Basf Aktiengesellschaft

Ludwig Wambach

Martin Fischer

Ulrich Hammon

Klaus Harth

Gerhard Olbert

Matthias Irgang

Thomas Fetzer

Dirk Demuth

Karl-Heinz Ross

Peter Reuter

Franz Corr

Helmuth Menig

Harro Wache

Andreas Northemann

Thomas Wendrich

Volker Pratsch

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 () and has to be removed, it is proposed that the ratio of tube spacing t to external tube diameter dbe made dependent on the reactor diameter or on the external tube bundle diameter d. At an external diameter of the catalyst tube bundle () of more than 4 meters, a ratio of tube spacing d to external tube diameter dof at least 1.3 is preferred.

Multi-tube fixed-bed reactor, especially for catalytic gas phase reactions

Preparation of carbonyl compounds

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.

Method and composition to increase the life of Liquid hydroxy-and

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

Gas-phase preparation of vinyl phosphonic acid derivatives

.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.6 -alkyl, the product obtainable in this procedure is reacted with an alkylating agent to introduce a C.sub.1 -C.sub.6 -alkyl group.

Preparation of alpha-pyrrolidones and their imines

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 III

Preparation of substituted lactams

.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.6 -alkyl, the product obtainable in this procedure is reacted with an alkylating agent to introduce a C.sub.1 -C.sub.6 -alkyl group.

.alpha.-pyrrolidones and a method for preparation thereof

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.

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Schwetzingen, Germany

Ludwig Wambach