Abstract: The purification of N-substituted aminobenzaldehydes, such as p-dimethylaminobenzaldehyde, is facilitated via the use of stripping agents.

Abstract: The distillation of 2,2'bis(4-aminocyclohexyl)propane to yield high purity product is effectively carried out using high boiling organic solvents.

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: Process for dehydrating aliphatic alcohols admixed with water wherein the alcohols-water mixture is subjected to a first fractionation in the presence of a selective solvent, giving a vapor effluent containing dehydrated light alcohols and a liquid phase containing heavy alcohols, water and the selective solvent, said liquid phase being subjected to a second fractionation giving as vapor effluent an hetero-azeotropic mixture of water and heavy alcohols and, as liquid effluent, the selective solvent, which is fed back, said hetero-azeotropic mixture being condensed and separated into:(a) a light phase of high alcohol content which is subjected to a third fractionation giving a vapor effluent which is fed back and dehydrated heavy alcohols as liquid effluent, and(b) a heavy phase which is subjected to a fourth fractionation giving a vapor effluent which is fed back and water as liquid effluent.

Abstract: In a process for producing a 2-hydroxyalkyl acrylate or methacrylate which comprises esterifying acrylic or methacrylic acid with an alkylene oxide having 2 to 4 carbon atoms in the presence of an esterification catalyst and distilling the resulting reaction mixture in a distillation column, the improvement wherein the vapor of the ester monomer from the distillation column, while being maintained in the superheated state, is introduced into a condenser of the gas-liquid direct contact type whose inner wall corresponding to its gas inlet portion is kept at a temperature below the boiling point of the ester at the operating pressure, to contact it directly with a concurrently flowing spray liquid of the ester-precooled to a temperature below the boiling point of the ester at the operating pressure, whereby said vapor is condensed to a liquid at said temperature below the boiling point of the ester at the operating pressure.

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: A process for the treatment of heavy products resulting from the manufacture of light hydrocarbons. The heavy products are subjected to steam distillation in the presence of a water-soluble surface-active agent.

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: A process of recovering an n-hexane product which is free from aromatic compounds by extractive distillation from a mixture of aromatic and non-aromatic compounds. The mixture is fed to and distilled in a first distillation column, from which a benzene-containing sump product and the overhead product consisting of non-aromatic compounds are withdrawn. The distillate is laterally withdrawn above the feeding point of the feed mixture and transferred to the upper portion of a second distillation column. The hexane cut is withdrawn as sump product from the second distillation column and fed to an extractive distillation column approximately in the middle thereof and is extracted in the extractive distillation column with a selective solvent which is fed above the feeding point of the hexane cut consisting of the sump product of the second distillation column. The sump product containing the selective solvent is withdrawn from the extractive distillation column and the overhead thereof vapors are condensed.

Abstract: The formaldehyde hydrazone of UDMH can be removed from an aqueous solution f UDMH by codistillation with a hydrocarbon or other solvent which is inert to both acidic or basis mediums. The solvent can then be recovered from the hydrazone solution by washing with an acid solution and the solvent can be reused.

Abstract: A multi-stage process for the solvent extraction of isoprene or cyclopentadiene from a mixed feed stock containing the same, piperylene and C-5 saturated and olefinic hydrocarbons is disclosed wherein the feed stock is contacted with N-formyl morpholine and C-5 saturated and olefinic hydrocarbons are separated therefrom in a first stage, the solvent, piperylene and cyclopentadiene present in the feed stock are separated from the isoprene in a second stage, and the solvent is recovered and recycled to the second stage.

Abstract: The present invention provides a process for purifying an organic isocyanate which comprises heating an organic isocyanate in admixture with a treating agent selected from the group consisting of a metal salt of mercaptobenzothiazol, a dithiocarbamic acid derivative, an alkyl-substituted phenol, a thio-bisphenol, and a triaryl phosphite at a temperature not lower than 100.degree. C and subsequently distilling the thusly treated mixture to recover a purified organic isocyanate.

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 combination of phenothiazine and a phenolic compound, preferably tert-butylcatechol (TBC), as a polymerization inhibitor system in the presence of oxygen.

Abstract: Waste water resulting from the production of acrylonitrile by gas phase oxidation of propylene and ammonia with oxygen as washing water in the recovery section is purified by treating the waste water with 0.4 to 1 ton of steam per ton of waste water in a detoxification column attached to or following the separation column (for the separation of acetonitrile and acrylonitrile from the waste water in the acrylonitrile process) at a temperature from 100.degree. to 125.degree. C, at a pressure of 0 to 2 (gauge) atmospheres; separating the non-volatile resinous organic compounds from the thus treated waste water in an evaporator and using the vapors from the top of said evaporator to heat the said separation column and detoxification column; and optionally adding an organic amine to said distillation column or to said evaporator.

Abstract: A process is provided for the removal of water from a mixture of ethylene diamine and water and for the preparation of ethylene diamine having a water content below the azeotropic equilibrium water content between ethylene diamine and water, by distilling the mixture in the presence of a distillation adjuvant comprising one or more compounds selected from the group consisting of piperazine, diethylene, triamine, hydroxethyl ethylene diamine, and aminoethyl piperazine. The adjuvant can be removed later if desired.

Abstract: Dioxane is produced by reaction of ethylene glycol or a polyethylene glycol using an acid catalyst. The reaction product containing dioxane, water and byproducts is subjected to extractive distillation with a high-boiling agent which is miscible with water.

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: 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 a mixture of N-nitroso diphenyl amine and a dinitro-O-cresol.

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 a process for reacting an aromatic or hydroaromatic alicyclic or heterocyclic dicarboxylic acid or its anhydride with an aliphatic or aromatic alicyclic or heterocyclic mono- or di-amine to produce an N-substituted dicarboxylic acid imide with a splitting off of water, the improvement of carrying out the reaction in a liquid solvent mixture consisting essentially of a non-polar organic solvent and a strongly polar organic solvent which together form a ternary azeotrope with water at reaction temperatures between about 40.degree.C. and 160.degree.C. The imide products are generally known for use as intermediates and final products in a number of industries.

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.