Abstract: A process for the preparation of tetrahydrofuran or tetrahydrofuran and .gamma.-butyrolactone from the product of the hydrogenation of maleic acid, succinic acid, maleic anhydride, succinic anhydride and/or fumaric acid, by treating the crude hydrogenation product, without prior work-up, at from 100.degree. to 300.degree. C. with a protic acid, and isolating pure tetrahydrofuran and .gamma.-butyrolactone from the resultant reaction mixture by distillation.

Abstract: The invention is directed to a frequency-doubling solid state laser having pump light sources at opposite ends thereof. A folding and out-coupling mirror is antireflection coated on both sides with respect to the wavelength of the light generated by the pump light sources. The pump light sources include a total of four laser diodes with each laser diode generating 3 Watts of light power. An output power at 532 nm is obtained using a Nd:YAG laser rod and a frequency-doubling crystal made of potassium titanyl phosphate. The folding angle defined by the folding and out-coupling mirror is in the range of 10.degree. to 60.degree. and is typically 50.degree..

Abstract: In a tube bundle reactor for carrying out catalytic organic reactions in the gas phase, comprising reaction tubes (A) arranged between tubesheets (B), the reaction tubes have an inside diameter ranging from 0.5 to 3 cm, the ratio of reaction tube length to inside diameter ranges from 2 to 10, and the reaction tubes (A) are surrounded by a fluid heat transport medium flowing in the crosswise direction; said tube bundle reactor is useful in particular in exothermic organic reactions.

Abstract: Muscone of the formula I ##STR1## is prepared by a process in which an open-chain 2,15-diketone of the general formula IICH.sub.3 --CO--X--CO--CH.sub.3 (II)whereX is one of the radicals--(--CH.sub.2 --).sub.12 -- (a)--CH.dbd.CH--(--CH.sub.2 --).sub.8 --CH.dbd.CH-- (b)--CH.sub.2 --CH.dbd.CH--(--CH.sub.2 --).sub.6 --CH.dbd.CH--CH.sub.2 --(c)--CH.sub.2 --CH.sub.2 --CH.dbd.CH--(--CH.sub.2 --).sub.4 --CH.dbd.CH--CH.sub.2 --CH.sub.2 -- (d)or--CH.sub.2 --CH.sub.2 --CH.sub.2 --CH.dbd.CH--(--CH.sub.2 --).sub.2 --CH.dbd.CH--CH.sub.2 --CH.sub.2 --CH.sub.2 -- (e)is brought into contact, at from 300.degree. to 400.degree. C. in the presence of from 5 to 15% by weight, based on the amount of catalyst, of water, in the gas phase, with a fixed-bed catalyst containing TiO.sub.2, CeO.sub.2 or ThO.sub.2 as the catalytically active compound and the unsaturated cyclic ketone formed by intramolecular aldol condensation is subjected to catalytic hydrogenation.

Abstract: Muscone of the formula I ##STR1## is prepared by a process in which an open-chain 2,15-diketone of the general formula IICH.sub.3 --CO--X--CO--CH.sub.3 (II)where X is one of the radicals--(--CH.sub.2 --).sub.12 -- (a)--CH.dbd.CH--(--CH.sub.2 --).sub.8 --CH.dbd.CH-- (b)--CH.sub.2 --CH.dbd.CH--(--CH.sub.2 --).sub.6 --CH.dbd.CH--CH.sub.2 --(c)--CH.sub.2 --CH.sub.2 --CH.dbd.CH--(--CH.sub.2 --).sub.4 --CH.dbd.CH--CH.sub.2 --CH.sub.2 -- (d) or--CH.sub.2 --CH.sub.2 CH.sub.2 --CH.dbd.CH--(--CH.sub.2 --).sub.2 --CH.dbd.CH--CH.sub.2 --CH.sub.2 --CH.sub.2 -- (e)is brought into contact, at from 300.degree. to 400.degree. C. in the presence of from 5 to 15% by weight, based on the amount of catalyst, of water, in the gas phase, with a fixed-bed catalyst containing TiO.sub.2, CeO.sub.2 or the ThO.sub.2 as the catalytically active compound and the unsaturated cyclic ketone formed by intramolecular aldol condensation is subjected to catalytic hydrogenation.

Abstract: The invention is directed to a cooling arrangement for a semiconductor pump source which develops heat during operation. The cooling arrrangement includes a heat sink defining a seat for accommodating the pump source thereon and a cooling channel is formed in the heat sink for conducting a coolant therethrough to remove a major portion of the heat. A Peltier device is connected to the heat sink for finely controlling the temperature of the heat sink so as to permit the semiconductor pump source to emit radiation having a predetermined optional wavelength.

Abstract: Process for the preparation of 1,4-butanediol or tetrahydrofuran or both by the catalytic hydrogenation of maleic anhydride, succinic anhydride, maleic acid, succinic acid, fumaric acid, or the alkyl esters of these acids at temperatures of from 100.degree. C. to 350.degree. C. and pressures of from 50 bar to 350 bar over a catalyst containing cobalt as the active metal and one or both of the elements copper and phosphorus, if necessary in the presence of an aliphatic alcohol.

Abstract: Aldehydes and ketones of the general formula I ##STR1## where R.sup.1 is hydrogen or an organic radical of 1 to n carbon atoms and R.sup.2 is a non-aromatic organic radical of 1 to m carbon atoms, (m+n) ranging from 2 to 24 and R.sup.1 and R.sup.2 being combinable to form a 4- to 12-membered ring, are prepared in a continuous manner by oxidizing an alcohol of the general formula II ##STR2## with oxygen or an oxygen-containing gas at elevated temperatures in the gas phase in the presence of a catalyst, by effecting the oxidation by means of a supported catalyst composed of an inert carrier having a smooth surface and from 0.1 to 20% by weight, based on the amount of carrier, of an active layer of copper, silver and/or gold in a tubular reactor or tube bundle reactor where the internal diameter D of the tube or tubes ranges from 10 to 50 mm and the largest diameter d of the coated supported catalysts is subject to the relationship d=from 0.1 to 0.2 D.

Abstract: A process for the continuous preparation of 3-alkyl-buten-1-als by oxidative dehydrogenation of 3-alkyl-buten-1-ols at from 320.degree. to 650.degree. C. with oxygen over a catalyst containing copper and/or silver, wherein, within one second after contact with the catalyst, the vaporous reaction mixture, which is at from 320.degree. to 650.degree. C., is brought into contact with a liquid comprising water and/or the condensed reaction mixture at from -20.degree. to 50.degree. C., and the 3-alkyl-buten-1-als are separated off from the resulting condensate.