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: 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: 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: A process for producing mixtures of mono-, di- and triethanol-amine by reacting ammonia and ethylene oxide in a cooled tubular reactor at temperatures from 110.degree. to 160.degree. C. and pressures from 50 to 120 bar comprises using ammonia and ethylene oxide in a molar ratio from 1:1 to 100:1 and ammonia in the form of a from 60 to 99.99% strength aqueous solution and adding from 1 to 80% of the ethylene oxide in from one to ten aliquots over from 10 to 70% of the total length of the tubular reactor.

Abstract: A process for the isolation of a carboxylic acid of the general formula (I)R.sup.1 --COOH (I),in which R.sup.1 denotes hydrogen, methyl, ethyl, or vinyl, from a dilute aqueous solution thereof by extraction with a secondary amide of the general formula (II) ##STR1## in which R.sup.1 has the meanings stated, and R.sup.2 and R.sup.3 are independently of each other C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.8 -cycloalkyl, C.sub.4 -C.sub.20 -cycloalkylalkyl, aryl, C.sub.7 -C.sub.20 -aralkyl, or R.sup.2 and R.sup.3 together form a 1,4- or 1,5-alkylene group which may be mono- to penta-substituted by C.sub.1 -C.sub.4 -alkyl, wherein the losses of secondary amide (II) are compensated by the addition of the corresponding amine of the general formula (III) ##STR2## in which R.sup.2 and R.sup.3 have the meanings stated above.