Abstract: Polychlorinated phenols (e.g., pentachlorophenol) of improved color are made by vacuum distilling polychlorinated phenols containing dark color-forming impurities in the presence of a color inhibitor such as free radical-acting substances (e.g., free radical-acting compounds of the phenol, hydroquinone, organic sulfur derivative, organic phosphite, amine and aldehyde type). In addition, the chlorodioxin content of the impure pentachlorophenol (generally about) 2,000 p.p.m.) is reduced to a residual chlorodioxin content of less than 25 p.p.m. during distillation.

Abstract: A mixture of cresylic acids containing a substantial amount of 2,6-xylenol is contacted with an ester-forming phosphorus compound in an amount in the range of 0.5 to 5.0 equivalents per equivalent of cresylic acids other than 2,6-xylenol. The temperature is in the range of 50.degree.-250.degree. C., and a catalyst may or may not be employed. Under these conditions, aryl phosphates are formed more rapidly from the cresylic acids other than the 2,6-xylenol. The substantially unreacted 2,6-xylenol is readily separated from the aryl phosphates.

Abstract: A recovery method by means of which an antimony compound is separated from polyester still bottoms. If desired, the method can be employed so as to recover in usable form, the antimony compound, and the monomers polymerized to produce the polyester.

Abstract: A process for separating lower-boiling chlorohydrocarbons and water from neutralized crude chlorohydrocarbons having at least two carbon atoms, which comprises fractionally distilling the crude chlorohydrocarbons in a fractionating column, thereby obtaining a fraction A containing the desired product which is withdrawn at the bottom of the column practically free of impurities, and a fraction B, comprising water, impurities having a lower boiling point, and entrained amounts of the desired chlorohydrocarbon, withdrawing said fraction B from the top of the column and, while still in gaseous state, neutralizing fraction B with an aqueous solution of a mixture of basic compounds, thereby avoiding corrosion of the apparatus, and thereafter subjecting the gaseous fraction to stepwise condensation with recovery of the entrained portions of said chlorohydrocarbon by returning them to the fractionating column, while separately removing water and undesirable impurities.

Abstract: Ultra high purity hexachlorocyclopentadiene is obtained by a two-stage distillation procedure, in the first stage of which crude hexachlorocyclopentadiene is distilled to separate hexachlorobutadiene as a distillate and in the second stage, ultra high purity hexachlorocyclopentadiene is obtained as a distillate fraction and octachlorocyclopentene is obtained as a distillation residue.

Abstract: Process for the purification of adiponitrile containing chloride impurities by contacting said adiponitrile with a high boiling amine and recovering the purified adiponitrile containing lower amounts of chloride impurities.

Abstract: In the purification of impure titanium tetrachloride comprising adding an agent to said titanium tetrachloride and thereafter distilling off purified titanium tetrachloride while leaving the impurity in the distillation residue, the improvement which comprises employing as said agent at least one amine of the formula ##EQU1## in which R.sub.1 and R.sub.2 each independently is hydrogen, alkyl or alkenyl of up to 6 carbon atoms, cycloalkyl of 5 to 7 carbon atoms, or aryl, andR.sub.3 is cycloalkyl of 5 to 7 ring carbon atoms, or aryl, orR.sub.2 together with R.sub.3 is butylene, pentylene or hexylene, in which eventR.sub.1 is hydrogen, alkyl of up to 6 carbon atoms or aryl.The preferred agents are aniline, cyclohexylamine, N,N-dimethyl-aniline, diphenylamine, 2,3-dimethyl-aniline and 2,6-dimethyl-aniline. The process serves to remove vanadium impurities.

Abstract: A method of inhibiting the thermopolymerization of isoprene or butadiene in the process of isolation thereof by extractive distillation from a mixture of hydrocarbons obtained in dehydrogenation of isopentane and butane. The method of inhibiting includes, prior to the introduction of said mixture of hydrocarbons and a polar extractant into an extractive distillation metal apparatus, treating the surface of the apparatus with a 1-25% aqueous solution of passivators, viz. nitrites, sulphites or phosphates of alkali metals at a temperature of 20.degree.-100.degree.C. The mixture of hydrocarbons and the polar extractant with an inhibitor of isoprene or butadiene thermopolymerization introduced into the polar extractant are then fed into said apparatus in an amount of 0.01-1% of the extractant weight. The present method makes it possible to reduce markedly the formation of isoprene and butadiene and, hence, to prevent the plugging of the extractive distillation apparatuses with the aforementioned thermopolymers.

Abstract: Adiponitrile is separated from impurities of boiling point close to that of adiponitrile, especially 5-cyanovaleric acid and 2-cyanocyclopenten-(1)-ylamine, by reacting the impurities with a primary or secondary amine to give compounds of higher boiling point and then fractionally distilling to separate the adiponitrile.

Abstract: Process for removing hydrochloric acid and other impurities which are contained in vinyl chloride monomer, by treatment in a distillation zone, comprising the addition to crude vinyl chloride, in the course of distillation thereof, of at least one alcohol selected from the group of C.sub.4 to C.sub.10 tertiary aliphatic alcohols and C.sub.3 to C.sub.10 primary or secondary alcohols with unsaturation in the alpha position, and rectifying the vinyl chloride monomer from the resulting mixture.

Abstract: Substantial capital and operating cost savings and improved recovery of acrylonitrile and methacrylonitrile are realized by the recycle of the product column bottoms to the quench liquid of the reactor effluent quench system.