56 results about "Dimethyl maleate" patented technology

The invention discloses a method for preparing dimethyl succinate. The method comprises two reaction processes of esterification and hydrogenation and the reaction processes are as follows: (1) after pre-esterification reaction, maleic anhydride-methanol solution enters a catalytic distillation tower from the upper rectifying section of the tower, methanol enters the tower from the lower stripping section of the catalytic distillation tower, the reaction section is filled with solid acid catalyst, the two material flows perform countercurrent contact on the surface of the catalyst to perform esterification reaction and synthetize dimethyl maleate; and (2) dimethyl maleate and hydrogen are placed in a fixed bed reactor to perform hydrogenation reaction and generate the dimethyl succinate product in the presence of hydrogenation catalyst under a certain reaction condition. The method of the invention has the advantages of high raw material conversion rate and good product selectivity; and the process flow is simple, the energy consumption is low, no pollution can be caused and the scale production of dimethyl succinate can be realized.

The invention relates to a method for preparing dimethyl succinate, which comprises the following steps that: (1) dehydration and decontamination: methanol and alkali-earth metal oxide are mixed, dehydrated and decontaminated; (2) separation of solid and liquid; (3) monoesterification reaction: maleic anhydride is added in the liquid-phase material which is obtained in the previous step; (4) vacuum distillation; (5) 2-esterification reaction; (6) evaporation; (7) mixing of oil and water; (8) separation of oil and water; (9) re-eesterification; (10) evaporation; (11) mixing of oil and water; (12)separation of oil and water; (13) electrochemical reduction: hydrogen is introduced to reduce dimethyl maleate to dimethyl succinate; (14) cooling and crystallization; (15) separation of solid and liquid: solid material enters the next step; (6) re-crystallization and separation: the product dimethyl succinate is obtained. The method is simple, and has reasonable process, low preparation cost, high product purity and good quality.

The invention discloses a continuous preparation method of 1,4-butanediol. The method comprises the following steps: carrying out a monoesterification reaction on bio-based succinic acid and methanolto obtain a succinic acid monoesterification liquid containing succinic acid monomethyl ester; mixing with monomethyl maleate to obtain a mixed esterification liquid; feeding into a double esterification reaction tower, and carrying out a double esterification reaction to generate a mixture of dimethyl succinate and dimethyl maleate; feeding the mixture into a hydrogenation reactor, and carrying out a hydrogenation reaction, wherein the the dimethyl maleate in the mixture is hydrogenated to generate dimethyl succinate; and performing a cascade reaction to convert into an intermediate product gamma-butyrolactone, and then generating 1,4-butanediol and tetrahydrofuran. According to the method, the bio-based succinic acid is adopted to partially replace monomethyl maleate to produce 1,4-butanediol, so that the consumption of petroleum chemicals is reduced, and the production cost of 1, 4-butanediol is reduced; and bio-based succinic acid and methanol are subjected to a monoesterificationreaction, and then mixing is performed with monomethyl maleate, so that the mutual influence caused by co-monoesterification of succinic acid and maleic anhydride is avoided.

The invention discloses a synthesis process of dimethyl maleate. The synthesis process comprises steps as follows: maleic anhydride and methanol are subjected to a reaction in a mono-esterification reaction kettle at the temperature of 70-100 DEG C, and monomethyl maleate is generated; monomethyl maleate enters a catalytic esterification tower from a tower, methanol steam enters the catalytic esterification tower from the position below upper liquid level of each layer of tower plate and is contacted with monomethyl maleate and a solid catalyst on the tower plate, and dimethyl maleate is generated. With the adoption of continuous production, energy utilization rate is increased by full use of waste heat of the esterification reaction; with the adoption of multiple methanol steam inputs, methanol steam is distributed on each tower plate, each tower plate forms one small reactor in a boiling state, the contact area of monomethyl maleate and methyl alcohol is increased, the contact time of monomethyl maleate and methyl alcohol is prolonged, the problem of uneven distribution of methanol in the tower due to liquefied reflow of the methyl alcohol steam in a rising process is solved, the reaction efficiency and the esterification rate are increased, the methanol utilization rate is increased, the production cost is reduced while the yield is increased, and the synthesis process is suitable for industrial application.

The invention relates to a preparation method of a copper hydrogenation catalyst, which comprises the following steps: adding a mixed salt solution of soluble copper salt and other metal soluble salts into an alkali solution to prepare corresponding hydroxide precipitate, filtering, washing with water, uniformly mixing with a sodium hydroxide solid phase, adding warm water and aluminum powder paste into the mixed material, and uniformly stirring, and maintaining for a certain time at a certain temperature, then transferring into a still kettle for treatment, then replacing sodium ions in the system through hydrothermal treatment, and finally drying and roasting to obtain the copper-based catalyst. The copper-based catalyst prepared by the method has the characteristics of small stacking density, large porosity, high activity and multiple catalytic functions, and is particularly suitable for and simultaneously used as a catalyst for preparing ethylene glycol by hydrogenation of dimethyl oxalate, preparing butanediol by hydrogenation of dimethyl maleate/dimethyl succinate, preparing 1, 4-cyclohexanedimethanol by hydrogenation of 1, 4-cyclohexanedicarboxylic acid dimethyl ester, preparing 2-methyl furan by hydrogenation of furfural/furfuryl alcohol, and the like.

The invention provides a production method of dimethyl maleate, and in particular relates to a method used for producing the dimethyl maleate by enabling mixed liquid, which is obtained by using dimethyl maleate as a solvent to absorb maleic anhydride in maleic anhydride-containing mixed gas and is taken as a raw material, and methanol to be subjected to an esterification reaction. The production method comprises the following steps: enabling the maleic anhydride-containing mixed gas to be subjected to heat exchange and preliminary cooling, and then enabling the maleic anhydride-containing mixed gas to enter the bottom of an absorption tower and be in counter-current contact with the dimethyl maleate sprayed from the top of the tower so as to obtain absorption liquid; filling an esterification tower with solid acid esterification catalyst filler, pumping the absorption liquid from the top of the esterification tower, and enabling the pumped absorption liquid and the methanol at the bottom of the esterification tower to be subjected to a contact type reaction; obtaining a dimethyl maleate crude product at the bottom of the tower, distilling to obtain the dimethyl maleate product, and returning part of the dimethyl maleate product for absorbing the maleic anhydride in a spraying way; carrying out distillation and separation on water-containing methanol steam on the top of the tower to obtain methanol and water, and returning the methanol for the esterification reaction.

The invention belongs to the technical field of chemical products, and particularly relates to a dimethyl maleate hydrogenation reaction catalyst as well as a preparation method and an application thereof. The catalyst comprises the following elements in percentage by mole: 30 to 40 percent of Cu, 20 to 30 percent of Mn, 10 to 20 percent of Al, 10 to 20 percent of Zn, 0 to 5 percent of Ag and 0 to 5 percent of Ru. The Al element, the Ag element and the Ru element are added into the catalyst, so that dispersion and modification of active components in the catalyst are realized, the total selectivity of BDO and gamma-butyrolactone can reach 93%, the cost can be effectively reduced, and the catalyst is green and environment-friendly. According to the present invention, with the catalyst, the 1, 4-butanediol and/or gamma-butyrolactone can be prepared with high selectivity by changing the reaction conditions during the 1, 4-butanediol preparation process through the dimethyl maleate hydrogenation reaction catalyst; the preparation method of the catalyst is simple and low in cost, and the prepared catalyst is environmentally friendly and has long service life.

The invention discloses a preparation method of an inorganic solid catalyst, which is used for synthesizing dimethyl maleate and belongs to a catalyst synthesis technology. The method comprises the following steps of: firstly heating and activating a zeolite molecular sieve, then processing with an ammonium chloride solution, a ferric chloride solution or a magnesium chloride solution, and then calcining and activating to obtain the inorganic solid catalyst with selective catalytic activity. The catalyst can be used for a continuous reaction rectifying production process, is easy to separate, can be recycled, has good heat resisting property, high activity, good selectivity and less side reaction, can be used under the conditions of pressurized high temperature, is not easy to age or deteriorate and can not pollute products, and the single pass yield of the dimethyl maleate reaches more than 90 percent.

The invention discloses leather used flame retardant and a preparation method thereof. The leather used flame retardant is composed of the following components in weight part: 10-20 parts of PVC (polyvinyl chloride) resin, 20-30 parts of tricresyl phosphate, 3-8 parts of chlorinated paraffin, 2-5 parts of orthophthalic dimethyl formamide, 10-20 parts of dimethyl maleate, 2-6 parts of calcium chloride, 1-3 parts of sodium acetate, 4-8 parts of triethanolamine, 30-50 parts of butyl acetate and 400-600 parts of water. Compared with the prior art, the leather used flame retardant has the benefits as follows: (1) good flame retardant effect, no damage to leather surface; and (2) simple preparation process, easy-to-obtain raw materials and low cost.

An oxidation resisting calcium carbonate filler is prepared from the following raw materials in parts by weight: 1-2 parts of ammonium polyphosphate, 1-2 parts of ASA, 1-2 parts of cyclohexanone, 0.4-0.8 part of epoxy soja bean oil, 0.8-1.1 parts of zinc diricinoleate, 1.5-1.8 parts of dimethyl maleate, 1.5-1.8 parts of bismaleimide resin, 0.1-0.2 part of lauric acid polyoxyethylene esters, 2.6-2.9 parts of dibutylhydroxytoluene, 3-5 parts of alcohol, 20-30 parts of modified wood meal, 180-200 parts of light calcium carbonate, and 60-80 parts of water. The oxidation resisting calcium carbonate filler provided by the invention has excellent oxidation resistance, and can reinforce oxidation resistance and weather resistance of a plastic; through adoption of the modified wood meal, the oxidation resisting calcium carbonate filler is compatible with PVC, and can reinforce heat preservation performance, shock resistance and coloration properties of the plastic; the oxidation resisting calcium carbonate filler is suitable for manufacturing of doors and windows of PVC and other plastics, can reduce the cost, improve machining property, and prolong service life, is recycled easily, and can protect the environment.

The invention relates to an esterification reactor and a production method of dimethyl maleate. The esterification reactor is suitable for esterification reactions of carboxylic acids and alcohols. The reactor is composed of a plurality of tower plates; each tower plate is provided with a downtake pipe and an ascension pipe, wherein the ascension pipe is connected with a gill type gas distributor; each tower plate reserves a certain liquid level liquid, wherein the liquid contains a solid catalyst; and the liquid phase is a component containing a carboxylic acid, flows downward from an esterification tower plate to the following tower plate in the reactor, and reacts with rising alcohol steam countercurrent. The esterification reactor has the advantages of adequate contact of three phases (gas, liquid and solid), high reaction efficiency, high volume utilization rate of the reactor, and the like; and is suitable for various esterification reaction processes.

The invention discloses long-acting antibacterial PAE resin, a preparation method thereof and a coating composition. Dimethyl maleate and hydroxyl quaternary ammonium salt are subjected to transesterification, the obtained maleate quaternary ammonium salt and aliphatic diamine are subjected to Michael addition reaction, and the long-acting antibacterial PAE resin is obtained. Due to the high branching characteristic of the resin, the flowability of the resin is better, and the resin has sufficient operation time during polyurea double-component floor construction by adjusting the proportion; and meanwhile, the dendritic macromolecular structure contains a large number of cavities and has a good effect on stabilizing and dispersing the nano-silver, and the antibacterial effect does not decline remarkably along with long-time use or aging of the terrace.

The invention relates to a method for one-step production of 1, 4-butanediol through liquid phase hydrogenation of dimethyl maleate. The method comprises the following steps: adding dimethyl maleate, a catalyst and a solvent dioxane into a high-pressure reaction kettle, sealing, introducing hydrogen until the pressure is 5-7MPa, and reacting for 7-12 hours at 140-220 DEG C while stirring to obtain 1, 4-butanediol, the catalyst is a copper-zinc-magnesium catalyst or a silylation reagent modified copper-zinc-silicon catalyst; according to the invention, 1, 4-butanediol with the yield of 97.8% can be obtained under the temperature and pressure condition equivalent to or milder than that of gas phase hydrogenation, which is higher than that of most hydrogenation in the prior art, and heat and hydrogen consumption required by raw material gasification are saved.

The invention discloses a synthesis method of 2-acetonyl-1, 4-dimethyl succinate, which comprises the following steps: mixing acetone (1), dimethyl maleate (2) and pyrrolidine, reacting at 20-200 DEG C for 0.5-20 hours, and post-treating the reaction liquid to obtain 2-acetonyl-1, 4-dimethyl succinate (3); the reaction system is simple, raw materials are cheap and easy to obtain, post-treatment operation is simple and convenient, and industrial production is facilitated;