Abstract: The invention relates to a process for preparing isocyanates by reacting the corresponding amines with phosgene in the liquid phase, if appropriate in the presence of at least one inert medium, in which the amine and the phosgene are first mixed in a mixing chamber (1) to give a reaction mixture and the reaction mixture is fed to a reactor, the amine being added through an orifice (3) arranged coaxially to the mixing chamber (1) and the phosgene being added through feed orifices (5) in at least two planes (7, 9) arranged at right angles to the axis (11) of the mixing chamber (1), or the phosgene being added through the orifice (3) arranged coaxially to the mixing chamber and the amine through the feed orifices (5) in at least two planes (7, 9) arranged at right angles to the axis (11) of the mixing chamber (1). At least one plane (9) is arranged upstream and at least one plane (7) downstream of the orifice (3) arranged coaxially to the mixing chamber (1) in main flow direction of the reaction mixture.

Abstract: The invention relates to a process for preparing isocyanates by reacting the corresponding amines with phosgene in the liquid phase, if appropriate in the presence of at least one inert medium, in which the amine and the phosgene are first mixed in a mixing chamber (1) to give a reaction mixture and the reaction mixture is fed to a reactor, the amine being added through an orifice (3) arranged coaxially to the mixing chamber (1) and the phosgene being added through feed orifices (5) in at least two planes (7, 9) arranged at right angles to the axis (11) of the mixing chamber (1), or the phosgene being added through the orifice (3) arranged coaxially to the mixing chamber and the amine through the feed orifices (5) in at least two planes (7, 9) arranged at right angles to the axis (11) of the mixing chamber (1). At least one plane (9) is arranged upstream and at least one plane (7) downstream of the orifice (3) arranged coaxially to the mixing chamber (1) in main flow direction of the reaction mixture.

Abstract: Crude ammonia is separated into a low boiler fraction, a high boiler fraction and an intermediate-boiling pure fraction by continuous fractional distillation in a distillation apparatus configured either as a dividing wall column or as a system of thermally coupled distillation columns. In the process of the present invention, the low boiler fraction is taken off at the top of the distillation apparatus. The intermediate-boiling pure fraction is obtained at a side offtake which is preferably provided with droplet precipitators. In addition, the gas loading of the distillation column is restricted so that the operating pressure is in the range from 2 to 30 bar and the F factor does not exceed 2.0 Pa0.5.

Abstract: A process for preparing at least one unsaturated alcohol (B) comprises the steps (I) to (III) below: (I) reaction of at least one alkali metal hydroxide or alkaline earth metal hydroxide with at least one alcohol (A) in at least one organic solvent (L) to give a mixture (G-I) comprising at least the alcohol (A), the solvent (L) and an alkoxide (AL); (II) reaction of at least one carbonyl compound of the formula R—CO—R? with at least one alkyne of the formula R?—C?C—H and the mixture (G-I) obtained in step (I) to give a mixture (G-II) comprising at least the alcohol (A), the solvent (L) and an unsaturated alcohol (B); (III) distillation of the mixture (G-II) obtained in step (II) to give the alcohol or alcohols (B) and a mixture (G-III) comprising the solvent (L) and the alcohol (A), wherein the solvent (L) obtained in step (III) and the alcohol (A) obtained in step (III) are recycled as a mixture to step (I).

Abstract: Higher &agr;,&bgr;-unsaturated alcohols are prepared by monoethynylation of a ketone by the NH3/KOH method, if desired hydrogenation of the acetylene alcohol in the presence of hydrogen over a Pd-containing thin layer catalyst, purifying distillation of the hydrogenation product, preferably in a dividing wall column with recirculation of the unreacted ketone to the ethynylation step, and, if desired, preparation of higher alcohols having in each case 5 more carbon atoms in the chain by reacting the alcohols prepared by monoethynylation and, if desired, partial hydrogenation with alkyl acetoacetates diketene in a Carroll reaction to form ketones and using these as starting materials for the steps ethynylation, optional hydrogenation and fractional distillation.

Abstract: A process for the single-stage preparation of polytetrahydrofuran and/or tetrahydrofuran copolymers having a mean molecular weight of from 650 to 5000 dalton by polymerization of tetrahydrofuran over a heterogeneous acid catalyst in the presence of at least one telogen and/or comonomer selected from the group consisting of alpha,omega-diols, water, polytetrahydrofuran having a molecular weight of from 200 to 700 dalton and cyclic ethers comprises a) separating off the catalyst and/or downstream products of the catalyst suspended and/or dissolved in the output from the polymerization, b) fractionating the resulting catalyst-free output from the polymerization in at least one distillation step to give a distillation residue comprising the polymerization product and at least one tetrahydrofuran fraction and returning at least part of the tetrahydrofuran fraction to the polymerization and c) separating low molecular weight polytetrahydrofuran and/or tetrahydrofuran copolymers having a mean molecular weight of

Abstract: The invention relates to a process for the preparation of organic disulfides by oxidation of mercaptans with sulfur dissolved in an organic disulfide using an amine as catalyst, where the mercaptans are used as “crude mercaptan stream” from a reaction of alcohols with hydrogen sulfide over a catalyst suitable for mercaptan synthesis. Furthermore, the invention relates to the use of the organic disulfides for the preparation of alkanesulfonic acids.

Abstract: A process for the single-stage preparation of polytetrahydrofuran and/or tetrahydrofuran copolymers having a mean molecular weight of from 650 to 5000 dalton by polymerization of tetrahydrofuran over a heterogeneous acid catalyst in the presence of at least one telogen and/or comonomer selected from the group consisting of alpha,omega-diols, water, polytetrahydrofuran having a molecular weight of from 200 to 700 dalton and cyclic ethers comprises

Abstract: The invention relates to a process for the prepartaion of alkanesulfonic acids, comprising the following steps: (a) oxidation of alkylmercaptans and/or dialkyl disulfides and/or dialkyl polysulfides having from three to nine sulfur atoms with nitric acid to form alkanesulfonic acids, water, nitrogen oxides and other byproducts, (b) regeneration of the nitrogen oxides obtained from step (a) with oxygen to give nitric acid and recycling of the nitric acid to step (a), where steps (a) and (b) are carried out in reaction chambers separate from one another.

Abstract: Higher &agr;,&bgr;-unsaturated alcohols are prepared by monoethynylation of a ketone by the NH3/KOH method, if desired hydrogenation of the acetylene alcohol in the presence of hydrogen over a Pd-containing thin layer catalyst, purifying distillation of the hydrogenation product, preferably in a dividing wall column with recirculation of the unreacted ketone to the ethynylation step, and, if desired, preparation of higher alcohols having in each case 5 more carbon atoms in the chain by reacting the alcohols prepared by monoethynylation and, if desired, partial hydrogenation with alkyl acetoacetatesor diketene in a Carroll reaction to form ketones and using these as starting materials for the steps ethynylation, optional hydrogenation and fractional distillation.

Abstract: Dimethyl sulfite is prepared by transesterification of a cyclic alkylene sulfite of at least 2 carbon atoms with methanol, in the presence or absence of a catalyst, by a process which is carried out continuously in a column.

Abstract: A method of distillation for separating a material which is solid at ambient temperature from a lower boiling and lower melting point material, and the apparatus.

Abstract: The invention relates to a method for producing alkyne diols by reacting ketones with acetylenic hydrocarbons in an organic solvent in the presence of a base which contains potassium alcoholates of primary and/or secondary alcohols. The alkyne diols are produced while forming adducts which precipitate out of the reaction mixture and which are comprised of alkyne monoalcohols and/or alkyne diols and a base. The stoichiometries of the reaction partners are selected such that gelatinous adducts are formed which comprise a spherical surface, whereby the reaction mixture remains agitable during the entire reaction.

Abstract: Crude ammonia is separated into a low boiler fraction, a high boiler fraction and an intermediate-boiling pure fraction by continuous fractional distillation in a distillation apparatus configured either as a dividing wall column or as a system of thermally coupled distillation columns. In the process of the present invention, the low boiler fraction is taken off at the top of the distillation apparatus. The intermediate-boiling pure fraction is obtained at a side offtake which is preferably provided with droplet precipitators. In addition, the gas loading of the distillation column is restricted so that the operating pressure is in the range from 2 to 30 bar and the F factor does not exceed 2.0 Pa0.5.