摘要:
Crude ammonia is separated into a low boiler fraction, a high boiler fraction and an intermediate-boiling pure fraction by continuous fractional distillation in a distillation apparatus configured either as a dividing wall column or as a system of thermally coupled distillation columns. In the process of the present invention, the low boiler fraction is taken off at the top of the distillation apparatus. The intermediate-boiling pure fraction is obtained at a side offtake which is preferably provided with droplet precipitators. In addition, the gas loading of the distillation column is restricted so that the operating pressure is in the range from 2 to 30 bar and the F factor does not exceed 2.0 Pa0.5.
摘要:
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).
摘要:
A method of distillation for separating a material which is solid at ambient temperature from a lower boiling and lower melting point material, and the apparatus.
摘要:
Apparatus and processes for continuous distillative separation of a mixture comprising one or more alkanolamine(s) are described. The separation is performed in one or more dividing wall column(s) and the alkanolamine or the alkanolamines is/are withdrawn as a side draw stream or side draw streams (side fraction(s)).
摘要:
What is described is a process for obtaining maleic anhydride by distillation from a solution of maleic anhydride in a high-boiling absorbent which has been obtained by gas phase oxidation of a hydrocarbon and at least partial absorption of the oxidation products into the absorbent, by i) introducing the solution into the side of a feed column with a rectifying section disposed above the feed point and a stripping section disposed below the feed point, ii) providing an upper combining column which communicates with the upper end of the rectifying section and a lower combining column which communicates with the lower end of the stripping section, iii) providing a draw column which communicates with the upper combining column and the lower combining column, iv) drawing maleic anhydride off as a side draw from the draw column, and drawing off compounds having a lower boiling point than maleic anhydride at the top of the upper combining column and the high-boiling absorbent at the bottom of the lower combining column. The maleic anhydride obtained as a side draw has a low content of acrylic acid and acetic acid.
摘要:
A process is described for continuously hydrogenating unsaturated compounds, in which particles of a first hydrogenation catalyst are suspended in a liquid phase in which an unsaturated compound is dissolved, the liquid phase, in the presence of a hydrogenous gas at a first partial hydrogen pressure and at a first temperature, is conducted through a packed bubble column reactor in cocurrent counter to the direction of gravity, the effluent from the bubble column reactor is sent to a gas-liquid separation, the liquid phase is sent to a crossfiltration to obtain a retentate and a filtrate, the retentate is recycled into the bubble column reactor and the filtrate, in the presence of a hydrogenous gas at a second partial hydrogen pressure and at a second temperature, is passed over a bed of a second hydrogenation catalyst, wherein the second partial hydrogen pressure is at least 10 bar higher than the first partial hydrogen pressure.
摘要:
The present invention provides a process for preventing fumaric acid deposits in the preparation of maleic anhydride, comprising the following steps:a) absorption of a C4-dicarboxylic acid or of a derivative from a crude product mixture into an organic solvent or water as an absorbent,b) removal of the C4-dicarboxylic acid or of a derivative from the absorbent,the absorbent thus recovered being catalytically hydrogenated fully or partly and recycled fully or partly into the absorption stage (a).
摘要:
A process is described for preparing tetrahydrogeranylacetone in which pseudoionone, geranylacetone and/or dihydrogeranylacetone in a liquid phase, in which particles of a catalyst which is capable of preferentially hydrogenating carbon-carbon double bonds over carbon-oxygen double bonds are suspended, is conducted through a device which inhibits the transport of the catalyst particles in the presence of a hydrogen-containing gas.
摘要翻译:描述了一种制备四氢ger anyl anyl A A is ger ger ger through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through through 在含氢气体的存在下抑制催化剂颗粒的输送的装置。
摘要:
The invention relates to a method for the separation of ascorbic acid from a mixture containing ascorbic acid and 2-keto-L-gulonic acid in a polar, preferably aqueous solvent, by means of liquid/liquid extraction using an amide. The method preferably also comprises steps for the back-extraction of the ascorbic acid, recycling of the extraction solvent and/or the back extraction solvent and for isolation of the ascorbic acid from the back extraction solvent. The invention further relates to a method for the production of ascorbic acid from KGA and isolation of the ascorbic acid so produced.
摘要:
The present invention relates to a process for the gas-phase hydrogenation of C4-dicarboxylic acids and/or their derivatives over a catalyst based on copper oxide to give substituted or unsubstituted &ggr;-butyrolactone and/or tetrahydrofuran, which comprises, which a first reaction zone in which the C4-dicarboxylic acid and/or its derivatives is/are reacted to give a mixture comprising a substituted or unsubstituted &ggr;-butyrolactone as main product and a subsequent second reaction zone in which the substituted or unsubstituted &ggr;-butyrolactone present in the mixture from the first hydrogenation step is reacted at a temperature lower than the temperature in the first hydrogenation step to give substituted or unsubstituted tetrahydrofuran.