Abstract:
The invention relates to a method for production of polyvalent alcohols with low acetal content by catalytic hydrogenation of methylolalkanals of general formula (I), where R 1 and R 2 independently = a further methylol or C 1 - 22 alkyl group or C 6 - C 33 aryl or aralkyl group in the liquid phase on a hydrogenation catalyst, characterised in that at least one tertiary amine, inorganic base or inorganic or organic acid is added to the hydrogenation feed to adjust the pH value of the hydrogenation product to 7.0 to 9.0.
Abstract:
The invention relates to a method for producing 1,6-hexanediol having a purity of > 99.5 wt. % by catalytic dimerisation of acrylic acid esters, catalytic hydrogenation of the thus obtained hexene diacidic diester in order to form 1.6-hexanediol. Said method consists in: a) dimerising C1- C8-acrylic acid esters in the presence of at least one rhodium compound in order to form mixtures predominantly of 2- and 3-hexene diacdic diesters, b) hydrating the obtained dimerisation discharge in the presence of chrome-free catalysts containing mainly copper as a hydrogenation component and c) purifying the thus obtained raw 1.6-hexanediol by fractionating distillation.
Abstract:
The invention relates to a method for producing (meth) acrylic acid esters of polyhydric alcohols by reacting (meth) acrylic acid and the corresponding polyhydric alcohols in the presence of at least one acid catalyst and, optionally, of at least one polymerization inhibitor and, optionally, in the presence of a solvent, whereby the polyhydric alcohol that is used has a content of bound formaldehyde of less than 500 ppm.
Abstract:
The invention relates to a method for removing acetals containing formaldehy de from polyvalent alcohols, especially trimethylolpropane. The inventive metho d is characterised in that the polyvalent alcohol is liberated of low-boiling constituents after it has been produced by distillation, is then subjected t o tempering and is repurified, preferably by means of distillation.
Abstract:
Procedimiento para la descomposición de formiato de trialquilamonio a partir de metilolalcanos, que han sido obtenidos mediante condensación de formaldehído con un aldehído superior, a 100 hasta 250ºC y a una presión mayor que 106 Pa, caracterizado porque se descompone el formiato de trialquilamonio sobre catalizadores que contienen, al menos, un metal de los grupos octavo a decimosegundo del Sistema Periódico, con aporte de gases que contengan hidrógeno.
Abstract:
Trimethylolpropane is isolated from a reaction mixture which has been obtained by reaction of n-butyraldehyde with formaldehyde in the presence of a base and, if appropriate, hydrogenation of the resulting mixture by distilling the mixture by means of a dividing wall column or a distillation column with a precolumn or a distillation column with an after-column. The process has low capital costs and a low energy consumption and gives reduced formation of high-boiling by-products.
Abstract:
Production of 1,6-hexanediol of purity at least 99.5 % comprises: (1) catalytically dimerizing a 1-8C acrylic acid ester in presence of rhodium compounds to a mixture mainly of 2- and 3-hexenedioic acid diesters; (2) hydrogenating the ester mixture in chromium-free mainly copper-containing catalysts; and (3) purifying the resulting diol mixture by fractional distillation.
Abstract:
The invention provides a process for preparing polyester polyols of polyhydric alcohols by mono- or polyesterification of at least one carboxylic acid having at least two acid groups and/or at least one derivative of a dicarboxylic acid with polyhydric alcohols, optionally with the addition of a catalyst, while removing the water of reaction, wherein the polyhydric alcohol used has a formaldehyde acetal content of less than 500 ppm.
Abstract:
(Meth)acrylates of polyhydric alcohols are prepared by reacting (meth)acrylic acid and the corresponding polyhydric alcohol in the presence of at least one acidic catalyst and, if required, at least one polymerization inhibitor and in the presence or absence of a solvent, by a process in which the polyhydric alcohol used contains less than 500 ppm of bound formaldehyde.
Abstract:
The invention provides a process for preparing polyetherols of polyhydric alcohols by reacting an alkylene oxide with the appropriate polyhydric alcohol in the presence of a base and in the presence or absence of a solvent, wherein the polyhydric alcohol used has a formaldehyde acetal content of less than 500 ppm.