Abstract: Anhydrous, stable, crystalline .delta.-form of prazosin hydrochloride, having an infrared spectrum in potassium bromide of FIG. 1 having the following sharp absorption bands at 7.95.mu., 13.3.mu., and a triplet at 9.95.mu. and the x-ray diffractogram of FIG. 2 having sharp bands in 10.5.degree., 12.0.degree., 16.9.degree., and doublets in 24.5.degree. and 26.5.degree.. The .delta.-form of prazosin hydrochloride is prepared by removing the water of crystallization of prazosin hydrochloride hydrate by azeotropic distillation with selected organic solvents having a boiling point in the range of 55.degree.-160.degree. C. The .delta.-form of prazosin hydrochlorie is useful as a hypotensive agent.

Abstract: There is disclosed an improved process for the manufacture of glyoxylic acid obtained by oxidation of glycolic acid. For processing purposes alkyl esters of these acids are employed. Increased efficiency is obtained by recovering glycolate rich streams from one or more distillation operations and after treatment to remove acetic acid by-product the streams are recycled to the oxidation reaction.

Abstract: An improved process for separating high purity alkyl glyoxylate from complex mixtures containing alkyl glyoxylate, alkyl glycolate, water, alcohol and miscellaneous impurities by an azeotropic distillation operation using an azeotroping agent selected from the group consisting of methylene dichloride, 1,1,1--trichloroethane, and benzene.

Abstract: A process for recovering brominated acenaphthylene and its condensate in the form of powder, comprising dropping a solution of brominated acenaphthylene and its condensate produced from acenaphthene by reactions of bromination, condensation and dehydrobromination into hot water containing a carboxylic acid ester of polyoxyalkylene sorbitan, while the solvent is being distilled off, to recover the brominated acenaphthylene and its condensate in the form of powder dispersed in water.

Abstract: A process for extracting pure components from a multi-component system, said system comprising a mixture of at least two solids or liquids in a supercritical fluid at constant pressure, which involves making use of the cross-over pressure points of the components which comprise the system.

Abstract: A process for extracting poly-beta-hydroxybutyrates from an aqueous suspension of microorganisms, in which an azeotropic distillation, and an extraction of the polymer by means of the solvent used, are carried out simultaneously.The poly-beta-hydroxybutyrates obtained can be used in medicine.

Abstract: The production of solutions of hydrogen peroxide in phenol or its derivatives, e.g. hydrocarbyl substituted phenols, halo substituted phenols or phenol ethers, is carried out in a single step. Practically no loss of hydrogen peroxide occurs since a total distillation of hydrogen peroxide together with phenol or phenol derivative is avoided. Simultaneously the solutions obtained are practically free from water. The mixture of phenol or phenol derivative and aqueous hydrogen peroxide is treated with a material that boils below the boiling point of hydrogen peroxide, phenol or phenol derivative or forms an azeotrope with water that boils below the boiling point of hydrogen peroxide, phenol or phenol derivative and the water removed as an azeotrope. The solution of hydrogen peroxide in phenol or phenol derivative which remains behind is suitable for carrying out oxidation reactions and above all, also for hydroxylation reactions.

Abstract: m-Xylene is difficult to separate from o-xylene by conventional distillation or rectification because of the close proximity of their boiling points. m-Xylene can be readily separated from o-xylene by using extractive distillation in which the extractive agent is a mixture polychloro aromatic compounds. Typical examples of effective agents are 2,3,4,6-tetrachlorophenol and p-dichlorobenzene; dimethyltetrachloroterephthalate, 2,3,4,6-tetrachlorophenol and 1,2,4,5-tetrachlorobenzene; 2,4,5-trichlorophenol, benzene hexachloride, o-dichlorobenzene and dioctyl phthalate.

Abstract: Diethoxymethane (ethylal), prepared by reacting formaldehyde with ethanol, may be recovered from the product mixture in substantially pure form by first distilling off an azeotrope comprising ethanol and diethoxymethane, adding a selected solvent to the azeotrope which will form an azeotrope with the ethanol, distilling off said latter azeotrope and recovering the substantially pure diethoxymethane.

Abstract: A process for decolorizing polyethylene polyamines using a chlorinated hydrocarbon. The discolored polyethylene polyamine and chlorinated hydrocarbon are contacted to form a decolorizing mixture, and the mixture is distilled. The decolored polyethylene polyamine is collected from the distillate.

Abstract: Improvement in an azeotropic distillation process, the improvement being the use of an entrainer characterized in that it is an organic compound in which one or more hydrogen atoms are replaced by halogen atoms, including at least one fluorine atom; it is miscible, under process conditions, with the organic compound being dehydrated; its volatility is sufficiently close to the volatility of the organic compound being dehydrated such that, under the process conditions, it forms an azeotrope with the organic compound; it is less miscible, under process conditions, with water than is the corresponding organic compound in which the halogen atoms are replaced with hydrogen atoms; and it is chemically stable under the process conditions.

Abstract: Hydrogen chloride is recovered from a mixture with propylene by extractive distillation with an inert extraction solvent to minimize reaction between hydrogen chloride and propylene during such distillation. The temperature and pressure conditions are coordinated with the extraction solvent and amount thereof to prevent the presence of hydrogen chloride in a liquid state. The process is particularly suitable for recovering hydrogen chloride in the production of allyl chloride by thermal chlorination of propylene.

Abstract: Phenol containing MBF impurity is distilled in the presence of water and an extraction solvent for MBF (preferably AMS and/or cumene) to recover a phenol bottoms having reduced impurities. The use of solvent permits a reduction in the amount of water used, which reduces the amount of phenol in the overhead, thereby lowering costs.

Abstract: An improvement of a method for purifying 1,2-dichloroethane by passing through a distillation column a crude 1,2-dichloroethane produced by oxychlorination of ethylene with at least one of a crude 1,2-dichloroethane produced by direct chlorination of ethylene and a crude uncracked 1,2-dichloroethane recovered in thermal cracking of 1,2-dichloroethane, the improvement which comprises feeding the oxychlorination-produced 1,2-dichloroethane to an upper plate of the distillation column which is above a plate of the column to which at least one of the direct chlorination-produced 1,2-dichloroethane and the uncracked 1,2-dichloroethane is fed, and recovering 1,2-dichloroethane as a bottom product. The purification method is very useful in the production of vinyl chloride by thermal cracking of 1,2-dichloroethane since carbon tetrachloride effective as a thermal cracking catalyst is recovered in concentrations stabilized within the range of .+-.500 p.p.m.

Abstract: A process for the decomposition of complexes of ortho-benzoyl benzoic acids, hydrogen fluoride, and boron trifluoride, whether or not the ortho-benzoyl benzoic acid is substituted, is disclosed wherein the ortho-benzoyl benzoic acid is obtained separately from the hydrogen fluoride and boron trifluoride. This process is characterized in that the complex is treated with an inert solvent at a temperature of at least 20.degree. C., in a distillation column having at least about 8 theoretical plates whereby the solvent reflux is operated at a rate equal to about 5 to about 40 times the weight of the feed delivery rate of the column.The process of the present invention also makes it possible to recover hydrogen fluoride and boron trifluoride for reuse as catalysts in the synthesis of ortho-benzoyl benzoic acid without causing decomposition of the acid.

Abstract: Quaternary azeotropic mixtures of 1,1,2-trichloro-1,2,2-trifluoroethane, methylene chloride, methanol and cyclopentane are provided. These azeotropic mixtures are useful as solvents to remove buffing compounds residues. These mixtures are useful not only because of their high solvency characteristics but also because they exhibit essentially the constant boiling characteristics of an azeotrope which is formed between these components, thereby facilitating handling and purification of the solvent mixtures without significantly altering their compositions. [The quaternary mixtures disclosed herein exhibit certain advantageous solvency characteristics of glycol based compositions, over the known binary or ternary azeotropic systems containing 1,1,2-trichloro-1,2,2-trifluoroethane, methylene chloride, methanol and cyclopentane.

Abstract: The fractionation of the methanol- or ethanol-containing methyl-(or ethyl)-tertiary-butyl ether reactor effluent is improved by employing 2-methylpentane to azeotrope methanol or ethanol overhead, or by using 1,1,3-trichloro-1,2,2-trifluoroethane (F113) to azeotrope methanol overhead, leaving a substantially pure MTBE or ETBE bottoms.

Abstract: Ethylene oxide is extracted from aqueous solutions by carbon dioxide under (near) super-critical conditions and thereafter recovered by distillation at sub-critical conditions. Improved distillation is obtained by adding to the carbon dixoide a gas (or gases) which adjust the critical temperature of the gas mixture of the top of the distillation column within the range of about 32.degree. C. to about 75.degree. C. Preferred gases are the saturated hydrocarbons, particularly propane, n-butane, isobutane and pentane.

Abstract: A process has been developed for the purification of expoxides containing carbonyl compounds as impurities wherein the carbonyl compound content is up to 2% by weight of epoxide. Purification is effected by treatment with compounds containing at least one NH.sub.2 group.

Abstract: Toluene is virtually impossible to separate from similar boiling non-aromatic hydrocarbons by conventional rectification or distillation. Toluene can be readily separated from similar boiling non-aromatic hydrocarbons by using extractive distillation in which the extractive agent is a mixture of phthalic anhydride and/or maleic anhydride plus a suitable solvent. A typical mixture comprises phthalic anhydride, maleic anhydride and glycerol triacetate.

Abstract: The separation of mixtures of hexafluoropropylene oxide and hexafluoropropylene is effected by extractive distillation in the presence of methylene chloride, whereby an excellent separating effect is achieved at a low energy consumption.

Abstract: A process for the recovery of carboxylic acids from mixtures containing glycol esters derived from these acids. The process comprises reacting these mixtures at boiling with water to form carboxylic acid and entraining the carboxylic acid formed by means of the water by azeotropic distillation, so as to separate off a mixture of carboxylic acid and water. This mixture is subjected to extractive distillation by means of an organic solvent which is insoluble in water and in which water is insoluble. A mixture of water and organic solvent is thereby separated from a solution of carboxylic acid in the organic solvent.

Abstract: An improvement of a method for purifying 1,2-dichloroethane by passing through a distillation column a crude 1,2-dichloroethane produced by oxychlorination of ethylene with at least one of a crude 1,2-dichloroethane produced by direct chlorination of ethylene and a crude uncracked 1,2-dichloroethane recovered in thermal cracking of 1,2-dichloroethane, the improvement which comprises feeding the oxychlorination-produced 1,2-dichloroethane to an upper plate of the distillation column than a plate of the column to which at least one of the direct chlorination-produced 1,2-dichloroethane and the uncracked 1,2-dichloroethane is fed, and recovering 1,2-dichloroethane as a bottom product.

Abstract: The invention involves a process for substantially separating the components of mixtures of substances at least one of which is of low volatility while the other is of low or no volatility, the process using a compressed gas under supercritical conditions and an entrainer which increases the concentration of said mixture in the gaseous phase as well as the separation factor between the components to be separated. The process operates in two distillation zones the first of which substantially separates the components of low volatility in a process similar to a rectification process while the second distillation zone separates the top product of the first distillation zone from the gas with the aid of the entrainer which is condensed partially and in this state is passed in countercurrent to the gas carrying the separated component of low volatility.

Abstract: In a process for the continuous preparation of pure organic solutions of percarboxylic acids having 2 to 5 carbon atoms, by(a) contacting aqueous hydrogen peroxide with a carboxylic acid containing 2 to 5 carbon atoms in the presence of an acid catalyst at a feed molar ratio of H.sub.2 O.sub.2 to carboxylic acid of 0.

Abstract: Ethylene dichloride is separated from unsaturated organic impurities such as trichloroethylene and benzene by extractive distillation in the presence of a high boiling chloroalkene solvent, such as perchloroethylene.

Abstract: A process for separating phenol from a mixture of the same with cresol which comprises including in the mixture a component which has a dipole moment of 0 to 0.5 Debye and has a boiling point, under 1 bar, in the temperature range from 120.degree. to 220.degree. C. or which has a dipole moment of 0.5 to 2.5 Debyes and has a boiling point, under 1 bar, in the temperature range from 150.degree. to 190.degree. C. and distilling off phenol together with said component to leave behind said cresol.

Abstract: A process for completing the esterification of aliphatic carboxylic acids of 1 to 8 carbon atoms with aliphatic or cycloaliphatic alcohols of 3 to 10 carbon atoms at the boiling point of the alcohol in a column operated with bottom heating, the lower space of the column being free from fitments, the middle space being provided with a packing and the upper space being provided with a packing or other fitments, in which process the water of esterification is driven off at the top of the column by azeotropic distillation, the starting mixture is fed into the side of the column from 5 to 10 m above the liquid level, the ester formed is taken off as liquid from the column bottom, and the column is operated with flooding such that the liquid level is from 6 to 10 m, with the liquid mixture filling the lower column space, which is free from fitments, and the lower part of the packed layer above the said space.

Abstract: A novel nonazeotropic mixture containing R-22 and either R-124 or R-152a. This mixture has an improved efficiency in cooling and heating applications. Also provided is a method for producing refrigeration and a method for producing heating using this mixture.

Abstract: Ethylbenzene and para-xylene and/or meta-xylene are difficult to separate by distillation because they boil only 2.3 C..degree. and 3.1 C..degree. apart. Ethylbenzene can be readily separated from the xylenes by using extractive distillation in which the extractive distillation agent is a mixture of pentachlorophenol admixed with certain chlorinated and/or oxygenated organic compounds boiling higher than the xylenes. A typical mixture comprises pentachlorophenol, benzene hexachloride and 1,2,4-trichlorobenzene.

Abstract: An azeotropic distillation is conducted by feeding a part of an entrainer to the lower region of an azeotropic zone in a distillation column.

Abstract: Dimethyl carbonate is obtained pure, from its solutions in methanol, by extractive distillation carried out with a temperature of from 60.degree. C. at the top to 250.degree. C. at the bottom of the column and employing, as the extractant, an aprotic organic liquid which is substantially inert toward dimethyl carbonate, boils at above 100.degree. C. at standard pressure, is miscible with dimethyl carbonate in all proportions and has a dielectric constant .epsilon. of from 4 to 90 and a dipole moment .mu. of from 1.5 to 5 Debye.

Abstract: Carbon tetrachloride and chloroform are separated as a light fraction from ethylene dichloride by distilling the ethylene dichloride under reflux conditions to maintain a chloroform concentration greater than 51.5 mole percent in the reflux liquid.

Abstract: A method for stabilizing acetylene against explosive decomposition comprising mixing together with the acetylene a chemical free radical scavenging agent chosen from the group consisting of nitric oxide, hydrogen chloride, hydrogen bromine, hydrogen iodide and vinyl bromine as well as mixtures thereof.

Abstract: Disclosed is a process for the distillation of readily polymerizable vinyl aromatic compounds which comprises subjecting such compounds to distillation conditions in the presence of an effective amount of a 4-halo-3,5-dinitrotoluene as a polymerization inhibitor.

Abstract: The relative volatility of cis-1,4-dichlorobutene-2 to trans-1,4-dichlorobutene-2 is increased when these two isomers are fractionated in the presence of 3,4-dichlorobutene-1.

Abstract: 1,1,1,3,3,3-Hexafluoroisopropyl trifluoroacetate is separated from a crude reaction mixture by adding fluorotrichloromethane to said mixture and subjecting the resulting composition to fractional distillation to fractionally distill an azeotrope consisting of said 1,1,1,3,3,3-hexafluoroisopropyl trifluoroacetate and said fluorotrichloromethane from the crude mixture.

Abstract: Constant boiling binary admixtures are formed by 1,2-dichloro-1,1,2-trifluoroethane with trichlorofluoromethane, with diethyl ether, and with dichloromethane. A constant boiling ternary admixture is formed by 1,2-dichloro-1,1,2-trifluoroethane, diethyl ether, and 1,2-dibromo-1,1,2,2-tetrafluoroethane.

Abstract: The present invention relates to the recovery of N,N-dimethylacetamide from a mixture containing N,N-dimethylacetamide and acetic acid. Potassium hydroxide is added to the mixture to neutralize the acetic acid and form potassium acetate having a low solubility in N,N-dimethylacetamide and a high affinity for water. The water concentration is adjusted to a desired range and a water non-solvent such as benzene is added to effect separation of an aqueous solution of potassium acetate from the dimethylacetamide as two distinct phases. The phases are then separated and the dimethylacetamide removed from the solvent phase by distillation.

Abstract: A method for removing antimicrobials such as pentachlorophenol from waste water by liquid-liquid extraction with a water immiscible organic liquid in a packed column; recovering the antimicrobial from the organic phase by distillation if desired; and, treating of the aqueous phase to remove residual antimicrobial and organic liquid. The process of the present invention recovers about 99 percent of the antimicrobial pentachlorophenol in the waste water producing a waste water containing less than 30 ppm pentachlorophenol and less than about 2 percent organic liquid, both of which may be removed by conventional carbon absorption or soil percolation to acceptable ecological levels for introduction into a stream or reuse as process water.