Abstract: A multitube fixed bed reactor and the use of such a reactor for carrying out catalytic gas-phase reactions, in particular for carrying out exothermic and endothermic catalytic gas-phase reactions such as the preparation of phthalic anhydride (PA), acrylic acid, methacrylic acid (MAA), acrolein, maleic anhydride (MA), glyoxal, phosgene, hydrocyanic acid or vinyl formamide (VFA). In a relatively large multitube reactor in which a large amount of heat of reaction is generated owing to the numerous catalyst tubes (17) and has to be removed, it is proposed that the ratio of tube spacing t to external tube diameter da be made dependent on the reactor diameter or on the external tube bundle diameter dRBa. At an external diameter of the catalyst tube bundle (18) of more than 4 meters, a ratio of tube spacing d to external tube diameter da of at least 1.3 is preferred.

Abstract: Carbonyl compounds of the formula where R1 is a hydrogen atom or an alkyl radical having from 1 to 3 carbon atoms, R2 is a hydrogen atom, an unsubstituted or C1-C3-alkyl-monosubstituted to -trisubstituted C2-C4-alkenyl radical or a radical of the formula where R3 is a hydrogen atom or together with R4 is an oxygen atom, R4 is the radical OR6 or together with R3 is an oxygen atom, R5 is a hydrogen atom, an alkyl radical having from 1 to 8 carbon atoms, an unsubstituted or C1-C3-alkyl-monosubstituted to -trisubstituted C2-C4-alkenyl radical or a cyclohexyl or cyclopentyl radical and R6 is an alkyl radical having from 1 to 4 carbon atoms, a cyclohexyl or cyclopentyl radical or a radical of the formula —CH2—CHO or —CH2—CH2—O—CH2—CHO, are prepared by gas-phase oxidation of methanol or alcohols of the formula where R1 and R5 are as defined above, by means of an oxygen-containing gas in the presence of copper- and/or silv

Abstract: A method for increasing the shelf life of liquid hydroxy- and alkoxyalkyl ketones by adding from 0.0001 to 1% by weight of a base is described.

Abstract: A process for the preparation of vinyl phosphonic derivatives of the general formula I ##STR1## in which R.sup.1 and R.sup.2 are the same or different and may stand for hydrogen or a C.sub.1 -C.sub.8 -alkyl, a C.sub.6 -C.sub.10 -aryl, or a C.sub.8 -C.sub.10 -aralkyl radical optionally substituted by Cl or Br, and in which R.sup.1 and R.sup.2 may alternatively be joined together to form an alicyclic ring having from 3 to 12 carbon atoms in the ring, wherein an ethane phosphonic ester of the general formula II ##STR2## in which R.sup.3 and R.sup.4 have the meanings stated above for R.sup.1 and R.sup.2 except for hydrogen and X denotes a hydroxy group, a halogen atom, or a radical of the formula--OR.sup.5,in which R.sup.5 is a hydrogen atom or a radical of the formula ##STR3## in which R.sup.6 is a C.sub.1 -C.sub.6 -alkyl radical or an alicyclic ring, is converted in the gas phase in the presence of a solid catalyst.

Abstract: .alpha.-Pyrrolidones and cyclic amidines 1a and 1b, respectively, for washing gases ##STR1## where R.sup.1 and R.sup.2 are each C.sub.1 -C.sub.8 -alkyl, C.sub.1 -C.sub.8 -alkoxy, C.sub.3 -C.sub.10 -cycloalkyl or C.sub.3 -C.sub.10 -cycloalkoxy or are bonded to one another to form a ring, R.sup.3 is hydrogen, C.sub.1 -C.sub.6 -alkyl, phenyl or naphthyl and R.sup.4 and R.sup.5 are each hydrogen or C.sub.1 -C.sub.4 -alkyl, are prepared by a method in which an amine II ##STR2## where R.sup.3' is hydrogen, tert-butyl, phenyl or naphthyl, is reacted with an .alpha.,.beta.-unsaturated carboxylic acid derivative III ##STR3## where X is OR', --NR'R", --NHR' or --NH.sub.2 and R' and R" are each C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.8 -cycloalkyl or phenyl, or with an .alpha.,.beta.-unsaturated nitrile IV ##STR4## in the presence of a free radical initiator, and, where R.sup.3' is hydrogen and it is intended to prepare a compound in which R.sup.3' is C.sub.1 -C.sub.

Abstract: Preparation of substituted lactams Ia to Ic ##STR1## where n is 0 or 1, X is --O--CO--R.sup.1, --O--SO.sub.2 --R.sup.1, --CO--R.sup.2, --CO--O--R.sup.3 or --CO--NR.sup.4 R.sup.5, R.sup.1 is a C.sub.1 -C.sub.8 -radical of a carboxylic or sulfonic acid, R.sup.2 is C.sub.1 -C.sub.8 -alkyl, R.sup.3 is H or alkyl, aryl or aralkyl of not more than 8 carbon atoms, R.sup.4 and R.sup.5 are each H or C.sub.1 -C.sub.4 -alkyl or together form a 5-membered or 6-membered ring, by reacting a lactam II ##STR2## with a vinyl compound IIICH.sub.2 .dbd.CH-Xand a compound IV which forms free radicals to give Ia, and preparation of Ib by hydrolysis of a compound Ia in which X is (--O--CO--R.sup.1) or (--O--SO.sub.2 --R.sup.1), and preparation of Ic by thermolysis of Ib or of a compound Ia in which X is (--O--CO--R.sup.1) or (--O--SO.sub.2 --R.sup.1), and the novel substituted lactams Ia and Ib where X is (--O--CO--R.sup.1) and (--O--SO.sub.2 --R.sup.1).

Abstract: .alpha.-Pyrrolidones and cyclic amidines Ia and Ib, respectively, for washing gases. ##STR1## where R.sup.1 and R.sup.2 are each C.sub.1 -C.sub.8 -alkyl, C.sub.1 -C.sub.8 -alkoxy, C.sub.3 -C.sub.10 -cycloalkyl or C.sub.3 -C.sub.10 -cycloalkoxy or are bonded to one another to form a ring, R.sup.3 is hydrogen, C.sub.1 -C.sub.6 -alkyl, phenyl or naphthyl and R.sup.4 and R.sup.5 are each hydrogen or C.sub.1 -C.sub.4 -alkyl, are prepared by a method in which an amine II ##STR2## where R.sup.3' is hydrogen, tert-butyl, phenyl or naphthyl, is reacted with an .alpha., .beta.-unsaturated carboxylic acid derivative III ##STR3## where X is OR', --NR'R", --NHR' or --NH.sub.2 and R' and R" are each C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.8 -cycloalkyl or phenyl, or with an .alpha.,.beta.-unsaturated nitrile IV ##STR4## in the presence of a free radical initiator, and, where R.sup.3' is hydrogen and it is intended to prepare a compound in which R.sup.3' is C.sub.1 -C.sub.

Abstract: Furan is prepared by decarbonylation of furfural in the gas phase at elevated temperatures and under from 0.1 to 10 bar in the presence of hydrogen and a catalyst which contains platinum and/or rhodium and contains an alkali metal. The reaction is carried out in the presence of hydrogen. Catalysts which contain platinum and/or rhodium and to which cesium has been added are preferably used.