摘要:
In the hydrogenation of phenol with H.sub.2 over Pd supported catalysts, the ratio of the products formed, cyclohexanone and cyclohexanol, can be predetermined by specific treatment of the catalysts during the initial activation and regeneration by O.sub.2 pretreatment and H.sub.2 treatment, the following time/temperature conditions being used:a) Cyclohexanone:cyclohexanol=85:15 to 98:2a1) for initial activation, no O.sub.2 pretreatment and H.sub.2 treatment for 50-10 hours at 300.degree.-500.degree. C.;a2) for regeneration, O.sub.2 pretreatment for 30-0.5 hours at 220.degree.-380.degree. C. and H.sub.2 treatment for 2-6 hours at 150.degree.-250.degree. C.;b) Cyclohexanone:cyclohexanol=30:70 to below 85:15b1) for initial activation, O.sub.2 pretreatment for 40-3 hours at 250.degree.-500.degree. C. and H.sub.2 treatment for 2-6 hours at 150.degree.-250.degree. C.;b2) for regeneration, O.sub.2 pretreatment for 30-0.5 hours at 380.degree.-600.degree. C. and H.sub.2 treatment for 2-6 hours at 150.degree.-250.degree. C.
摘要:
A description is given of the preparation of hydroxybiphenyl by dehydrogenation of completely or partially hydrogenated precursors using a supported Rh catalyst which additionally contains chromium, manganese and alkali metal and can contain a sulphur compound. The Rh catalyst which can be used according to the invention is prepared from halide-free starting materials. The Rh catalyst is distinguished by a low dependence of the initial selectivity, with the selectivity in the run-in state and the running-in time on the conditions of the reductive pretreatment and requires only short running-in times to reach the optimum state.
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:
Alkylene carbonates can be prepared by catalytic reaction of alkylene oxides with carbon dioxide, catalysts which can be regenerated of the formulaa[MX]/b[ZnY.sub.2 ] (III)whereinM denotes an alkali metal,X and Y independently of one another denote chlorine, bromine or iodine anda and b denote fractions or integers in a range from 0.001 to 2being employed.The catalysts (III) can be regenerated by treating with a halogen compound. The halogen compounds which can be used for this purpose belong to the group comprising hydrogen halides, inorganic and organic acid halides, interhalogen compounds and organic halides with mobile halogen.
摘要翻译:碳酸亚烷基酯可以通过烯化氧与二氧化碳的催化反应制备,催化剂可以再生成式[MX] / b [ZnY 2](III),其中M表示碱金属,X和Y彼此独立地表示 氯,溴或碘,a和b表示使用0.001至2范围内的分数或整数。 催化剂(III)可以通过用卤素化合物处理再生。 可以用于此目的的卤素化合物属于包含卤化氢,无机和有机酰卤,卤间化合物和具有可移动卤素的有机卤化物的基团。
摘要:
A bubble column reactor is described which is characterized by a slenderness ratio at a ratio of height to diameter of 2 to 50, a feed, at the bottom end of the bubble column, for the ethylene glycol carbonate (EGG) or propylene glycol carbonate (PGC) already present serving as reaction medium, one or more metering sites for the starting materials CO.sub.2 and ethylene oxide (EOX) or propylene oxide (POX) above the feed for the reaction medium, an outlet for the reaction mixture at the top end of the bubble column, a dividing apparatus connected thereto for the reaction mixture flowing off for dividing it into reaction mixture to be taken off and worked up on the one hand and reaction mixture to be recycled on the other hand and additionally a return line to the feed for the reaction mixture to be recycled. This bubble column reactor can be advantageously used in a process for the continuous preparation of EGG or PGC which is carried out in the temperature range from 100.degree. to 200.degree. C., in the pressure range from 5 to 200 bar and at a molar ratio of 1.01 to 1.5 mol of CO.sub.2 per mol of alkylene oxide in EGG or PGC already present as reaction medium in an amount which is 7 to 350 times that of the newly formed EGG or PGC.
摘要:
This invention provides a process for the purification of diphenyl carbonate (DPC) from crude products of diphenyl carbonate production. In this process, crude products are used that have a distillable fraction consisting of over 70 wt. % diphenyl carbonate and are fractionally crystallised from the melt (fractionating melt crystallisation).
摘要:
The preparation of optionally substituted diphenylamine by reaction of optionally substituted aniline with optionally substituted cyclohexanone using a supported Rh catalyst containing rhodium or a combination of rhodium with another platinum metal from the group of palladium, platinum, ruthenium or iridium and which can additionally contain chromium, manganese, alkali metal and a sulphur compound is described. The catalyst of the invention is prepared from halide-free starting materials. The Rh catalyst is distinguished by a low dependence of the initial selectivity, the selectivity in the run-in state and the running-in time on the conditions of the reductive pretreatment and requires only short running-in times to the optimum state.
摘要:
Ethylene glycol carbonate (EGC) can be obtained in purified form from contaminated material which contains impurities from the production or work-up process, by subjecting it to treatment with activated carbon. The treatment is carried out at 40.degree.-250.degree. C. and at 1-200 bar. The activated carbon has a BET surface area of 200-3,000 m.sup.2 /g.
摘要:
Isocyanates or isocyanate mixtures which contain no appreciable amounts of color causing materials are produced by phosgenating the amine corresponding to the desired isocyanate and treating the isocyanate-containing phosgenation mixture with hydrogen in the presence of a supported catalyst. The supported catalyst is in a form such that its shortest dimension is from about 0.3 to about 3.0 mm. This catalyst has a BET surface of from about 0.5 to about 150 m.sup.2 /g. No alkali material can be present in the catalyst. These isocyanates are particularly useful for the production of light-colored foams.
摘要:
A process is described for the catalytic preparation of ethylene glycol carbonate by reaction of ethylene oxide and CO.sub.2 in ethylene glycol carbonate as the reaction medium at elevated temperature and at elevated pressure with work-up by distillation to separate the resulting ethylene glycol carbonate from the catalyst. The process is carried out continuously under adiabatic temperature conditions. Per unit of time, ethylene glycol carbonate as reaction medium runs into the reactor in a amount 10 to 120 times that of ethylene glycol carbonate formed per unit of time. A CO.sub.2 excess over the other reaction partner ethylene oxide is maintained at all sites of the reactor. 80 to 98% by weight of the reaction mixture flowing out is returned to the inlet of the reactor, while the remainder is worked up by distillation to give ethylene glycol carbonate. The sensible heat produced in the reaction product as a result of the adiabatic temperature conditions, is used for the work-up.