Abstract: Inhibition of the formation of unsaturated carbon compounds during the heating of 141b involving the addition of various inhibitors such as butylene oxide and/or the use of a vessel made of a nickel alloy.

Abstract: 9,11- Diene C18 fatty acid cannot be separated from 10,12-Diene C18 fatty acid by conventional rectification because of the proximity of their boiling points. 9,11-Diene C18 fatty acid can be readily separated from 10,12-Diene fatty acid by azeotropic distillation. Effective agents are propyl formate, butyl ether, methyl pivalate and cyclopentanone.

Abstract: 3-Methyl-2-pentenal cannot be separated from 1-butanol by conventional rectification because of the proximity of their boiling points. 3-methyl-2-pentenal can be readily separated from n-butanol by azeotropic distillation. Effective agents are dimethoxymethane, petroleum ether and tetramethylortho-silicate.

Abstract: 2-Methyl-1-butanol and 3-methyl-1-butanol are difficult to separate from 1 pentanol by conventional distillation or rectification because of the proximity of their boiling points. 2-Methyl-1-butanol and 3-methyl-1-butanol can be easily separated from 1-pentanol by extractive distillation. Effective agents are 3-carene, propylene glycol phenyl ether and dimethylsulfoxide.

Abstract: Propylene oxide obtained by an epoxidation process which uses methanol as a solvent may be effectively treated to remove acetaldehyde by subjecting the crude epoxidation reaction product to fractional distillation. The methanol solvent is utilized during such distillation to lower the relative volatility of the acetaldehyde impurity, thereby making it possible to obtain a bottoms fraction containing substantially all the acetaldehyde. Purified propylene oxide having a reduced acetaldehyde concentration is removed as an overhead stream. Water may also be effectively separated from the propylene oxide using this procedure.

Abstract: Ethyl acetate cannot be separated from ethanol by distillation or rectification because of the closeness of their boiling points. Ethyl acetate is readily separated from ethanol by azeotropic distillation. Effective agents are ethyl ether, methyl formate and cyclohexane.

Abstract: Natural cresylic acid is processed to remove neutral oil impurities by countercurrent liquid/liquid extraction using a heavy phase solvent of a mixture of glycerol and another polyhydric alcohol, preferably triethylene glycol. The light phase solvent is a light paraffinic or cycloparaffinic hydrocarbon.

Abstract: A process for the purification of 1-chloro-1,2,2,2-tetrafluoroethane (F124) containing 1,2-dichlorotetrafluoroethane (F114) and/or 1,1-dichlorotetrafluoroethane (F114a). The F124 to be purified is subjected to extractive distillation, the extractant being chosen from C.sub.5 -C.sub.8 aliphatic or cycloaliphatic hydrocarbons and C.sub.4 -C.sub.8 perfluoroalkyl halides.

Abstract: 2-Methyl-1-propanol cannot be separated from t-amyl alcohol by distillation or rectification because of the closeness of their boiling points. 2-Methyl-1-propanol is readily separated from t-amyl alcohol by azeotropic distillation. Effective agents are butyl propionate, cyclohexane and 2,2-dimethoxypropane.

Abstract: t-Amyl alcohol cannot be separated from n-butanol by distillation or rectification because of the closeness of their boiling points. t-Amyl alcohol is readily separated from n-butanol by azeotropic distillation. Effective agents are propyl acetate, tetrahydrofuran and heptane.

Abstract: Acetone cannot be separated from a mixture of isopropanol and water because of the closeness of their boiling points. Acetone can be easily separated from isopropanol and water by extractive distillation. Effective extractive agents are 1-nitropropane, 3-carene, dimethylsulfoxide and 3-pentanone.

Abstract: A process for the separation of dimethyl ether and chloromethane in mixturesA process for the separation of dimethyl ether and chloromethane in mixtures by two distillation steps. In the first step, the mixture is subjected to an extractive distillation with water, aqueous salt solutions or organic liquids as extractant, the top product being chloromethane. In the second step, the dimethyl ether is separated from the extractant.

Abstract: A process for separating inorganic salts from a solution of dimethyl sulfoxide, water and salts including feeding the solution plus a hydrocarbon based oil to a vacuum thin film evaporator. The DMSO and water are vaporized and condensed outside the evaporator for reuse or further purification. The salt and oil exit the evaporator as a liquid phase slurry. Water is added to the slurry to dissolve the salt and produce an aqueous phase and an oil phase which are separated. The oil phase is recycled to the thin film evaporator portion of the process.

Abstract: 4-Methyl-2-pentanol cannot be separated from 3-methyl-1-butanol by distillation because of the closeness of their boiling points. 4-Methyl-2-pentanol can be easily separated from 3-methyl-1-butanol by extractive distillation. Effective agents are dodecane, dimethylformamide and dimethylsulfoxide.

Abstract: 3-Carene is difficult to separate from limonene by conventional distillation or rectification because of the proximity of their boiling points. 3-Carene can be readily separated from limonene by extractive distillation. Effective agents are o-cresol, 2,6-dimethyl-4-heptanone and triethylene glycol.

Abstract: A method for separating hexamethylcyclotrisiloxane that does not require the use of a distillation set up adapted for use with solids and that collects the hexamethylcyclotrisiloxane in the form of an easy-to-handle solution. The method comprising inducing the ascent in the gaseous state of a hexamethylcyclotrisiloxane-containing mixture of polydimethylcyclosiloxanes in a distillation column provided with a sidestream element in the middle region of the column so as to induce the ascent of gaseous hexamethylcyclotrisiloxane to at least the level of the sidestream element, supplying into said distillation column solvent having a boiling point below that of hexamethylcyclotrisiloxane and capable of dissolving hexamethylcyclotrisiloxane, so as to form a liquid mixture of hexamethylcyclotrisiloxane and said solvent in the vicinity of the sidestream element, and withdrawing the said liquid mixture from the sidestream element.

Abstract: Ethanol, isopropanol and water cannot be separated from each other by distillation or rectification because of minimum azeotropes. They are readily separated by extractive distillation. Effective agents are: dimethylsulfoxide for ethanol, phenol for isopropanol.

Abstract: 2-Butanol cannot be separated from isobutanol by distillation or rectification because of the closeness of their boiling points. 2-Butanol is readily separated from isobutanol by extractive distillation. Effective agents are propylene glycol propyl ether, 2-methoxyethanol and ethyl acetate.

Abstract: 4-Methyl-2-pentanol cannot be separated from 3-methyl-1-butanol by distillation because of the closeness of their boiling points. 4-Methyl-2-pentanol can be easily separated from 3-methyl-1-butanol by azeotropic distillation. Effective agents are m-xylene and cumene.

Abstract: 1-Propanol cannot be separated from t-amyl alcohol by distillation or rectification because of the closeness of their boiling points. 1-Propanol is readily separated from t-amyl alcohol by azeotropic distillation. Effective agents are heptane, ethyl acetate and tetrahydrofuran.

Abstract: 1-Propanol and t-amyl alcohol cannot be separated by distillation or rectification because of the closeness of their boiling points. 1-Propanol is readily separated from t-amyl alcohol by extractive distillation. Effective agents are dipentene, amyl acetate and 1,4-dioxane.

Abstract: 3-Methyl-1-butanol cannot be separated from 1-pentanol by distillation or rectification because of the closeness of their boiling points. 3-Methyl-1-butanol is readily separated from 1-pentanol by extractive distillation. Effective agents are butyl benzoate, 2-undecanone and diethylene glycol methyl ether.

Abstract: 3-Methyl-1-butanol cannot be separated from 1-pentanol by distillation or rectification because of the closeness of their boiling points. 3-Methyl-1-butanol is readily separated from 1-pentanol by azeotropic distillation. Effective agents are methylcyclohexane, methyl formate and tetrahydrofuran.

Abstract: Close boiling hydrocarbon impurities are separated from acetone by extractive distillation using a C.sub.9 -C.sub.14 alkane and/or a C.sub.8 -C.sub.12 aromatic hydrocarbon extractive distillation solvent.

Abstract: 2-Butanol cannot be separated from t-amyl alcohol by distillation or rectification because of the closeness of their boiling points. 2-Butanol is readily separated from t-amyl alcohol by azeotropic distillation. Effective agents are methyl acetate, ethyl propionate and octane.

Abstract: 2-Methyl-1-propanol is difficult to separate from 1-butanol by conventional distillation or rectification because of the proximity of their boiling points. 2-Methyl-1-propanol can be readily separated from 1-butanol by extractive distillation. Effective agents are ethyl benzene, amyl acetate and propoxypropanol.

Abstract: Butyraldehyde cannot be separated from ethanol by conventional distillation or rectification because they form a minimum boiling azeotrope. Butyraldehyde can be readily separated from ethanol by extractive distillation. Effective agents are 2-propanol, m-xylene and dimethylsulfoxide.

Abstract: The invention relates to an improved distillation method wherein hexamethylcyclotrisiloxane is isolated from a crude blend thereof by mixing the crude blend with a hydrocarbon co-solvent having a normal boiling point of 125.degree. C. to 150.degree. C. and distilling the resulting mixture in an apparatus having a reboiler, a fractionating column and a condenser, whereby deposition of solid hexamethylcyclotrisiloxane in the condenser is eliminated.

Abstract: 2-Methyl-1-butanol is impossible to separate from 3-methyl-l-butanol because they both boil at 130.degree. C. 2-Methyl-1-butanol can be readily separated from 3-methyl-1-butanol by extractive distillation. Effective agents are o-xylene, 3-carene and 1-methoxy-2-propanol.

Abstract: 2-Methyl-1-propanol is difficult to separate from 2-butanol by conventional distillation or rectification because of the proximity of their boiling points. 2-Methyl-1-propanol can be easily separated from 2-butanol by azeotropic distillation. Effective agents are sulfolane, acetonitrile and acetal.

Abstract: A polymerization inhibitor composition for inhibiting the polymerization of aromatic vinyl monomers at elevated temperatures comprising:(a) a benzofuroxan derivative of the formula ##STR1## wherein R is C.sub.1 -C.sub.4 alkyl or alkoxy; R.sup.1 is a nitro group; and m and n are each independently 0, 1, or 2; and(b) a solvent selected from the group consisting of toluene, xylene, ethylbenzene, vinyltoluene, divinylbenzene, alpha-methylstyrene, and a C.sub.12 -C.sub.18 hydrocarbon,and methods for inhibiting the polymerization of aromatic vinyl monomers at elevated temperatures using this composition.

Abstract: The polymerization of a vinyl aromatic monomer such as styrene is inhibited by the addition of a composition of a benzoquinone derivative and a hydroxylamine compound.

Abstract: 2-Methyl-1-propanol is difficult to separate from 2-methyl-1-butanol by conventional distillation or rectification because of the proximity of their boiling points. 2-Methyl-1-propanol can be readily separated from 2-methyl-1-butanol by azeotropic distillation. Effective agents are tetrahydrofuran, methyl acetate and toluene.

Abstract: 3-Carene and limonene cannot be separated from each other by rectification because of the closeness of their boiling points. They are readily separated by azeotropic distillation. Effective agents are: cyclopentanol, 2-nitropropane, ethyl formate amyl acetate dimethyl carbonate, tetrahydrofuran, acetic acid and 2-amino-amethyl-1-propanol.

Abstract: Butyraldehyde cannot be separated from ethanol by conventional distillation or rectification because they form a minimum boiling azeotrope. Butyraldehyde can be readily separated from ethanol by azeotropic distillation. Effective agents are ethyl formate, hexane and isopropyl ether.

Abstract: Azeotropic compositions made up of from about 64 to about 80% by weight of 1,1,1,4,4,4-hexafluorobutane and from about 20 to about 36% by weight of 2-methyl butane have been found to be particularly useful as blowing agents for the production of polyurethane foams.

Abstract: For the regeneration of a liquid desiccant, a stripping agent is used which is liquid at ambient temperature and pressure, and forms a heteroazeotrope with water, along with the following steps: (a) distillation of the water-laden liquid desiccant to form vapor and partially regenerated liquid desiccant; (b) reboil partially regenerated liquid desiccant; (c) stripping of partially regenerated liquid desiccant during (a) and (b), using vaporized stripping agent; (d) a condensing of vapor the exiting the distillation, the condensation producing two liquid phases, one mainly water and the other mainly stripping agent; (e) heating the stripping agent-rich liquid phase exiting step (d) to generate a vapor phase which is richer in water than said liquid phase and a water-depleted liquid phase; and (f) returning the vaporized liquid phase exiting step (e) to step (c).

Abstract: A purification process for cyclic formals, in which water is efficiently removed from a mixture of a cyclic formal and water which is difficult to be separated from the mixture, thereby obtaining a cyclic formal of high purity which contains only an extremely small amount of water.The purification process for cyclic formals is characterized by the steps of supplying a mixture of a cyclic formal and water into a distillation tower, effecting distillation while supplying n-pentane into the distillation tower and taking out a purified cyclic formal as a bottom liquid.

Abstract: 3-Methyl-2-butanol, 2-pentanol and 1-butanol are difficult to separate by conventional distillation or rectification because of the proximity of their boiling points. Mixtures of these three can be readily separated from each other by azeotropic distillation. Effective agents are hexyl acetate, hexane and 3-methyl pentane.

Abstract: Ethanol is difficult to separate from isopropanol by conventional distillation or rectification because of the proximity of their boiling points. Ethanol can be readily separated from isopropanol by extractive distillation. Effective agents are dipentene, anisole and ethyl benzene.

Abstract: Ethanol is difficult to separate from isopropanol by conventional distillation or rectification because of the proximity of their boiling points. Ethanol can be readily separated from isopropanol by azeotropic distillation. Effective agents are sec. butyl acetate, hexene-1 and 1,3-dioxolane.

Abstract: A distillation process for separating spent organic solvents such as trichloroethane or d-limonene from their contaminants such as oil is improved by the addition of a perfluorinated alkane or mixture of such alkanes to permit more efficient separation of the solvents from the oil.

Abstract: Propylene glycol is difficult to separate from ethylene glycol by conventional distillation or rectification because of the proximity of their boiling points. Propylene glycol can be readily separated from ethlene glycol by azeotropic distillation. Effective agens are m-diisopropyl benzene, 1-octene, 3-carene and myrcene.

Abstract: Propylene glycol is difficult to separate from 1,2-butanediol by conventional distillation or rectification because of the proximity of their boling points. Propylene glycol can be readily separated from 1,2-butanediol by azeotropic distillation. Effective agents are 2,2-dimethyl butane, 3-carene and diethyl benzene.

Abstract: Glycerine is difficult to separate from bis(hydroxymethyl)tetrahydrofuran by conventional distillation or rectification because of the proximity of their boiling points. Glycerine can be readily separated from bis(hydroxymethyl)tetrahydrofuran by azeotropic distillation. Effective agents are m-xylene, beta-pinene and dicyclopentadiene.

Abstract: 1-Butanol is difficult to semarate from 2-pentanol by conventional distillation or rectification because of the proximity of their boiling points. 1-Butanol can be readily separated from 2-pentanol by azeotropic distillation. Effective agents are 1-octene, hexane and methyl cyclohexane.

Abstract: 3-Methyl-2-butanol is difficult to separate from 1-butanol by conventional distillation or rectification because of the proximity of their boiling points. 3-Methyl-2-butanol can be readily separated from 1-butanol by extractive distillation. Effective agents are ethyl n-valerate, dimethylacetamide and dimethylsulfoxide.

Abstract: 3-Methyl-2-butanol is difficult to separate from 2-pentanol by conventional distillation or rectification because of the proximity of their boiling points. 3-Methyl-2-butanol can be readily separated from 2-pentanol by azeotropic distillation. Effective agents are pentane, 2,2-dimethyl butane and dioxane.

Abstract: 1-Butanol is difficult to separate from 2-pentanol by conventional distillation or rectification because of the proximity of their boiling points. 1-Butanol can be readily separated from 2-pentanol by extractive distillation. Effective agents are ethyl benzene, d-limonene and terpinolene.

Abstract: The present invention relates to a process for the preparation of tetrafluorophthalic acid and/or tetrafluorophthalic anhydride by reacting a compound of the formula ##STR1## in which X is a radical ##STR2## which is optionally mono- or polysubstituted on the aromatic nucleus by fluorine and/or chlorine and/or alkyl groups having 1 to 4 carbon atoms, or is a radical ##STR3## in which R.sub.1, R.sub.2 and R.sub.3 are as defined, with water, and subsequently removing the water still present by azeotropic distillation or extracting the tetrafluorophthalic acid and/or its anhydride with a water-insoluble solvent or solvent mixture.