Abstract: Process for purifying hexamethyldisiloxane contaminated with toluene or other solvents that cannot be completely separated from the hexamethyldisiloxane by distillation, based on the discovery that hexamethyldisiloxane forms a previously unknown azeotrope with acetonitrile. This azeotrope has a heavier phase that is rich in acetonitrile and a lighter phase that is rich in hexamethyldisiloxane. These phases are mutually immiscible. The azeotrope starts to boil at 71.4.degree. C., which permits the hexamethyldisiloxane to be separated at relatively low temperatures from the impurities. The process involves one or more entrainment distillations in the presence of an excess of acetonitrile and the re-separation of the acetonitrile from the resulting lighter phase by distillation. Two further novel azeotropic systems, one consisting of hexamethyldisiloxane and toluene and the other of acetonitrile and toluene, are provided.

Abstract: This invention relates to a process for working up the distillation residue obtained in the commercial production of tolylene diisocyanate by grinding, optionally accompanied and/or followed by chemical modification reactions. The finely divided powder obtained may be used as a reactive filler in the production of a variety of plastics.

Abstract: Indene is separated from close boiling, olefinically unsaturated alkylaromatic compounds by extractive distillation. For example, indene is separated from trans-.beta.-methylstyrene, and from 2-, 3- and 4-methylstyrene by extractive distillation using 1-methyl-2-pyrrolidone as the extracting agent.

Abstract: The separation of butadiene-1,3 from other C-4 hydrocarbons of lesser degree of unsaturation by extractive distillation with alkoxynitrile or aqueous alkoxynitrile as selective solvent is carried out with improved selectivity, without appreciable formation of butadiene-1,3 polymer and with consequent savings in energy by adding to the alkoxynitrile or aqueous alkoxynitrile an organic cosolvent which is dimethyl sulfoxide, sulfolane, butyrolactone, N-methyl pyrrolidone, morpholine, or trimethyl phosphate and/or an inhibitor which is 2,4-dinitrophenol or 2,4-dinitro-ortho-cresol. The organic cosolvent is present in the selective solvent composition in an amount of 5 to 30 percent by weight and the inhibitor in an amount of 0.05 to 0.6 percent by weight.

Abstract: Formation of butadiene-1,3 polymer during the extractive distillation of a C-4 hydrocarbon mixture to separate and purify butadiene-1,3 using a solvent composition in which an alkoxynitrile is present in a proportion of 50-99 percent by weight, is decreased through inclusion in the solvent of a synergistic combination of 2,4-dinitrophenol and phosphoric acid, each in a proportion of 0.05 to 0.5 percent by weight.

Abstract: A method of inhibiting the polymerization of styrene which comprises mixing with the styrene a minor but effective quantity of an inhibitor compound selected from the group consisting of 2-methylbenzoquinone-4-oxime, 2,3,5-trimethylbenzoquinone-4-oxime and mixtures thereof.

Abstract: An improved process for the manufacture of levulinic acid which comprises esterification of furfuryl alcohol in the presence of a different alcohol selected from unsubstituted primary and secondary carbon-chain or carbon-ring alcohols containing 1 to 10 carbon atoms in the presence of a small amount of acid as a catalyst, purification of the resulting levulinate ester by vacuum distillation of a mixture of the levulinate ester and a high boiling solvent and hydrolysis of the purified levulinate ester in the presence of water and a small amount of strong acid catalyst to yield levulinic acid-water mixture. The improvement resides in the purification being carried out prior to hydrolysis and in using a high boiling solvent in the purification step to prevent the formation of a solid resin.

Abstract: A method is disclosed for inhibiting the polymerization of acrylic and methacrylic acids at ambient or above ambient temperature, such as during preparation, purification or storage of the acids under substantially anaerobic conditions, by adding thereto a polymerization inhibiting amount of a compound having the formula:R--NOwhere R is alkyl or aryl, and if R is aryl, a hydroxyl group para to the NO group enhances inhibition.

Abstract: The separation of acrylic acid from a mixture of acrylic acid and acetic acid found in the reaction product stream obtained in the process of producing acrylic acid by the oxidation of propylene or acrolein is improved by removing a vapor sidestream from the solvent recovery column found in the process. Acetic acid is then separated from this stream without the addition of external heat.

Abstract: A method for the partial or total separation by extractive distillation of C.sub.1 to C.sub.3 clorinated aliphatic hydrocarbons from mixtures of at least two such chlorinated hydrocarbons. The mixture of the chlorinated hydrocarbons is distilled in the presence of one or more other organic compounds having a boiling temperature higher than the substances to be separated, and selected from the group comprising saturated polyols, ethylene carbonate, propylene carbonate, dimethyl formamide, furfural, N-methylpyrrolidone, cyclohexanone, dimethylsulfoxide and, preferably, sulfolane and alkylsulfolanes in which the alkyl group is C.sub.1 or C.sub.2 ; use of this method for the separation of mixtures containing or essentially consisting of trichlorethylene and 1,2-dichloroethane.

Abstract: A process is provided for increasing the rate of solar evaporation of water from alkaline trona-process waste liquors which comprises introducing to the waste liquors an effective amount of a dye selected from the group consisting of Acid Black 2 and Acid Green 1, and subjecting said waste liquors to solar radiation for evaporation of water therefrom.

Abstract: Copper is processed via solutions of copper salts, both cupric and cuprous, in acidified aqueous solutions containing organic nitriles. Methods of producting solutions of cuprous salts include reduction of cupric salts and oxidation of copper and copper sulphides. Solutions of cuprous salts are thermally or electrochemically disproportionated to produce copper and solutions of cupric salts.

Abstract: A method is disclosed for stabilizing vinylbenzyl chloride and vinyltoluene against violent decomposition in the presence of iron and chlorine at ambient and above ambient temperatures which comprises contacting the vinylbenzyl chloride or vinyltoluene with an amount of a Lewis base sufficient to inhibit the decomposition during the preparation, purification or storage of said vinylbenzyl chloride or vinyltoluene.

Abstract: A mixture of methylethylsulfone and at least one compound from the group including methylethylketone, acetone, and tetrahydrofuran is employed as a selective solvent in extractive distillation process for separation of diolefins from olefins.

Abstract: Butadiene is produced in relatively pure form by an oxidative dehydrogenation process in which a crude butadiene stream comprising butadiene, butylenes, vinyl acetylene and propylene is first extractively distilled with an extractant consisting of a sulfolane/acetone mixture. From a purified stream consisting essentially of butadiene and vinyl acetylene, the vinyl acetylene in a second extractive distillation step is removed using a sulfolane/acetone mixture as the extractant to produce a pure butadiene stream.

Abstract: Disclosed is a process for the distillation of readily polymerizable vinyl aromatic compounds and a new polymerization inhibitor therefor. The process comprises subjecting a vinyl aromatic compound to distillation conditions in a distillation system and adding to the system the new polymerization inhibitor comprising an adduct of nitric oxide and styrene.

Abstract: A method of partially or totally separating chlorinated aliphatic C.sub.1 to C.sub.3 hydrocarbons from mixtures of at least two of the chlorinated hydrocarbons by extractive distillation.The mixture of the chlorinated hydrocarbons is distilled in the presence of one or more third organic compounds having a boiling point higher than that of the substances to be separated, selected from the group comprising methyl, ethyl, normal propyl and isopropyl mono and di-chloroacetates; benzyl alcohol; salicylaldehyde, benzaldehyde, n-heptanal, methylisobutylketone, tetramethylurea, .gamma.-butyrolactone; normal propyl, isopropyl, normal, secondary and tertiary butyl acetylacetates; diethyl oxalate, dimethyl succinate and preferably methyl and ethyl acetylacetates; acetic anhydride, N-formyl-morpholine, 2-chloro ethanol, hexamethylphosphotriamide, dimethyl sulphate and normal tributyl and triisobutyl phosphates.

Abstract: Hydrocarbons having different degrees of saturation are separated by extractive distillation using selective solvent comprising a mixture of dimethylsulfone, methylethylketone and sulfolane.

Abstract: N-lower alkyl lactam solvent is recovered from a solution of polymer such as PVC residue in such solvent by adding to the solution a plasticizer for the polymer and then recovering the lactam from the solution by distillation. The plasticizer has a boiling point of at least about 25.degree. C above the boiling point of the lactam solvent. A stabilizer for the polymer may also be used.

Abstract: The present invention relates to the use of quinone alkides as polymerization inhibitors in a styrene purification process. The inhibitors are prepared by oxidizing hindered phenols to the corresponding quinone alkide.

Abstract: Methods of reducing aqueous solutions of cupric sulfate to cuprous solutions by using organic nitrile compositions are disclosed. The particular nitrile used is acetonitrile and the reductant is sulphur dioxide. The method has application commercially to leaching ores containing oxidised copper to obtain cuprous ion solutions. Such solutions can be treated by electrochemical or thermal disproportionation methods to obtain very pure copper.

Abstract: A process is disclosed for distilling corrosive carboxylic acids free of olefinic unsaturation in distillation apparatus constructed of corrodible metal, which includes the steps of introducing a crude dilute solution of such a corrosive acid into the distillation zone, distilling in the presence of an effective amount of p-benzoquinone or of 1,4-naphthoquinone, and recovering the concentrated corrosive acid outside the distillation zone. The amount of p-benzoquinone or of 1,4-naphthoquinone is such as to effectively prevent or reduce to acceptable limits the corrosion of the metal distillation apparatus by such acids, and also to permit this distillation process to be effectuated at those high acid vapor temperatures which otherwise would not be feasible because of the heightened degree of corrosiveness exhibited by the acids at such temperatures.

Abstract: Method of preparing cuprous sulfate and bisulfate solutions from materials containing copper and impurities by a leaching process are disclosed. The leaching composition contains sulfuric acid, cupric ions, water and an organic nitrile. The leaching composition may be used with copper sulfide ores in particulate form. The cuprous solutions resulting from the leaching can be treated by disproportionation methods to recover pure copper.

Abstract: Process for the manufacture of succinic anhydride by eliminating water from succinic acid using a chemically inert hydrophilic solvent which does not form an azeotropic mixture with water, and fractional distillation.