Abstract:
In a dividing wall column comprising as segments a) an upper column region (6), b) an inflow section (7), c) an offtake section (8) and d) a lower column region (9), the inflow section b) (7) and the offtake section c) (8) are separated from one another laterally by a dividing wall (10) fixed in the column and the dividing wall (10) is located between the upper column region a) (6) and the lower column region d) (9). The present invention provides for the dividing wall (10) to be constructed at least partly of an elastic material, the dividing wall (10) to have a slightly overdimensional width and the dividing wall (10) to be fixed in the column by the dividing wall exercising an elastic recovery force on the interior wall of the column. The dividing wall can easily be installed in, in particular, relatively small columns.
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:
A process for preparing cyclohexanol from benzene by: a) preparing cyclohexene by hydrogenating benzene in the presence of a catalyst, and b) preparing cyclohexanol by hydrating the cyclohexene in the presence of a catalyst, comprises: carrying out steps a) and b) in a reaction facility which has a bottom region at the lower end, a top region at the upper end, and a reaction zone between the top region and the bottom region which contains the catalyst according to steps a) and b), evaporating a portion of the benzene using the heat of reaction in the reaction zone, condensing it in the top region and returning it to the reaction zone, and withdrawing a reaction mixture containing cyclohexanol in the bottom region.
Abstract:
A process for preparing 1,3-diols having 6 or more carbon atoms comprises a) provision of at least one alkanal having at least three carbon atoms; b) thermal treatment of the alkanal in the absence of a basic catalyst; c) hydrogenation of the aldol addition product formed in step b); and d) isolation of the 1,3-diol obtained. The process of the present invention makes it possible to prepare 1,3-diols simply and inexpensively.
Abstract:
In a process for isolating &agr;-ethynyl carbinols from the liquid reaction mixture from the addition of acetylene onto &agr;,&bgr;-unsaturated carbonyl compounds by distillation, the distillation is carried out continuously, the feed stream is introduced into the middle section of a distillation column (K), the major part of the water is distilled off azeotropically together with the solvent at the top of the column, and the &agr;-ethynyl carbinol target product is taken off below the feed point to the column.
Abstract:
A process for separating 2-aminomethylcyclopentylamine from a mixture consisting of hexamethylenediamine and 2-aminomethylcyclopentylamine by distilling the mixture at a pressure from 1 to 300 mbar.
Abstract:
Hydroxybenzaldehydes of the formula (I) are prepared from a benzaldehyde of the formula (II) or its acetal, in which R.sup.1 in the R.sup.1 O-phenyl ether group is an alkyl, cycloalkyl, alkylcycloalkyl or alkylaryl radical, R.sup.2 is H or OH or is identical to R.sup.1 and one or more R.sup.1 O-phenyl ether groups are ortho, meta or para to the aldehyde function, by a process in which a benzaldehyde of the formula (II) or its acetal, in which R.sup.1 and R.sup.2 have the abovementioned meanings and one or more R.sup.1 O-phenyl ether groups occupy the abovementioned position with respect to the aldehyde function, is converted into a hydroxybenzaldehyde of the formula (I) in the presence of water over a zeolite as a heterogeneous catalyst. ##STR1## The catalysts used are, in particular, zeolites of the pentasil type.
Abstract:
Method of devulcanizing rubber and/or elastomers without the need for a chemical agent, in which method the vulcanized rubber and/or elastomers are fed into a planetary roller extruder, which planetary roller extruder has a housing, a central spindle, and at least one group of planetary spindles. Mechanical and thermal stress is generated on the vulcanized rubber and/or elastomers by kneading and/or crushing the vulcanized rubber and/or elastomers using the central spindle and the planetary spindles. The mechanical and thermal stress alone is sufficient to break or destroy the molecular chains or bonds of the vulcanized rubber and/or elastomers.
Abstract:
The present invention relates to a process for preparing a cyclic ketone having from 7 to 16 carbon atoms, which comprises at least the steps (a) oxidation of a composition (I) comprising at least one cyclic alkene which has from 7 to 16 carbon atoms and at least one C—C double bond by means of dinitrogen monoxide to give a composition (A), (b) treatment of the composition (A) with at least one base to give a composition (B), (c) hydrogenation of the composition (B) in the presence of at least one catalyst to give a composition (C), (d) purification of the composition (C), comprising at least the steps (di) thermal treatment of the composition (C) with at least one acid or at least one catalyst comprising at least one transition metal, (dii) further purification by a method selected from the group consisting of distillation, extraction and crystallization.
Abstract:
The present invention relates to a process for purifying a composition (I) comprising at least one cyclic ketone having from 7 to 16 carbon atoms, which comprises thermal treatment of the composition (I) with at least one acid and further purification by means of a process selected from the group consisting of distillation, extraction and crystallization, Furthermore, the present invention relates to a process for preparing cyclododecanone, which comprises such a purification, and the use of at least one acid for purifying a composition (I) comprising at least one cyclic ketone having from 7 to 16 carbon atoms by thermal treatment of the composition (I) with the acid.