this solvent mixture as a feed stream to a continuously operated methanol distillation column at a feed point in the middle section of said column to provide an overhead product comprising at least 90% by weight methanol and a bottoms product comprising at least 90% by weight water; the addition of a liquid defoamer, having a solubility in the feed stream of less than 10 mg/kg at 25° C. and a surface tension at the liquid air interface of less than 22 mN/m at 20° C., at or above the feed point in an amount exceeding the solubility of the liquid defoamer in the feed stream suppresses foam formation in the methanol distillation column.
Abstract:
The invention relates to a process for hydrogenating an aromatic amine that has at least one amino group bound to an aromatic nucleus with hydrogen in the presence of a supported catalyst that contains at least ruthenium as active metal. The catalyst support has a BET surface area in the range from greater than 30 m2/g to less than 70 m2/g and more than 50% of the pore volume of the catalyst support is formed by macropores having a pore diameter of greater than 50 nm and less than 50% are mesopores having a pore diameter of 2 to 50 nm.
Abstract:
In a fuel pump (6) designed as a side channel pump, in each case two conveying chambers (20-23) one surrounding the other concentrically are arranged on two impellers (9, 10). The conveying chambers (20, 21) of one impeller (9) are connected to an inlet duct (25), while the conveying chambers (22, 23) of the other impeller (10) are connected to an outlet duct (26). A connection (24) of the conveying chambers (20-23) is arranged in a partition (17) keeping the impellers (9, 10) at a distance from one another. As a result, the fuel pump (6) has an especially high volume flow, along with a very high conveying pressure.
Abstract:
The invention relates to a process for the production of hydrogen peroxide by the anthraquinone process, comprising a hydrogenation stage, an oxidation stage and an extraction stage. According to the invention, catalytic hydrogenation of anthraquinone derivatives dissolved in a working solution is carried out in the presence of added molecular oxygen. Per mol hydrogen, 0.1 to 10 mmol oxygen is preferably introduced into the hydrogenation stage with the hydrogenating gas, in mixture with an inert gas and/or dissolved and/or dispersed in the working solution. This increases the residence time of the catalyst.
Abstract:
The invention relates to a process for increasing the selectivity of the hydrogenation of 4,4′-diaminodiphenylmethane (4,4′-MDA) to diaminodicyclohexylmethane (4,4′-HMDA) by catalytic hydrogenation of a mixture containing 4,4′-MDA as the main component and its mono-N-methyl derivative as a secondary component. According to the invention, the hydrogenation is terminated before a conversion of 4,4′-MDA to 4,4′-HMDA of 99% is achieved. Under these conditions, a substantially smaller proportion of the N-methyl-4,4′-MDA is hydrogenated to N-methyl-4,4-HMDA.
Abstract:
The invention relates to a process for hydrogenating an aromatic amine that has at least one amino group bound to an aromatic nucleus with hydrogen in the presence of a supported catalyst that contains at least ruthenium as active metal. The catalyst support has a BET surface area in the range from greater than 30 m2/g to less than 70 m2/g and more than 50% of the pore volume of the catalyst support is formed by macropores having a pore diameter of greater than 50 nm and less than 50% are mesopores having a pore diameter of 2 to 50 nm.