Abstract: N-Methyl-2-pyrrolidone (NMP) is prepared by preparing a mixture comprising monomethylamine, dimethylamine and trimethylamine and ammonia in a first process step by reacting ammonia with methanol at elevated temperature in the presence of a catalyst, separating 10 off the ammonia, reacting the mixture comprising the methylamines with gamma-butyrolactone (&ggr;-BL), in a molar ratio of monomethylamine to &ggr;-BL of at least 1 in a second process step at elevated temperature and superatmospheric pressure, separating NMP and unreacted methylamines from the reaction product and returning unreacted methylamines to the first process step for reaction with methanol and ammonia.

Abstract: Preparation of alkanolamines having improved color quality by treating the alkanolamine with an effective amount of phosphorous acid or hypophosphorous acid or compounds thereof initially at elevated temperature over a period of at least 5 min (step a), and then distilling it in the presence of an effective amount of one of these phosphorus compounds (step b).

Abstract: A brake unit comprising at least one brake and at least one brake pad having at least one friction lining is described. The brake has a disk brake with a brake rotor made of a ceramic-metal composite (CMC) whose outer surface or surfaces at least partially form a friction surface for the at least one friction lining, and a disk brake cup that is mounted on the disk brake by way of one or more mounting elements. The friction surface of the disk brake has a hardness of approximately 1600 to 2500 HV, and the at least one friction lining has a coefficient of friction of approximately 0.3 to 0.5. The disk brake cup and/or the mounting elements form a corrosion-inhibiting attachment to the disk brake. The brake unit can be operated in corrosion-free fashion over a service life of at least approximately eight to 10 years or approximately 200,000 to 300,000 km.

Abstract: Preparation of alkanolamines having improved color quality by treating the alkanolamine with hydrogen in the presence of a hydrogenation catalyst at elevated temperature, by using, as hydrogenation catalyst, a heterogeneous catalyst comprising Re, Ru, Rh, Pd, Os, Ir, Pt and/or Ag and a support material chosen from the group consisting of activated carbon, alpha-aluminum oxide, zirconium dioxide and titanium dioxide, where the catalyst, in the case of activated carbon as support material, has a cutting hardness of at least 10 N, a side crushing strength of at least 30 N or a compressive strength of at least 25 N.

Abstract: N-Methyl-2-pyrrolidone (NMP) is prepared by preparing a mixture comprising monomethylamine, dimethylamine and trimethylamine and ammonia in a first process step by reacting ammonia with methanol at elevated temperature in the presence of a catalyst, separating off the ammonia, reacting the mixture comprising the methylamines with gamma-butyrolactone (&ggr;-BL), in a molar ratio of monomethylamine to &ggr;-BL of at least 1 in a second process step at elevated temperature and superatmospheric pressure, separating NMP and unreacted methylamines from the reaction product and returning unreacted methylamines to the first process step for reaction with methanol and ammonia.

Abstract: Halides are removed from halide-containing nitrile mixtures by(a) thermally treating the halide-containing nitrile mixture,(b) subsequently adding a base to the thermally treated nitrile mixture and(c) subsequently separating off the base from the nitrile mixture.Amines are prepared by(A) reacting alkyl halides with metal cyanides in an at least two-phase reaction medium in the presence of halide-containing phase-transfer catalysts to give alkanenitriles,(B) separating off the resulting halide-containing alkanenitrile mixture phase and(C) further treating the halide-containing alkanenitrile mixture phase, as described in the stages(a)-(c) removing halides from halide-containing nitrile mixtures and(d) hydrogenating nitrites obtained in stage (c) to give amines, in the presence of suspended or fixed-bed catalysts.

Abstract: A process for the preparation of 3-aminomethyl-3,5,5-trimethylcyclohexylamine having a cis/trans isomer ratio of at least 70:30 bya) imination of 3-cyano-3,5,5-trimethylcyclohexanone with ammonia in the presence of an imination catalyst at temperatures of from 20.degree. to 150.degree. C. and pressures of from 1.5 to 30 MPa to form 3-cyano-3,5,5-trimethylcyclo-hexanone imine followed byb) hydrogenation of the 3-cyano-3,5,5-trimethylcyclohexanone imine in the presence of ammonia over a catalyst containing copper and/or a Group VIII metal at a temperature of from 80.degree. to 160.degree. C. and under a pressure of from 5 to 30 MPa,wherein the catalytic hydrogenation of the 3-cyano-3,5,5-trimethylcyclohexanone imine is carried out in the presence of an acid used in an amount such as to give an acid number of from 0.1 to 2, based on 3-cyano-3,5,5-trimethylcyclohexanone used.

Abstract: A method for increasing the shelf life of liquid hydroxy- and alkoxyalkyl ketones by adding from 0.0001 to 1% by weight of a base is described.

Abstract: The invention relates to a hat-shaped brake disc made from a castable metal for vehicle wheels. It has, within the friction ring, a nave with a nave casing and nave bottom, the latter having screw-passage holes for screwing the brake disc to the wheel hub. The friction ring contains indentations rounded out on both sides in the region of transition to the nave casing. The brake disc consists completely, up to and including that immediate surface of the friction ring which is subjected to frictional stress during braking, of a particle reinforced composite aluminum material with intercalated hard-material particles of ceramic, particularly of aluminum oxide or silicon carbide (so-called Al-MMC=Aluminum-Metal-Matrix-Composite) and/or of a hypereutectic Al/Si alloy with intercalated silicon crystals. It is designed and produced as a die casting, all the surface parts of the casting being cast with a very small shape and dimension deviation.

Abstract: A process for the preparation of 3-aminomethyl-3,5,5-trimethylcyclohexylamine from 3-cyano-3,5,5-trimethylcyclohexanone which requires three spatially separated reaction spaces, in order to carry out the following three steps in sequence:a) reacting the 3-cyano-3,5,5-trimethylcyclohexanone with excess ammonia on acidic metal-oxide catalysts in a first reaction space at from 20.degree. to 150.degree. C. and from 50 to 300 bar,b) hydrogenating the resultant reaction products using hydrogen in a second reaction space in the presence of excess ammonia and preferably liquid ammonia on hydrogenation catalysts, optionally using basic components or on neutral or basic supports at from 50.degree. to 100.degree. C. and at from 50 to 300 bar, andc) hydrogenating the resultant reaction products in the presence of hydrogen and also ammonia in a third reaction space on hydrogenation catalysts, optionally using basic components or on neutral or basic supports at from 110.degree. to 160.degree. C. and at from 150 to 300 bar.

Abstract: A process for the preparation of a color-stable dialkylaminoethanol of the formula ##STR1## in which R.sup.1 and R.sup.2 independently are C.sub.1 -C.sub.20 -alkyl, by reacting ethylene oxide with a dialkylamine of the formula HNR.sup.1 R.sup.2, in which R.sup.1 and R.sup.2 have the same meaning, in the presence of from 2.5 to 50% by weight of water, based on the reaction mixture, at a temperature of from 95.degree. to 170.degree. C., and separating off the water and high-boiling constituents by distillation under a reduced pressure and at a temperature of from 40.degree. to 90.degree. C. at the column bottom.

Abstract: A process for the preparation of methyl formate by reacting methanol and carbon monoxide in the presence of an alkali metal alcoholate or alkaline earth metal alcoholate at from 30.degree. to 150.degree. C. and from 50 to 300 bar, wherein a nonionic complexing agent is used to bind the alkali metal cations or alkaline earth metal cations.

Abstract: A process for the preparation of the sought-after scent 2,5-dimethyl-4-hydroxy-2,3-dihydrofuran-3-one, and novel intermediates for the preparation of this compound.2,5-Dimethyl-4-hydroxy-2,3-dihydrofuran-3-one is prepared by first epoxidizing hex-3-ene-2,5-diol in the liquid phase with hydrogen peroxide to give the novel compound 3,4-epoxy-hexane-2,5-diol, which at 40.degree.-280.degree. C. is converted, by means of a catalytic amount of an acid, to the novel compound 2,5-dimethyl-3,4-dihydroxy-tetrahydro-furan. The latter is dehydrogenated by means of oxygen over a silver catalyst or copper catalyst to give the nove compound 2,5-dimethyl-4-hydroxy-tetrahydrofuran-3-one, which is oxidized by means of bismuth oxide, in concentrated acetic acid solution, to give the desired compound 2,5-dimethyl-4-hydroxy-2,3-dihydrofuran-3-one.

Abstract: Diketones are prepared by oxidizing glycols in the presence of a silver catalyst and/or copper catalyst of a specific particle size, under specific temperature conditions and with a specific composition of the catalyst. The end products are starting materials for the preparation of dyes, drugs, plastics, scents, wrinkle-resist finishes and assistants for increasing the tear strength and resilience of fibrous materials, hardeners for use in the photographic industry, textile assistants for preventing shrinkage after washing, and paper assistants.

Abstract: Aliphatic hydroxycarbonyl compounds etherified with aliphatic groups are prepared by oxidizing hydroxyalcohols in the presence of a metal catalyst which consists of one or more layers, each of a particular weight and each containing particles of a particular size, the catalyst bed also having a particular total thickness, and the catalyst components used being silver and copper, with or without added copper/tin/phosphorus or silver alone. The etherified hydroxyaldehydes and hydroxyketones obtainable by the process of the invention are valuable starting materials for the preparation of dyes, pesticides, plastics and scents.

Abstract: Alkyl pyruvates are prepared by oxidizing alkyl lactates in the presence of a silver catalyst of a defined particle size, at from 450.degree. to 700.degree. C. The products are starting materials for the preparation of drugs, synthetic resins and plastics.