Abstract: The invention concerns a method for producing esters of a hydroxy acid and a C1-C8 alcohol. The invention is characterized by the fact that the esterification is carried out by reactive distillation on a heterogeneous catalyst. The invention makes it possible in particular to produce high purity lactic acid esters in high yields.

Abstract: Process for the recovery of pure hydrocarbons from a hydrocarbon mixture, more particularly, a high aromatics content hydrocarbon mixture, by extractive distillation in an extractive distillation column. A first solvent feed for a first sub-flow of a selective solvent is provided between the top part of the column and the bottom part thereof. The selective solvent used is an N-substituted morpholine. Substantially non-aromatics are withdrawn as the raffinate from the head of the extractive distillation column and substantially aromatics and selective solvent are withdrawn as the extract from the sump of the extractive distillation column. A second sub-flow of the selective solvent is introduced via a second solvent feed in the top part of the column above the first solvent feed. The quantity of solvent supplied with the second sub-flow constitutes less than 50% of the total quantity of solvent.

Abstract: In the production of aromatic hydrocarbon from coking crude by-product benzene after a vaporization stage in which the crude benzene is evaporated to leave a residue, the crude benzene is subjected to pressure refining in the presence of hydrogen. The residue is distilled to form high and low boiling fractions and at least the gas pressure and temperature of the distillation stage is controlled so that the sump product apart from styrene is substantially free from aromatic hydrocarbons with less than 9 carbon atoms. The rate of withdrawal of the vaporization residue from the vaporizing column is controlled, depending upon the concentration of polymer formers in the crude benzene to be in the range of 6 to 40% of the rate of feed of the coking by-product benzene to the vaporizing column.

Abstract: The production of high purity benzene and high purity toluene is obtained by utilizing the initial gas separating column for the treatment of the aromatic containing starting material as a separating column for separating a benzene rich from a toluene rich component. The benzene rich component is subject directly to distillation while the toluene is subject to predistillation to separate high boiling components and only then to extractive distillation is distilled to separate the high purity benzene from the high purity toluene.

Abstract: The process for separating an aromatic from an entry hydrocarbon mixture also containing nonaromatics, by an extractive distillation method using an extractive distillation column with a selective solvent consisting essentially of an N-substituted Morpholine having substituents each of which contain no more than seven carbon atoms, includes distilling off the nonaromatics from the top of the extractive distillation column as a top product, drawing the aromatic and selective solvent from the extractive distillation column and subsequently separating the selective solvent from the aromatic in a separator column. The extractive distillation column is provided with an additional column portion for separation of a selective solvent residue from the separated nonaromatics without a separate top product distillation column.

Abstract: The method of obtaining a pure aromatic hydrocarbon from a hydrocarbon starting mixture includes extractively distilling the hydrocarbon starting mixture with a selective solvent; feeding the sump product of the extractive distillation through a first and second auxiliary boilers connected in series to form a cooled sump product at a temperature from 105.degree. to 120.degree. C.

Abstract: Process for obtaining a pure hydrocarbon from a starting material containing the hydrocarbon including performing an extractive distillation of the starting material containing the hydrocarbon in an extractive distillation column using a solvent comprising an N-substituted morpholine having substituents with no more than seven carbon atoms; feeding the sump product of the extractive distillation column into a distillation separator column at an entry point in a center portion of the distillation separator column; distilling off the hydrocarbon from the top of the distillation separator column but advantageously returning a minor portion of it as a reflux; drawing off solvent from the sump of the distillation separator column; feeding the solvent drawn off from the sump of the distillation separator column into an evaporator to form a vapor in the evaporator at the pressure, p.sub.2, the pressure p.sub.2 in the evaporator being lower than the pressure p.sub.

Abstract: A process for separating an aromatic from a mixture containing also nonaroma includes distilling off the nonaromatics from the top of the extractive distillation column as a top product, drawing the aromatic and selective solvent from the extractive distillation column and subsequently separating the selective solvent from the aromatic in a separator column. The extractive distillation column is provided with a separate top product distillation column for recovery of a selective solvent residue from the separated nonaromatics. The entry hydrocarbon mixture is heated prior to admission to the extractive distillation column by an indirect heat exchange with selective solvent drawn from the separator column and heated to a temperature of from 130.degree. to 150.degree. C.The heated entry hydrocarbon mixture is depressurized to form a liquid phase and a vapor phase and these phases are separately fed into the extractive distillation column, the vapor phase entry point being below the liquid phase entry point.

Abstract: A method of separation of aromates from hydrocarbon mixtures by extractive distillation with a selective solvent, includes introducing a hydrocarbon mixture into the extractive distillation column, distillating out non-aromate components of the introduced hydrocarbon mixture from a head of the extractive distillation column, withdrawing aromates together with a used solvent from a sump of the extractive distillation column and supplying to a driving-out column, separating the aromates from the solvent in the driving-out column, withdrawing the aromates as a head product and the solvent as a sump product from the driving-out column, reintroducing the withdrawn solvent into the extractive distillation column, the withdrawing of the solvent from the driving-out column including withdrawing only part of the solvent with a high temperature required for the complete aromate driving-out from the sump of the driving-out column, while a rest of the solvent with a certain aromate content and a lower temperature is with

Abstract: A simultaneous recovery of pure benzene and pure toluene is performed by extractive distillation with N-formylmorpholine and/or other N-substituted morpholines whose substituents contain not more than seven C-atoms as a solvent. From the entry product by predistillation, a benzene fraction boiling in the region between 75.degree. and 85.degree. C. and a toluene fraction boiling in the region between 99.degree. and 111.degree. C. is separated. The benzene fraction is supplied in the lower part, and the toluene fraction is supplied in the upper part of the extractive distillation column separated by a chimney plate into two parts.

Abstract: A stripping column installation especially for separating starting materials with a high boiling point difference comprises a stripping column having a withdrawal plate and a column sump, and a circulating boiler connected with the stripping column and having a pipe bundle through which a sump product from the stripping column flows. The circulating boiler has an upper plate and a separating wall which separates a space above the upper plate into two chambers. One of the chambers has a connection for receiving the sump product from the stripping column, while the other of the chambers has a connection for discharging the sump product after heating in the boiler.