192results about "Preparation from carboxylic acid anhydrides" patented technology

The invention discloses a technological process for continuously producing succinic anhydride and co-producing succinic acid through maleic anhydride catalytic hydrogenation. The whole process comprises three steps, namely, reaction, rectification and hydrolysis, wherein two stages of hydrogenation reactors are used for reaction, a primary hydrogenation reactor is a fixed bed reactor with hydrogen entering from the lower part and reaction liquid exiting from the upper part, and a secondary hydrogenation reactor is a trickle bed reactor with hydrogen and reaction liquid entering from the upper part and exiting from the lower part. The technological process adopts an external circulating heat radiation manner, and reaction heat is uniformly removed, so that the average operation temperature of the whole reactor is effectively controlled, and the reaction temperature in the whole main reactor is balanced. Furthermore, the primary hydrogenation reactor adopts the manner that both the maleic anhydride solution and hydrogen flow upward simultaneously, so that the reaction temperature of the whole reactor is controlled to be balanced, local hot spot temperature is effectively controlled and lowered, and the reactants are prevented from polymerizing and depositing carbon or coking.

The invention provides a method for degrading and recycling an unsaturated polyester resin material. The method comprises the following steps: preparing a reaction solution by a catalyst and a reaction solvent; mixing the reaction solution with an unsaturated polyester material to prepare an unsaturated polyester degrading system; heating the prepared unsaturated polyester degrading system for degradation; adding a separation solvent into the cooled unsaturated polyester degrading system; filtering to obtain solids, namely enhanced fibers and a catalyst; drying and sieving, and recycling; adding water into filtrate so as to separate out a polymer degrading component containing a styrene structure, and filtering; drying and recycling the filtered polymer solids containing the styrene structure; and evaporating filtrate to obtain substances mainly comprising resin degraded products which do not contain the styrene structure. The method for degrading and recycling the unsaturated polyester resin material has the advantages of low cost, moderate recycling conditions and high degrading activity.

The invention discloses a method for preparing butanedioic acid under catalytic hydrogenation, which is characterized in that one or more of maleic anhydride water solution, fumaric acid water solution or maleic acid water solution are arranged inside a fixed bed reactor with catalyst to be hydrogenated to obtain butanedioic acid. By adopting the fixed bed, the catalytic hydrogenation preparationof butanedioic acid realizes the continuous mass production; transformation rate of raw materials and selectivity of the butanedioic acid reach more than 99 percent, and the purity of the product reaches more than 99.5 percent; the catalyst is of a particle-shaped load-type catalyst, and the separation of the product and the catalyst is not required; by adopting the mother liquid cycling utilization technology, raw material is saved, cost is reduced, yield can reach 100 percent, and zero emission of the three wastes is realized; and the process flow is simple, the economies of scale are large, the yield is high, and the production cost and the energy consumption are low.

A chemically-modified graphene includes a graphene layer and a plurality of functional groups that are grafted to the graphene layer and each of which is represented by —CO—R—COOH, wherein R is an optionally substituted C₁-C₅ alkylene group or an optionally substituted C₁-C₅ alkenylene group. A method for producing a chemically-modified grapheme includes subjecting a cyclic anhydride and graphite to a Friedel-Crafts reaction in the presence of a Lewis acid.

The invention discloses a preparation method of 4-bromophthalic acid. The preparation method comprises the following steps: by taking phthalic anhydride, sodium hydroxide and sodium bromide as raw materials, evenly mixing phthalic anhydride and sodium hydroxide, under the ultrasonic condition, adding a sodium hypochlorite water solution for reaction, and controlling the pH value of the reaction liquor, to obtain a target product 4-bromophthalic acid. The purity of the 4-bromophthalic acid obtained by adopting the method is more than 98.5%, and the yield is more than 80%, so that the method meets the green and environment-friendly demands. Compared with the prior art, the preparation method has the advantages that the use of high-toxicity and volatile high-price bromine can be avoided, the utilization rate of bromine can achieve more than 90%, the unreacted phthalic acid can be recovered, and thus the green chemical demand is met; under the ultrasonic condition, the method is good in selectivity, the reaction is slow and easy to control, the 4-bromophthalic acid is high in yield, stable in quality and suitable for industrial production.

Processes for forming butyric acid are provided. In one process, maleic anhydride is formed by oxidizing a hydrocarbon containing gas. The maleic anhydride is then hydrogenated in the presence of a hydrogenation catalyst to form butyric acid. The selectivity of maleic anhydride to butyric acid is at least about 35 molar percent.

The invention provides a clean production method for acetic acid cracking for preparation of diketene. The method comprises the steps of cracking, condensation, absorption, polymerization, distillation, and residue hydrolysis treatment. The method is characterized in that dilute acetic acid is added in the residue hydrolysis section to obtain acetone, acetic acid and secondary residue; the acetone is for recycling, part of the acetone is mixed with the secondary residue to provide heat for fuel production; and acetic acid is subjected to separation, extraction and concentration and enters the cracking section as a production raw material. The invention has the advantages that by optimizing the process and the circular route, the generated waste gas and residue in the production process are digested and absorbed in the system, so as to realize clean production.

The invention provides a method for preparing 2-alkyl anthraquinone by taking solid super acids as catalysts. The 2-alkyl anthraquinone (alkyl is straight or branched alkyl with the number of carbon atoms of 1-6) is obtained by adopting the solid super acids like perfluorinated sulfonic acid resin and heteropoly acid as the catalysts, taking 2-(4'-alkyl benzoyl) benzoic acid as a raw material andperforming acylated dewatering closed loop through Friedel-Crafts reaction. The method provided by the invention is characterized in that traditional smoking sulfuric acid catalysts are replaced by the solid super acids, so that the environment is friendly, and no waste acid is discharged; the operation process is simple, and the solid catalysts are easy to recover; therefore, the method is a green pollution-free new process.

The invention discloses a method for preparation of acetic anhydride and acetic acid by means of carbonyl synthesis of methyl acetate and methanol azeotrope. The synthesis reaction is operated in a carbonyl synthesizing kettle (1) which is provided with a mixer, a bypass circulation device controlled by a high-pressure pump and a gas distributor (8) at the bottom. The method includes steps of adding azeotrope and catalyst from the upper portion of the kettle, and gaseous carbon monoxide is fed into the kettle from the bottom of the kettle through the gas distributor (8). The internal pressureof the kettle is 3.0-4.5MPa, and the reaction temperature is 140-220 GEG C. The catalyst includes rhodium catalyst, catalysis-supporting methyl iodide and lithium acetate, the rhodium catalyst with the concentration ranging from 200ppm to 800ppm is selected from rhodium triiodide or rhodium chloride, adding quantity of the methyl iodide is 10-30% of that of the azeotrope, and the concentration ofthe lithium acetate is two to three times of that of the rhodium catalyst. Reaction liquid sequentially passes through a flash evaporation kettle (2), a light component removing tower (3), an acetic acid tower (4) and an acetic anhydride tower (5) to obtain acetic anhydride with purity higher than 97% and acetic acid with purity higher than 99%. The method effectively resolves the problem of comprehensive utilization of methyl acetate and methanol azeotrope.

The invention provides a device and process for continuously producing chloroacetic acid by differential circle flow. The device comprises a main reactor, a pre-reactor, a separator, a circulating pump, a primary condenser, a secondary condenser, a demister, a discharge pump, pipelines and automatic control instruments, wherein both the main reactor and the pre-reactor are a tubular micro-channelreaction heat exchanger; a plurality of micro-channels are arranged in the main reactor; the main reactor is provided with a plurality of longitudinal main-reactor tube passes and a plurality of transverse main-reactor shell passes; the main-reactor shell passes are connected with a main-reactor cooling water inlet and a main-reactor cooling water outlet respectively arranged on two sides of the main reactor; and a gas-liquid mixing chamber is arranged at the bottom of the main reactor. Compared with the traditional technology, the device and process have the following advantages: a hydrodechlorination device and an auxiliary hydrogen chloride absorption device are saved, the equipment investment cost is reduced, generated polychlorinated compounds in the chlorination liquid are reduced bythe differential circle flow process and the production efficiency and quality of chloroacetic acid are improved.

The invention discloses a tert-carboxylic acid synthesis method. According to the method, olefin and carbon monoxide serve as raw materials, and a tert-carboxylic acid product is obtained through catalyzed synthesis under normal pressure or low pressure in the presence of strongly acidic ionic liquid-metal carbonyl complex catalyst. Corrosion is avoided, catalyst consumption is low, three-waste discharge is low, the tert-carboxylic acid product and the catalyst can be separated easily after reaction ends, and the defects of existing technologies that separation effect is poor and dilute sulphuric acid recovery is hard are overcome.

The invention is a method for catalytic synthesis of cinnamic acid by water-soluble calixarene phenolate, belonging to the technical field of preparation of organic compounds. The method comprises thefollowing steps: with the water-soluble calixarene phenolate as a catalyst, allowing the water-soluble calixarene phenolate to catalyze benzaldehyde and acetic anhydride to generate a perkin reaction, or catalyze benzaldehyde and propane diacid to generate a Knoevenagel reaction so as to prepare the cinnamic acid, wherein the calixarene phenolate can be repeatedly utilized for a plurality of times. According to the invention, the calixarene phenolate is calixarene phenolate sodium(possitium) salt which is formed through a reaction of calix[n]arene sulfonic acid (n is equal to 4, 6 and 8) andthiocalix[4]arene sulfonic acid with NaOH, KOH, Na2CO3 and K2CO3; and the usage amount of the calixarene phenolate accounts for 5 to 10% of the mass of the benzaldehyde. In the perkin reaction, the mass ratio of the benzaldehyde to the acetic anhydride is 1: 1 to 1: 4; the temperature of the reaction is 140 to 170 DEG C; and the time of the reaction is 1 to 2 h. In the Knoevenagel reaction, the mass ratio of the benzaldehyde to the propane diacid is 1: 1 to 1: 4; the temperature of the reaction is 120 to 150 DEG C; and the time of the reaction is 1 to 2 h. The process of the reaction does notgenerate three industrial wastes like waste gas, waste water and waste residue and is a green chemical process, so the pollution to the environment is reduced; and after completion of the reaction, the product is easily to be separated from the catalyst. The method provided by the invention has the advantages of simple process, high yield, environmental friendliness and low cost, and is a method applicable to industrial production.

The invention relates to a method for the continuous production of unsaturated carboxylic acid anhydrides of formula (I) R-C(O)-O-C(O)-R (I), wherein R is an unsaturated organic group with 2 to 12 C atoms, by anhydride exchange interaction of an aliphatic carboxylic acid anhydride with a carboxylic acid of formula (II) R-COOH (II), wherein R is defined as above, in a rectification column having an upper, a middle and a lower zone. The method is characterized in that f) an inert boiling oil is present in the sump of the column, g) the feed-stock is fed to a reaction zone in stoichiometric ratios, h) the carboxylic acid formed as a by-product is removed at the top of the column, i) the non-reacted feed-stock is returned to the reaction zone, and j) the product of formula (I) is obtained via a lateral outlet, preferably between the middle and the lower column zone.

A process which comprises reacting a 1,2,3,4-cyclobutanetetracarboxylic-1,2:3,4-dianhydride [1] with an alcohol [2] in the presence of an acid catalyst to obtain a compound [3], isomerizing the compound [3] with a base catalyst into a compound [4], reacting the compound [4] with an organic acid to obtain a compound [5], and reacting the compound [5] with a dehydrating agent to obtain a 1,2,3,4-cyclobutanetetracarboxylic-1,3:2,4-dianhydride: wherein R¹ and R² are each independently hydrogen, halogeno, alkyl of 1 to 10 carbon atoms, halogenated alkyl of 1 to 10 carbon atoms, cycloalkyl of 3 to 8 carbon atoms, phenyl, or cyano; and R³ is alkyl of 1 to 10 carbon atoms.

The invention provides a calcium carbonate modifier and a preparation method thereof. The calcium carbonate modifier is eleostearic acid estolide hydrolysate, which is prepared by taking eleostearic acid and maleic anhydride as materials to directly synthesize eleostearic acid estolide by one-step procedure and using a proper amount of water to hydrolyze the eleostearic acid estolide. The invention has the advantages of simple production process, low production cost, high yield, easy popularization and the like. The calcium carbonate modifier has more action points and can chemically react with calcium carbonate, thereby having better effect than the traditional stearic acid modifier.

The invention discloses a synthesis method for 3,3',4,4'-biphenyltetracarboxylic acid. The synthesis method comprises the following steps: with 4,4'-dimethyl biphenyl as a starting raw material, subjecting the 4,4'-dimethyl biphenyl and cyclic anhydride as shown in a formula I which is described in the specification to a Friedel-Crafts acylation reaction so as to obtain an intermediate II, and carrying out an oxidation reaction so as to obtain the 3,3',4,4'-biphenyltetracarboxylic acid, wherein the cyclic anhydride as shown in the formula I is selected from the group consisting of succinic anhydride, glutaric anhydride, adipic anhydride and maleic anhydride. The method provided by the invention does not need an expensive catalytic system, so the production cost of synthesizing the 3,3',4,4'-biphenyltetracarboxylic acid is greatly reduced; the method provided by the invention is simple to operate, mild in reaction conditions, less in three wastes, easy in wastewater treatment and friendly to the environment; and the raw material, namely the 4,4'-dimethyl biphenyl adopted in the method provided by the invention is a byproduct of a medical intermediate, namely sartan biphenyl, and theproduction amount of the byproduct accounts for about 10% of the production amount of the sartan biphenyl, so the waste can be turned into treasure after the byproduct is applied to synthesis of the3,3',4,4'-biphenyltetracarboxylic acid.