摘要:
In a process for the catalytic hydrogenation of a polymethylolalkanal or a monomethylolalkanal of the formula (I) where R may be identical or different and are each a substituted or unsubstituted aliphatic hydrocarbon having from 1 to 22 carbon atoms, an aryl or arylalkyl group having from 6 to 22 carbon atoms or a methylol group, in the presence of a copper-containing catalyst, the hydrogenation feed comprising the polymethylolalkanal or monomethylolalkanal has a total content of metal ions of groups 3 to 14 of the Periodic Table of the Element of up to 5 ppm.
摘要:
A process for greatly improving the color index of polyhydric alcohols, especially trimethylolpropane, by hydrogenation comprises using, in the hydrogenation, an alcohol which has already been purified by distillation. The catalysts used are those conventionally employed in hydrogenations, preferably copper, nickel, palladium or ruthenium catalysts.
摘要:
A process is provided for increasing the yield in the preparation of polyhydric alcohols obtained from methylolated alkanals by hydrogenation, wherein derivatives of these alcohols are decomposed by adding 5 ppm to 1% by weight, preferably 100 to 1000 ppm, of a suitable acid to an anhydrous mixture containing these derivatives, heating the mixture to temperatures of 100 to 300° C. and then separating off the polyhydric alcohol by distillation. This process makes it possible simply and efficiently to decompose compounds which boil above the polyhydric alcohol and are unwanted by-products of its synthesis.
摘要:
Formaldehyde is removed by distillation from reaction solutions containing a methlolated alkanal which was obtained from the reaction of formaldehyde with an alkanal which has at least one acidic hydrogen atom &agr; to the carbonyl function or from the reaction of a 2-alkylacrolein or acrolein with water and formaldehyde, by a process in which this reaction was carried out in the presence of catalytic amounts of organic amine. The process permits the improved removal of formaldehyde from the reaction mixture and furthermore facilitates the hydrogenation of the alkanals thus obtained to give polyols.
摘要:
A process is disclosed for the purification, by distillation, of trimethylolpropane originating from the hydrogenation of 2,2-dimethylolbutanal, said process including the following steps: (a) reaction of n-butyraldehyde with formaldehyde in the presence of catalytic amounts of a tertiary amine, and hydrogenation of the resulting mixture to give a mixture containing trimethylolpropane; (b) separation of water, methanol, trialkylamine and/or trialkylammonium formate by distillation; (c) heating of the residue obtained in (b) under reduced pressure to a temperature at which TMP is volatile and compounds boiling above TMP are cleaved, in order to separate off, by distillation, TMP and compounds more volatile than TMP; (d) distillation of the distillate obtained in (c) in order to separate off the more volatile compounds and recover pure TMP; and (e) optional distillation of the TMP obtained in (d) in order to recover TMP with a low APHA color index. A process is also disclosed in which trialkylammonium formate is distilled under mild conditions from crude mixtures of polyhydric alcohols, predominantly trimethylolpropane.
摘要:
A catalyst comprises, based on the total weight of the catalyst,0.1-6% by weight of cobalt, nickel or a mixture thereof,0.001-25% by weight of ruthenium,0-10% by weight of copper and0-5% by weight of promoterson a porous metal oxide carrier.It preferably comprises 0.1-3% by weight of cobalt and 0.1-3% by weight of nickel. It can be used in hydrogenation reactions, dehydrogenation reactions or hydrogenation/dehydrogenation reactions, in particular in the amination of alkylene oxides, alcohols, aldehydes or ketones with ammonia or primary or secondary amines.
摘要:
The invention relates to a multistage process for the continuous preparation of organic, distillable isocyanates, preferably diisocyanates, particularly preferably aliphatic or cycloaliphatic diisocyanates, by reaction of the corresponding organic amines with urea and alcohols to liberate ammonia and form low molecular weight monomeric urethanes and thermal dissociation of the latter, in which by-products formed are at least partly utilized.
摘要:
The invention relates to a multistage process for the continuous preparation of organic, distillable isocyanates, preferably diisocyanates, particularly preferably aliphatic or cycloaliphatic diisocyanates, by reaction of the corresponding organic amines with urea and alcohols to liberate ammonia and form low molecular weight monomeric urethanes and thermal dissociation of the latter, in which by-products formed are at least partly utilized.
摘要:
The diagnosis of the heating of a catalytic converter situated in an exhaust system of an internal combustion engine is described. The system includes monitoring the actual ignition angle intervention. A current ignition angle is acquired over a specified time and converted into a torque model used for catalytic converter heating. Using the torque model, a degree of fulfillment of executed catalytic converter heating measures is obtained and an error signal is generated by comparing the obtained degree of fulfillment to a limiting value.
摘要:
A process for the catalytic hydrogenation of a carbonyl compound or of a mixture of two or more carbonyl compounds in the presence of a catalyst which comprises an inorganic support containing TiO2, and as active component copper or a mixture of copper and at least one of the metals selected from the group of zinc, aluminum, cerium, a noble metal and a group VIII metal, wherein the copper surface area does not exceed 10 m2/g.