Abstract: The present invention relates to a process for preparing an anhydride of formula A-C(?O)—O—(O?)C-A, where A is —CR?CH2 and R is —H or —CH3, comprising: a) a step of reacting an anhydride B—C(?O)—O—(O?)C—B with an acid A-COOH, A being as defined above, wherein the step results in the formation of an anhydride A-C(?O)—O—(O?)C—B and of an acid B—COOH, A and B being such that said acid B—COOH is more volatile than said acid A-COOH, and b) a step of reacting said anhydride A-C(?O)—O—(O?)C—B with the acid A-COOH under conditions such that the amount of acid B—COOH is less than the amount of acid A-COOH, resulting in the formation of the anhydride A-C(?O)—O—(O?)C-A, in which said reaction steps are carried out in the presence of an acid catalyst which is more volatile than said anhydride A-C(?O)—O—(O?)C-A.

Abstract: In a process for producing anhydrides in a tubular reactor, gaseous reactants are passed downwardly through at least one reactor tube to a catalyst carrier where they pass into a passage defined by an inner perforated wall of a catalyst container before passing radially through the catalyst bed towards a perforated outer container wall. The reaction occurs as gas contacts the catalyst. Unreacted reactant and product exits the container though the perforated outer wall and then upwardly between an inner surface of a container skirt and the outer wall of the container and then over the end of the skirt and caused to flow downwardly between the outer surface of the skirt and the inner surface of the reactor tube where heat transfer takes place. These steps are repeated at any subsequent catalyst carrier product is then removed from the reactor outlet.

Abstract: It is an object of the present invention to provide a method for producing (meth)acrylic anhydride that provides high yield and high efficiency and can suppress side reactions, in a method for reacting (meth)acrylic acid with a fatty acid anhydride to produce (meth)acrylic anhydride. The method for producing (meth)acrylic anhydride according to the present invention is a method for producing (meth)acrylic anhydride, including reacting a fatty acid anhydride with (meth)acrylic acid to produce (meth)acrylic anhydride, while extracting a fatty acid produced as a by-product, wherein the reaction is performed, while adjustment is performed so that a molar ratio of the (meth)acrylic acid to the (meth)acrylic anhydride in a reaction liquid is 0.3 or more.

Abstract: In a process for producing anhydrides in a tubular reactor, gaseous reactants are passed downwardly through at least one reactor tube to a catalyst carrier where they pass into a passage defined by an inner perforated wall of a catalyst container before passing radially through the catalyst bed towards a perforated outer container wall. The reaction occurs as gas contacts the catalyst. Unreacted reactant and product exits the container though the perforated outer wall and then upwardly between an inner surface of a container skirt and the outer wall of the container and then over the end of the skirt and caused to flow downwardly between the outer surface of the skirt and the inner surface of the reactor tube where heat transfer takes place. These steps are repeated at any subsequent catalyst carrier product is then removed from the reactor outlet.

Abstract: It is an object of the present invention to provide a method for producing (meth)acrylic anhydride that provides high yield and high efficiency and can suppress side reactions, in a method for reacting (meth)acrylic acid with a fatty acid anhydride to produce (meth)acrylic anhydride. The method for producing (meth)acrylic anhydride according to the present invention is a method for producing (meth)acrylic anhydride, including reacting a fatty acid anhydride with (meth)acrylic acid to produce (meth)acrylic anhydride, while extracting a fatty acid produced as a by-product, wherein the reaction is performed, while adjustment is performed so that a molar ratio of the (meth)acrylic acid to the (meth)acrylic anhydride in a reaction liquid is 0.3 or more.

Abstract: Process for continuously preparing unsaturated carboxylic anhydrides of the general formula I R—C(O)—O—C(O)—R??(I) in which R is an unsaturated organic radical having 2 to 12 carbon atoms by transanhydridization of an aliphatic carboxylic anhydride with a carboxylic acid of the general formula II R—COOH??(II) in which R is as defined above in a rectification column having an upper, middle and lower region, characterized in that f) an inert boiling oil is initially charged in the bottom of the column, g) the reactants are fed into a reaction region in stoichiometric ratios, h) the carboxylic acid formed as the by-product is withdrawn at the top of the column, i) the unconverted reactants are recycled into the reaction region and j) the product of the formula I is obtained via a side draw, preferably between the middle and lower column region.

Abstract: 2,3,3?,4?-biphenyltetracarboxylic acid is heat-dehydrated in a molten state at a temperature not lower than 200° C. in a flow of an inert gas in a reactor 10 having at least one reaction vessel 11 by stirring the molten material to produce 2,3,3?,4?-biphenyltetracarboxylic dianhydride. Thus obtained 2,3,3?,4?-biphenyltetracarboxylic dianhydride in the molten state is subsequently cooled and solidified in an inert gas or dry air, or cooled and solidified in the ambient air at a temperature of 40° C. or lower or 100° C. or higher.

Abstract: The invention provides an improved process for preparing unsaturated carboxylic anhydrides of the general formula I R—C(O)—O—C(O)—R??(I) in which R is an unsaturated organic radical having 2 to 12 carbon atoms by transanhydridizing an aliphatic carboxylic anhydride with a carboxylic acid of the general formula II R—COOH??(II) in which R is as defined above, in an apparatus consisting of a reaction region and a rectification column, characterized in that a) the reactants are fed into a reaction region in stoichiometric ratios, b) the carboxylic acid formed as a by-product is removed from the reaction mixture, c) the carboxylic anhydride of the formula I is subsequently drawn off, d) the unconverted reactants are recycled into the reaction region, e) the reaction region comprises a heterogeneous catalyst and f) one or more polymerization inhibitors are added.

Abstract: A process for preparation of 7-[D-?-amino-?-(4-hydroxyphenyl)acetamido]-3-(1-propen-1-yl)-3-cephem-4-carboxylic acid viz. Cefprozil of formula (I) in high purity, substantially free of impurities, which comprises preparation of mixed acid anhydride by selecting the sequence and temperature of addition of the reagents and its subsequent condensation with a protected 7-APCA; followed by hydrolysis, isolation and purification to give Cefprozil of formula (I) in the form of a monohydrate.

Abstract: A process for producing 2,3,3?,4?-biphenyltetracarboxylic dianhydride (a-BPDA), comprising dehydrating 2,3,3?,4?-biphenyltetracarboxylic acid in an inert gas atmosphere under heating at 180 to 195° C. is disclosed. This process produces high-purity a-BPDA which is suitable for production of a polyimide.

Abstract: A catalyst is described which has a catalytically active composition which contains a phase A and a phase B in the form of three-dimensional delimited regions, wherein phase A is a silver-vanadium oxide bronze and phase B a mixed oxide phase based on titanium dioxide and vanadium pentoxide. The catalyst serves to prepare aldehydes, carboxylic acids and/or carboxylic anhydrides from aromatic or heteroaromatic hydrocarbons by gas phase oxidation.

Abstract: A process for producing N-carboxyanhydrides is disclosed. The process produces N-carboxyanhydrides as a product and HCl as a by-product. The HCl by-product is purged from the reaction mixture by passing a purge gas through the reaction mixture as a carbonylation reagent is reacting with an amino acid or a salt thereof. The N-carboxyanhydrides produced by this process have a relatively lower chloride impurity content, relatively higher yields can be achieved, and the N-carboxyanhydrides can be produced on a larger scale.

Abstract: A process for the batchwise preparation of (meth)acrylic anhydride, in which acetic anhydride is reacted with (meth)acrylic acid and the acetic acid is at least partly removed gradually as it is formed. In the process, the acetic acid removed is at least partly replaced by introducing into the reaction medium, during the reaction, acetic anhydride and/or (meth)acrylic acid. The (meth)acrylic anhydride obtained by this process may be used in the synthesis of (meth)acrylic thioesters, (meth)acrylic amides and (meth)acrylic esters, in polymerization reactions or as crosslinking agents.

Abstract: This process for the manufacture of isobutyric anhydride by reacting acetic anhydride with isobutyric acid, distilling the acetic acid generated as it is formed, is characterized in that the reactor is initially loaded with at least a portion of one of the reagents and a portion of the other such that the reagents are in an excess molar ratio relative to the stoichiometry of one of the reagents, and the reaction is carried out while adding the remainder of the reagents as the reaction progresses and according to the place left free in the reactor by the distillation of the acetic acid produced by the reaction, until the desired overall molar ratio of the reagents is reached.

Abstract: The present invention relates to a process for preparing an unsaturated carboxylic acid anhydride by reacting an unsaturated carboxylic acid and a lower aliphatic carboxylic acid anhydride in the presence of a stabilizer and catalyst that contains a metal salt of an anionic organic compound which has at least one carboxyl group.

Abstract: According to the present invention there is provided a process for producing an acid anhydride by reacting a carboxylic acid, preferably a carboxylic acid having a polymerizable group, with a sulfonyl halide compound in the presence of a tertiary amine or in the presence of a tertiary amine and an inorganic base, wherein the tertiary amine or the tertiary amine and the inorganic base are used in an amount of 0.9 to 1.2 equivalents relative to the acid generated from the sulfonyl halide compound.

Abstract: The invention provides substituted phenol compounds and pharmaceutical compositions containing substituted phenol compounds which are useful for inducing or maintaining anesthesia or sedation in a mammal. This invention also provides methods for inducing or maintaining anesthesia or sedation in a mammal using substituted phenol compounds.

Abstract: There is disclosed an advantageous mixed acid anhydride production method of formula (1): R1C(O)OY(O)n(R2)p  (1) wherein R1, R2 and Y denote the same as defined below, n and p denote an integer of 1 or 2, which is characterized by adding a carboxylic acid of formula (2); R1COOH  (2) wherein R1 denotes a hydrogen atom, an optionally substituted alkyl group or the like, an organic base to a solution of a carboxylic acid activating agent of formula (3); (R2)pY(O)nX  (3) wherein R2 denotes an optionally substituted aliphatic hydrocarbyl group or the like, Y denotes a carbon atom, a phosphorus atom, or a sulfur atom, and X denotes a chlorine atom or the like.

Abstract: Disclosed herein are compositions comprising organic anhydrides having a reduced tendency to discolor with time, even when held at elevated temperatures for extended times. The compositions are produced by mixing at least one acid halide and various derivatives of hydroxy carboxylic acids with an anhydride to form a homogenous solution. Also disclosed is a process for preparing the compositions.

Abstract: This invention is related to the production of trimellitic anhydride (TMA). More specifically, the invention is related to the addition of a mineral acid or salt thereof in the production process of trimellitic anhydride to reduce the viscosity of the bottoms fraction when TMA is purified by distillation and thus to prevent fouling/plugging. This permits the use of lower levels of TMA in the bottoms fraction and increases TMA recovery.

Abstract: There is provided a process for producing high molecular weight polymer comprising the step of reacting one or more preformed linear polymers with one or more cores (as hereinbefore defined) to form high molecular weight polymers, wherein the preformed linear polymers are at a temperature in the range from the melting point of the preformed linear polymers to 330° C.

Abstract: Aromatic hydrocarbons are partially oxidized in the gas phase over a catalyst at elevated temperature to form carboxylic acids or carboxylic anhydrides in a process in which a gas stream laden with the starting materials is passed through a shell-and-tube reactor whose temperature is controlled by means of one or more separate thermostatting baths conveyed in countercurrent to the starting gas stream, wherein the difference between the temperature of the thermostatting bath in the region of the reactor outlet and the temperature of the product gas stream leaving the reactor is employed to control the selectivity of the gas-phase oxidation.

Abstract: Disclosed herein are compositions comprising organic anhydrides having a reduced tendency to discolor with time, even when held at elevated temperatures for extended times. The compositions are produced by mixing at least one acid halide and various derivatives of hydroxy carboxylic acids with an anhydride to form a homogenous solution. Also disclosed is a process for preparing the compositions.

Abstract: Processes for producing citraconic anhydride and citraconic acid using porous materials with specific surface acidities and surface areas are described. The preferred catalyst is a porous gamma alumina. Itaconic acid is produced from citraconic acid. Itaconic acid is an intermediate to a variety of compounds including polymers.

Abstract: The invention relates to a method for producing shell catalysts for the catalytic vapor-phase oxidation of aromatic carboxylic acids and/or carboxylic acid anhydrides comprised of a supporting core and of catalytically active metal oxides which are deposited in a shell-shaped manner on said supporting core. The inventive catalysts are obtained by spraying an aqueous active mass suspension, said suspension containing the active metal oxides, at higher temperatures onto the hot supporting material which has a temperature ranging from 50 to 450° C. The aqueous active mass suspension contains 1 to 10 wt. %, with regard to the solid content of the active mass suspension, a binding agent comprised of A) a polymerizate obtained by radical polymerization, containing 5 to 100 wt. % of monomers (a) in the form of ethylenically unsaturated acid anhydrides or ethylenically unsaturated dicarboxylic acids whose carboxyl groups can form an anhydride and containing 0 to 95 wt.

Abstract: The invention relates to a process for the batchwise preparation of (meth)acrylic anhydride, in which acetic anhydride is reacted with (meth)acrylic acid and the acetic acid is at least partly removed gradually as it is formed.

Abstract: A process for preparing an unsaturated carboxylic acid anhydride, which includes: reacting an unsaturated carboxylic acid and a lower aliphatic carboxylic acid anhydride in the presence of: a catalyst; and a stabilizer.

Abstract: Xylene derivatives, such as chloro-ortho-xylene, are oxidized in the absence of solvent or added promoter in the presence of at least one metal catalyst. The primary products are chlorophthalic anhydride and chlorotoluic acid.

Abstract: Xylene derivatives, such as chloro-ortho-xylene, are oxidized in a solvent in the presence of at least one metal catalyst with addition of promoter after the reaction has proceeded to an intermediate stage of conversion to product mixture. The product comprises chlorophthalic acid or chlorophthalic anhydride.

Abstract: There is disclosed an advantageous mixed acid anhydride production method of formula (1):

Abstract: The invention concerns a method consisting in making a mixed (meth)acrylic anhydride of formula (I) by reacting an alkaline (meth)acrylate of formula (II) and a chloroformate of formula (III), carrying out said reaction in an aqueous medium and in the absence of amines, the mol ratio chloroformate (III)/alkaline (meth)acrylate (II) being at least equal to 1.15. R1 represents H or CH3; R2 represents an alkyl, alkenyl, aryl, alkaryl or aralkyl residue; and M is an alkaline metal.

Abstract: A method for generating a solution containing rhodium at a concentration of at least 0.01 M and preferably at least 0.20 M, comprising treating solid rhodium iodide or other solid source of rhodium with a reducing agent selected from a source of hydrazine, hydrazine hydrate, hydrazinium salts, organic derivatives of hydrazine, hypophosphorous acid and salts of hypophosphorous acid.

Abstract: Process for the preparation of N-carboxy-t-leucine anhydride in which the corresponding N-carboxy-t-leucine is subjected to a cyclization with the aid of an acyl halogenide. Preferably, acetyl chloride is used as acyl halogenide.

Abstract: The invention relates to a method for producing gas-phase catalysts gas-phase oxidation of aromatic hydrocarbons into carboxylic acids and/or carboxylic acid anhydrides upon whose carrier material a coating containing catalytically active metal oxide is applied in the form of a shell, wherein a powder is initially produced from a solution and/or suspension of catalytically active metal oxides and the precursor compounds thereof or simply the precursor compounds in the presence or absence of auxiliary agents in order to produce the catalyst. Said powder is then applied, in the form of a shell, to the carrier in the presence or absence of auxiliary agents after or without previous conditioning and without previous thermal treatment to produce the catalyst. The carrier which is thus coated undergoes thermal treatment in order to produce catalytically active metal oxides.

Abstract: In a liquid phase carbonylation process for the production of acetic anhydride by reacting a feed stream which includes methyl acetate, methanol and carbon monoxide using a Group VIII metal-containing catalyst, and preferably a rhodium containing material, a liquid reaction product is continuously withdrawn from the carbonylation zone and fed to an evaporation/separation zone for separating volatile constituents of the reaction from the non-volatile constituents which, includes a portion of the Group VIII metal catalyst from the carbonylation reactor. The Group VIII metal catalyst is contacted with a gas stream which includes hydrogen for a period of from about 0.001 seconds to about 200 seconds as it is being returned to the carbonylation zone.

Abstract: The present invention relates to compositions comprising mixtures of two enantiomeric forms of diacyl tartaric anhydride and mixtures obtainable by reacting an organic compound with a mixture comprising two enantiomeric forms of diacyl tartaric anhydride. The invention also relates to a method for the preparation of such enantiomeric mixtures, starting from a mixture comprising D-tartaric acid and L-tartaric acid. The method involves reacting tartaric acid with a fatty acid anhydride under dielectric heating conditions.

Abstract: Polymer-bound mixed carboxylic anhydrides can be prepared under mild conditions by the condensation of carboxylic acids (including N-protected amino acids) with polymer-bound acid chlorides. These mixed anhydrides function as polymeric reagents in the sense that they will react readily with monomeric nucleophiles such as amines to form amide or peptide products, depending on the identities of the mixed anhydride and amine reactants. However, in spite of their reactivity, these polymeric mixed anhydrides exhibit a significant degree of stability under conditions of prolonged storage, which suggests that such compounds have commercial utility as a relatively stable form of highly activated carboxylic acids. The polymeric support can be reactivated and recycled for repeated use in the derivatization process.

Abstract: Dialkyl dicarbonates are obtained particularly advantageously from halogenoformic esters by reaction with alkalis in the presence of water-immiscible organic solvents and in the presence of a catalyst, if the catalyst used is benzylalkyldimethylammonium halides. The catalyst is then particularly easy to separate off and to recycle from the reaction mixture.

Abstract: Disclosed is a process for the coproduction of (1) an alkyl iodide and (2) an .alpha.-iodocarboxylic acid, a mono-.alpha.-iodocarboxylic anhydride or a mixture thereof which comprises contacting a mixture of an iodine compound and a carboxylic anhydride with a peroxide at an elevated temperature.

Abstract: Excess terephthalic acid or isophthalic acid is reacted with a phosgene/DMF complex nearly to completion in one or more stages to form terephthaloyl chloride or isophthaloyl chloride; in another stage, by-product formylbenzoyl chloride is oxidized and terephthaloyl chloride or isophthaloyl chloride containing less than 100 ppm of formylbenzoyl chloride and/or dichlorotoluoylchloride is recovered.