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: 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: The oxidation of liquid n-butane with oxygen gas at a temperature of from 120.degree. C. up to 235.degree. C. in the presence of an acetic acid solution containing bromide ion in combination with ions of cobalt or cobalt and manganese produces a reaction effluent containing mainly acetic acid (65 to 72 weight percent) and water (23 to 27 weight percent) together with impurity concentrations of esters and ketones boiling lower than acetic acid, higher carbon (C.sub.3 and C.sub.4) aliphatic monocarboxylic acids boiling higher than acetic acid and the difficultly separable 3-bromo-2-butanone impurity. The concentration of said bromoketone can be decreased by maintaining said reaction effluent or its debutanized residue at a temperature of from 150.degree. C. up to 200.degree. C. for 15 to 150 minutes. Subsequent distillation even further decreases the concentration of the bromoketone in the acetic acid distillate fraction.

Abstract: Excessive energy consumption of a combination of multi-fractionations and multi-distillations of concentrating aqueous acetic acid product of liquid phase oxidations, especially oxidation of liquid n-butane with oxygen gas while the butane is dissolved in liquid acetic acid containing a catalyst system comprising Co-Br or Co-Mn-Br, is avoided and an otherwise hard to remove bromo-ketone is readily removed by a combination of sequential steps of decompressing the oxidation reaction mixture to remove unreacted butane as well as gaseous products, heat treating the decompressed liquid at a temperature of from 150.degree. C. up to 200.degree. C. for from 15 up to 150 minutes, subjecting the heat treated liquid to fractionation while recycling to the rectification zone thereof an aqueous portion of low boiling impurities as a means for concentrating the acetic acid and thereafter further concentrating the acetic acid produced by continuous fractional crystallization.

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: A method for purifying raw acetic acid containing formaldehyde is provided wherein raw acetic acid is heat-treated at a temperature of about its boiling point or higher, in advance of the conventional distillation for removing a lower boiling fraction, and the acetic acid thus heat-treated is distilled to remove the lower boiling fraction, whereby the content of formaldehyde can be reduced down to 30 ppm or lower.

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: 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 process for recovering heavy metal ions or heavy metal ions and halogen values from a solution comprising a lower aliphatic monocarboxylic acid, which comprises the steps of:(1) contacting a lower aliphatic carboxylic acid solution containing heavy metal ions or heavy metal ions and halogen values with an anion exchange resin, at least 60% of the ion-exchange groups of said anion exchange resin being in the bromide or chloride state, while the water concentration in the lower aliphatic monocarboxylic acid solution has been adjusted to a level lower than 20% by weight, thereby to adsorb the heavy metal ions or the heavy metal ions and the halogen values on the anion exchange resin; and(2) desorbing the adsorbed heavy metal ions or the adsorbed heavy metal ions and the adsorbed halogen values from the anion exchange resin by elution with an eluent.

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: Water is separated by distillation from organic multiple component mixtures containing at least one component partly miscible with water. The component miscible with water is distilled azeotropically with the water contained in the mixture, the distillate is separated into water and a zeotrope forming agent and the latter is recycled to the distilling column. In the recycling process, one part of the azeotrope forming agent is conducted to the top of the column and the other part is fed into the column at the feed mixture inlet or at a location thereunder.

Abstract: Concentrated acetic acid of 95 to 100 weight percent concentration containing both ionic and coordinate bromine can be successfully purified to a bromine content of less than 3 ppm by the sequential steps of catalytic hydrogenation, contacting the resulting acetic acid with alkali metal hydroxide, carbonate or bicarbonate, and then distilling acetic acid from the alkali metal.

Abstract: Acetic acid of 95 to 100 weight percent strength containing ionic and coordinate bromide impurities can be purified to a bromine content of less than 3 ppm by the sequence of steps comprising catalytic hydrogenating said acetic acid, treating the hydrogenated acetic acid with a solid absorbant and separating acetic acid therefrom.

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: According to the present invention an impure liquid containing ethylene glycol or propylene glycol, lower carboxylate esters of the glycol, water, carboxylic acid and glycol-azeotroping agent is treated for removal of substantially all of said glycol-azeotroping agent by a process which comprises distilling the impure liquid in a distillation zone to form an overheads product comprising water and glycol-azeotroping agent and a bottoms product comprising the glycol, esters and carboxylic acid, which is substantially free of said glycol-azeotroping agent, said bottoms product containing water in an amount of at least about 1 weight percent of the amount of water passed to said distillation zone with said impure liquid.

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 process for converting butane to acetic acid wherein a mixture containing butane, molecular oxygen, acetic acid and cobaltic ions is continuously passed through a reaction zone under elevated temperatures and elevated pressures while maintaining therein a partial pressure of molecular oxygen of about 0.6 to about 15 pounds per square inch (0.04 to about 1.1 kilograms per square centimeter).

Abstract: A lower carboxylic acid such as acetic acid is separated and recovered from an aqueous medium by the steps which include contacting, in an extraction zone, the aqueous medium with an extracting agent such as trioctyl phosphine oxide dissolved in an organic solvent such as a mixture of paraffins having a boiling range of about 160.degree. C. to 175.degree. C.

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.