Abstract: A process for preparing N,N-dimethylacetamide (DMAC) by continuously reacting methyl acetate (MeOAc) with dimethylamine (DMA) in the presence of a basic catalyst, wherein MeOAc is used in the form of a methanolic solution which is obtained as a by-product in the preparation of polyTHF by transesterifying polyTHF diacetate with methanol.

Abstract: A process for preparing N,N-dimethylacetamide (DMAC) by continuously reacting methyl acetate (MeOAc) with dimethylamine (DMA) in the presence of a basic catalyst, wherein MeOAc is used in the form of a methanolic solution which is obtained as a byproduct in the preparation of polyTHF by transesterifying polyTHF diacetate with methanol.

Abstract: The invention relates to a reactor for performing high-pressure reactions, comprising at least one tube (31) whose ends are each conducted through a tube plate (33) and which is bonded to the tube plate (33). The tube plates (33) and the at least one tube (31) are surrounded by an outer jacket, such that an outer space (39) is formed between the tube (31) and the outer jacket. The tube plates (33) each have at least one surface composed of a nickel-base alloy and the at least one tube (31) is in each case welded on to the surface composed of the nickel-base alloy. The surface composed of the nickel-base alloy points in each case in the direction of the particular reactor end. The outer jacket has a thickness which is sufficient to absorb tensile forces which occur between tube (31) and outer jacket owing to a temperature difference in the event of different expansion. The invention further relates to a process for starting up the reactor and for performing an exothermic reaction in the reactor.

Abstract: A process for preparing N,N-dimethylacetamide (DMAC) by continuously reacting methyl acetate (MeOAc) with dimethylamine (DMA) in the presence of a basic catalyst, wherein MeOAc is used in the form of a methanolic solution and the continuous distillative workup is effected in such a way that methanol and any other low boilers are initially removed overhead in a column A and the bottom effluent of column A is fed to a column B in which DMAC is removed via a side draw a purity of ?99.7% by weight.

Abstract: The present invention relates to a process for the industrial preparation of a diamine starting from a corresponding alkenyl nitrile comprising at least one C—C double bond, which comprises the steps (a) reaction of the alkenyl nitrile with a corresponding monoamine in a first reactor so that the monoamine adds exothermically onto the at least one double bond to form an aminoalkyl nitrile, with the monoamine and water being charged initially and the alkenyl nitrile being fed in; (b) evaporation of unreacted alkenyl nitrile and monoamine to increase the concentration of the aminoalkyl nitrile product in the bottoms of the first reactor; (c) transfer of the aminoalkyl nitrile bottom product from step (b) to a second reactor; (d) batchwise catalytic hydrogenation of the aminoalkyl nitrile transferred in step (c) to the diamine in the second reactor, with each batch being obtained by initially charging a catalyst suitable for the hydrogenation of nitriles to amines and also water, the desired diamine and a bas

Abstract: The present invention relates to a process for the industrial preparation of a diamine starting from a corresponding alkenyl nitrile comprising at least one C-C double bond, which comprises the steps (a) reaction of the alkenyl nitrile with a corresponding monoamine in a first reactor so that the monoamine adds exothermically onto the at least one double bond to form an aminoalkyl nitrile, with the monoamine and water being charged initially and the alkenyl nitrile being fed in; (b) evaporation of unreacted alkenyl nitrile and monoamine to increase the concentration of the aminoalkyl nitrile product in the bottoms of the first reactor; (c) transfer of the aminoalkyl nitrile bottom product from step (b) to a second reactor; (d) batchwise catalytic hydrogenation of the aminoalkyl nitrile transferred in step (c) to the diamine in the second reactor, with each batch being obtained by initially charging a catalyst suitable for the hydrogenation of nitriles to amines and also water, the desired diamine and a bas

Abstract: Shaped body comprising an aluminosilicate and aluminum oxide, wherein the shaped body has a molar Al/Si ratio in the range from 10 to 30 and an at least bimodal pore distribution for pores having a diameter of greater than 1 nm, with the volume of the pores of the shaped body having a diameter of greater than 10 nm corresponding to at least 40% of the total pore volume of the shaped body, process for producing it and process for the continuous preparation of methylamines by reaction of methanol and/or dimethyl ether with ammonia in the presence of a heterogeneous catalyst, wherein the abovementioned shaped bodies are used as catalyst.

Abstract: A process for preparing N,N-dimethylacetamide (DMAC) by continuously reacting methyl acetate (MeOAc) with dimethylamine (DMA) in the presence of a basic catalyst, wherein MeOAc is used in the form of a methanolic solution which is obtained as a by-product in the preparation of polyTHF by transesterifying polyTHF diacetate with methanol.

Abstract: A process for preparing N,N-dimethylacetamide (DMAC) by continuously reacting methyl acetate (MeOAc) with dimethylamine (DMA) in the presence of a basic catalyst, wherein MeOAc is used in the form of a methanolic solution and in the range from 0.0002 to 0.09 mol of catalyst per mole of MeOAc, and performing the reaction at a temperature in the range from 90 to 140° C. and at an absolute pressure in the range from 10 to 30 bar.

Abstract: The invention relates to a method of avoiding corrosion in the separation of methylamine from a product stream (10) which is obtained in the preparation of methylamines by gas-phase reaction of methanol and ammonia and includes monomethylamine, dimethylamine, trimethylamine, ammonia and methanol as components, where ammonia is separated off by pure distillation in a first column (1), the remaining components of the product stream obtained as bottoms (12) are fed to a second column (2). Trimethylamine (14) is separated off in the second column (2) by extractive distillation with introduction of water. The further of the product stream obtained as bottoms (15) from the second column (2) are fed to a third column (3), in which monomethylamine and dimethylamine are separated off at the top. The monomethylamine and dimethylamine are separated by distillation in a fourth column (4). To avoid corrosion alkali metal hydroxide is added to the second or third column (3).

Abstract: The invention relates to a process for preparing methylamines by gas-phase reaction of methanol and ammonia as starting materials at a pressure in the range from 15 to 30 bar in the presence of heterogeneous catalyst. The starting materials are vaporized in one or more heat exchangers (1, 2, 3), superheated to produce a feed gas stream and subsequently fed into a reactor (4), with the mixing of the starting materials being able to be carried out in the feed stream to one of the heat exchangers (1, 2, 3) or at any desired position in a heat exchanger (1, 2, 3). A product gas stream comprising monomethylamine, dimethylamine and trimethylamine and also reaction by-products is taken off from the reactor (4). To control the reactor inlet temperature of the starting materials to a temperature in the range from 360° C. to 370° C., all or some of the feed gas stream or the product gas stream is passed through an adjustable valve (5) in order to vary the pressure and thus the condensation temperature.

Abstract: Process for the continuous preparation of an amine by reaction of a primary or secondary alcohol, aldehyde and/or ketone with hydrogen and a nitrogen compound selected from the group consisting of ammonia, primary and secondary amines at a temperature in the range from 60 to 300° C in the presence of a copper-containing catalyst, wherein the catalytically active composition of the catalyst prior to reduction with hydrogen comprises from 20 to 85% by weight of aluminum oxide (Al2O3), zirconium dioxide (ZrO2), titanium dioxide (TiO2) and/or silicon dioxide (SiO2), from 1 to 70% by weight of oxygen-containing compounds of copper, calculated as CuO, from 0 to 50% by weight of oxygen-containing compounds of magnesium, calculated as MgO, oxygen-containing compounds of chromium, calculated as Cr2O3, oxygen-containing compounds of zinc, calculated as ZnO, oxygen-containing compounds of barium, calculated as BaO, and/or oxygen-containing compounds of calcium, calculated as CaO, and less than 30% by weight of oxygen-

Abstract: Process for the continuous preparation of N-methyl-2-pyrrolidone (NMP) by reacting gamma-butyrolactone (GBL) with monomethylamine (MMA) in the liquid phase, wherein GBL and MMA are used in a molar ratio of from 1:1.08 to 1:2 and the reaction is carried out at from 320 to 380° C. and an absolute pressure of from 70 to 120 bar.

Abstract: A process for continuously preparing 2-pyrrolidone by reacting gamma-butyrolactone with ammonia in the liquid phase in the presence of water, wherein the reaction is carried out at a temperature of from 275 to 300° C. and an absolute pressure of from 140 to 180 bar.

Abstract: The invention relates to a method of avoiding corrosion in the separation of methylamine from a product stream (10) which is obtained in the preparation of methylamines by gas-phase reaction of methanol and ammonia and comprises monomethylamine, dimethylamine, trimethylamine, ammonia and methanol as components, where ammonia is separated off by pure distillation in a first column (1), the remaining components of the product stream obtained as bottoms (12) are fed to a second column (2). Trimethylamine (14) is separated off in the second column (2) by extractive distillation with introduction of water. The further components of the product stream obtained as bottoms (15) from the second column (2) are fed to a third column (3), in which monomethylamine and dimethylamine are separated off at the top. The monomethylamine and dimethylamine are separated by distillation in a fourth column (4). To avoid corrosion alkali metal hydroxide is added to the second or third column (3).

Abstract: Process for the continuous preparation of N-methyl-2-pyrrolidone (NMP) by reacting gamma-butyrolactone (GBL) with monomethylamine (MMA) in the liquid phase, wherein GBL and MMA are used in a molar ratio of from 1:1.08 to 1:2 and the reaction is carried out at from 320 to 380° C. and an absolute pressure of from 70 to 120 bar.

Abstract: A process for continuously preparing 2-pyrrolidone by reacting gamma-butyrolactone with ammonia in the liquid phase in the presence of water, wherein the reaction is carried out at a temperature of from 275 to 300° C. and an absolute pressure of from 140 to 180 bar.

Abstract: A combined spring-and-shock-absorber system for supporting wheel suspensions or axles on a vehicle body has a tubular roll bellows (U-bellows) arranged between a wheel-bearing or wheel-controlling connection and a connection on the vehicle body side, the bellows being arranged between an outer bell and a rolling piston, the outer bell and the rolling piston, in each case, having at least partially varying diameters over the height of the corresponding component, and having walls that contact the tubular roll bellows. Both ends of the tubular roll bellows being sealingly secured on the rolling piston at segments having different diameters, the lower mounting section having a larger diameter than the upper mounting section. For this purpose, a tubular roll bellows is used, which is configured as a differential roll bellows, whose interior is filled with a fluid and communicates with a hydraulic accumulator supported on the chassis and/or vehicle body.

Abstract: In a device for minimizing the roll movement of vehicle bodies having rigid axles or independent suspensions, with a non-torsion bar mounted pivotably on the vehicle body and oriented approximately transversely to the vehicle longitudinal direction, and two parallel cantilever arms disposed approximately horizontally in a neutral position of the vehicle, essentially vertically oriented spring/damper units are supported between free ends of the cantilever arms and the vehicle wheel suspensions, the spring/damper units being cylinder/piston units filled with a hydraulic fluid, with the pistons in the cylinder/piston units being centered, free of play, so as to be pre-stressed between springs.

Abstract: Method of purifying triethanolamine prepared by reacting aqueous ammonia with ethylene oxide in the liquid phase under pressure and at elevated temperature by removing excess ammonia, water and monoethanolamine from the reaction product, reacting the resulting crude product with ethylene oxide at temperatures of from 110 to 180° C., and then rectifying the mixture in the presence of phosphorous or hypophosphorous acid or compounds thereof.