Abstract: In accordance with the present invention, there are provided improved methods for the preparation of maleimide monomers. This new method for the synthesis of maleimides is clearly superior to those documented in the prior art. Furthermore, the invention method utilizes materials with reduced toxicity, thus the overall process has a minimal impact on the environment. Thus, in accordance with the present invention, it has been discovered that certain amine salts can be successfully used to replace the polar, aprotic solvents cited in the prior art for the cyclodehydration of maleamic acids. The use of these salts provides competitive reaction times and product yields relative to results obtained with the polar, aprotic solvents. These salts have the advantage of having no vapor pressure and, therefore, have no possibility to co-distill with the water produced by the cyclodehydration reaction. Furthermore, such salts can be tailored to have desirable solubility characteristics (i.e.

Abstract: The salt of a sulfonated succinic acid is cyclized, then converted to novel sulfonated hydroxamic acids by reaction with hydroxylamine (which is added or formed in situ), and the novel hydroxamic acid is then cyclized to the sulfo-N-hydroxysuccinimide salt. This synthetic procedure is simple, direct, and more rapid than present procedures for synthesis of the succinimide. Novel sulfo-hydroxamic acid intermediates are formed during this procedure.

Abstract: The present invention provides a process for recovering fumaric acid formed as a by-product during the production of maleic anhydride so that both fumaric acid and maleic anhydride are obtained. The process of the present invention further eliminates the wasting of MAN that occurs when fumaric acid is incinerated and improves the production of maleic anhydride by eliminating a source of fouling caused by the fumaric acid which leads to down-time in the reaction process to clean out the fumaric acid.

Abstract: A system provides an oxygen-bearing gas and gaseous reactant stream to a fluidized bed reactor using a sparger to entrain the oxygen-bearing gas into the reactant gas stream. A feed line couples the sparger to the reactor's fluidized bed and introduces the reactant gas stream and entrained oxygen-bearing gas directly into contact with the fluidized bed. A controller controls and maintains both the amount of oxygen-bearing gas and the gaseous reactant above an upper flammability limit, preferably with a safety margin of at least 10%.

Abstract: The salt of a sulfonated succinic acid is cyclized, then converted to novel sulfonated hydroxamic acids by reaction with hydroxylamine (which is added or formed in situ), and the novel hydroxamic acid is then cyclized to the sulfo-N-hydroxysuccinimide salt. This synthetic procedure is simple, direct, and more rapid than present procedures for synthesis of the succinimide. Novel sulfo-hydroxamic acid intermediates are formed during this procedure.

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: In producing maleic anhydride by catalytic oxidation of butane in vapor phase, the reaction mixture consists of butane and a recycle gaseous current made of compressed air and exhaust gas recovered from the absorption stage by a solvent of the maleic anhydride produced; oxygen and total butane concentration in the recycle stream are controlled.

Abstract: An apparatus and process for the recovery of airborne anhydrides such as anhydride vapor or dust wherein these airborne anhydrides are contacted with hot glycol, such as diethylene glycol, in the liquid phase to first dissolve and then react with the airborne anhydrides yielding a useable by-product, such as half-esters. In the preferred embodiment, first airborne anhydrides are introduced at the top of a venturi where the anhydrides are contacted with diethylene glycol of at least 270.degree. F. The airborne anhydrides dissolve in the glycol and then react with the glycol to form a solution of half-esters and glycol. The venturi enhances the contact between the glycol and the first airborne anhydrides, facilitating the dissolution of the anhydrides in the glycol. Second airborne anhydrides are introduced at the discharge side of the venturi such that the second airborne anhydrides dissolve in unreacted hot glycol and then react to form additional half-esters.

Abstract: Citraconic anhydride is prepared in a single step by heating itaconic acid, optionally in an inert organic solvent medium, in the presence of a catalytically effective amount of an at least partially organic acid/base catalyst compound having a pKa ranging from 4 to 10, in particular a salt catalyst such as pyridinium tosylate, itaconate or hydrochloride, ammonium itaconate, or phosphinium hydrobromide.

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: A process for producing a vanadium-phosphorus oxide-containing catalyst precursor, which comprises (a) introducing into an organic solvent a vanadium alkoxide as a pentavalent vanadium compound and a phosphorus compound in the presence of a reducing agent capable of reducing the pentavalent vanadium compound to a tetravalent state, (b) hydrolyzing at least a part of the vanadium alkoxide before or after the introduction of the phosphorus compound, and (c) heating the vanadium-containing liquid medium obtained in step (b), in the presence of the phosphorus compound to reduce at least a part of vanadium to a tetravalent state.

Abstract: In the purification of maleic anhydride obtained with an oxidation process, by means of absorption with an organic solvent and fractionation of the resulting liquid phase and purification of the crude maleic anhydride thus separated, the above purification being accomplished through two serially placed fractionating columns, the accumulation of polymerisable acrylic acid overhead the first fractionating column of the purification section, and of water as well as of maleic acid overhead the second fractionating column of the purification section, is avoided by carrying the overhead vapours of said first fractionating column to an absorption tower, preferably operating with the same absorption organic solvent used to absorb the crude maleic anhydride from the reaction mixture, and by carrying the overhead vapours of said fractionating column of said purification section to two condensers placed in series, so that the gaseous fraction, coming out of the first condenser, is fed to said second condenser.

Abstract: Hydrocarbon derivatives are produced by contacting a hydrocarbon with oxygen obtained from an air separation unit in the presence of a partial oxidation reaction catalyst. After separation of the hydrocarbon derivative from the reactor effluent, unreacted hydrocarbon is recovered from the effluent by adsorbing the unreacted hydrocarbon onto an adsorbent at superatmospheric pressure and removing the adsorbed hydrocarbon from the adsorbent by depressurizing said adsorbent and purging the adsorbent with nitrogen obtained from the air separation unit. The recovered unreacted hydrocarbon is recycled to the partial oxidation reactor.

Abstract: A process for producing a precursor of a phosphorus-vanadium oxide catalyst for production of maleic anhydride by vapor phase oxidation of a hydrocarbon having 4 carbon atoms, which comprises reacting phosphoric acid and a pentavalent vanadium compound in an organic solvent capable of reducing at least a portion of the pentavalent vanadium to a valence state of +4, the phosphoric acid being substantially composed of orthophosphoric acid, and a phosphoric acid solution whose concentration is 88 to 96% being used as a source of the phosphoric acid; and a process for producing the catalyst comprising dry-pulverizing the catalyst precursor.

Abstract: Disclosed are a fixed-bed, cross-flow catalytic reactor wherein reaction heat can be exchanged against a heat exchange medium circulating indirectly through the catalyst bed, and a catalytic process comprising operation of the cross-flow reactor. The reactor comprises a catalyst bed having internally embedded banks of heat exchange tubes. An inlet distributor distributes reactants along the axial length of the bed. The distributed fluid passes through the bed in a cross-flow path wherein a catalytic reaction occurs. The reaction effluent is then collected from the bed by an outlet product collector. A heat exchange medium circulated through the internal heat exchange tubes adds or removes reaction heat as required for enhanced conversion in the reactor. Multiple heat exchange tubes can be used, and inlet and discharge manifolds are provided for distributing the circulating heat exchange medium.

Abstract: A process for producing a vanadium-phosphorus oxide-containing catalyst precursor, which comprises (a) introducing into an organic solvent a vanadium alkoxide as a pentavalent vanadium compound and a phosphorus compound in the presence of a reducing agent capable of reducing the pentavalent vanadium compound to a tetravalent state, (b) hydrolyzing at least a part of the vanadium alkoxide before or after the introduction of the phosphorus compound, and (c) heating the vanadium-containing liquid medium obtained in step (b), in the presence of the phosphorus compound to reduce at least a part of vanadium to a tetravalent state.

Abstract: A method for the production of maleic anhydride in which a hydrocarbon of 4 to 6 carbon atoms is subjected to a vapor phase catalytic oxidation reaction in the presence of a metal oxide catalyst, characterized in that the metal oxide catalyst includes a metal oxide containing Mo, V, Te and X (X representing one or more elements selected from the group consisting of Nb, Ta, W, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb, Bi, B, In, P and Ce) as constituent elements thereof, and the proportion of Mo to the total metal elements in the metal oxide is 0.25 or greater in terms of the atomic ratio, and the atomic ratio of each of the other constituent elements V, Te and X with respect to Mo is in the range of 0.01-1.0.According to the method, the object maleic anhydride may be produced at a high yield using a hydrocarbon of 4 to 6 carbon atoms, particularly n-butane, as the starting material.

Abstract: Process for improving a controlled oxidation reaction between at least one reactant and oxygen, in which at least one reactant is reacted with oxygen or an oxygen containing gas, constituting a reaction mixture, in the presence of at least one additional gas which is introduced into said reaction mixture and is selected from methane, ethane and helium, and the resulting reaction product from the oxidation reaction is possibly treated so as to give a final product.

Abstract: Unsaturated compounds which can be dissolved in aqueous based solvents, such as ethylenic or acetylenic carboxylate or alcohols with less than 10 carbon atoms, especially maleic and/or acrylic acid or propargyl alcohol, are reacted with alkali metal phosphite in aqueous solution at neutral or alkaline pH in the presence of free radical initiators such as persulphate to form threshold scale and corrosion inhibitors.

Abstract: The present invention relates to processes and apparatus for mixing oxidizable reactants with oxidant and/or oxidizing oxidizable reactants. Through using particular mixing and/or oxidizing arrangements, the risk of flammable or explosive reactions can be significantly reduced or prevented. When ammonia is used as the reactant, nitric acid can be obtained.

Abstract: In the production of maleic anhydride, a crude maleic anhydride is produced which contains acrylic acid and other by-products. The crude maleic anhydride is dissolved in a solvent and the acrylic acid is distilled off. To avoid the polymerization of the acrylic acid, an inhibitor of phenothiazine is added to the distillation process.

Abstract: An improved process is provided for the production of a partial oxidation product by the vapor phase reaction of a hydrocarbon with substantially pure oxygen in the presence of a suitable catalyst. In the improved process, the partial oxidation product is removed, carbon dioxide and excess carbon monoxide, present in the reactor effluent as by-products, are also removed and the remaining gaseous effluent, comprised mainly of carbon monoxide and unreacted hydrocarbon, is recycled to the reactor. The concentration of carbon monoxide throughout the system is maintained sufficiently high to prevent the formation of a flammable mixture in the reactor or associated equipment.

Abstract: The present invention relates to processes and apparatus for mixing oxidizable reactants with oxidant and oxidizing oxidizable reactants. When ammonia is used as the reactant, nitric acid can be obtained. Through using particular mixing and oxidizing arrangements, the volume of reactant oxidized can be significantly increased.

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: 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: A process for producing anhydrides by passing a solution of the acid, preferably an organic polyacid, which is to undergo anhydridation over an acidified clay and a process for producing the catalysts therefor.

Abstract: A process for the production of carboxylic anhydrides from aromatic hydrocarbons in gas phase oxidation by using a high activity and high selectivity fluid catalyst, comprising 50 to 95% by weight calculated as TiO.sub.2 +SiO.sub.2 +B.sub.2 O.sub.3 of component (A) which comprises titanium oxide, silicon dioxide and boron oxide and5 to 50% by weight calculated as V.sub.2 O.sub.5 +M.sub.2 O (M represents an alkali metal) +SO.sub.3 of component (B) comprising vanadium oxide, an alkali metal oxide and sulfuric anhydride, wherein weight ratios of B.sub.2 O.sub.3 to TiO.sub.2 and SiO.sub.2 to TiO.sub.2 in said component (A) are in the range of 0.02 to 0.5 and 0.25 to 1.0, respectively, is provided.

Abstract: A process for reacting a fluid phase (gaseous and/or liquid phase) in contact with a solid phase in a reaction zone, wherein the improvement in said process comprises reacting the fluid phase in contact with the solid phase in a horizontally-oriented fluidized bed vessel. The vessel includes at least two compartments or stages, and includes means for vibrating the vessel. The process of the present invention enables one to effect fluidization of the solid phase independently of the flow rate or velocity of the fluid phase, thus enabling proper contact time of the fluid phase with the solid phase and minimizing the amount of fluid phase reactant to be recycled.

Abstract: An improvement in a process for the manufacture of maleic anhydride by catalytic oxidation of n-butane in the presence of trimethyl phosphate over a fixed bed vanadium phosphorus oxide catalyst in a tubular reactor. The trimethyl phosphate content of the gas entering the reactor within a range of between about (0.9) N and about (1.1) N where N is a normative concentration of trimethyl phosphate in ppm as determined by the following relationship:N+5.times.C.sub.4 +6.times.(H.sub.2 O-2.4)+0.75.times.(CONV-c)+(SV/(25.times.P.sub.in))where:C.sub.4 .times.the mole % of n-butane in the gas entering the reactor;H.sub.2 O.times.the mole % moisture in the gas entering the reactor;CONV.times.% butane conversion in the reactor;SV.times.gas hourly space velocity of the gas at the inlet of the reactor, reduced to one atmosphere pressure and 60.degree. F.;P.sub.in .times.the pressure at the inlet of the reactor (psig); andc.times.84-0.05[(SV.times.C.sub.4)/P.sub.

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: A monochloro-substituted aliphatic alcohol containing 3-8 carbon atoms, a copper compound and a zinc compound are added to maleic anhydride to prevent discoloration of the maleic anhydride. Deterioration of the quality of the maleic anhydride can be inhibited when it is stored for a long period of time or heat-melted.

Abstract: A catalyst for producing maleic anhydride by oxidation of n-butane comprising V,P and additionally Mg or Zr is prepared by(a) heating a pentavalent vanadium compound in an organic medium to reduce at least a part of the pentavalent vanadium to tetravalent vanadium,(b) reacting the resulting vanadium compound with phosphoric acid in the presence of at least one of a magnesium compound and a zirconium compound to form a catalyst precursor,(c) separating the resulting catalyst precursor from the organic medium, and(d) drying and calcining the catalyst precursor.

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: Process for the recovery of maleic anhydride from a gaseous mixture thereof, in which the gaseous mixture containing maleic anhydride is contacted with an absorbant for the maleic anhydride to give an enriched absorbant. Water present in the enriched absorbant is then substantially removed by contacting the enriched absorbant with a water adsorbant or with a low humidity stripping gas to produce a dried enriched absorbant. The maleic anhydride is then recovered from the dried enriched absorbant.

Abstract: A process for the aromatization of 4-chlorotetrahydrophthalic anhydride and 4,5-dichlorotetrahydrophthalic anhydride which comprises heating a solution of either substance in the presence of activated carbon and in the partial absence of air.

Abstract: Crude maleic anhydride produced by catalytic oxidation is distilled and then n-propyl gallate, cuprous chloride and zinc chloride are added thereto.Alternatively, crude maleic anhydride is distilled in the presence of tridecyl phosphite. Further, these procedures can be used in combination. Thermal stability and color stability of the maleic anhydride is improved.

Abstract: Novel maleic anhydride catalysts comprising phosphorus-vanadium oxides and phosphorus-vanadium-co-metal oxides wherein said catalysts do not expand under reaction conditions for the manufacture of maleic anhydride and a process for preparing these catalysts are disclosed. The process comprises reacting a vanadium compound with a phosphoryl halide in the presence of water in an atmosphere comprising at least about 0.1% oxygen wherein the molar ratio of water to phosphorus from the phosphoryl halide is in the range of about 2.25:1 to about 3.75:1.

Abstract: An improved process is provided for the production of anhydrides from hydrocarbons by reaction with an oxygen-containing gas comprising oxygen, air or a gas enriched in oxygen relative to air, in the presence of a suitable catalyst. In the process, a selective separator provides recycle of a substantial portion of the unreacted hydrocarbon as well as for a controlled amount of a gaseous flame suppressor in the system. The gaseous flame suppressor comprises a substantially unreactive hydrocarbon containing 1 to 5 carbon atoms, carbon dioxide, and nitrogen when present in the feed to the oxidation reactor. The use of air or oxygen-enriched air in the feed to the oxidation reactor is particularly advantageous from an economic view in combination with a pressure swing adsorption unit as the selective separator. The process is characterized by high selectively to the formation of the anhydride product.

Abstract: A catalytic hydrogenation process for converting maleic anhydride and/or succinic anhydride to gamma-butyrolactone, a novel selective catalyst for use in such process and a method of preparing the catalyst are provided. The process comprises contacting maleic anhydride and/or succinic anhydride with hydrogen in the presence of catalysts whereby the anhydride is converted to predominantly gamma-butyrolactone. The catalyst of the invention is comprised of transition metals, their oxides and mixtures thereof on a silica gel support having a high surface area and pore volume.

Abstract: Very pure maleic anhydride having a stable color is obtained by fractional distillation of crude maleic anhydride by a method in which the maleic anhydride vapor separated off from low boilers and high boilers is partially condensed so that from 0.5 to 15% by weight of the maleic anydride vapor is separated off from the vapor phase as a liquid precondensate, and the remaining very pure maleic anhydride vapor is then completely condensed.

Abstract: Novel maleic anhydride catalysts comprising phosphorus-vanadium oxides and phosphorus-vandium-co-metal oxides and the process for making such catalysts are disclosed. These catalysts under reaction conditions for the manufacture of maleic anhydride from butane feedstock do not expand to the point of crushing and producing fines. Moreover, the halogen level of such a catalyst is reduced.

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: Disclosed are herbicidal compounds of the general formula I: ##STR1## wherein A is O-alkylene of 1 to 5 carbon atoms, O-alkenylene of 3 to 6 carbon atoms in which the unsaturation is non-adjacent the oxygen atom thereof or NH-alkylene in which the alkylene is of 1 to 5 carbon atoms, and --COZR is an acid function or forms certain ester or thioester functions, and the mono- and di-salt forms thereof.

Abstract: A method of preparing fine crystal particles of maleic anhydride is provided. The method contains the steps of putting a molten mass of maleic anhydride into a hermetically closed container moved at a moving rate of 1 to 30 times per minute and cooling the molten mass to room temperature over three hours or more. A maleic anhydride composition contains 0.01 to 5 wt. parts of colloidal silica relative to 100 wt. parts of maleic anhydride particles.

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: Alpha, beta carbonyl compounds are prepared from an acid anhydride selected from the group consisting of glutaric anhydride and 3-alkyl glutaric anhydride, and a beta-hydroxy carbonyl compound having the following chemical formula:R.sub.2 COH--CHR--CRO or R.sub.2 COH--CHR--CNwhere each R is any substitutent group.The process comprises: (a) reacting the acid anhydride and the beta-hydroxy carbonyl compound in the presence of a catalytically effective amount of an acid catalyst to form an ester; (b) reacting the ester in the presence of a catalytically effective amount of a base catalyst to form a alpha, beta-unsaturated carbonyl compound and a carboxylic acid; and (c) separating the alpha, beta-unsaturated carbonyl compound and the carboxylic acid.

Abstract: A process for the production of maleic anhydride by catalytic air oxidation of hydrocarbons capable of being so oxidized at a temperature in the range of 300.degree.-450.degree. C.

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.