Abstract: Crude diphenyl phthalates, including isomeric mixtures thereof which are prepared by reacting mixtures of isophthalic and terephthalic acids with phenol, preferably in the presence of an organotitanate, organozirconate, or organostannate catalyst, are purified by dissolving the crude phthalate in an organic solvent, contacting the resulting solution with dilute aqueous alkali to neutralize the ester, separating the resulting oil and aqueous phases, and thereafter recovering from the oil phase a purified diaryl phthalate of reduced color and low acidity.

Abstract: The new esters derived from a chiral compound containing two OH groups and at least one mesogenic carboxylic acid which have the general formula (I) ##STR1## in which X.sup.1 =O--H or O--CO--(C.sub.1 to C.sub.12)alkyl and X.sup.2 =O--MC or X.sup.1 and X.sup.2 denote O-MC independently of each other, where MC is the molecular radical of a mesogenic monocarboxylic acid after splitting off an OH group.The esters or esters substituted in the aromatic part of the phenolic part preferably find application as an admixture intwistable liquid crystal phases in which they produce a temperature compensation and a high degree of twisting.

Abstract: Color properties of crude phenolic esters of aromatic dicarboxylic acids are improved by subjecting the esters to hydrogenation in the presence of hydrogen and a hydrogenation catalyst.

Abstract: Disclosed is a process for producing dimethyl or novel diphenyl derivatives of stilbenedicarboxylic acids from dimethyl toluates or diphenyl toluates and sulfur. The reaction requires an excess of toluate to sulfur of at least about 5:1. In addition hydrogen sulfide is removed from the reaction zone.

Abstract: Color properties of crude phenolic esters of aromatic dicarboxylic acids are improved by distilling the esters in the presence of a boron oxide compound.

Abstract: Color properties of crude phenolic esters of aromatic dicarboxylic acids are improved by comminuting the ester to a finely divided particle size in the presence of an aqueous or alcoholic alkali solution and thereafter distilling the esters to obtain phenolic esters of reduced color.

Abstract: A method of recovering useful components at least containing dimethyl terephthalate from high-boiling byproducts occurring in the production of dimethyl terephthalate, which comprises oxidizing p-xylene and/or methyl p-toluate with a molecular oxygen-containing gas in the presence of a heavy metal oxidation catalyst, subjecting the resulting oxidation product to esterification with methanol, separating dimethyl terephthalate and esters having lower boiling points than dimethyl terephthalate from the esterification reaction product by distillation, and thereafter treating the distillation residue containing byproducts having higher boiling points than dimethyl terephthalate with methanol to recover at least dimethyl terephthalate from the treated product; wherein the treatment of the distillation residue with methanol is carried out at a temperature of 110.degree. to 240.degree. C. under a pressure sufficient to maintain methanol in the liquid phase.

Abstract: Bis(2-ethyl-1-hexyl) tetrabromophthalate produced by the reaction of tetrabromophthalic anhydride with 2-ethyl-1-hexanol in the presence of titanium isopropoxide catalyst may be purified by contacting the reaction mixture with sodium carbonate decahydrate with agitation for a time and at a temperature sufficient to enhance product quality, followed by isolation of bis(2-ethyl-1-hexyl) tetrabromophthalate.

Abstract: A block of dimethylterephthalate having a needle-like crystal structure. The block is easily cleavable, and has a reduced tendency to fuse to other blocks when subjected to bag-stacking pressure.

Abstract: A method of collecting pyromellitic anhydride, which comprises introducing a high-temperature gas containing pyromellitic anhydride together with an inert cooling gas into an empty column-type collecting device whose wall temperature is maintained at 150.degree. to 200.degree. C., effecting heat exchange between the high-temperature gas and the cooling gas in the collecting device to lower the temperature of the high-temperature gas to 150.degree. to 200.degree. C., thereafter passing the gaseous mixture through the collecting device at an average linear gas velocity of 0.05 to 0.5 m/sec with an average residence time to 5 to 60 seconds, and recovering needle-like crystals of pyromellitic anhydride from the bottom of the collecting device.

Abstract: A process for improving the rate of crystallization of a diphenylisophthalate/diphenylterephthalate monomer. The process comprises dissolving the monomer in an organic solvent, filtering the solution to remove impurities, and crystallizing the monomer to remove impurities. The precipitated monomer is then separated from the solvent by a centrifuge and dried. The monomer has a desired crystal size of about 2 mm. The process also is more efficient in that it reduces scaling inside the reactor system.

Abstract: The invention relates to a process for separating dimethyl isophthalate (DMI) and dimethyl orthophthalate (DMO) and other by-products from their mixture with dimethyl terephthalate (DMT), formed in the oxidation of p-xylene followed by esterification with methanol, by crystallization from the melt.Initially, the esterification product is here distilled once or several times. The DMT-rich fraction obtained is then subjected wholly or partially to one or several crystallizations from the melt, and the DMI-DMO fraction thus obtained is at least partially removed from the system. As an alternative, the DMT-rich fraction is first recrystallized from methanol, the methanol is then evaporated from the mother liquor and the remaining residue is subjected to one or several crystallizations from the melt. The DMI-DMO fraction thus obtained is again at least partially removed from the system.

Abstract: There is disclosed a process for the reduction of the diether impurities formed when a dihydroxy aromatic compound is reacted with an alkylating agent in an alcoholic solvent in the presence of two to three equivalents of base. The diether impurities are removed by removing a quantity of the alcoholic solvent and adding a solvent into which the diether impurities may be extracted.

Abstract: Disclosed is a highly efficient continuous method for the aqueous extraction of water-soluble oxidation catalyst material from a residue such as that generated in the production of dimethyl terephthalate from p-xylene by the molecular oxygen oxidation and methanol esterification process. In the method the desired end product is an aqueous solution of the catalyst material. The residue to be extracted is established in finely dispersed condition in part of the aqueous solution at a weight ratio of aqueous solution to residue of above about 1:1 and maintained in that condition for a length of time sufficient for maximum transfer of catalyst material from the residue to the aqueous solution to take place. The resulting dispersion then is separated in a phase separation zone into an aqueous phase and an extracted residue phase. The separated aqueous phase is withdrawn from the phase separation zone as the aqueous solution.

Abstract: A general method of resolution of chiral alcohols is based on the relatively facile chromatographic resolution of their diastereomeric esters with optically active amino acids. The naturally occurring L-amino acids and D-(-)-phenylglycine are especially useful, and the method is applicable to a range of alcohols of diverse structure.

Abstract: A process for preparing esters which comprises reacting a polycarboxylic acid with an excess of alcohol and in the presence of an organotitanate catalyst, treating the crude mixture with a suitable chelate compound, removing the unreacted alcohol and hydrolyzing the treated titanium catalyst residues with steam, and recovering the purified ester by filtration.

Abstract: A process for the recovery and reuse of heavy metal oxidation catalyst from residues in the Witten DMT process by extraction, which involves mixing and settling of the residue with water or dilute aqueous solutions of water-soluble, low-molecular, aliphatic monocarboxylic acids at 70.degree.-160.degree. C. and recycling of the extract of the high-boiling distillation residues into the DMT process. The high-boiling distillation residue and the extractant are used in a quantitative ratio of 1:0.9 to 1:0.1, preferably 1:0.5 to 1:0.3.

Abstract: Hydroxyl terminated reactive liquid polymers are prepared by reacting ethylene oxide, in presence of an amine catalyst, with a carboxyl terminated reactive liquid polymer serum which contains, in addition to the carboxyl terminated liquid polymer, a solvent, an initiator, other reaction products formed during the reaction, and any unreacted reactants; adding a strong acid to form water-soluble amine salts; water-washing; coagulating; separating; drying; and recovering a shelf stable product.

Abstract: A process for the recovery and reuse of a heavy-metal oxidation catalyst solution from a high-boiling distillation residue having a cobalt content of 1-10 g/kg of residue is disclosed. The distillation residue is obtained in the production of dimethyl terephthalate by the oxidation of mixtures containing p-xylene and/or methyl p-toluate in the liquid phase with oxygen or an oxygen-containing gas under an elevated pressure and at an elevated temperature in the presence of dissolved heavy-metal oxidation catalyst, by subsequent esterification of the oxidation product with methanol and by a distillatory separation of the esterification product into a fraction rich in methyl p-toluate, a fraction rich in dimethyl terephthalate, and the high-boiling distillation residue.

Abstract: Disclosed is an improvement in a method for the recovery for recycle to the cooxidation-coesterification process for the production of dimethyl terephthalate from p-xylene, air and methanol of oxidation catalyst by aqueous extraction of a distillation residue containing the same. To minimize recycle of any iron present in the residue, iron oxidant material (for example, hydrogen peroxide) is admixed in one embodiment with the residue and water in the aqueous extraction procedure, and in a second embodiment with the resulting aqueous extract. In both embodiments, if any iron is present, it is precipitated. In the first embodiment the precipitate stays with the residue. In the second embodiment the aqueous extract is separated from the precipitate.

Abstract: Preparation of a fluorocarbon compound used to make a soil-resistant yarn is improved by removing most of the impurities from the fluoro-carbon compound mass with heat and vacuum after the final washing step and then adding an emulsifier to the fluorocarbon compound mass so that the mass can be handled as a liquid concentrate rather than a tacky solid.

Abstract: In a process for purifying an ester with little contamination by catalytic metal components in a high yield which comprises treating an esterification reaction mixture with a basic substance, said esterification reaction mixture being obtained by reacting an organic carboxylic acid or its anhydride with an alcohol in the presence of an organometallic compound as an esterification catalyst, and purifying the product in a manner known per se; the improvement wherein prior to said treatment with the basic substance, water is added to the esterification reaction mixture and the mixture is heated.

Abstract: A method for producing plasticizers which contain titanium in only a very small amount is provided. According to this method, the amount of waste water is very small. This method comprises reacting phthalic anhydride with an alcohol having 4-18 carbon atoms in the presence of, as a catalyst, a tetraalkyl titanate or a polymer thereof, and has a feature in the treatment of the resultant ester with a solid alkali and adsorbing agent(s) in the absence of water.

Abstract: There is provided an improved continuous homogeneous catalytic carbonylation process wherein a mixed gas stream is removed from the carbonylation reactor, condensable liquids separated from said gas stream and said gas stream vented, the improvement comprising contacting said gas stream with a plurality of hollow fiber membranes selectively permeable to hydrogen under conditions substantially non-degrading of the membranes to generate a non-permeated gas stream of higher carbon monoxide content and recycling said non-permeated gas stream to the carbonylation process reactor. There is also provided for the recovery and recycle to the process of carbonylation products such as acetic or propionic acids by adsorption and removal from a solid adsorbent or absorption in a liquid absorbent.

Abstract: A continuous process for the preparation in at least one esterification reactor of phthalate diesters utilizing phthalic acid or anhydride and a stoichiometric excess of at least one saturated aliphatic alcohol containing about 4 to about 10 carbon atoms comprises (a) reaction of phthalic acid or anhydride with said alcohol in a reactor zone, (b) purification of the diester in a purification zone in which the reaction product is neutralized with an alkali metal hydroxide, i.e., sodium hydroxide, to separate the diester and the unreacted phthalic acid or anhydride together with said saturated alcohol utilized in the reaction, said reaction product is separated into an organic phase and an aqueous waste phase.

Abstract: Disclosed is a process for recovering dimethyl terephthalate and intermediate products from the tarry fraction of the residue generated in the production of dimethyl terephthalate from p-xylene and methanol by the cooxidation procedure. In the process the tarry fraction is established in admixture with a catalytic quantity of alkali metal material, examples of which are sodium and potassium carbonate, at about 200.degree.-350.degree. C., and the resulting reaction mixture is maintained in this temperature range until at least a substantial quantity of dimethyl terephthalate has formed. Generally, dimethyl terephthalate and intermediate products are separated from the reaction mixture. The separation in preferred embodiments is by distillation.

Abstract: A process for preparing esters which comprises reacting a polycarboxylic acid with an alcohol, removing the unreacted alcohol from the resultant esterification reaction mixture, heating the crude ester at a temperature of 160.degree. to 340.degree. C., contacting the heat-treated crude ester with an adsorbent, and recovering the ester of high purity. The ester obtained has superior electrical insulation, transparency and thermal stability.

Abstract: A process is disclosed for converting a bis-(diol) terephthalate to dimethyl terephthalate, by interchange in a methanol medium in the presence of magnesium methylate as catalyst. In this way dimethyl terephthalate may be regenerated from scrap of polyterephthalate or copolyterephthalate filaments or films, for the purpose of manufacturing fresh polyterephthalates or copolyterephthalates which can then be used for the manufacture of, for example, filaments or films.

Abstract: A process for producing dimethyl terephthalate from high-boiling tarry residues from the combined oxidation of p-xylene and p-toluate in the liquid phase, esterification of the resulting acids with methanol and separation of the resulting dimethyl terephthalate which include the steps of subjecting the high-boiling residues to treatment with methanol at temperatures above 250.degree. C. and thereafter separating the resulting dimethyl terephthalate in accordance with conventional separation techniques.

Abstract: A process for mass transfer between heterogeneous systems or phases in a vertical exchange column having at least one plate, a heavier stream of matter being introduced above the plate and, a lighter stream of matter being introduced countercurrently thereto from the bottom of the plate, wherein (a) a heavier stream of matter fed from the top is deflected, above the plate, into a mixing zone in which the heavier stream undergoes vertical rotary movement and is mixed with a lighter stream of matter passing from below through a first passgeway of the plate and introduced into the mixing zone to also undergo vertical rotary movement, (b) a heavier phase, suspension, or the like fluid-like mass forming in the mixing zone during the mass transfer therein is accumulated in a zone superjacent to a second passageway of the plate; and (c) after a sufficient pressure gradient has been built up, the accumulated mass flows as another heavier stream through the second passageway into a space underneath the plate and is at

Abstract: A method is provided for the removal of contaminating alkanes from the vaporized carbonylation products of a process wherein carboxylic acids are produced by the reaction in the liquid phase of an alcohol or an ester, halide or ether derivative of said alcohol with carbon monoxide in the presence of a catalyst system containing a rhodium or iridium component and an iodine or bromine component. The method involves distillation of the alkane-containing vaporized carbonylation products, phase separation of the overhead from said distillation, further distillation of a slipstream of the resulting heavy phase using carbon monoxide as stripping gas and removal of the alkanes as the bottoms stream from the latter distillation.

Abstract: In the process for preparing dimethyl terephthalate by oxydizing p-xylene and/or methyl p-toluate with molecular oxygen or a molecular oxygen-containing gas in the presence of a heavy metal catalyst, esterifying the resulting oxidation reaction mixture with methanol, followed by submitting the resulting esterification reaction mixture to distillation to separate dimethyl terephthalate and fractions of lower boiling point than dimethyl terephthalate, and thereafter recycling to said oxidation step (A) the distillation residue containing said heavy metal catalyst and/or (B) the extract portion containing said heavy metal catalyst obtained by further extraction treatment of said distillation residue (A), the improvement which comprises contact-treating said distillation residue (A) or said extract portion (B) with methanol prior to recycling same.

Abstract: A process for the production of dimethyl terephthalate and intermediate products of the dimethyl terephthalate manufacture from the high-boiling by-products obtained during the air oxidation of p-xylene and methyl p-toluate in the liquid phase, subsequent esterification of the thus-formed acids, and separation of the thus-produced esters, which comprises treating said high-boiling by-products with methanol at an elevated temperature and then separating the resultant product rich in dimethyl terephthalate by distillation with the addition of a carrier gas or a carrier vapor.

Abstract: Recovery of ethylene terephthalate polymer from waste material is accomplished by glycolysis of the polyester to form bis-(2-hydroxyethyl)terephthalate for repolymerization. Formation of objectionable diethylene glycol is inhibited when glycolysis is accomplished by heating the polyester in a reaction mixture with bis-(2-hydroxyethyl)terephthalate, ethylene glycol and sodium acetate trihydrate, and water is introduced continuously into the reaction mixture during depolymerization of the polyester.

Abstract: Disclosed is a process for the catalytic hydrogenation of the aldehyde content of molten aldehydic dimethyl terephthalate (DMT). The process comprises first dissolving in the molten aldehydic DMT a quantity of molecular hydrogen sufficient to hydrogenate at least a substantial portion of the aldehydic content, and then contacting the molten aldehydic DMT with its dissolved hydrogen content with a hydrogenation catalyst for a period of time sufficient for reaction of the dissolved hydrogen with the aldehydic content to take place, but insufficient for substantial ring hydrogenation to occur.

Abstract: A process for removing organic components from the waste water effluent obtained in the production of an ester plasticizer through esterification of a polybasic aliphatic or aromatic carboxylic acid with an aliphatic alcohol in the presence of a sulfuric acid catalyst, which waste water contains an alkyl hydrogen sulfate or a dialkyl sulfate, esterification reactants and esterification products, which comprises:A. heating said waste water to a temperature above 200.degree. C under the particular prevailing pressure; andB. thereafter thermally or mechanically removing an organic phase from an aqueous phase.

Abstract: The instant invention relates to a continuous process for the hydrolytic degradation of plastics wherein a hydrolyzable material is introduced with water into a screw machine, and is subjected therein to a temperature of 100 to 300.degree. C, and a pressure of 5 to 100 bars for 2 to 100 minutes. The invention also relates to an apparatus useful in conducting the process.

Abstract: In a method of obtaining purified 2,6-naphthalenedicarboxylic acid dimethyl ester by vacuum distilling crude 2,6-naphthalenedicarboxylic acid dimethyl ester under conditions of application of heat, the improvement which comprises vacuum distilling a crude 2,6-naphthalenedicarboxylic acid dimethyl ester having an acid value (A.sub.f), as expressed in milligrams of KOH required for neutralizing the carboxyl groups contained in one gram of said crude 2,6-naphthalenedicarboxylic acid dimethyl ester, of from 1.0 to 50.