摘要:
Cyclopentenones of the formula I ##STR1## where each of R.sup.1 to R.sup.4 is independently of the others hydrogen or an organic radical, are prepared by converting a carboxylic ester of the formula IIa, IIb or IIcR.sup.1 CH.dbd.CR.sup.2 --CHR.sup.3 --CHR.sup.4 --CO.sub.2 R.sup.5 (IIa) and/orR.sup.1 CH.sub.2 --CR.sup.2 .dbd.CR.sup.3 --CHR.sup.4 --CO.sub.2 R.sup.5(IIb) and/orR.sup.1 CH.sub.2 --CHR.sup.2 --CR.sup.3 .dbd.CR.sup.4 --CO.sub.2 R.sup.5(IIc),where each of R.sup.1 to R.sup.4 is as defined above and R.sup.5 is C.sub.1 -C.sub.8 -alkyl, over an acidic heterogeneous catalyst at 50.degree.-800.degree. C. and 0.001-50 bar.
摘要:
A process for the preparation of a 2-(3-aminopropyl)-cycloalkylamine of the general formula I ##STR1## in which the subscript n is an integer from 1 to 4, from a 2-(2-cyanoethyl)-cycloalkanone of the general formula II ##STR2## in which the subscript n has the meaning stated, wherein the following stages are carried out in discrete reaction chambers:a) the 2-(2-cyanoethyl)-cycloalkanone of formula II is reacted in a first reaction chamber with excess ammonia over an acidic heterogeneous catalyst at a temperature from 20.degree. to 150.degree. C. and a pressure of from 15 to 500 bar, andb) in a second reaction chamber, the reaction product from stage a) is hydrogenated at a temperature of from 60.degree. to 150.degree. C. and a pressure of from 50 to 300 bar in the presence of excess ammonia over a catalyst containing cobalt, nickel, ruthenium, and/or some other noble metal, which catalyst optionally contains a basic component or is supported on neutral or basic supporting material.
摘要:
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.
摘要:
A process for the separation of a mono(meth)acrylate of a C.sub.4 -C.sub.6 alkanediol from an aqueous solution containing a mono(meth)acrylate of a C.sub.4 -C.sub.6 alkanediol and the said C.sub.4 -C.sub.6 alkanediol, by extraction with an organic solvent, in which the extracting agent used is an organic solvent selected from the group comprising esters of C.sub.1 -C.sub.4 alkanecarboxylic acids and C.sub.1 -C.sub.5 alkanols, single and mixed dialkyl ethers having from 4 to 8 C atoms, and mixtures of such organic solvents.
摘要:
Crude (meth)acrylic acid is purified by a process in which a primary amine compound and an organic sulfonic acid are added to the crude (meth)acrylic acid and the latter is then worked up by distillation.
摘要:
A process for the separation of ortho-, meta- and para-tolunitrile from ternary mixtures of isomers entails removing ortho-tolunitrile from these mixtures by distillation under pressures of from 10.sup.2 and 10.sup.5 Pa and with a reflux ratio of from 1:1 to 200:1, and distilling the remaining binary mixture of meta- and para-tolunitrile to concentrate to more than 75 mol-% para-tolunitrile, and freezing out the paratolunitrile at below 26.degree. C., and a process for the preparation of suitable ternary mixtures of isomers entails isomerization of pure ortho-, meta- or para-tolunitrile or mixtures thereof at from 380.degree. to 580.degree. C. on zeolite catalysts.
摘要:
1,4-butanediol mono(meth)acrylate is prepared by esterification of (meth)acrylic acid with 1,4-butanediol, by a process in which an aqueous solution of unconverted 1,4-butanediol is obtained, wherein the 1,4-butanediol present in the aqueous solution is converted into readily volatile tetrahydrofuran in the presence of a catalytic amount of a strong acid and the tetrahydrofuran is separated off from the aqueous solution.
摘要:
A process for the preparation of mixtures of isomeric cresols with a molar ratio of para- to meta-cresol of from 0.6:1 to 10:1 by isomerization of cresol mixtures or ortho- and/or metal-cresol on zeolite catalysts of the pentasil type in the gas phase at from 300.degree. to 600.degree. C. under from 0.01 to 50 bar entails the mean particle size of the zeolite catalyst being at leat 3 .mu.m, and the selectivity in the established test for the disproportionation of ethylbenzene to diethylbenzene isomers being at least 60% for para-diethylbenzene.
摘要:
Aldehydes and ketones are prepared from epoxides of the formula ##STR1## where R.sup.1 and R.sup.2 are each alkyl, alkenyl, aryl, alkoxy or aralkyl and R.sup.3 has the same meanings or is hydrogen, by a catalytic rearrangement reaction in the presence of various catalysts, in particular zeolites of the pentasil type.
摘要:
A diester of (meth)acrylic acid with a C.sub.4 -C.sub.6 -alkanediol is separated from a mixture which essentially consists of the C.sub.4 -C.sub.6 -alkanediol, the monoester of (meth)acrylic acid with the C.sub.4 -C.sub.6 -alkanediol and the diester of (meth)acrylic acid with the C.sub.4 -C.sub.6 -alkanediol by extraction with an organic solvent in the presence of water, by a process in which the diester-containing mixture is added continuously in the middle section of an extraction column and in addition water and the organic extracting agent are passed continuously countercurrent in the extraction column.