Abstract: A process for preparing a diamine from a corresponding aminoalkyl nitrile, which is prepared by reaction of a corresponding monoamine with a corresponding alkenyl nitrile in a continuous mode of operation, comprising the steps: a) introduction of the corresponding monoamine into a continuously conveyed reaction stream; b) introduction of the corresponding alkenyl nitrile into the reaction stream, with this already comprising the aminoalkyl nitrile on addition; c) reaction of the reaction stream in a first reaction region; d) at least partial transfer of the reaction stream into at least one second reaction region for further reaction; e) discharge of the reaction stream from the second reaction region after the reaction; f) introduction of the reaction stream discharged in step (a) into a reduction region; and g) reduction of the aminoalkyl nitrile present in the reaction stream to the corresponding diamine.

Abstract: A process for preparing a diamine from a corresponding aminoalkyl nitrile, which is prepared by reaction of a corresponding monoamine with a corresponding alkenyl nitrile in a continuous mode of operation, comprising the steps: a) introduction of the corresponding monoamine into a continuously conveyed reaction stream; b) introduction of the corresponding alkenyl nitrile into the reaction stream, with this already comprising the aminoalkyl nitrile on addition; c) reaction of the reaction stream in a first reaction region; d) at least partial transfer of the reaction stream into at least one second reaction region for further reaction; e) discharge of the reaction stream from the second reaction region after the reaction; f) introduction of the reaction stream discharged in step (a) into a reduction region; and g) reduction of the aminoalkyl nitrile present in the reaction stream to the corresponding diamine.

Abstract: The present invention relates to a process for preparing an aminoalkyl nitrile by reaction of a corresponding monoamine with a corresponding alkenyl nitrile in a continuous mode of operation, which comprises the steps (a) introduction of the corresponding monoamine into a continuously conveyed reaction stream; (b) introduction of the corresponding alkenyl nitrite into the reaction stream, with this already comprising the aminoalkyl nitrile on addition; (c) reaction of the reaction stream in a first reaction region; and (d) at least partial transfer of the reaction stream into at least one second reaction region for further reaction. The invention further relates to a process for preparing a diamine from the aminoalkyl nitrile, suitable apparatuses for carrying out the processes and their corresponding use.

Abstract: A process for obtaining oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers from a methanolic crude product which contains polytetrahydrofuran or tetrahydrofuran copolymers and is obtained in the transesterification of the mono- and/or diesters of polytetrahydrofuran or tetrahydrofuran copolymers with methanol, which includes a) removing the majority of the methanol from the crude product in a first distillation stage, b) separating the resulting bottom product by distillation into a top fraction containing the oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers, and polytetrahydrofuran or tetrahydrofuran copolymer, and c) condensing the oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers out of the top fraction from stage b).

Abstract: The present invention relates to a process for preparing an aminoalkyl nitrile by reaction of a corresponding monoamine with a corresponding alkenyl nitrile in a continuous mode of operation, which comprises the steps (a) introduction of the corresponding monoamine into a continuously conveyed reaction stream; (b) introduction of the corresponding alkenyl nitrite into the reaction stream, with this already comprising the aminoalkyl nitrile on addition; (c) reaction of the reaction stream in a first reaction region; and (d) at least partial transfer of the reaction stream into at least one second reaction region for further reaction. The invention further relates to a process for preparing a diamine from the aminoalkyl nitrile, suitable apparatuses for carrying out the processes and their corresponding use.

Abstract: The invention provides a process for preparing polytetrahydrofuran, tetrahydrofuran copolymers, their monoesters or diesters and the monoesters or diesters of polytetrahydrofuran having a low color number in the presence of a catalyst, which comprises converting crude tetrahydrofuran which has been prepared in a manner per se into pure tetrahydrofuran by distillation, subsequently subjecting the latter to essentially complete hydrogenation and using the high-purity tetrahydrofuran obtained in this way for the polymerization directly after its preparation.

Abstract: A process for obtaining oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers from a methanolic crude product which contains polytetrahydrofuran or tetrahydrofuran copolymers and is obtained in the transesterification of the mono- and/or diesters of polytetrahydrofuran or tetrahydrofuran copolymers with methanol, which comprises a) removing the majority of the methanol from the crude product in a first distillation stage, b) separating the resulting bottom product by distillation into a top fraction comprising the oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers, and polytetrahydrofuran or tetrahydrofuran copolymer, c) condensing the oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers out of the top fraction from stage b).

Abstract: The invention relates to a process for the continuous preparation of THF by reaction of a 1,4-butanediol-containing reaction mixture over a heteropolyacid catalyst which has not been predried, wherein the reaction mixture comprises 2-(4-hydroxybutoxy)tetrahydrofuran.

Abstract: The invention relates to a process for the continuous preparation of THF by reaction of a 1,4-butanediol-containing reaction mixture over a heteropolyacid catalyst which has not been predried, wherein the reaction mixture comprises 2-(4-hydroxybutoxy)tetrahydrofuran.

Abstract: Process for working up an at least partially deactivated hydrogenation catalyst for the color number hydrogenation of PTHF and/or PTHF esters, in which the hydrogenation catalyst is purified by treatment with steam at from 100 to 250° C. and a gauge pressure of from 0 to 40 bar.

Abstract: The invention provides a process for preparing polytetrahydrofuran, tetrahydrofuran copolymers, their monoesters or diesters and the monoesters or diesters of polytetrahydrofuran having a low color number in the presence of a catalyst, which comprises converting crude tetrahydrofuran which has been prepared in a manner per se into pure tetrahydrofuran by distillation, subsequently subjecting the latter to essentially complete hydrogenation and using the high-purity tetrahydrofuran obtained in this way for the polymerization directly after its preparation.

Abstract: In a process for preparing polytetrahydrofuran having terminal OH groups (PTHF) from the corresponding polytetramethylene ether having acyloxy end groups by transesterification with alcohols in the presence of a sodium-containing catalyst followed by passing the alcoholic PTHF solution in the presence of a catalytic amount of water directly through at least one ion exchanger to remove the sodium ions, the removal of the sodium ions is carried out in a fully continuous ion exchange unit which comprises: a plurality of ion exchange cells (Z) which are arranged on a rotary platform and are each provided with a distribution element and a collection element and a central valve (V) having a stator disk (S) and a rotor disk (R) via which the introduction and discharge of all liquid streams into or out of the ion exchange unit occurs, and feed and discharge lines from each ion exchange cell (Z) to the central valve (V).

Abstract: In a process for preparing polytetrahydrofuran, tetrahydrofuran copolymers, diesters or monoesters of these polymers having a low color number, the polymers obtained by cationic polymerization of tetrahydrofuran are hydrogenated in the presence of a macroporous, supported heterogeneous catalyst comprising at least one metal of groups 7 to 10 of the Periodic Table of the Elements as active metal.

Abstract: In a process for preparing polytetrahydrofuran having terminal OH groups (PTHF) from the corresponding polytetramethylene ether having acyloxy end groups by transesterification with alcohols in the presence of a sodium-containing catalyst followed by passing the alcoholic PTHF solution in the presence of a catalytic amount of water directly through at least one ion exchanger to remove the sodium ions, the removal of the sodium ions is carried out in a fully continuous ion exchange unit which comprises:

Abstract: A process for working up at least partially deactivated polymerization catalysts for the polymerization or copolymerization of THF which are contaminated with the products of the polymerization or copolymerization of THF comprises (a) in a first step, cleaning the polymerization catalyst by treatment with steam at from 80 to 250° C. and a pressure of from 0.5 to 40 bar and, preferably, (b) in a second step, regenerating the clean polymerization catalyst.

Abstract: In a process for preparing polytetrahydrofuran, tetrahydrofuran copolymers, diesters or monoesters of these polymers having a low color number, the polymers obtained by cationic polymerization of tetrahydrofuran are hydrogenated in the presence of a macroporous, supported heterogeneous catalyst comprising at least one metal of subgroups VII [sic] to X [sic] of the Periodic Table of the Elements as active metal.

Abstract: Catalyst and process for the preparation of butene-2-diol-1,4 by the hydrogenation of butyne-2-diol-1,4 in aqueous solution over a palladium-containing fixed-bed catalyst, which is doped with lead or cadmium, in which a catalyst is used which has been made by applying Pd and Pb or Pd and Cd successively, by vapor deposition or sputtering, to a metal gauze or a metal foil acting as support material followed by forming the catalyst at an elevated temperature in air.

Abstract: A process is disclosed for the selective hydrogenation of butynediol to 2-butene-1,4-diol using a palladium catalyst to which either copper and zinc, or silver and zinc, or copper, silver and zinc are added as doping agents. In the preferred embodiment, it has been possible, by optimizing the composition of the catalyst, to improve the activity and selectivity of the catalysts in question while also eliminating the need to handle toxic substances during the catalyst manufacturing process.

Abstract: Fuels for gasoline engines contain small amounts of polyetheramines IR.sup.1 --(OBu).sub.n --NR.sup.2 R.sup.3 (I)whereR.sup.1 is C.sub.2 -C.sub.30 -alkyl,R.sup.2 and R.sup.3, independently of one another, are each hydrogen, C.sub.1 -C.sub.8 -alkyl, aminoalkylene of the general formula II--R.sup.4 --NR.sup.5 R.sup.6 (II)or polyaminoalkylene of the general formula III--(R.sup.4 --NR.sup.5).sub.m --R.sup.6 (III)whereR.sup.4 is C.sub.2 -C.sub.10 -alkylene, R.sup.5 and R.sup.6, independently of one another, are each hydrogen or C.sub.1 -C.sub.8 -alkyl and m is from 2 to 8,Bu is a butylene radical derived from butylene oxide andn is from 12 to 28.

Abstract: In a process for preparing diamines from aminoalcohols and nitrogen compounds selected from the group consisting of ammonia and primary and secondary amines at from 80.degree. to 250.degree. C. and pressures of from 1 to 400 bar using hydrogen in the presence of a zirconium, copper, nickel catalyst, the catalytically active composition comprises from 20 to 85% by weight of oxygen-containing zirconium compounds, calculated as ZrO.sub.2, from 1 to 30% by weight of oxygen-containing compounds of copper, calculated as CuO, from 30 to 70% by weight of oxygen-containing compounds of nickel, calculated as NiO, from 0.1 to 5% by weight of oxygen-containing compounds of molybdenum, calculated as MoO.sub.3, and from 0 to 10% by weight of oxygen-containing compounds of aluminum and/or manganese, calculated as Al.sub.2 O.sub.3 and MnO.sub.2 respectively.