Abstract: A process for preparing a high purity lithium salt from lithium carbonate comprises steps A to D as defined hereinbelow: A: treating a mixture comprising lithium carbonate and water by means of CO2 to obtain an aqueous mixture comprising lithium bicarbonate, B: passing said aqueous mixture comprising lithium bicarbonate through an ion exchanger module, C: precipitating lithium carbonate from the ion exchange module treated lithium bicarbonate mixture obtained in step B, and D: working up the precipitated lithium carbonate or converting the precipitated lithium carbonate into some other high purity lithium salt.

Abstract: In a process for preparing mixtures of diphenylmethane diisocyanates and polyphenylpolymethylene polyisocyanates having a reduced content of chlorinated by-products and a reduced iodine color number by two-stage reaction of the corresponding mixtures of diphenylmethanediamines and polyphenylpolymethylenepolyamines with phosgene in the presence of at least one inert organic solvent at elevated temperature, separation of the excess phosgene and solvent after the phosgenation is complete and thermal treatment of the reaction product, the mass ratios of phosgene to hydrogen chloride in the residence time apparatus of the second stage of the phosgenation are at the same time 10-30:1 in the liquid phase and 1-10:1 in the gas phase.

Abstract: Secondary amines of the formula (II) (X—CH2—)2NH  (II) where X is a C1-20-alkyl, C2-20-alkenyl or C3-8-cycloalkyl group which may be unsubstituted or substituted by C1-20-alkyl, C3-8-cycloalkyl, C4-20-alkylcycloalkyl, C4-20-cycoalkylalkyl, C2-20-alkoxyalkyl, C6-14-aryl, C7-20-alkylaryl, C7-20-aralkyl, C1-20-alkoxy, hydroxy, C1-20-hydroxyalkyl, amino, C1-20-alkylamino, C2-20-dialkylamino, C2-12-alkenylamino, C3-8-cycloalkylamino, arylamino, diarylamino, aryl-C1-8-alkylamino, halogen, mercapto, C2-20-alkenyloxy, C3-8-cycloalkoxy, aryloxy and/or C2-8-alkoxycarbonyl, are prepared by reacting nitriles of the formula (III) X—CN  (III) with hydrogen at from 20 to 250° C. and pressures of from 60 to 350 bar in the presence of an Rh-containing catalyst comprising from 0.

Abstract: Secondary amines of the formula 1

Abstract: The present invention relates to a process for the dissociation of allophanates, in which a thermal dissociation is carried out in a reaction vessel and the gaseous dissociation products obtained are removed from the reaction vessel using an inert carrier gas or the vapor of a liquid as stripping medium and are condensed.

Abstract: Secondary amines of the formula (II)

Abstract: Mixtures of primary amines of the formula (I)

Abstract: are prepared by single-stage reaction of alkoxydihydropyrans of the formula (II) with water and hydrogen in the presence of a catalyst comprising oxides of nickel, zirconium and copper. In the formulae (I) and (II), R, R′, R″, R′″ can be identical or different and are each hydrogen or a linear or branched saturated hydrocarbon radical having from 1 to 20 carbon atoms in which the hydrocarbon chain may contain O, S and N as heteroatoms and which may be monosubstituted or polysubstituted by hydroxy, thiol or amino groups or halogens.

Abstract: A process for separating chlorine of high purity from a chlorine-containing feed gas by absorption of the chlorine using an inert absorbent and downstream desorption of the chlorine from the absorbent/chlorine mixture drawn off from the absorption stage by the supply of mixture to a desorption distillation column which is coupled to a chlorine separation column in such a way that the top of the chlorine separation column and an upper section of the desorption distillation column and a lower section of the desorption distillation column and the bottom of the chlorine separation column are connected to one another on both the gas and the liquid side, the absorbent/chlorine mixture being supplied exclusively to the desorption distillation column, and high-purity chlorine being drawn off from a middle region of the chlorine separation column.

Abstract: In a distillation column for separating a liquid mixture into a plurality of pure fractions, the distillation column being divided into 2 parts, a feed part and a take-off part, in its middle region by a separation effective in the longitudinal direction, the separation consists of two walls with a gas space in between, the distance between the two walls being from 1 to 50 mm, preferably from 3 to 10 mm.