摘要:
The invention relates to a method for increasing yield in the production of polyvalent alcohols, especially trimethylolpropane, obtained by condensing formaldehyde with a higher aldehyde. According to the inventive method, acid treatment is carried out on a mixture (high-boiling fraction) that is obtained by reprocessing, contains derivatives of said alcohols and has a higher boiling point than the respective alcohol, and the polyvalent alcohol is recovered from the acid-treated high-boiling fraction. The inventive method is characterised in that the water content of the high-boiling fraction amounts to between 20 and 90 wt. % in relation to the entire mixture of the high-boiling fraction and water.
摘要:
The invention relates to a method for increasing yield in the production of polyvalent alcohols, especially trimethylolpropane, obtained by condensing formaldehyde with a higher aldehyde. According to the inventive method, acid treatment is carried out on a mixture (high-boiling fraction) that is obtained by reprocessing, contains derivatives of said alcohols and has a higher boiling point than the respective alcohol, and the polyvalent alcohol is recovered from the acid-treated high-boiling fraction. The inventive method is characterised in that the water content of the high-boiling fraction amounts to between 20 and 90 wt. % in relation to the entire mixture of the high-boiling fraction and water.
摘要:
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.
摘要:
A method for removing trialkyl ammonium formate from a methylol alkanes obtained by condensation of formaldehyde with a higher aldehyde. The invention is characterized in that trialkyl ammonium formate is decomposed at a high temperature using catalysts containing at least one metal from groups 8-12 of the classification of elements in the presence of gas containing hydrogen. The method makes it possible to separate trialkyl ammonium formate according to the organic Cannizzaro method and according to the hydrogenation method.
摘要:
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.
摘要:
(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.
摘要:
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.
摘要:
A process for removing trialkylammonium formate from methylolalkanes which have been obtained by condensation of formaldehyde with a higher aldehyde comprises decomposing trialkylammonium formate at elevated temperature in the presence of a hydrogen-containing gas over a catalyst comprising ruthenium supported on titanium dioxide. The process makes it possible to separate off the trialkylammonium formate from methylolalkanes prepared by the organic Cannizzaro process or by the hydrogenation process.
摘要:
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.
摘要:
Process for the catalytic hydrogenation of methylolalkanals of the formula where R1 and R2 are each, independently of one another, a further methylol group or an alkyl group having from 1 to 22 carbon atoms or an aryl or aralkyl group having from 6 to 33 carbon atoms, in the liquid phase over a hydrogenation catalyst, wherein the pH of the hydrogenation feed is set to from 6.3 to 7.8 by addition of at least one tertiary amine.