摘要:
1,3-Di(alkoxycarbonylamino)propanes of the general formula I ##STR1## where R.sup.1, R.sup.2 and R.sup.3 can be identical or different and each is hydrogen, or an aliphatic, cycloaliphatic, araliphatic or aromatic radical, and R.sup.4 is an aliphatic, cycloaliphatic or araliphatic radical, are prepared by reacting an .alpha.,.beta.-unsaturated aldehyde with a carbamic acid ester by reacting in a first stage as the .alpha.,.beta.-unsaturated aldehyde a compound of the general formula II ##STR2## where R.sup.1, R.sup.2 and R.sup.3 have the abovementioned meanings, with a carbamic acid ester of the general formula III ##STR3## where R.sup.4 has the abovementioned meanings, at 0.degree.-150.degree. C. to give a 1,1,3-tri(alkoxycarbonylamino)propane of the general formua IV ##STR4## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 have the abovementioned meanings, and in a second stage heating the compound of the general formula (IV) in the presence of a hydrogenation catalyst and hydrogen under 1-300 bar at 100.degree.-300.degree. C.
摘要:
Neopentyl glycol hydroxypivalate is isolated from a reaction mixture obtained from a Tishchenko reaction of hydroxypivalaldehyde in the presence of calcium hydroxide, barium hydroxide or strontium hydroxide, by adding acid, removing the salts formed by adjusting the water content in the reaction mixture to 20-60% and extracting the salts at above 50.degree. C. and working up the residual mixture by distillation.
摘要:
.alpha.-substituted acrylamides of the general formula I ##STR1## where R.sup.1 is a straight-chain, branched or cyclic alkyl radical of not more than 15 carbon atoms which can be unsubstituted or further substituted, are prepared by a process in which the corresponding .alpha.-substituted acrolein oximes are heated at from 40.degree. to 250.degree. C. in the presence of a copper(II) carboxylate.
摘要:
Novel ether-aldols of the general formula (I) ##STR1## where R.sup.1 and R.sup.2 are each alkyl, can be prepared by reacting a 2-alkylacrolein (H.sub.2 C.dbd.CHR.sup.2 --CHO), an alcohol (R.sup.1 OH) and formaldehyde, preferably aqueous formaldehyde, in the presence of a tertiary amine.
摘要:
.alpha.-Alkylacroleins are prepared by a process wherein an alkanal is reacted with formaldehyde in the presence of a secondary amine and in the presence or absence, of an acid, in the liquid phase, under superatmospheric pressure and at above 150.degree. C., for not more than 25 minutes.The .alpha.-alkylacroleins obtainable by the process are useful starting materials for dyes, drugs and pesticides.
摘要:
An oxidation catalyst wherein the catalytically active component has the general formulaMo.sub.12 P.sub.a Rh.sub.b Cu.sub.c V.sub.d Cs.sub.e X.sub.f Y.sub.g Z.sub.h O.sub.x,where X is Cr and/or Fe, Y is Nb, Z is Na, Li, K and/or Rb, a is 0.1-4, b is 0.001-1, c is 0.05-2, d is 0.05-4, e is 0.1-5, f is 0-2, g is 0-3 and h is 0-2, and x is the number of oxygen atoms required to saturate the valencies of the other constituents, is very suitable for the preparation of methacrylic acid by gas phase oxidation of methacrolein with an oxygen-containing and steam-containing gas mixture.
摘要:
Organic isocyanates, preferably alkyl, mono-, di- and/or polyisocyanates or aryl-mono-, di- and/or polyisocyanates, are prepared by thermally cleaving the corresponding urethanes at temperatures of 175.degree. C. to 600.degree. C. in the presence of carbon, preferably in an agitated carbon bed or in a fluidized bed containing carbon.
摘要:
Formaldehyde is prepared by dehydrogenation of methanol in the presence of a catalyst containing copper, zinc and tellurium, at from 300.degree. to 750.degree. C.The formaldehyde obtainable by the process of the invention is a disinfectant, tanning agent, reducing agent and valuable starting material for the preparation of synthetic resins, adhesives, plastics and auxiliaries in numerous sectors of industry.
摘要:
A process for the production of mixtures of diphenylmethane diisocyanates and polyphenyl polymethylene polyisocyanates comprising the steps ofA. reacting aniline and an O-alkyl carbamate to form N-phenylurethanes;B. isolating the N-phenylurethanes;C. condensing, in the presence of an acid, the N-phenylurethanes with formaldehyde or bifunctional compounds having the formulaX--CH.sub.2 --X in which X stands for a RO--, RS-- or ROCO radical and R denotes an alkyl radical, to form mixtures of methylene bis(phenylurethanes) and polymethylene polyphenylurethanes;D. cleaving the mixtures of methylene bis(phenylurethanes) and polymethylene polyphenylurethanes at temperatures of 175.degree. C. to 600.degree. C.; andE. isolating the mixtures of diphenylmethane diisocyanates and polyphenyl polymethylene polyisocyanate resulting from step D.
摘要:
.alpha.,.beta.-Unsaturated nitriles are prepared by reacting an aldehyde with formamide in the presence of an acid and the presence or absence of a non-aromatic solvent to give an N-alkenyl-formamide, which is then passed, in the gas phase, over a dehydration catalyst at an elevated temperature.The nitriles obtainable by the process of the invention are valuable starting materials for the preparation of dyes, crop protection agents, plasticizers and drugs.