Abstract: Separation and purification of hydroquinone from crude mixtures thereof essentially containing hydroquinone in combination with very small amounts of impurities including resorcinol and pyrogallol, include a topping distillation allowing the resorcinol to be removed as the distillation top product, and allowing a crude mixture essentially containing hydroquinone and the heavy impurities to be recovered at the column bottom, such mixture then being subjected to a bottoming distillation which allows the pyrogallol to be removed at the column bottom and allows hydroquinone in a purified form to be recovered at the column top.

Abstract: A process for preparing highly pure hydroquinone freed of the impurities resulting from the production thereof includes at least the following steps: a) the crude hydroquinone in a liquid form and comprising at least resorcin and pyrogallol as impurities is subjected to a controlled cooling ensuring the crystallization of pure hydroquinone, b) the pure hydroquinone crystals are separated from the mother liquors, c) heating and partial melting thereof is next is carried out, d) the purified hydroquinone is then completely melted, and e) the purified hydroquinone is recovered.

Abstract: Hydroquinone devoid of impurities is prepared from a crude hydroquinone essentially containing hydroquinone and small amounts of impurities including at least resorcinol, pyrogallol and traces of pyrocatechol and comprises at least the following steps: dissolving the crude hydroquinone in water, crystallizing the hydroquinone, separating the purified hydroquinone, and, optionally, drying the purified hydroquinone.

Abstract: Purified hydroquinone is prepared and formed from raw compounds essentially containing hydroquinone associated with very small quantities of impurities including resorcinol and pyrogallol, and includes a distillation purification step in which the resorcinol and pyrogallol are eliminated, directly followed by a step in which the purified hydroquinone is formed.

Abstract: A method and installation for separating and purifying a crude mixture containing hydroquinone, resorcinol and possibly tars and/or catechol, comprising the following steps: —a possible distillation stage (I) in order to obtain a catechol head, —the foot (I) or crude mixture undergoes distillation (II) in order to obtain a fraction that is rich in resorcinol, —the foot of (II) undergoes distillation (III) in order to obtain a fraction that is rich in hydroquinone, whereupon said rich fractions are refined (IV or V). Preferably, one or several stages in which tar is removed (I,I?) precede stage (I) or (II).

Abstract: The present invention provides a process for the production of two molecules of 4-aryl-2 butanols having the general formula 1 given below: Wherein R═H or glucose from the leaves of Taxus wallichiana, which comprises: (a) defatting air dried, pulverized leaves with aliphatic hydrocarbon solvents, (b) extracting the defatted leaves with chlorinated solvents and polar solvent successively at room temperature, (b) concentrating the chlorinated solvent soluble faction to a residue and treating the residue with aqueous solution of alkali and extracting with chlorinated solvents, (d) acidifying the alkali layer with mineral acid and extracting with ethyl acetate and concentrating the ethyl acetate phase to give compound of formula 1 where R═H, (e) concentrating the polar solvent fraction from step (b) to a residue and treating the residue with aqueous solution of alkali and extracting with chlorinated solvent, and (f) acidifying the alkali phase with mineral acid and extracting wit

Abstract: A process for the coextraction of para-cresol and meta-cresol from a feed mixture comprising p-cresol, o-cresol and m-cresol and one other alkyl phenol with an adsorbent comprising an X zeolite exchanged with barium ions or a mixture of barium and potassium ions at exchangeable sites to preferentially adsorb both para- and meta-cresol. The adsorbent must contain at least about 5 wt. % water (LOI method). The coextracted cresol isomers are thereafter removed from the adsorbent by contacting it with a desorbent material and recovering said coextracted cresols as a product stream. Para-cresol and meta-cresol can thereafter be recovered as purified individual isomers by a second state adsorptive separation using a second adsorbent selective for para-cresol, e.g., said first adsorbent dried to an LOI of less than about 4 wt. %, preferably about 2 wt. % water. In a preferred embodiment, the process uses a simulated moving-bed countercurrent flow system in both adsorption separation steps.

Abstract: Separate isomers via supercritical gas extraction.

Abstract: A method for simultaneously extracting and recovering 2,2-bis(4-hydroxy phenyl) propane and phenol from aqueous effluent streams by liquid-liquid extraction using toluene.

Abstract: A process is disclosed for separating 3,5-xylenol or 3,4-xylenol from other closely boiling polymethylated phenolics by treating a mixture of the phenolics with a metal halide salt. The metal halide salt preferentially forms a complex with the xylenol over other related phenolics in the mixture. The preferentially-formed complex of the xylenol may then be isolated from the mixture and the complex decomposed to provide a product substantially enriched in, or substantially entirely composed of the xylenol.

Abstract: A process for the preparation of pyrocatechol and hydroquinone by reaction of phenol with a peroxidic hydroxylating reagent followed by working-up of the resultant reaction mixture is disclosed. The work-up procedure is carried out in a first rectification column operated under specified conditions and having specified separation stages in a rectification section and a stripping section whereby there is distilled overhead components which boil at a temperature lower than phenol. Taken off from the bottom is a mixture comprising phenol and materials of higher boiling point which are fed into a second rectification column which is also operated under very specified conditions whereby pure phenol is recovered overhead leaving a bottoms comprising phenol pyrocatechol and hydroquinone which are then processed to separate phenol from a mixture of pyrocatechol and hydroquinone.

Abstract: A process for the isolation of hydroquinone, pyrocatechol, phenol and carboxylic acid from the reaction mixture containing the same such as one obtained by reaction of phenol with percarboxylic acid is disclosed. The reaction mixture is fed to a first rectification column and subjected to distillation whereby there is obtained a bottoms product containing pyrocatechol, hydroquinone and phenol. The top product is largely condensed and recycled, there being withdrawn from the top of the rectification column a mixture comprising phenol and carboxylic acid. The phenol and carboxylic acid mixture are continuously fed to a second rectification column where carboxylic acid is separated from phenol and substantially pure phenol is withdrawn from the stripping section and/or bottom of the second rectification column.

Abstract: A process is described for the isolation of pyrocatechol and hydroquinone from mixtures containing the same, and phenol and higher boiling accompanying substances. The mixture can be one obtained by reacting phenol with a peroxidic hydroxylating agent and removing some of the phenol and the substances which have a lower boiling point than phenol. The mixture is subjected to a first rectification in which phenol and substances which have a boiling point between phenol and pyrocatechol are obtained overhead to leave behind a bottom product containing pyrocatechol and hydroquinone. The bottom product is subjected to a second rectification in which the pyrocatechol is obtained overhead to leave behind a bottom product containing hydroquinone and higher boiling accompanying substances. This bottom product is fed to a concentrating unit in which hydroquinone is evaporated overhead to leave behind high boiling accompanying substances as residue.

Abstract: Effluent containing cresols such as are contained in Lurgi tar acids are separated by preferentially treating the cresols with an aqueous alkali metal carbonate or bicarbonate at elevated temperature for a time sufficient to form the alkali metal salt of at least part of the cresols, but not so long as to form any appreciable alkali metal salt of 2,6-xylenol or o-ethylphenol. The water soluble alkali metal salts of cresols are then separated from the water insoluble phenols and said salts acidified to "spring" the cresols and the water insoluble cresols separated from the aqueous solution.

Abstract: 2,6-xylenol admixed with meta,para-cresol is reacted with methanol in a contact with a titanium/SO.sub.4 /magnesium oxide catalyst to yield a product stream which can be readily distilled to give 2,6-xylenol in high purity. The particular catalyst used allows low loss of 2,6-xylenol during the reactions and low amounts of side products obtained.

Abstract: Phenol, ortho-cresol, meta- and para-cresols, guaiacol, vanillin, acetovanillone and other phenols are separated from alkaline pulping spent liquors by extracting the alkaline liquors with a lower aliphatic alcohol having from 2-5 carbon atoms inclusive, separating the solvent and aqueous phases, and thereafter separating the phenols from the solvent phase.

Abstract: An inclusion compound comprising meta-cyclophane of the formula ##STR1## and at least one benzene derivative included therein. And a process for separating an isomer containing a substituent at least at the 1- and 4-positions from a mixture containing isomers of a benzene derivative, which comprises contacting the meta-cyclophane with the mixture containing isomers of a benzene derivative thereby to form an inclusion compound in which an isomer containing a substituent at least at the 1- and 4-positions is included in the meta-cyclophane, then separating the inclusion compound from the mixture, and thereafter separating the isomer from the inclusion compound.