摘要:
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.
摘要:
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.12 -alkyl, is converted in the presence of an acidic catalyst at from 150.degree. to 450.degree. C. and under from 0.001 to 50 bar, some of the compounds obtained being novel.
摘要:
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.
摘要:
2-Substituted 4-acyloxy-2-butenals of the general formula I ##STR1## where R.sup.1 is alkyl of 1 to 12 carbon atoms which may be substituted by cycloalphatic, aromatic or heterocyclic radicals, by alkenyl or alkynyl or by hydroxyl, ether, thioether, acetoxy acyl, alkylamino, carboxyl or carbalkoxy, and R.sup.2 is acyloxy, are prepared by reacting a monosubstituted acetaldehyde of the general formula II ##STR2## where R.sup.2 has the abovementioned meaning, with an aldehyde of the general formula III ##STR3## where R.sup.1 has the abovementioned meaning, in the presence of a linear or cyclic secondary amine and of an organic acid at from 20.degree. to 100.degree. C.
摘要:
A storage-stable, moisture-cured, single-component polyurethane system comprising(a) a polyurethane prepolymer having an NCO content of from about 1 to 10 weight percent prepared by the reaction of higher molecular polyols and aromatic polyisocyanates,(b) at least one polyaldimine having the structural formula ##STR1## in which R is a multivalent linear or branched or cyclic hydrocarbon radical, which optionally is interrupted by alkylene-, sulfonyl-, thio- and/or oxy groups as bridge members, or is a multivalent polyoxyalkylene radical,(c) optionally an aromatic and/or aliphatic carboxylic acid or arylsulfonic acid, and(d) optionally auxiliaries and/or additives.The polyurethane systems are useful as sealing, casting, patching, cementing and coating compounds.
摘要:
2,2-Disubstituted 3-chloropropionic esters I ##STR1## where R.sup.1 and R.sup.2 are each C.sub.1 -C.sub.6 -alkyl, C.sub.2 -C.sub.6 -oxaalkyl, C.sub.2 -C.sub.6 -alkenyl, C.sub.2 -C.sub.6 -oxaalkenyl, aryl or C.sub.7 -C.sub.12 -aralkyl or R.sup.1 -C-R.sup.2 is 5-, 6- or 7-membered ring, R.sup.3 is C.sub.2 -C.sub.6 -oxaalkyl, C.sub.2 -C.sub.6 -alkenyl, C.sub.2 -C.sub.6 -oxaalkenyl or C.sub.7 -C.sub.12 -aralkyl, are prepared by converting 2,2-disubstituted 3-hydroxypropanals II ##STR2## into the esterdiol III ##STR3## reacting this esterdiol III in the presence of a transesterification catalyst with an alcohol R.sup.3 OH to give the 3-hydroxyester IV ##STR4## reacting the hydroxyester IV with a stoichiometric or greater than stoichiometric amount of the thionyl chloride and thermally decomposing the product to give the chloropropionic ester I.
摘要:
This invention relates to novel 2-(alkoxymethyl) pentane-1,5-diisocyanates, 2-(alkoxymethyl)-pentane-1,5-diurethanes, and 2-(alkoxymethyl)-pentane 1,5-dicarbamic acid chlorides having the structure: ##STR1## in which R is a straight chain or branched C.sub.1 -C.sub.20 -alkyl radical, a straight chain or branched C.sub.2 -C.sub.20 -alkenyl radical, a straight chain or branched C.sub.3 -C.sub.20 -oxaalkyl radical, an optionally substituted C.sub.5 -C.sub.12 -cycloalkyl radical, or an optionally substituted C.sub.7 -C.sub.20 -aralkyl radical and X is a --NCO--, --NH--CO.sub.2 R.sup.1 --, --NHCO.sub.2 R.sup.2 -- OR - NHCOCl-group whereby R.sup.1 and R.sup.2 can be the same or different and are a straight chain or branched C.sub.1 -C.sub.20 -alkyl radical or a C.sub.5 -C.sub.12 cycloalkyl radical, as well as a process for their preparation. The 2-(alkoxymethyl)-pentane-1,5-diurethanes or 2- (alkoxymethyl)-pentane-1,5-dicarbamic acid chlorides are suited for the preparation of 2-(alkoxymethyl)-pentane-1,5-diisocyanates, which in turn are used for the preparation of plastics using the polyisocyanate addition polymerization process.
摘要:
Nitriles of the general formula IR.sup.1 --CN (I)where R.sup.1 is a saturated or unsaturated, straight-chain, branched or cyclic alkyl radical, an aralkyl radical or an aryl radical, each of which is of not more than 20 carbon atoms and can be unsubstituted or further substituted, and (meth)acrylamide are prepared simultaneously by a process in which an aldoxime of the general formula IIIR.sup.1 --CH.dbd.NOH (III)where R.sup.1 has the above meanings, is heated at from 50.degree. to 180.degree. C. in the presence of a copper(II) carboxylate and of (meth)acrylonitrile.
摘要:
Hexamethylene diisocyanate and/or isomeric alkylene diisocyanates having 6 carbon atoms in the alkylene radical, preferably 2-methylpentamethylene 1,5-diisocyanate and/or 2-ethyltetramethylene 1,4-diisocyanate are prepared without the use of phosgene in a multiple-step process by means of(a) reacting hexamethylene 1,6-diamine and/or isomeric alkylene diamines having 6 carbon atoms in the alkylene radical with urea and alcohol in the presence of dialkyl carbonate and/or carbamic acid alkyl ester as well as, in some cases, catalysts to form hexamethylene 1,6-dialkylurethane and/or isomeric alkylene dialkylurethanes having 6 carbon atoms in the alkylene radical,(b) separation and return to reaction step (a) of alcohol, dialkyl carbonate, and/or carbamic acid alkyl ester from the reaction mixture(c) evaporation of the hexamethylene 1,6-dialkylurethane and/or isomeric alkylene dialkylurethanes having 6 carbon atoms in the alkylene radical,(d) cleavage of the vaporized diurethanes into hexamethylene diisocyanate and/or isomeric alkylene diisocyanate having 6 carbon atoms in the alkylene radical and alcohol, and(e) fractional condensation of the cleavage products.