Abstract: A method for separating carboxylic acids from mixtures with non-acids by an extractive distillation method using a lactam with a 5- or 6-membered ring, preferably N-methyl-2-pyrrolidone, as an extractant to extract the acids from the mixture with non-acids, followed by separating the extracted acids from the extractant by rectification.

Abstract: In extracting object material from its aqueous solution by using an organic solvent, a mixer-settler extractor is employed as the extractor and operated while a solvent dispersion is maintained in the mixer, and part of the aqueous phase discharged from the settler is recycled to the mixer so that the organic solvent phase in the mixer is stably maintained as the disperse phase.

Abstract: A process to recover acrylic acid or methacrylic acid by using a split quench process which allows acrylic acid or methacrylic acid to be recovered from the resulting aqueous solutions by a combination of solvent extraction and azeotropic dehydration that minimizes the amount of solvent required.

Abstract: A catalyst composition useful for the oxidation of unsaturated aldehydes, particularly the oxidation of methacrolein to produce methacrylic acid, comprises the combination of oxides of molybdenum, copper, phosphorus, antimony, and cesium and/or calcium and optionally may include one or more of the elements Ni, Zn, Ru, Rh, Pd, Pt, As, K, Rb, Sr, Ba, Cr, V, Nb, W, Mn, Re, and rare earth metals including La.

Abstract: A process for isolating methacrylic acid by solvent extraction from an aqueous methacrylic acid solution obtained from a gas phase catalytic oxidation reaction, characterized in that the aqueous methacrylic acid solution is previously first contacted with an extraction solvent, polymers precipitated out from the aqueous methacrylic acid solution are removed and the remainder is fed into an extraction column.

Abstract: A catalyst composition useful for the oxidation of unsaturated aldehydes, particularly the oxidation of methacrolein to produce methacrylic acid, comprises the combination of oxides of molybdenum, copper, phosphorus, antimony, cesium and rhenium in predetermined relative atomic ratios.

Abstract: An oxidation catalyst wherein the catalytically active component has the general formulaMo.sub.12 P.sub.a Rh.sub.b Cu.sub.c V.sub.d Cs.sub.e X.sub.f Y.sub.g Z.sub.h O.sub.x,where X is Cr and/or Fe, Y is Nb, Z is Na, Li, K and/or Rb, a is 0.1-4, b is 0.001-1, c is 0.05-2, d is 0.05-4, e is 0.1-5, f is 0-2, g is 0-3 and h is 0-2, and x is the number of oxygen atoms required to saturate the valencies of the other constituents, is very suitable for the preparation of methacrylic acid by gas phase oxidation of methacrolein with an oxygen-containing and steam-containing gas mixture.

Abstract: The present invention provides an improvement in methods for preparing and processing readily polymerizable acrylate monomers. The improvement comprises employing phenyl-para-benzoquinone, 2,5-di-phenyl-para-benzoquinone, and mixtures thereof as process inhibitors. The process inhibitors are present in a concentration of about 50 to 3000 ppm, preferably about 250 to 2000 ppm, and most preferably about 500 ppm.

Abstract: The acid conversion of certain precursors, e.g. .gamma.-vinyl-.gamma.-butyrolactone, to sorbic acid is improved by presence of copper or silver ions along with the acid.

Abstract: A catalyst composition useful for the oxidation of unsaturated aldehydes, particularly the oxidation of methacrolein to produce methacrylic acid, comprises the combination of oxides of molybdenum, copper, phosphorus, antimony, and cesium in predetermined relative atomic ratios.

Abstract: Disclosed is a method of preparing alpha-beta and beta-gamma unsaturated monocarboxylic acids having electron withdrawing, electrophilic substituents at the site of unsaturation. The acids are prepared by reacting metal salts of the unsaturated acids with strong mineral acids under substantially anhydrous conditions.

Abstract: A process of removing unsaturated hydrocarbons containing at least one non-aromatic unsaturation from feedstreams which comprises contacting the feedstream with at least one of Cu.sub.2 O or Ag.sub.2 O and a fluorinated acetylacetonate of the formula ##STR1## where R.sup.1 is C.sub.1 -C.sub.6 fluoroalkyl, C.sub.1 -C.sub.8 alkyl, C.sub.4 -C.sub.6 heterocycle containing O, S or N or C.sub.6 -C.sub.10 aryl, R.sup.2 is H or C.sub.1 -C.sub.6 alkyl with the proviso that R.sup.1 and R.sup.2 together with the carbons to which they are attached may be joined together to form a C.sub.6 ring and n is from 1 to 8, in an inert organic solvent.

Abstract: In the production of acrylic acid by a two-stage, vapor-phase catalytic oxidation of propylene, a composite oxide catalyst expressed by the formula Mo.sub.a Bi.sub.b Ni.sub.c Co.sub.d Fe.sub.e Na.sub.f Mn.sub.g B.sub.h K.sub.i Si.sub.j O.sub.x is used in the first-stage reaction, which is carried out under specific reaction and operational conditions, and the second-stage reaction is carried under specific reaction and operational conditions while oxygen is supplied by a specific mode.

Abstract: Carbonyl impurities in acrylic acid are removed by reacting them with a 1,2-glycol prior to distillation. The acetal-type products remain as heavies in the distillation bottoms.

Abstract: In the process for oxidizing methacrolein to a methacrylic acid salt with an oxidizing gas in a strongly alkaline medium at a temperature of 0 to 100.degree. C. and in the presence of a finely divided silver catalyst and recovering methacrylic acid by acidification, the improvement which comprises carrying out said oxidation in the presence of a small amount of dissolved alkali metal carbonate.

Abstract: A process for recovering carboxylic acids with a material of which the main component is a polymeric compound having a pyridine skeletal structure and a crosslinked structure, followed by desorbing the captured carboxylic acids by use of a desorbing agent.

Abstract: A catalyst composition useful for the oxidation of unsaturated aldehydes, particularly the oxidation of methacrolein to produce methacrylic acid, comprises the combination of oxides of molybdenum, copper, phosphorus, antimony, and calcium in predetermined relative atomic ratios.

Abstract: In a process for producing acrylic acid which comprises contacting with water an acrylic acid-containing reaction product gas which has been obtained by the catalytic vapor phase oxidation of an olefinic compound of a general formula, CH.sub.2 .dbd.CHX, wherein X represents at least one group selected from the group consisting of CH.sub.

Abstract: A catalyst composition useful for the oxidation of unsaturated aldehydes, particularly the oxidation of methacrolein to produce methacrylic acid, comprises the combination of oxides of molybdenum, copper, phosphorus, antimony, calcium, tungsten and optionally arsenic in predetermined relative atomic ratios.

Abstract: A process for producing sorbic acid and its derivatives, which comprises reacting crotonaldehyde with ketene in the presence of a catalyst and decomposing or hydrolyzing the resulting adduct, said catalyst comprising a zinc salt of an aliphatic carboxylic acid and a phosphine or a pyridine.

Abstract: An aqueous solution of acrylic acid and water containing 30 wt. % or less acrylic acid, can be concentrated to 40-60 wt. % acrylic acid in the overhead of a distillation column through the addition of certain salts that reverse the relative volatility between acrylic acid and water. Suitable salts can be ferrous, lithium and calcium chlorides.

Abstract: A method of removing chromium ion from an aqueous solution of an organic acid of an acid concentration of up to 95% which comprises treating the solution with a cation exchange resin at a temperature higher than 55.degree. C.

Abstract: Planar organic molecules, such as divinylbenzene or para-dioxin molecules, are adsorbed from mixtures of planar and non-planar molecules, such as commercial divinylbenzenes containing non-planar ethylvinylbenzene, or commercial 2,4,5-T herbicide containing non-planar 2,4,5-trichlorophenoxyacetic acid, by partially pyrolyzed, macroporous, resinous polymer particles.

Abstract: The present invention relates to a method of purifying readily polymerizable high boiling vinyl monomers, in particular the acrylates and methacrylates of alkylene oxides and their ether and ester derivatives to obtain pure water white esters. The process involves flash evaporation of the preheated esters followed by condensation in the presence of polymerization inhibitors under specific conditions. The purified esters thus produced find use either as such or in the form of their copolymers in coatings, enamel paints, weather resistant finishes, adhesive compositions, as plasticizers, as lubricants for cellulose films and fibers, in magnetic tape recording media and as oil additives.

Abstract: The presence of solid polymer in distillation columns and their associated reboilers used for the recovery of methacrylic and acetic acids produced by the oxidation of methacrolein may be minimized by the use of inhibitors and introduction of molecular oxygen at a rate above a predetermined threshold value, which is a function of the operating temperature of the equipment. For a given temperature, the amount of solids has been found to be greatly increased below the threshold value of oxygen, while above the threshold value, the rate of appearance of solids has been found to be minimized and further increases in oxygen rate have only a minimal effect. At a typical operation temperature of 120.degree. C., the threshold value of about 0.1 SLH O.sub.2 /100 gm of liquid. A gas containing a relatively high concentration of oxygen is preferred.

Abstract: Separation of certain water soluble organic monomers such as acrylic acid from an aqueous solution can be accomplished by extraction with carbon dioxide, crystallizing the extract to remove carbon dioxide hydrate, and flashing off the remaining carbon dioxide solvent from the extract.

Abstract: Process for recovering carboxylic acids from dilute aqueous solutions of alkali metal salts of such carboxylic acids by mixing such solutions with from 10 to 1000% of a supercritical solution comprising at least 10 mole % carbon dioxide at a pressure from 80 to 500 atm and preferably 100 to 350 atm and at a temperature of from 35.degree. to 200.degree. C. and preferably from 35.degree. to 100.degree. C. whereby the salt reacts with the carbon dioxide to form the carboxylic acid which dissolves in the supercritical fluid. The aqueous phase is allowed to separate from the supercritical fluid phase. The pressure of the supercritical phase is lowered which lowers the solubility of the carboxylic acid in the supercritical fluid so that an acid phase is formed separate from the supercritical fluid phase whereby recovery of the acid is effected.

Abstract: A method for producing crystals of sorbic acid by recrystallization with an aqueous solution of an alcohol and wherein an alkali metal ion is employed as a crystal-modifying ion.According to this method, a recrystallized product of sorbic acid having a superior hardness, bulk density, fluidity, etc. is obtained.

Abstract: Pure acrylic acid may be obtained from an aqueous solution containing acrylic acid by fractional crystallization wherein a salt is added to the aqueous solution that eliminates the eutectic point between acrylic acid and water.

Abstract: C.sub.2 -C.sub.6 monocarboxylic and dicarboxylic acids are scrubbed from gas phase mixtures of such acids and water by gas absorption techniques utilizing a liquid solvent comprising a polyoxyalkylene glycol or a monoalkyl or dialkyl ether thereof. The solvent enriched with the acid is subjected to distillation to recover a substantially anhydrous acid product.

Abstract: Acrylic acid is separated from its solutions in tri-n-butyl phosphate by establishing from such a solution a vapor phase comprising substantially all of the acrylic acid and a portion of the solvent, at a temperature below the degradation point of the acrylic acid; next partially or totally condensing said vapor phase; and then distilling the acrylic acid from such condensation product, while maintaining an amount of acrylic acid at the base of the distillation column, and conducting the distillation under conditions such that neither solvent degradation nor acrylic acid crystallization results.

Abstract: Carboxylic acids of the general formula IR.sup.1 -COOH Iwhere R.sup.1 is hydrogen, methyl, ethyl or vinyl, are isolated from their dilute aqueous solutions by extraction followed by distillation of the mixtures obtained, the extractant used being a secondary amide of the general formula II ##STR1## where R.sup.2 and R.sup.3 are alkyl, cycloalkyl, aryl or aralkyl or conjointly are 1,4- or 1,5-alkylene, in each case of not more than 8 carbon atoms, with the proviso that the sum of the carbon atoms of R.sup.2 and R.sup.3 is from 7 to 14 and that only one of these radicals is aryl, and where R.sup.4 is one of the radicals R.sup.1.

Abstract: Differential esterification or hydrolysis is utilized to effect separations of isomeric acids or esters.

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: A process for purifying crude acrylic acid characterized in that high-purity purified acrylic acid containing little or no low boiling aldehydes is obtained by rectifying a crude acrylic acid consisting essentially of acrylic acid and containing low boiling substances such as acetaldehyde, acrolein, water and acetic acid and/or high boiling substances such as maleic acid, phenol, benzaldehyde and acrylic acid dimer, thereby removing said low boiling substances and then high boiling ones, and then stripping trace amounts of remaining low boiling aldehydes with an inert gas such as nitrogen or air at a liquid to gas molar ratio of 2 to 20.

Abstract: The process comprises the vapor phase oxidation of lower molecular weight olefins to the corresponding unsaturated aldehydes and unsaturated carboxylic acids in the presence of a catalyst comprising the oxides of iron, bismuth, molybdenum and at least one element of the Group II elements as essential components, and optionally the oxides of phosphorus, arsenic and an alkali metal.

Abstract: A process for the recovery of methacrylic acid formed from an aqueous sodium methacrylate solution derived from the silver catalyzed oxidation reaction of methacrolein and an aqueous solution of sodium hydroxide which comprises contacting the aqueous sodium methacrylate solution at a suitable temperature, in the presence of a high gaseous carbon dioxide pressure, with a water immiscible alkane, cycloalkane, alkyl benzene, or carboxylic acid ester solvent to extract and form a methacrylic acid-containing organic solvent phase, an aqueous phase and a precipitated sodium bicarbonate solid phase and recovering the methacrylic acid from the organic solvent phase. Liquid CO.sub.2 which may be employed with the water immiscible solvent at 800 psig may also be employed alone at its equilibrium vapor pressure as the reactant and extractant medium.

Abstract: The process comprises the vapor phase oxidation of lower molecular weight olefins to the corresponding unsaturated aldehydes and unsaturated carboxylic acids in the presence of a catalyst comprising the oxides of iron, bismuth, molybdenum and at least one element of the Group II elements as essential components, and optionally the oxides of phosphorus, arsenic and an alkali metal.

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: The addition of a salt comprising a group III A metal halide, such as aluminum chloride, to an acrylic acid-water solution obtained from the oxidation of propylene or acrolein, allows recovery of a 95% or better acrylic acid solution by phase separation.

Abstract: Process for preparing sorbic acid which comprises contacting .gamma.-vinyl-.gamma.-butyrolactone with at least one catalyst selected from the group consisting of (A) solid acids, (B) transition metal oxides, (C) metals of Group VIII of the Periodic Table and (D) halides of metals of Groups I-B, II-B, III-B, IV-B, V-B, VI-B and VIII of the Periodic Table.

Abstract: Acrolein and other light ends are removed from the effluent of a process for the production of acrylic acid by the vapor phase catalytic oxidation of acrolein or an acrolein precursor, such as propylene, by passing the effluent to the base of a fractionation tower and contacting such with the descending stream of liquid within the tower so as to partially condense the condensibles in the effluent, a portion of the liquid bottoms being recycled to the upper portions of the tower and a portion withdrawn as crude acrylic acid product. Acrolein is removed overhead.

Abstract: A process for producing acrylic acid from propylene through acrolein as an intermediate by catalytic vapor phase oxidation, which comprises passing a starting reactant gas mixture containing propylene, a molecular oxygen-containing gas and steam through a first-stage reactor packed with a molybdenum-containing multi-component catalyst, passing the resulting acrolein-containing gas through a second-stage reactor packed with a multi-component catalyst containing vanadium and molybdenum, introducing the resulting acrylic acid-containing gas to an acrylic acid collector thereby to recover acrylic acid in the form of an aqueous solution, and incorporating a part of the exhaust gas from the collector in the starting reactant gas mixture.

Abstract: A process for the preparation of a .alpha.,.beta.-unsaturated carboxylic acid by reacting formaldehyde, another aldehyde and a mineral acid salt of a secondary amine to form an intermediate Mannich base salt; oxidizing the Mannich base salt to the corresponding aminoacid salt; thermally cracking the aminoacid salt to yield an aqueous reaction products mixture of an .alpha.,.beta.-unsaturated carboxylic acid and the mineral acid salt of the secondary amine; and separating and isolating the aqueous reaction products.

Abstract: Waste water produced in an acrylonitrile plant and containing significant amounts of acrylonitrile and acrylic acid is processed so as to reduce its organics content for disposal purposes and to recover the acrylonitrile and acrylic acid contained therein. The waste water is treated by contact with activated carbon to adsorb the organics contained therein. The activated carbon is periodicaly regenerated with a desorbing liquid and the desorbate product is distilled to yield acrylonitrile and acrylic acid. Every fifth regeneration cycle, the activated carbon is regenerated thermally rather than means of a liquid in order to restore its activity to its original value.

Abstract: A method for separating and purifying methacrylic acid is disclosed in which an aqueous solution (A) of methacrylic acid containing acetic acid is brought into contact under counter-current flow with a mixed solvent (B) of methyl methacrylate and toluene in a ratio of from 3 : 2 to 1 : 9 by weight, to extract substantially the whole amount of methacrylic acid in solution (A) into mixed solvent (B); after which the methacrylic acid is separated and purified by distillation.