Abstract: Alkanals having a 2-alkyl branch are obtained from mixtures which contain the alkanals having a 2-alkyl branch in addition to n-alkanals, 3-alkylalkanals and/or further isomers by a process in whicha) the alkanal mixture is reacted with an aqueous formaldehyde solution in the presence of a secondary amine and of a carboxylic acid as a catalyst,b) the aqueous phase containing the catalyst and any unconverted excess formaldehyde is separated off andc) the alkanals having a 2-alkyl branch are isolated by distillation from the condensates of the other alkanals with formaldehyde.

Abstract: 4-oxaaldehydes of the formula ##STR1## are prepared by catalytic isomerization of 1,3-dioxanes by a process in which a 1,3-dioxane of the formula ##STR2## where R.sup.1, R.sup.2, R.sup.4 and R.sup.5 are identical or different and are each hydrogen, a straight-chain or branched alkyl, alkenyl or alkynyl radical of not more than 18 carbon atoms, a cycloalkyl or cycloalkenyl radical of 5 to 8 carbon atoms, an aryl, alkylaryl, aralkyl, aralkenyl or alkenylaryl radical of 5 to 16 carbon atoms or a heterocyclic radical and furthermore R.sup.1 and R.sup.2 and/or R.sup.4 and R.sup.5 together with the carbon atoms to which they are bonded may form a cycloalkane, a cycloalkene or a heterocyclic structure, and the stated radicals may furthermore carry substituents which are inert under the reaction conditions, and R.sup.3 is hydrogen or straight-chain or branched alkyl, is isomerized using a metal oxide catalyst, which has been treated with an acid, and/or a silica phase having a zeolite structure.

Abstract: Mixtures which contain 1,4-butanediol and tetrahydrofuran are prepared by heating 4-hydroxybutyraldehyde of the formula ##STR1## at 20.degree.-300.degree. C. in the presence or absence of 1,4-butanediol and subjecting the resulting acetals of the formulae ##STR2## to a catalytic hydrogenation at 50.degree.-300.degree. C. and 1-350 bar.

Abstract: Cyclic 6-membered to 8-membered 1,2-vinylenedioxy compounds of the general formula I ##STR1## where A is ##STR2## R.sup.1 to R.sup.7 independently of one another are each hydrogen, C.sub.1 -C.sub.8 -alkyl, C.sub.2 -C.sub.16 -alkoxyalkyl, C.sub.2 -C.sub.8 -alkenyl, C.sub.2 -C.sub.8 -alkynyl, C.sub.5 -C.sub.8 -cycloalkyl, aryl, C.sub.7 -C.sub.10 -alkylphenyl, C.sub.7 -C.sub.10 -phenalkyl, C.sub.8 -C.sub.10 -phenalkenyl or a heterocyclic structure, or R.sup.2 and R.sup.3, R.sup.2 and R.sup.4, R.sup.3 and R.sup.4, R.sup.2 and R.sup.6, R.sup.3 and R.sup.6, R.sup.4 and R.sup.5 or R.sup.6 and R.sup.7 together form a cycloaliphatic or heterocyclic ring, and R.sup.1 to R.sup.7 may furthermore carry substituents which are inert under the reaction conditions, and n is 0 or 1, are prepared by a process in which a cyclic 2-oxymethyl-1,3-dioxa compound or one of its derivatives of the general formula II ##STR3## where R.sup.1 to R.sup.7, A and n have the abovementioned meanings, and R.sup.8 is hydrogen or C.sub.1 -C.sub.

Abstract: 5-Formylvaleric esters are prepared by a process which comprises the following steps:(a) Hydroformylation of a pentenoic ester by reaction with carbon monoxide and hydrogen at elevated temperatures and under superatmospheric pressure in the presence of a carbonyl complex of a metal of group 8 of the Periodic Table with formation of a mixture of 5-, 4- and 3-formylvaleric esters,(b) Isolation of the 5-formylvaleric ester from the resulting mixture of 5-, 4- and 3-formylvaleric esters, a mixture essentially consisting of 4- and 3-formylvaleric esters remaining,(c) Cleavage of the mixture essentially consisting of 4- and 3-formylvaleric esters at from 50.degree. to 400.degree. C. in the presence of a catalyst to give pentenoic esters and(d) Recycling of the pentenoic esters to stage (a).

Abstract: Olefinically unsaturated carboxylic esters having a terminal ester group and of the general formulae Ia and IbR.sup.1 --CH.sub.2 --CH.dbd.CH--(CH.sub.2).sub.r--1 --COOR.sup.2 (Ia)R.sup.1 --CH.dbd.CH--(CH.sub.2).sub.r --COOR.sup.2 (Ib)and, if desired, further double bond isomers, where R.sup.1 is hydrogen or an organic radical, R.sup.2 is C.sub.1 -C.sub.8 -alkyl and r is from 1 to 20, are prepared by a process in which an .alpha.-substituted .alpha.,.omega.-(n-alkylenedicarboxylic ester) of the general formula II ##STR1## where R.sup.1 and R.sup.2 and r have the abovementioned meanings and R.sup.3 is C.sub.1 -C.sub.8 -alkyl, is converted over an acidic heterogeneous catalyst at from 150.degree. to 800.degree. C. and under from 0.01 to 50 bar.

Abstract: 1,1-disubstituted ethylene compounds of the general formula I ##STR1## where Z is COOR.sup.2, CN or COR.sup.3, R.sup.1 is an aliphatic, cycloalophatic, araliphatic, aromatic or heterocyclic radical which may be further substituted by functional groups which are inert under the reaction conditions, R.sup.2 is an aliphatic, cycloaliphatic or araliphatic radical of 1 to 15 carbon atoms and R.sup.3 is an aliphatic, cycloaliphatic or araliphatic radical of 1 to 15 carbon atoms which may be substituted by groups which are inert under the reaction conditions, and R.sup.1 together with R.sup.2 or R.sup.1 together with R.sup.3 may furthermore form an alkylene chain of 2 to 10 carbon atoms which may be substituted by groups which are inert under the reaction conditions, are prepared from a formyl compound of the general formula II ##STR2## where Z, R.sup.1, R.sup.2 and R.sup.3 have the above meanings, by a process in which the reaction is carried out in the presence of formaldehyde or paraformaldehyde and(a) a C.sub.

Abstract: Bridged, water-soluble copolymers are obtainable by(A) copolymerization of a monomer mixture of(a) from 50 to 99 mol % of acrylamide and/or methacrylamide,(b) from 50 to 1 mol % of a monoethylenically unsaturated monomer containing actual groups and(c) from 0 to 20 mol % of monomers which differ from (a) and (b),in the presence of a polymerization initiator under conditions such that the acetal groups of the monomers (b) undergo virtually no hydrolysis,(B) hydrolysis of the acetal groups of the monomers (b), present as copolymerized units in the copolymers (A),(C) condensation of the copolymers (B) containing aldehyde groups at a pH above 5, at most to a degree such that the resulting condensates are still water-soluble and(D) stopping of the condensation reaction by adding acid until the pH reaches 3 or less,and are used as paper stock additives in papermaking for increasing the wet strength of paper.

Abstract: 3-Dialkylaminopropionitriles ##STR1## where R.sup.1 and R.sup.2 are each C.sub.1 -C.sub.4 -alkyl which may furthermore be bonded to form a 5-membered or 6-membered ring, bis-(2-cyanoethyl) ether IINC--CH.sub.2 --CH.sub.2 --O--CH.sub.2 --CH.sub.2 --CN IIand, if desired, ethylenecyanohydrin IIIHO--CH.sub.2 --CH.sub.2 --CN IIIare prepared jointly by a process in which(a) acrylonitrile and water are reacted in the presence of a base at from 60.degree. to 150.degree. C. to give a mixture of acrylonitrile, water and bis-(2-cyanoethyl) ether II, the base being a mineral base, a quaternary nitrogen base or a mixture of these,(b) this mixture is reacted at about 0.degree.-50.degree. C.

Abstract: Caprolactam is prepared by heating a 6-aminocaproic ester in liquid phase in the presence of water to 230.degree.-350.degree. C. under superatmospheric pressure in a reaction medium comprising a liquid aromatic hydrocarbon having a boiling point of from 80.degree. to 240.degree. C. which is inert under reaction conditions, and isolating caprolactam from the reaction mixture.

Abstract: Caprolactam is prepared in a process comprising the following steps:(a) reacting the 5-formylvaleric ester with liquid ammonia as reaction medium and hydrogen in the presence of a ruthenium catalyst in liquid phase at from 80.degree. to 140.degree. C. under a hydrogen partial pressure of from 40 to 100 bar,(b) replacing the reaction medium ammonia by an aromatic hydrocarbon having a boiling point of from 80.degree. to 240.degree. C. which is liquid under the reaction conditions,(c) heating the resulting mixture in liquid phase under superatmospheric pressure at 230.degree.-350.degree. C. to form caprolactam, and(d) isolating caprolactam from the resulting reaction mixture.

Abstract: 6-Aminocaproic acid is prepared by(a) reacting a 5-formylvaleric acid ester with water in the presence of an acid agent at 30.degree.-200.degree. C. and(b) reacting the 5-formylvaleric acid thus obtained with excess ammonia and hydrogen in the presence of a hydrogenation catalyst and of a solvent which is inert under the reaction conditions at 50.degree.-150.degree. C. under superatmospheric pressure.

Abstract: 4-Oxaaldehydes of the formula ##STR1## are prepared by catalytic isomerization of 1,3-dioxanes by a process in which a 1,3-dioxane of the formula ##STR2## where R.sup.1, R.sup.2, R.sup.4 and R.sup.5 are identical or different and are each hydrogen, a straight-chain or branched alkyl, alkenyl or alkynyl radical of not more than 18 carbon atoms, a cycloalkyl or cycloalkenyl radical of 5 to 8 carbon atoms, an aryl, alkylaryl, aralkyl or alkenylaryl radical of 5 to 16 carbon atoms or a heterocyclic radical, and furthermore R.sup.1 and R.sup.2 and/or R.sup.4 and R.sup.5 together with the carbon atom to which they are bonded may form a cycloalkane, a cycloalkene or a heterocyclic structure, and the stated radicals may furthermore carry substituents which are inert under the reaction conditions, and R.sup.3 is hydrogen or straight-chain or branched alkyl, is isomerized using a phosphate as a catalyst.

Abstract: Adipic acid is prepared by a process which comprises the following steps:(a) Hydroformylation of a pentenoic ester by reaction with carbon monoxide and hydrogen at elevated temperatures and under superatmospheric pressure in the presence of a cobalt carbonyl or rhodium carbonyl complex with formation of a mixture of 5-, 4- and 3-formylvaleric esters,(b) isolation of the 5-formylvaleric ester from the resulting mixture of 5-, 4- and 3-formylvaleric esters, a mixture essentially consisting of 4- and 3-formylvaleric esters remaining,(c) dehydrocarbonylation of the mixture consisting essentially of 4- and 3-formylvaleric esters in the presence of one or more elements of subgroup 8 of the Periodic Table at from 50.degree. to 400.degree. C.

Abstract: Oxidation catalysts of the general formulaMo.sub.12 P.sub.a W.sub.b Sb.sub.c As.sub.d Cu.sub.e X.sub.f O.sub.xwhereX is Nb, Fe, Mn, Sn and/or Cr,a is 0.1-3,b is 0.1-4,c is <0-2,d is 0-1,e is 0-1,d+e is <0-2,f is 0-1.5,e+f is 0-2 andx is the number of oxygen atoms formally required to saturate the valencies of the other catalyst components,may be used particularly advantageously for the preparation of methacrylic acid by gas phase oxidation of methacrolein.

Abstract: 3-pentenoates are prepared by isomerization of 2-pentenoates to 3-pentenoates by a process in which the 2-pentenoate is treated with from 0.01 to 0.5 mole of cyclic tertiary amine having a pK.sub.a of >6 per mold of 2-pentenoate at from 50.degree. to 250.degree. C. and the 3-pentenoate is distilled off continuously.

Abstract: Pentenoic esters are prepared by heating formylvaleric esters at from 50.degree. to 400.degree. C. in the presence of zeolites or one or more phosphates selected from the group consisting of aluminum phosphate, silicon aluminum phosphate, boron aluminum phosphate, silicon iron aluminum phosphate, cerium phosphate, zirconium phosphate, boron phosphate, iron phosphate and strontium phosphate.

Abstract: Pentenoic esters are prepared by a process in which 4- and/or 3-formylvaleric esters are heated to 50.degree.-400.degree. C. in the presence of a catalyst which contains one or more elements of subgroup VIII of the Periodic Table.

Abstract: 3,4-dihydro-2H-pyrans of the formula I ##STR1## where R.sup.1 is C.sub.4 -C.sub.20 -alkyl, C.sub.4 -C.sub.20 -alkoxyalkyl, aryl or C.sub.7 -C.sub.20 -arylalkyl, or is aryl or C.sub.7 -C.sub.20 -arylalkyl which bears from one to three substituents selected from the group consisting of halogen, C.sub.1 -C.sub.8 -alkyl, C.sub.1 -C.sub.8 -haloalkyl, C.sub.1 -C.sub.8 -alkoxy or C.sub.1 -C.sub.8 -haloalkoxy, R.sup.2 is hydrogen or C.sub.1 -C.sub.4 -alkyl, R.sup.3 is aryl, or aryl bearing from one to three substituents selected from the group consisting of halogen, C.sub.1 -C.sub.8 -alkyl, C.sub.1 -C.sub.8 -haloalkyl, C.sub.1 -C.sub.8 -alkoxy or C.sub.1 -C.sub.8 -haloalkoxy, or the radical ##STR2## where R.sup.4, R.sup.5 and R.sup.6 are hydrogen or C.sub.1 -C.sub.4 -alkyl, R.sup.7 is phenyl or benzoyl, or phenyl or benzoyl bearing from one to three substituents selected from the group consisting of halogen, C.sub.1 -C.sub.8 -alkyl, C.sub.1 -C.sub.8 -haloalkyl, C.sub.1 -C.sub.8 -alkoxy and C.sub.1 -C.sub.

Abstract: 3-Pentenoates are prepared by isomerization of 2-pentenoates to 3-pentenoates by a process in which the 2-pentenoate is treaated with from 0.01 to 0.5 mole of cyclic tertiary amine having a pK.sub.a of >6 per mole of 2-pentenoate at from 50.degree. to 250.degree. C. and the 3-pentenoate is distilled off continuously.