Abstract: The invention relates to a process and apparatus for the isothermal operation of heterogeneously catalyzed reactions involving at least three phases in the form of a gaseous phase, a liquid phase and a solid phase. The invention provides apparatus for carrying out reactions involving a gaseous phase, a liquid phase and a solid phase, comprising (i) a dispersing element for dispersing a gas phase in a liquid phase to generate a reaction fluid, (ii) at least one reactor which possesses an inlet, an outlet and a reactor space bounded by heat-removing walls which are spaced apart substantially uniformly along the main flow axis of the reaction fluid, and which is fitted with catalyst-coated metal fabric, and (iii) a feed line which routes the reaction fluid from the dispersing element to the reactor inlet and is sufficiently short that the degree of dispersion of the reaction fluid does not substantially change in the course of the passage through the feed line.

Abstract: The invention relates to catalyst packing and a production process for catalyst packing in which a fabricated woven or knitted fabric in the form of continuous web goods is shaped to give a package by stacking a plurality of layers, and segments (S) are cut out of the package and assembled to give one or more course(s) which completely fill the reactor cross section. A reactor containing catalyst packing of this type is particularly suitable for catalytic reactions, preferably for hydrogenations, selective hydrogenations, selective oxidations or isomerizations.

Abstract: In a process for the suspension hydrogenation of an anthraquinone compound or a mixture of two or more thereof in a reactor in which there are present the working solution in which at least one catalyst is suspended and, in addition, a hydrogen-containing gas phase, the working solution and the gas phase are, in the reactor, passed at least partly through a fitting having openings or channels whose hydraulic diameter is from 0.5 to 20 mm, preferably from 1 to 10 mm, particularly preferably from 1 to 3 mm.

Abstract: A process for hydrogenating an anthraquinone compound or a mixture of two or more thereof utilizes specific catalysts comprising, as active metal, a metal of transition group VIII of the Periodic Table of the Elements.

Abstract: Active compositions are deposited by means-of an impregnating process onto structured supports, where the impregnating medium has a surface tension of not more than 50 mN/m. Monoliths are made from the structured supports thus produced. The structured supports or the monoliths are used as catalysts in chemical processes.

Abstract: Alkenes are prepared by partial hydrogenation of alkynes in the liquid phase at from 20 to 250° C. and hydrogen partial pressures of from 0.

Abstract: A process for hydrogenating an anthraquinone compound or a mixture of two or more thereof utilizes specific catalysts comprising, as active metal, a metal of transition group VIII of the Periodic Table of the Elements.

Abstract: Alkenes are prepared by partial hydrogenation of alkynes in the liquid phase at from 20 to 250° C. and hydrogen partial pressures of from 0.

Abstract: A catalyst packing which can be produced by vapor deposition and/or sputtering of at least one substance active as catalyst and/or promotor onto woven or knitted fabrics or sheets as support material is used in a process for catalytic distillation in which a heterogeneously catalyzed reaction is combined with a simultaneous distillation or rectification over the catalyst packing.

Abstract: The fixed-bed catalyst comprises palladium and selenium or tellurium or a mixture of selenium and tellurium on a silicon dioxide support and has a BET surface area of from 80 to 380 m2/g and a pore volume of from 0.6 to 0.95 cm3/g in the pore diameter range from 3 nm to 300 &mgr;m, with from 80 to 95% of the pore volume being in the pore diameter range from 10 to 100 nm. It is prepared by impregnating a silicon dioxide support with a solution of a palladium compound and a selenium compound or tellurium compound or a mixture of a selenium compound and a tellurium compound, drying it and reducing it in the presence of hydrogen. The catalyst is used, in particular, for isomerizing 3-buten-1-ol compounds.

Abstract: The invention relates to catalyst packing and a production process for catalyst packing in which a fabricated woven or knitted fabric in the form of continuous web goods is shaped to give a package by stacking a plurality of layers, and segments (S) are cut out of the package and assembled to give one or more course(s) which completely fill the reactor cross section. A reactor containing catalyst packing of this type is particularly suitable for catalytic reactions, preferably for hydrogenations, selective hydrogenations, selective oxidations or isomerizations.

Abstract: A process for preparing 1,4-butanediol by continuous catalytic hydrogenation of 1,4-butynediol comprises reacting 1,4-butynediol with hydrogen in the liquid continuous phase in the presence of a heterogeneous hydrogenation catalyst at from 20 to 300° C., a pressure of from 1 to 200 bar and values of the liquid-side volumetric mass transfer coefficient kLa of from 0.1 s−1 to 1 s−1 a) using a catalyst suspended in the reaction medium, where if a packed bubble column is employed this is operated in the upflow mode and at a ratio of gas leaving the reaction vessel to gas fed to the reaction vessel of from 0.99:1 to 0.4:1, or b) passing the liquid and gas in cocurrent in an upward direction through a fixed-bed reactor operated in the gas-circulation mode while maintaining a ratio of the gas fed to the reaction vessel to gas leaving the reaction vessel of from 0.99:1 to 0.4:1.

Abstract: The fixed-bed catalyst comprises palladium and selenium or tellurium or a mixture of selenium and tellurium on a silicon dioxide support and has a BET surface area of from 80 to 380 m2/g and a pore volume of from 0.6 to 0.95 cm3/g in the pore diameter range from 3 nm to 300 &mgr;m, with from 80 to 95% of the pore volume being in the pore diameter range from 10 to 100 nm. It is prepared by impregnating a silicon dioxide support with a solution of a palladium compound and a selenium compound or tellurium compound or a mixture of a selenium compound and a tellurium compound, drying it and reducing it in the presence of hydrogen. The catalyst is used, in particular, for isomerizing 3-buten-1-ol compounds.

Abstract: In the dehydrogenation of secondary alcohols in the presence of a catalyst comprising zinc oxide and calcium carbonate at elevated temperature in the gas phase, secondary cyclic alcohols are used and the dehydrogenation is carried out in the presence of hydrogen and a catalyst whose active components comprise from 30 to 60% by weight of zinc oxide and from 40 to 70% by weight of calcium carbonate in the calcite modification.

Abstract: The invention relates to a process for the selective liquid-phase hydrogenation of .alpha.,.beta.-unsaturated carbonyl compounds of the formula I, ##STR1## where R.sub.1 is hydrogen or an organic radical, and R.sub.2, R.sub.3 and R.sub.4, independently of one another, are hydrogen or a C.sub.1 -- to C.sub.4 --alkyl group, to saturated carbonyl compounds of the formula II ##STR2## using hydrogen in the presence of a pulverulent palladium and/or rhodium catalyst and in the presence of an organic base. The process is carried out in a packed bubble column reactor (1, 2) with product recycling (11, 17) and circulating hydrogen gas (4, 15, 16). It is particularly suitable for the selective hydrogenation of citral to citronellal.

Abstract: The present invention relates to a gauze catalyst based on titanium or vanadium zeolites and inert gauze fabrics which is suitable for accelerating oxidation reactions such as epoxidation of olefins, hydrogen peroxide production or hydroxylamine synthesis.

Abstract: A process for preparing 1,2-butylene oxide by catalytic hydrogenation of vinyloxirane over a heterogeneous catalyst comprises using a catalyst comprising an element of subgroup I, VII or VIII of the periodic table, or mixtures of a plurality of these elements, in the presence or absence of one or more promoter elements, these elements and promoters having been applied by means of a vacuum vapor deposition technique to a support of metal foil or metal wire fabric.

Abstract: In a process for the catalytic hydrogenation of 2,5- and 2,3-dihydrofuran with hydrogen to give tetrahydrofuran, use is made of a catalyst in which a metal or a plurality of metals have been deposited by vapor deposition or sputtering on a metal wire mesh or a metal foil as support.

Abstract: Catalytic reactions are carried out in a reactor which contains a liquid phase in which at least one catalyst is suspended, and which may additionally contain a gas phase, by a process in which the liquid phase and, if present, also the gas phase are fed, at least partly, through an apparatus having orifices or channels in the reactor, the hydraulic diameter of which orifices or channels is from 0.5 to 20 mm, preferably from 1 to 10 mm, particularly preferably from 1 to 3 mm.

Abstract: Monomodal or polymodal catalyst supports or catalysts having a BET specific surface area of from 0.01 to 250 m.sup.2 /g and a monomodal or polymodal pore size distribution having a mean pore diameter of from 50 to 300,000 nm measured by the mercury pressure porosimetry method, whereina) from 10 to 95% of the pore volume is at from 0.1 to 3 times the mean pore diameter and/orb) from 10 to 80% of the pore volume is at from 0.4 to 3 times the mean pore diameter and/orc) from 50 to 95% of the pore volume is at from 0.1 to 1 times the mean pore diameter and/ord) from 50 to 80% of the pore volume is at from 0.4 to 1 times the mean pore diameter ande) the width at half height of the pore size distribution is less than 0.