摘要:
A process is described for the catalytic preparation of propylene glycol carbonate (PGC) by reacting propylene oxide (POX) and CO.sub.2 in PGC as reaction medium at elevated temperature and elevated pressure and separating off from the catalyst the PGC formed. The process is carried out continuously under adiabatic temperature conditions. Per unit of time, PGC as reaction medium flows into the reactor at 7 to 350 times the amount of the PGC formed per unit of time. At all points of the reactor a CO.sub.2 excess is maintained over the other reaction partner POX. Of the effluent reaction mixture, 80 to 98% by weight are returned to the entrance of the reactor, while the remainder is worked up to give PGC. The sensible heat of the reaction product resulting from the adiabatic temperature conditions can be used for the work-up.
摘要:
A process is described for the preparation of dialkyl carbonates by oxidative carbonylation of the corresponding alcohol in the presence of a copper-containing catalyst at elevated temperature and elevated pressure, which process permits simple separation of the copper-containing catalyst by sedimentation, and of the reaction water in the case of methanol by simple distillation from the reaction solution.
摘要:
The invention relates to a process for the production of caprolactam by thermal depolymerization of polyamide in the presence of small quantities of potassium carbonate at 250.degree. to 320.degree. C. and to a process for purifying the resulting caprolactam.
摘要:
Trialkylsilyloxy-1,1-diphenyl ethylenes corresponding to general formula I, new polymers produced therewith terminated by aryl trialkylsilyl ether groups or by phenolic hydroxyl groups and a process for the production of these polymers by anionic polymerization ##STR1## in which R.sup.1, R.sup.2 .dbd.H, C.sub.1 -C.sub.4 alkyl, OCH.sub.3,R.sup.3 .dbd.H, C.sub.1 -C.sub.4 alkyl, O--C.sub.1 -C.sub.4 alkyl,R.sup.4 .dbd.H, C.sub.1 -C.sub.4 alkyl,R.sup.5 .dbd.C.sub.1 -C.sub.4 alkyl,R.sup.6 .dbd.H, C.sub.1 -C.sub.4 alkyl.
摘要:
Polyesters and polyester carbonates ofa) aromatic diphenols,b.sub.1) aliphatic and/or cycloaliphatic and/or aromatic dicarboxylic acids and optionallyb.sub.2) carbonic acid,containingb.sub.1) in a quantity of 0.1 to 100 mol-% andb.sub.2) in a quantity of 0 to 99.9 mol-%, based on (b.sub.1 +b.sub.2), in which 0.1 to 100 mol-% of a) consists of 3,8-dihydroxy-5a,10b-diphenylcoumarano-2',3',2,3-coumarane corresponding to formula (I) ##STR1##
摘要:
The invention relates to a process for coating moldings via co-extrusion with a UV-absorber-containing layer containing special dimeric UV absorbers and to the moldings coated with a corresponding layer.
摘要:
N,N-dialkylanilines can be prepared by reacting the anilines on which they are based with lower alcohols or with the corresponding ethers, at an increased temperature in the gas phase in the presence of a proton-containing zeolite catalyst of the pentasil type having an SiO.sub.2 /Al.sub.2 O.sub.3 ratio of >60, it being advantageous to carry out the alkylation process under a pressure of 2-30 bar.
摘要翻译:N,N-二烷基苯胺可以通过使它们所基于的苯胺与低级醇或相应的醚反应,在气相中升高的温度下,在具有五 SiO 2 / Al 2 O 3比> 60,有利的是在2-30巴的压力下进行烷基化工艺。
摘要:
New polysaccharide carbonates are produced by acylation of polysaccharides with carbonic acid esters and have degrees of substitution of preferably 0.5 to 3.