Abstract: Mixed cyclic acrolein glycerol acetals can be obtained by reacting acrolein with glycerol in the presence of a solid acidic catalyst and by a distillation workup in a higher space-time yield and in very high selectivity in comparison to the state of the art if the reaction is carried out in the presence of the reaction mixture as solvent, which mixture consists essentially of acrolein, glycerol, cyclic acrolein glycerol acetals and water, and in the absence of heterogeneous solvents and, to the extent necessary, the reaction mixture freed of catalyst is compounded prior to being worked up by distillation with such an amount of pH-increasing substance that it exhibits a pH in a range of 4.5 to 7 in tenfold dilution with water. The reaction preferably takes place at 10.degree. to 30.degree. C. using strongly acidic organic or inorganic ion exchangers.

Abstract: Asymmetric hydrogenation of .alpha.-ketocarbonyl compounds, especially .alpha.-ketolactones, to the corresponding, optically active .alpha.-hydroxycarbonyl compounds in the presence of iridium diphosphine complexes as catalyst and dicarboxylic acid imides as co-catalyst.

Abstract: The hydration of acrolein in the presence of a chelate-forming ion exchange resin based on polystyrene/divinyl benzene as catalyst and on the subsequent hydrogenation of the reaction mixture freed of the non-reacted acrolein and containing 3-hydroxypropionaldehyde is disclosed. As a result of using chelate-forming ion exchangers with anchor groups of the formula ##STR1## in which Z=H, C.sub.1 -C.sub.6 -alkyl, --CH.sub.2 --CH(CH.sub.3)--Y' or --(CH.sub.2).sub.o --Y' and Y and/or Y'=--COOH, --OH, pyridyl or --P(O)(CH.sub.2 OH)OH, the hydration occurs at lower temperatures with a greater space-time yield and especially a greater selectivity than when using previously known ion exchangers. Resins with methylene imino diacetic acid anchor groups in the H form or partially doped with alkali-, alkaline-earth or earth-metal ions are especially suitable.

Abstract: Catalytic dealkoxylation of gem-dialkoxy compounds for synthesizing vinyl ethers is disclosed. Zeolites of the mordenite or ZSM5 type with an Na.sub.2 O/Al.sub.2 O.sub.3 molar ratio of 1:1.05 (.+-.0.25) are used as catalysts.

Abstract: A catalyst is described for the production of unsaturated aldehydes by means of oxidation with a oxygen-containing gas where an active mass, containing at least the elements Mo, Bi, P and O, as well as Si-containing carrier material, is used in the form of a catalyst body with a certain ratio between the outer surface and the volume and with a defined extent in terms of space, porosity, density, specific surface, breaking strength, abrasion, and gas through-flow capability. Also described is a method of making the catalyst.

Abstract: The present invention relates to a process for the production of acrolein by catalytic gas-phase oxidation of propene with air in the presence of steam and an inert gas or waste gas from the reaction, the starting materials being passed in defined quantitative ratios at 300.degree. to 380.degree. C. under 1.4 to 2.2 bar pressure over a catalyst containing the combination of elements MoFeCoNiBiP(As)K(Rb,Cs)SmSiO in the form of a bed of individual elements, the catalyst elements fulfilling certain geometric conditions and a number of critical physico-chemical parameters and a specific load of 2 to 8 mol propene/dm.sup.3 catalyst bed/h being adjusted.

Abstract: A method for preparing 1,3-propanediol is disclosed which comprises the hydration of acrolein in the presence of an acidic cation exchanger resin and the hydrogenation of the 3-hydroxypropionaldehyde obtained in the first stage. The volume-time yield was able to be increased in the hydration stage by using a cation exchanger resin with phosphonic acid groups, preferably a cation exchanger with chelating aminophosphonic acid groups. The hydrogenation catalyst can be repeatedly reused without appreciable loss of activity.

Abstract: A process is disclosed for preparing coated catalysts, inter alia, for gas phase oxidations in organic chemistry, comprised of an inert support and a coating of catalyst material enclosing this support, wherein a suspension of the starting material for the coating is sprayed onto an agitated bed of the support, while the suspending medium is being partially removed by a gas stream, and the raw material is then dried and heat-treated. For this purpose, the support bed is mechanically agitated and loosened by a gas stream blown in from below. The catalyst precursor containing a binder and, if appropriate, a pore-former is sprayed in an increasing amount from above onto the bed, the ratio between suspending medium sprayed on and drawn off remaining about constant. The thermal expansion coefficient of the precursor as a dry powder must not deviate by more than 15% from that of the support.

Abstract: A method of preparation for acetals utilizing saturated or unsaturated aldehydes, in particular, the preparation of dimethylacetals of acetaldehyde, acrolein and methacrolein. The production of the acetal takes place in a liquid phase in the presence of a solid acid catalyst, such as a strongly acidic ion exchange resin or zeolite. The conversion mixture is extracted by means of water and by means of water insoluble organic solvents. There is obtained not only the desired acetals, but in addition also the unconverted initial quantities of the starting materials by a simple method and with very good yields.

Abstract: A process is disclosed for preparing coated catalysts, inter alia, for gas phase oxidations in organic chemistry, comprised of an inert support and a coating of catalyst material enclosing this support, wherein a suspension of the starting material for the coating is sprayed onto an agitated bed of the support, while the suspending medium is being partially removed by a gas stream, and the raw material is then dried and heat-treated. For this purpose, the support bed is mechanically agitated and loosened by a gas stream blown in from below. The catalyst precursor containing a binder and, if appropriate, a pore-former is sprayed in an increasing amount from above onto the bed, the ratio between suspending medium sprayed on and drawn off remaining about constant. The thermal expansion coefficient of the precursor as a dry powder must not deviate by more than 15% from that of the support.

Abstract: A process is disclosed for preparing coated catalysts, inter alia, for gas phase oxidations in organic chemistry, comprised of an inert support and a coating of catalyst material enclosing this support, wherein a suspension of the starting material for the coating is sprayed onto an agitated bed of the support, while the suspending medium is being partially removed by a gas stream, and the raw material is then dried and heat-treated. For this purpose, the support bed is mechanically agitated and loosened by a gas stream blown in from below. The catalyst precursor containing a binder and, if appropriate, a pore-former is sprayed in an increasing amount from above onto the bed, the ratio between suspending medium sprayed on and drawn off remaining about constant. The thermal expansion coefficient of the precursor as a dry powder must not deviate by more than 15% from that of the support.

Abstract: A process is disclosed for preparing acrolein from propylene and methacrolein from isobutylene or tertiary butanol, by oxidation in oxygen-containing gas mixtures on specially prepared coated catalysts comprised of an inert support and a coating, enclosing this support, of an oxidic catalyst material containing the elements nickel, cobalt, iron, bismuth, phosphorus, molybdenum and tantalum or samarium and, if appropriate, also alkali metal or alkaline earth metal in certain atomic ratios. This coated catalyst is obtained by spraying a suspension of the starting material for the coating, which suspension contains a binder and, if appropriate, a pore-former, from above in an increasing amount onto a bed of the support, which bed is mechanically agitated and loosened up by a gas stream blow in from below, the ratio between suspending medium sprayed on and removed again by the gas stream remaining approximately constant.