Abstract: The present invention relates to a method for the synthesis of 2,5-furandicarboxylic acid, and more specifically, the present invention relates to a more efficient and economical method capable of preparing 2,5-furandicarboxylic acid having various functions with high purity and high yield, even without using a transition metal catalyst.

Abstract: The present disclosure relates to a single shell open interstage reactor (“SSOI”). The SSOI comprises a first reaction stage, an interstage heat exchanger, an open interstage region, and a second reaction stage. The SSOI may be configured for upflow or downflow operation. Further, the open interstage region of the SSOI may comprise a supplemental oxidant feed. When the open interstage region comprises a supplemental oxidant feed, the SSOI may further comprise a supplemental oxidant mixing assembly. Processes for producing acrylic acid through the oxidation of propylene are also disclosed.

Abstract: The present disclosure relates to a single shell open interstage reactor (“SSOI”). The SSOI comprises a first reaction stage, an interstage heat exchanger, an open interstage region, and a second reaction stage. The SSOI may be configured for upflow or downflow operation. Further, the open interstage region of the SSOI may comprise a supplemental oxidant feed. When the open interstage region comprises a supplemental oxidant feed, the SSOI may further comprise a supplemental oxidant mixing assembly. Processes for producing acrylic acid through the oxidation of propylene are also disclosed.

Abstract: A chemical reactor including: a plurality of heat exchange plates which between them define reaction compartments, in which reactor each heat exchange plate includes two walls between them defining at least one heat exchange space, the respective walls being fixed together by joining regions, and the reactor also comprises at least one injection device for injecting substance into the reaction compartments, said substance-injection device passing through the heat-exchange plates in respective joining regions thereof. Also, a chemical reaction process that can be carried out in this reactor.

Abstract: A process for preparing a catalyst by selecting an active catalyst and contacting the active catalyst with one or more fluids containing an organic solvent or mixture of organic solvents. In one embodiment, each organic solvent has a dielectric constant within a range of about 5 to about 55 when measured at a temperature of 20° C. to 25° C. The catalyst thus prepared may be used in a process for preparing maleic anhydride.

Abstract: A catalyst carrier for insertion in a radial tube reactor, said catalyst carrier comprising: an annular container for holding catalyst in use, said container having a perforated inner wall defining a tube, a perforated outer wall, a top surface closing the annular container and a bottom surface closing the annular container; a surface closing the bottom of said tube formed by the inner wall of the annular container; a skirt extending upwardly from the perforated outer wall of the annular container from a position at or near the bottom surface of said container to a position below the location of a seal; and a seal located at or near the top surface and extending from the container by a distance which extends beyond an outer surface of the skirt.

Abstract: A process for preparing a vanadium, phosphorus, and oxygen comprising catalyst precursor for preparing maleic anhydride by heterogeneously catalyzed gas-phase oxidation of a hydrocarbon having at least four carbon atoms, which comprises (a) reacting vanadium pentoxide with 102% to 110% strength phosphoric acid in the presence of isobutanol and optionally of a primary or secondary, noncyclic or cyclic, unbranched or branched, saturated alcohol having 3 to 6 carbon atoms in a temperature range from 80 to 160° C.; (b) isolating the precipitate formed; (c) (i) drying the isolated precipitate down to a residual isobutanol content of less than 5% by weight; (ii) then passing a gas which in addition to one or more inert gases comprises 0.1% to 9% by volume of oxygen through the dried precipitate, directly or after isolation, in the temperature range from 130° C. to 200° C.

Abstract: The invention relates to a catalyst molded body for preparing maleic anhydride by gas-phase oxidation of a hydrocarbon having at least four carbon atoms using a catalytically active composition contains vanadium, phosphorus and oxygen, where the shaped catalyst body has an essentially cylindrical body having a longitudinal axis, wherein the cylindrical body has at least two parallel internal holes which are essentially parallel to the cylinder axis of the body and go right through the body. The catalyst molded body has a large outer surface area, a lower pressure loss and sufficient mechanical stability.

Abstract: The catalytically active mass of a catalyst molded body comprises a multi-element oxide containing vanadium and phosphorus. The specific pore volume PV (in ml/g) of the catalyst molded body, the bulk density p of the catalyst molded body (in kg/l), the geometric surface area Ageo (in mm2), and the geometric volume Vgeo (in mm3) of the catalyst molded body satisfy the condition 0.275<PV·?·Ageo/Vgeo. In a method for producing maleic acid anhydride by heterogeneously catalytic gas phase oxidation of a hydrocarbon, the catalyst molded body allows a lower pressure loss and a high yield.

Abstract: In this disclosure, a system is described, comprising a shear device with at least one inlet and at least one outlet and a mixing vessel with at least one inlet and at least one outlet, wherein an inlet of the shear device is in fluid communication with an outlet of the mixing vessel. In certain embodiments, the shear device and the mixing vessel form a loop for fluid communication. Also disclosed herein is a method of high shear oxidation, comprising mixing an oxidant with a substrate to form a substrate-oxidant mixture and applying shear to the substrate-oxidant mixture to form a product. The product includes ethylene oxide, propylene oxide, terephthalic acid, phenol, acrylonitrile, maleic anhydride, phthalic anhydride, nitric acid, caprolactam, oxidized polyethylene, oxidized polypropylene, oxidized polyethylene copolymers, and oxidized polypropylene copolymers. Suitable oxidant includes air, oxygen, ozone, peroxide, organic peroxide, halogen, oxygen-containing gas, and halogen-containing gas.

Abstract: A novel polynary metal oxide phosphate of the general formula I MaV4-aOb(PO4)c is described, in which M is one or more metals selected from Ti, Zr, Hf, Cr, Fe, Co, Ni, Ru, Rh, Pd, Cu, Zn, B, Al, Ga and In, a is from 0 to 2.0, b is from 2.0 to 4.0, c is from 2.0 to 4.0, having a crystal structure whose powder X-ray diffractogram is characterized by defined reflections. Preferred representatives are V4O3(PO4)3, CrV3O3(PO4)3, FeV3O3(PO4)3 and TiV3O3(PO4)3. The metal oxide phosphates are suitable as gas phase oxidation catalysts, for example for preparing maleic anhydride from a hydrocarbon having at least four carbon atoms.

Abstract: A novel polynary vanadyl pyrophosphate of the general formula I (VO)a(M1-bVb)2(P2O7)c is described, in which M is one or more metals selected from Ti, Zr, Hf, Cr, Fe, Co, Ni, Ru, Rh, Pd, Cu, Zn, B, Al, Ga and In, a is from 0.5 to 1.5, b is from 0 to 0.9, c is from 1.5 to 2.5, having a crystal structure whose powder X-ray diffractogram is characterized by defined reflections. A preferred representative is (VO)Fe2(P2O7)2. The vanadyl pyrophosphates are suitable as gas phase oxidation catalysts, for example for preparing maleic anhydride from a hydrocarbon having at least four carbon atoms.

Abstract: A novel polynary metal oxide phosphate of the general formula I MaV2Ob(PO4)c is described, in which M is one or more metals selected from V, Cr, Fe, Co, Ni, Ru, Rh, Pd, Cu, Zn, Cd, Hg, Be, Mg, Ca, Sr and Ba, a is from 0.5 to 1.5, b is from 1.5 to 2.5, c is from 1.5 to 2.5, having a crystal structure whose powder X-ray diffractogram is characterized by defined reflections. Preferred representatives are CoV2O2(PO4)2, NiV2O2(PO4)2 or CuV2O2(PO4)2. The metal oxide phosphates are suitable as gas phase oxidation catalysts, for example for preparing maleic anhydride from a hydrocarbon having at least four carbon atoms.

Abstract: Multi-tubular reactors for fluid processing incorporate reactor tubes containing thermally conductive monolithic catalyst structures with relative dimensions and thermal expansion characteristics effective to establish both a non-interfering or slidably interfering fit between the monolith structures and the reactor tubes at selected monolith mounting temperatures, and geometries at reactor operating temperatures such that the operating gaps between tubes and monoliths under the conditions of reactor operation do not exceed about 250 ?m over tube sections where high heat flux to or from the monoliths is required.

Abstract: Processes comprising providing a catalyst precursor, and heating the catalyst precursor to a temperature of at least 350° C. in an atmosphere comprising air, wherein air is fed into the atmosphere at a rate of 0.05 to 4.0 standard m3/h, and wherein the catalyst precursor is activated at a temperature of at least 350° C. for more than 9 hours are described along with catalysts formed thereby and uses for such catalysts.

Abstract: Esters are prepared from hydroxyl-containing compounds and carboxylic acids or anhydrides or lower alkyl esters thereof using a multiple catalyst approach, wherein a first catalyst such as an organotin catalyst can be present at the beginning of the reaction and a second catalyst such as an organotitanium catalyst can be added any time after the addition of the first catalyst, or when the acid value of the reaction mixture falls below a predetermined acid value. The second catalyst can be added multiple times, and a third or additional catalysts can also be used.

Abstract: Active vanadium/phosphorus mixed oxide catalyst for the conversion of non-aromatic hydrocarbons, e.g., n-butane, into maleic anhydride. The catalyst is prepared from the catalyst precursor, that is, prepared by the reaction of a source of vanadium in an organic medium in the presence of a phosphorus source. The organic medium is (a) isobutyl alcohol or a mixture of isobutyl alcohol and benzyl alcohol and (b) a polyol. The catalyst precurso is transformed into the active catalyst by an activation process that includes a heat treatment that includes applying a temperature of up to 600° C.

Abstract: In a reactor (1) which has a bundle of catalyst tubes (2) and in which a heat transfer medium is circulated through the space surrounding the catalyst tubes, with the ring lines (3, 4) at both ends of the reactor with openings (5, 6) through the wall for introduction or removal of a heat transfer medium by means of one or more pumps, where the heat transfer medium is introduced into the lower ring line (4) and is returned via the upper ring line (3) to the pump(s) and the heat transfer medium or a substream of the heat transfer medium may, if desired, be passed over one or more external heat exchangers, and with deflecting plates (7) which alternately leave free an open cross section in the middle of the reactor and at the edge of the reactor, the lower ring line (4) is divided by means of a horizontal dividing wall (8) into two regions between which material can pass via preferably uniformly distributed openings (9) having a regulatable open cross section.

Abstract: A process for the preparation of maleic anhydride by heterogeneously catalyzed gas-phase oxidation in a reactor with feed for the reaction mixture at one end of the reactor and discharge of the product mixture at the opposite end of the reactor, and with devices for dissipating the heat of reaction which are arranged in the reactor interior and through which a heat-exchange medium flows and which are designed as heat-exchanger plates.

Abstract: A compound represented by the following formula (I): wherein R1 and R2 represent amino group that substitute at adjacent positions on the phenyl ring, provided that either of R1 and R2 represents a mono(C1-6 alkyl)-substituted amino group and the other represents an unsubstituted amino group; and R3 and R4 independently represent hydrogen atom or an acyl group, and an agent for measurement of nitrogen monoxide which comprises said compound.

Abstract: This invention relates to a method for producing a partially oxidized organic compound, e.g., an unsaturated aldehyde/carboxylic acid having three or more carbon atoms, or an organic acid anhydride/nitrile compound having four or more carbon atoms. This method requires a catalyst prepared by treating a carrier in such a manner that water used in the treatment achieves specific resistance.

Abstract: A process for producing maleic anhydride is described, which comprises (i) reacting a hydrocarbon with oxygen in a vapor phase in the presence of a catalyst to yield a reaction mixture gas containing maleic anhydride, (ii) bringing the reaction mixture gas into contact with an organic solvent to collect the maleic anhydride in the organic solvent, (iii) separating at least part of the maleic anhydride from the organic solvent, (iv) washing with an aqueous alkali solution at least part of the organic solvent from which maleic anhydride has been separated, and (v) reusing the resultant washed organic solvent and the residual organic solvent for contact with the reaction mixture gas.

Abstract: A process for recovering phthalic anhydride as a liquid from a vapor phase oxidation product which comprises mixing the vapor phase oxidation product having a temperature in the range of about 130.degree. C. or greater with a first stream comprising maleic anhydride and/or at least one compound selected from the group consisting of: citraconic anhydride, benzoic acid and phthalic anhydride in a rectification tower such that a substantial portion of the phthalic anhydride contained within the vapor phase oxidation product transfers from the vapor phase to a liquid phase and the by-products contained in the first stream which are more volatile than phthalic anhydride transfer from the liquid phase to the vapor phase and wherein a vapor-to-liquid weight ratio in the range between about 5 to 20 is exhibited within the rectification tower, thereby forming a liquid phase phthalic anhydride product having a phthalic anhydride concentration in the range between about 50-100 wt. %, preferably 90-100 wt.

Abstract: Petrochemicals are produced by the vapor phase reaction of a hydrocarbon with air in the presence of a suitable catalyst. The petrochemical product is removed from the product gas stream, and unreacted hydrocarbon in part or all of the remaining gas stream is recovered by subjecting the gas stream to a TSA process in which the adsorbed hydrocarbon is desorbed at elevated pressure by purging the adsorbent with hot compressed air, the air being heated by compression. The compressed air-desorbed hydrocarbon mixture is recycled to the reactor.

Abstract: A petrochemical is produced by the vapor phase reaction of a hydrocarbon with air in the presence of a suitable catalyst. The petrochemical is removed from the reactor effluent, and part or all of the remaining petrochemical-free gas stream is passed through a hydrocarbon-selective adsorbent, which adsorbs hydrocarbon from the gas stream, leaving a hydrocarbon-depleted waste gas. Hydrocarbon is purged from the adsorbent with air, and the air-hydrocarbon mixture is recycled to the partial oxidation reactor. The purge air, and preferably both the purge air and the petrochemical-free gas stream are dried by passage through beds of zeolite 3A prior to being introduced into the hydrocarbon-selective adsorbent, and the beds of zeolite 3A are regenerated by passing heated hydrocarbon-depleted waste gas therethrough.

Abstract: This invention is directed towards an improved process for the selective gas phase oxidation of a organic reactant using a metal oxide redox catalyst, wherein the organic reactant and air feeds are at a substantially continuous level, the improvement comprising adding a fluctuating flow of oxygen at alternating relatively high and relatively low levels. The invention also teaches means by which a gas may be provided to a reaction process on a fluctuating basis.

Abstract: An improved process for the preparation and recovery of maleic anhydride in which the recovery of maleic anhydride from a gaseous reaction mixture includes absorbing the maleic anhydride in a solvent and subsequently stripping maleic anhydride from the solvent to obtain crude maleic anhydride product and regenerated absorbing solvent containing polymeric tars and other contaminants. In accordance with the improvement, at least a portion of the regenerated solvent is contacted in an agitated extraction zone with an aqueous liquid extractant to hydrolyze the polymeric tars, transfer water-soluble contaminants to the aqueous extract phase and produce a mixture comprising an aqueous extract phase containing water-soluble contaminants and an organic raffinate phase comprising regenerated absorbing solvent having a reduced concentration of polymeric tars. The aqueous extract and organic raffinate phases are then separated and the organic phase is recycled and used again to absorb maleic anhydride.

Abstract: Petrochemicals are produced by the vapor phase reaction of a hydrocarbon with substantially pure oxygen in the presence of a suitable catalyst. In the improved process, the principal product is removed, carbon monoxide, present in the reactor effluent as a byproduct, is oxidized to carbon dioxide and part of the gaseous effluent, comprised mainly of carbon dioxide and unreacted hydrocarbon, is recycled to the reactor. Removal of carbon monoxide from the recycle stream reduces the hazard of a fire or explosion in the reactor or associated equipment. The use of carbon dioxide as the principal diluent increases heat removal from the reactor, thereby increasing the production capacity of the reactor.

Abstract: An improvement in the oxidation catalyst used for the partial oxidation of n-butane and containing vanadium and phosphorus, zinc and lithium mixed oxides which comprises adding a molybdenum compound modifier in an amount of from about 0.005 to 0.025/1 Mo/V to the catalyst during the digestion of the reduced vanadium compound by concentrated phosphoric acid. The addition of Mo produces a catalyst which is very stable more active system and longer lived than the unmodified catalyst.

Abstract: The invention relates to a catalyst for producing phthalic anhydride by gas phase catalytic oxidation of o-xylene and/or naphthalene with molecular oxygen or gas containing molecular oxygen and, to a process for producing phthalic anhydride by using said catalyst. The catalyst is made by supporting, on a heat-resistant inorganic carrier, a catalytic active substance which comprises: vanadium oxide; anatase type titanium dioxide having specific surface area of 10 to 60 m.sup.2 /g; niobium; at least one element selected from potassium, cesium, rubidium and thallium; phosphorus; and antimony. The catalytic active substance is prepared by using a five-valent antimony compound as an antimony source. The process for producing phthalic anhydride comprises use of said catalyst.

Abstract: Tetrabromophthalic anhydride and the corresponding free acid are propared by oxidizing in the liquid phase a compound of the formula ##STR1## each of A and A' is independently selected from oxygen, OH or acetoxy; each of R and R' is independently selected from H, OH, alkyl, alkylidene or oxygen;x is 0 or 1; y is 3-x; and R.sub.y and R'.sub.y may together form a closed alicyclic or heterocyclic ring structure.Mixtures of two or more compounds of formula (I), optionally in the presence of an oxidation catalyst, can also be employed as the starting material.

Abstract: An improved process is provided for the production of a petrochemical by the vapor phase reaction of a hydrocarbon with an oxygen-containing gas in the presence of a suitable catalyst to produce a flammable gaseous product stream comprising the desired petrochemical, unreacted hydrocarbon, oxygen, carbon monoxide and carbon dioxide. In the improved process, a cooled or liquefied inert gas is injected as a quench fluid into the gaseous product stream exiting the hydrocarbon oxidation reactor, thereby cooling the stream to a temperature below the autoignition temperature of the flammable components of the stream, the petrochemical is recovered from the gaseous product and unreacted hydrocarbon is removed from the gaseous product and recycled to the reactor.

Abstract: Use of the antibiotic purpuromycin for the topical treatment of infectious vaginitis and topical dosage forms containing said product. The antibiotic purpuromycin is simultaneously active against the main causative agents of infectious vaginitis i.e.: Candida vaginalis, Trichomonas vaginalis and Gardnerella vaginalis.

Abstract: This invention provides a process for the production of an anhydride by the vapor phase reaction of a hydrocarbon with substantially pure oxygen in the presence of a suitable catalyst. In the improved process, the anhydride product is removed, carbon monoxide, present in the reactor effluent as a by-product, is oxidized to carbon dioxide and part of the gaseous effluent, comprised mainly of carbon dioxide and unreacted hydrocarbon, is recycled to the reactor. Removal of carbon monoxide from the recycle stream reduces the hazard of a fire or explosion in the reactor or associated equipment. The use of carbon dioxide as the principal diluent increases heat removal from the reactor, thereby increasing the production capacity of the reactor.

Abstract: A fluid bed catalyst which has lost activity or fluidization quality through agglomeration, contamination, or a physical or chemical change on the surface of the catalyst is deagglomerated and/or its surface re-exposed, by contacting the fluidized catalyst with a high velocity gas sufficient to cause multiple collisions among the catalyst particles and thereby deagglomerating the particles and/or abrading the surface of the particles to expose fresh catalyst.

Abstract: A process is disclosed for increasing the recovery of maleic anhydride from the product condenser. Maleic anhydride is added to the oxidation reactor gaseous effluent. Maleic acid buildup in the condenser is reduced; condenser plugging is reduced; and process run time required to build up to production rates after periodic cleaning can be reduced.

Abstract: Process for obtaining maleic anhydride that is not prone to discolor by treating crude maleic anhydride with oxygen, a gas mixture containing oxygen, or a substance that releases oxygen before or while it is distilled.

Abstract: In accordance with the process of this invention, an improved catalyst for molecular oxidation of a hydrocarbon to form the corresponding carboxylic anhydrides is prepared by the steps of (a) forming a catalyst precursor by depositing on titanium dioxide solids in the anatase form at least a monolayer amount of at least one vanadium oxide source which is convertible to vanadium oxide upon calcining; (b) calcining the thus-formed catalyst precursor under conditions sufficient to convert the tantalum oxide source into the oxide form; (c) depositing upon the calcined catalyst precursor a catalytically effective amount of at least one vanadium oxide source which is convertible into vanadium oxide upon heating and at least one metal oxide source selected from the group consisting of oxides of Sb, Ga, Ge, In, T.sub.1, Pb, Se, Te, P and Bi, which is convertible into the corresponding metal oxide upon heating and which is reactive with V.sub.2 O.sub.

Abstract: In accordance with the process of this invention, an improved catalyst for molecular oxidation of hydrocarbons to form the corresponding carboxylic anhydrides is prepared by the steps of forming a catalyst precursor by depositing on titanium dioxide catalyst solids in the anatase form a continuous monolayer amount of at least one source of titanium oxide, calcining the thus-formed catalyst percursor under conditions sufficient to convert the titanium oxide source into the oxide form, depositing upon the calcined catalyst precursor a continuous monolayer amount of at least one vanadium compound which is convertible into vanadium oxide upon heating and calcining the vanadium-deposited solids under conditions sufficient to convert the vanadium compound into vanadium oxide.

Abstract: A process for the reactivation of vanadium-phosphorus-oxygen catalyst with alkyl esters of phosphoric acid and water is disclosed. The catalysts are useful for the manufacture of maleic anhydride from C.sub.4 hydrocarbon benzene feedstock.

Abstract: In accordance with the process of this invention, an improved catalyst for molecular oxidation of an aromatic hydrocarbon to form the corresponding aromatic carboxylic anhydrides is prepared by the steps of forming a catalyst precursor by depositing on titanium dioxide solids in the anatase form a continuous monolayer amount of at least one source of zirconium dioxide, calcining the thus-formed catalyst precursor under conditions sufficient to convert the zirconium oxide source into the oxide form, depositing upon the calcined catalyst precursor a catalytically effective amount of at least one vanadium compound which is convertible into vanadium oxide upon heating and calcining the vanadium-deposited solids under conditions sufficient to convert the vanadium compound into vanadium oxide.

Abstract: In the production of maleic anhydride, scale formation in an evaporator and pipes is a very difficult problem. By the process disclosed herein, scale formation in a maleic anhydride preparation apparatus can satisfactorily be prevented, and therefore, maleic anhydride preparation apparatus can be operated continuously for a long period. Further, it is also possible to significantly reduce the formation of fumaric acid. The process is that when conducting the concentration and dehydration of an aqueous solution of maleic acid, a small amount of hydrogen peroxide is added to the aqueous solution. Scale is formed by condensation of phenols and aldehydes, and quinones and aldehydes. Hydrogen peroxide added acts to oxidize aldehydes contained in the aqueous solution.

Abstract: A mixed oxide catalyst precursor comprising vanadium and phosphorus treated in finely divided form with phosphoric acid and water soluble compound of aluminum and/or boron to improve resistance to attrition.

Abstract: A process for oxidizing a hydrocarbon to maleic anhydride using a mixed oxide catalyst of vanadium and phosphorous prepared by a procedure including pretreating the dried catalyst precursor of the said mixed oxides in finely divided form with an acid solution.

Abstract: It has been found that phosphoric acid alone and in admixture with phenothiazine and/or methyl-p-benzoquinone reduces residue formed during the fractionation of aqueous crude maleic compositions for the production of maleic anhydride, and in particular, reduces residue due to the presence of small amounts, i.e., less than 10 ppm alkali metal ion. When the alkali metal ion is present at least 9 equivalent acid groups of phosphoric acid per atomic equivalent of alkali metal ion are present.

Abstract: Large surface area oxidation catalysts suitable for converting C.sub.4 to C.sub.10 hydrocarbons to maleic anhydride are disclosed, comprising the oxides of vanadium, phosphorus and tin in combination with a crystalline silica having a surface area between 100 M.sup.2 /g to 450 M.sup.2 /g and wherein the vanadium has an average valence in the range of from 3.5 to 4.9.

Abstract: The useful life of vanadium-phosphorus-oxygen (PVO) catalyst in fixed bed reactors can be substantially extended by treatment with a phosphorus compound followed by steam treatment. The PVO catalysts may be treated with steam after long periods (months) of only phosphorus compound treatment and the benefit of the present invention obtained or the phosphorus and steam treatments may be of only a few hours duration and sequential. In extending the useful life of the PVO catalyst according to the present invention, the temperature profile in the catalyst bed is restored to substantially the same profile as the fresh catalyst.

Abstract: A heterogeneous process for preparing a vanadium-phosphorus-oxygen containing catalyst for use in the preparation of carboxylic anhydrides is disclosed. This process employs an activation procedure in an air-hydrocarbon atmosphere.

Abstract: Catalytic material is provided by a composition comprising the elements vanadium, non-water-contained hydrogen, phosphorus and non-water-contained oxygen. Freshly prepared catalytic material proxides relatively high yields upon its initial use in the catalytic oxidation of hydrocarbon feedstocks, such as n-butane and benzene to maleic anhydride.

Abstract: In one of its embodiments this invention provides a process for recovering C.sub.4 -C.sub.6 dicarboxylic acid components contained in a waste byproduct stream derived from a reaction system in which adipic acid is produced by nitric acid oxidation of cyclohexanone/cyclohexanol.An important aspect of the process is the esterification and extraction of the C.sub.4 -C.sub.6 dicarboxylic acids in the aqueous byproduct stream with a mixture of C.sub.1 -C.sub.3 alkanol and C.sub.6 -C.sub.20 alkanol, and the subsequent recovery of di(C.sub.6 -C.sub.20 alkyl) esters of succinic acid, glutaric acid and adipic acid.In a broader aspect this invention provides a process for recovery of water miscible organic acid components contained in an aqueous solution as C.sub.6 -C.sub.20 alkyl esters of the organic acids.