Abstract: A process is described for selectively hydrogenating citronellal to citronellol in which a liquid phase, in which the citronellal is dissolved and particles of a catalyst are suspended which is capable of preferentially hydrogenating carbon-oxygen double bonds over carbon-carbon double bonds, is conducted through a device which inhibits the transport of the catalyst particles in the presence of a hydrogen-containing gas.

Abstract: Multimetal oxide materials containing molybdenum, vanadium, copper and antimony and one or more specific other metals and having a multicomponent structure are used for the gas-phase catalytic oxidative preparation of acrylic acid from acrolein.

Abstract: The present invention relates to a continuous process for the selective hydrogenation of olefinically unsaturated carbonyl compounds to give unsaturated alcohols in particular of citral to give a mixture of geraniol and nerol, in a reactor containing a liquid phase, in which at least one catalyst is suspended, and which can additionally contain a gas phase, wherein the liquid phase and, if present, the gas phase are passed through a device in the reactor having openings or channels.

Abstract: A catalyst suitable for the gas-phase oxidation of organic compounds to ?,?-unsaturated aldehydes and/or carboxylic acids and having an active phase comprising a multimetal oxide material is prepared by a process in which a particulate catalyst precursor which contains oxides and/or compounds of the elements other than oxygen which constitute the multimetal oxide material, which compounds can be converted into oxides, is prepared and said catalyst precursor is converted by calcination into a catalytically active form, wherein a stream of the particulate catalyst precursor is passed at substantially constant speed through at least one calcination zone at constant temperature for calcination.

Abstract: The present invention relates to a process for isomerizing reactant allyl alcohols to product allyl alcohols in the presence of a catalyst, wherein the reactant allyl alcohol is rearranged to product allyl alcohol in semicontinuous or continuous mode in a catalyst-containing suitable reactor. In particular, the process according to the invention is used to prepare linalool from Geraniol and/or nerol.

Abstract: A process for preparing annular unsupported catalysts by thermally treating annular shaped unsupported catalyst precursor bodies, wherein the side crushing strength of the annular shaped unsupported catalyst precursor bodies is ?12 N and ?23 N. In addition, resulting annular unsupported catalysts having a specific pore structure and also the use of such annular unsupported catalysts for the catalytic partial oxidative preparation in the gas phase of (meth)acrolein.

Abstract: The invention relates to a method for producing acrylic acid by the heterogeneously catalysed gas-phase oxidation of propane on a multi-metal oxide mass, said mass containing the elements Mo, V, Te and/or Sb and having a specific X-ray diffractogram.

Abstract: A process for preparing (meth)acrolein and/or (meth)acrylic acid by heterogeneously catalyzed gas phase partial oxidation of an organic precursor compound over a fresh fixed catalyst bed, in which the process is started up at a reduced hourly space velocity of charging gas mixture on the fixed catalyst bed.

Abstract: In a process for the thermal treatment of the precusor material of a catalytically active material in a rotary tube furnace through which a gas stream flows, at least a proportion of the gas stream flowing through the rotary tube furnace is circulated, and the associated rotary tube furnace apparatus and tube-bundle reactors for the partial gas-phase oxidation of acrolein to acrylic acid are loaded with catalysts whose catalytically active material is obtainable by the process for the thermal treatment.

Abstract: Multimetal oxide materials containing molybdenum, vanadium, antimony, one or more of the elements W, Nb, Ta, Cr and Ce and nickel and, if required, one or more of the elements Cu, Zn, Co, Fe, Cd, Mn, Mg, Ca, Sr and Ba and having a 2-component structure are used for the gas-phase catalytic oxidative preparation of acrylic acid.

Abstract: In a process for preparing a multiplephase multimetal oxide composition comprising Mo, V, Cu and, if desired, further elements, at least one phase is preformed separately and dispersed in a plastically deformable precursor composition of a further phase. The mixture is dried and calcined. The multimetal oxide composition is suitable as active composition of catalysts for the catalytically oxidation of organic compounds in the gas phase, in particular for the oxidation of acrolein to acrylic acid.

Abstract: The present invention relates to a process for the preparation of tetrahydrogeraniol, wherein the product mixtures and distillation residues from linalool, citronellal, citronellol or geraniol/nerol synthesis are fed directly to catalytic hydrogenation.

Abstract: In a process for the two-stage catalytic gas-phase oxidation of propene to acrylic acid, the reaction gas starting mixture is passed, in a tube-bundle reactor, with a propene loading of ≧160 l (S.T.P.) of propene/l·h, first over a fixed catalyst bed 1 present in two successive temperature zones A, B and then over a fixed catalyst bed 2 which is housed either in one further temperature zone C or in two further temperature zones D, E, the temperature of the zone A being kept at a lower temperature than the zone B and the temperature of the zone D at a lower temperature than the zone E.

Abstract: Multimetal oxide materials containing molybdenum, vanadium, antimony, one or more of the elements W, Nb, Ta, Cr and Ce and one or more of the elements Cu, Zn, Co, Fe, Cd, Mn, Mg, Ca, Sr and Ba and having a 2-component structure are used for the gas-phase catalytic oxidative preparation of acrylic acid.

Abstract: The invention relates to a method for the heterogenically catalysed gas-phase partial oxidation of precursor compounds of (meth)acrylic acid in a fixed catalyst bed, containing as the catalyst an activated mass of mixed oxide, shaped to form a geometric body. Said geometric body is a geometric base body, into whose surface a cavity is incorporated.

Abstract: A catalyst suitable for the gas-phase oxidation of organic compounds to &agr;,&bgr;-unsaturated aldehydes and/or carboxylic acids and having an active phase comprising a multimetal oxide material is prepared by a process in which a particulate catalyst precursor which contains oxides and/or compounds of the elements other than oxygen which constitute the multimetal oxide material, which compounds can be converted into oxides, is prepared and said catalyst precursor is converted by calcination into a catalytically active form, wherein a stream of the particulate catalyst precursor is passed at substantially constant speed through at least one calcination zone at constant temperature for calcination.

Abstract: The invention relates to a method for producing acrylic acid by the heterogeneously catalysed gas-phase oxidation of propane on a multi-metal oxide mass, said mass containing the elements Mo, V, Te and/or Sb and having a specific X-ray diffractogram.

Abstract: Coated catalysts which are suitable for the gas-phase catalytic oxidation of propene to acrolein are prepared by a process in which rings are used as supports and water is used as a binder.

Abstract: The invention relates to a method for producing a multiple-phase multi-metal oxide material that contains Mo, V, Cu and, optionally, other elements. According to the invention, at least one phase is separately pre-formed and is dispersed in a plastically deformable precursor material of another phase. The mixture is then dried and calcined. The multi-metal oxide material is suited for use as an active material of catalysts for catalytically oxidizing organic compounds in the gas phase, in particular, for oxidizing acrolein into acrylic acid.

Abstract: The present invention relates to a process for the preparation of tetrahydrogeraniol, wherein the product mixtures and distillation residues from linalool, citronellal, citronellol or geraniol/nerol synthesis are fed directly to catalytic hydrogenation.