摘要:
Caprolactam is prepared by a process in which(a) a 5-formylvalerate is reacted with excess ammonia and hydrogen in the presence of an alkanol as a solvent and in the presence of a hydrogenation catalyst under superatmospheric pressure in the liquid phase at from 40.degree. to 130.degree. C.,(b) excess ammonia and hydrogen are separated off from the reaction mixture and(c) the reaction mixture thus obtained is heated to 150.degree.-250.degree. C. and .epsilon.-caprolactam is obtained.
摘要:
Aldehydes with a higher number of carbon atoms and high selection are prepared by reacting olefins, in particular from petrochemical refinery products, by a hydroformylation with aldol condensation using a mixed catalyst of rhodium-carbonyl-phosphines and Mannich catalyst.
摘要:
Polyoxyalkylene glycols are prepared by a process in which tetrahydrofuran is polymerized with a total of not more than 95 mol %, based on the amount of tetrahydrofuran used, of one or more comonomers from the group consisting of the cyclic ethers and acetals in the absence of water and in the presence of a monohydric alcohol or of a monocarboxylic acid with the aid of an anhydrous heteropoly acid catalyst, and the polyoxyalkylene glycol is liberated from the resulting polyoxyalkylene glycol monoethers or polyoxyalkylene glycol monoesters by cleavage of the monoether or monoester bond.
摘要:
A 3-substituted 2-hydroxy-3-formylpropionic ester of the formula I ##STR1## where R.sup.1 is lower alkyl, and R.sup.2 is straight-chain or branched alkyl of 1 to 10 carbon atoms, is obtained by adding an alkanal of the fomrula II ##STR2## and an alkyl glyoxylate of the formula III ##STR3## simultaneously to a catalyst system composed of a salt or a mixture of a secondary amine and a carboxylic acid in such a way that the temperature does not exceed 90.degree. C., preferably 80.degree. C., or else adding one of the reactants of the formula II or III to a mixture of the catalyst system described above and the other reactant in such a way that the temperature does not exceed 90.degree. C. The 2-hydroxy-3-formylpropionic eater of the formula I can be converted by treatment with dehydrating agents, especially acetic anhydride, into good yields of the corresponding 3-substituted 3-formylacrylic ester.
摘要:
A 3-substituted 2-hydroxy3-formylpropionic ester of the formula I ##STR1## where R.sup.1 is lower alkyl, and R.sup.2 is straight-chain or branched alkyl of 1 to 10 carbon atoms, is obtained by adding an alkanal of the formula II ##STR2## and an alkyl glyoxylate of the formula III ##STR3## simultaneously to a catalyst system composed of a salt or a mixture of a secondary amine and a carboxylic acid in such a way that the temperature does not exceed 90.degree. C., preferably 80.degree. C., or else adding one of the reactants of the formula II or III to a mixture of the catalyst system described above and the other reactant in such a way that the temperature does not exceed 90.degree. C. The 2-hydroxy-3-formylpropionic ester of the formula I can be converted by treatment with dehydrating agents, especially acetic anhydride, into good yields of the corresponding 3-substituted 3-formylacrylic ester.
摘要:
Cyclopentanones of the general formula I ##STR1## where R.sup.1 and R.sup.2 are each an organic radical or R.sup.1 or R.sup.2 may be hydrogen and R.sup.3 is hydrogen or formyl, are prepared by a process in which a 2-formyl-3,4-dihydropyran of the general formula II ##STR2## where R.sup.1 and R.sup.2 have the abovementioned meanings, a) where R.sup.3 is formyl, is converted in the presence of an acidic heterogeneous catalyst at from 50.degree. to 500.degree. C., andb) where R.sup.3 is hydrogen,b.sub.1) is reacted with water or an alcohol in the presence of an acidic heterogeneous catalyst at from 100.degree. to 500.degree. C. in the gas phase orb.sub.2) a compound II or an acrolein of the general formula III ##STR3## is reacted with water or with water in the presence of an acid or with an alcohol in the presence of an acid at from 150.degree. to 400.degree. C. in the liquid phase. Novel 2-formylcyclopentanones are obtained.
摘要:
Methacrylic acid can be prepared with advantage by gas phase oxidation of methacrolein or isobutyraldehyde over Mo- and P-containing catalysts at from 250.degree. to 400.degree. C. with cooling of the hot reaction gas to below 100.degree. C., absorption of the methacrylic acid in a water-operated absorption column, at below 100.degree. C. and partial recycling into the oxidation reactor after admixture of methacrolein or isobutyraldehyde and oxygen by feeding a quantity of methacrolein or isobutyraldehyde equal to the quantity of methacrolein or isobutyraldehyde consumed in the reaction in liquid form together with a polymerization inhibitor into the reactor gas in the lower two-thirds of the absorber column and upstream of the feed point for the fresh methacrolein or isobutyraldehyde or down-stream of the absorption column splitting off the reactor off-gas a side stream which is washed in a wash column operated with water at
摘要:
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.
摘要:
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.
摘要:
2(5H)-furanones I ##STR1## where R.sup.1 and R.sup.2 are each hydrogen, C.sub.1 -C.sub.6 -alkyl, C.sub.5 - or C.sub.6 -cycloalkyl, C.sub.7 -C.sub.12 -aralkyl or aryl, are prepared by heating a 3-formylcarboxylate or 3-formylcarboxylic acid II ##STR2## where R.sup.3 is hydrogen, C.sub.1 -C.sub.12 -alkyl, C.sub.5 - or C.sub.6 -cycloalkyl, C.sub.7 -C.sub.12 -aralkyl or aryl, to 100.degree.-450.degree. C. in the presence of an acidic catalyst.