1848 results about "Dimethyl carbonate" patented technology

A lithium ion electrochemical cell having high charge/discharge capacity, long cycle life and exhibiting a reduced first cycle irreversible capacity, is described. The stated benefits are realized by the addition of at least one nitrate additive to an electrolyte comprising an alkali metal salt dissolved in a solvent mixture that includes ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate. The preferred additive is an organic alkyl nitrate compound.

A lithium ion electrochemical cell having high charge/discharge capacity, long cycle life and exhibiting a reduced first cycle irreversible capacity, is described. The stated benefits are realized by the addition of at least one nitrite additive to an electrolyte comprising an alkali metal salt dissolved in a solvent mixture that includes ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate. The preferred additive is an alkyl nitrite compound.

The invention relates to a non-aqueous electrolyte for high-voltage lithium ion batteries, which is prepared from the following raw materials in percentage by weight: 70-85% of carbonate, 3-20% of functional additive and 11-17% of lithium hexafluorophosphate. The carbonate is one or mixture of more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylethyl carbonate, methyl propyl carbonate and methyl butyl carbonate; and the functional additive is one or mixture of more of 0.5-10% of negative pole film-forming additive, 0.5-10% of high-temperature additive, 0.5-10% of positive pole film-forming additive, 0.5-10% of high-voltage additive and 0.001-2% of stability additive. The invention solves the problem of adaptation of the lithium ion battery electrolyte to the 4.35V high-voltage battery positive/negative pole, and provides an electrolyte for high-voltage batteries, which has the advantages of high cycle life, low inflation rate and favorable high-temperature properties.

The transesterification process for preparing methyl ethyl carbonate features that the materials dimehtyl carbonate and ethanol in the molar ratio of 1-4 to 1 produce transesterification reaction at normal pressure and 50-110 deg.c in the presence of binary heterogeneous solid alkali catalyst for 1-8 hr to prepare methyl ethyl carbonate. The solid alkali catalyst has consumption of 5-25 % of ethanol weight and is prepared through soaking process or sol-gel process, and used catalyst may be separated easy from the reaction product for reuse. The transesterification reaction is completed in a reaction-rectification apparatus and has methyl ethyl carbonate yield up to 90 %.

The invention discloses a continuous extractive distillation separation method of a dimethyl carbonate-methanol azeotropic mixture, and relates to a continuous extractive distillation method. The technical process of the method is as follows: ethylene glycol is used as an extraction agent at normal pressure; the solvent ratio is 1-3; the separated dimethyl carbonate-methanol azeotropic mixture is fed from the middle part of a tower, the extraction agent is fed from the top of the tower, and the reflux ratio is 2; high-purity methanol is extracted from the tower top of an extractive distillation tower, and the dimethyl carbonate and the extraction agent are extracted from the tower bottom; the fraction at the tower bottom enters an extraction agent recovery tower, and the reflux ratio is 3; and dimethyl carbonate is extracted from the tower top, and the extraction agent extracted from the tower bottom can be recycled. The method disclosed by the invention adopts ethylene glycol as an extraction agent, and improves the separation effect of the dimethyl carbonate-methanol azeotropic mixture; and since ethylene glycol is a co-production product in synthesizing dimethyl carbonate by a transesterification method, the source is conveniently available, and the cost caused by introducing other substances is avoided.

A process for the production of a dialkyl carbonate and a diol, such as dimethyl carbonate and ethylene glycol, by reacting a feed containing a cyclic carbonate, a hydroxy alkyl carbonate and an aliphatic monohydric alcohol in the presence of a transesterification catalyst is described. In another aspect, a process is described which is particularly useful for producing unsymmetric dialkyl carbonates, such as ethyl methyl carbonate.

A lithium ion electrochemical cell having high charge/discharge capacity, long cycle life and exhibiting a reduced first cycle irreversible capacity, is described. The stated benefits are realized by the addition of at least one dicarbonate additive to an electrolyte comprising an alkali metal salt dissolved in a solvent mixture that includes ethylene carbonate, dimethyl carbonate, ethylmethyl carbonate and diethyl carbonate. The preferred additive is an alkyl dicarbonate compound.

The present invention is directed to at least partially replacing PC and/or DME with a linear carbonate, preferably dimethyl carbonate, and a linear mono-ether, the most preferred being diisopropyl ether, in electrolytes useful for activating alkali metal-containing cells. This electrolyte has improved conductivity and provides electrochemical cells with enhanced discharge performance. A most preferred electrolyte comprises 1,2-dimethoxyethane, propylene carbonate, dimethyl carbonate and diisopropyl ether.

A method for producing dimethyl carbonate from methanol and carbon dioxide using a heterogeneous catalyst is described. The heterogeneous catalyst provides both acidic sites and basic sites. The reaction can be carried out at atmospheric pressure and relatively low temperatures.

The invention relates to a method for synthesizing methylethyl carbonate by ester exchange of dimethyl carbonate and diethyl carbonate, which is implemented by carrying out synthetic reaction of methylethyl carbonate on raw materials dimethyl carbonate and diethyl carbonate by using an imidazole ionic liquid as a catalyst at certain reaction temperature under ordinary pressure for some reaction time. The catalyst consumption is only 0.2-2 wt% of the dimethyl carbonate; the ionic liquid catalyst has high catalytic activity in the reaction process, the maximum yield of methylethyl carbonate is up to 62.31%, and the selectivity is 100%; and the catalyst can be recycled for cyclic utilization after being subjected to simple treatment after reaction, has the advantages of long service life and no pollution, and greatly lowers the preparation cost of methylethyl carbonate.

The invention relates to a technology and a device system for producing dimethyl oxalate by high-pressure carbonylation of industrial synthesis gases and producing ethylene glycol through dimethyl oxalate hydrogenation. The technology comprises the following steps: adopting industrial NO, O2 and methanol as raw materials for an esterification reaction to produce methyl nitrite; adopting industrial CO and methyl nitrite for a carbonylation reaction in a plate reactor to produce carbonylation products, which mainly include dimethyl oxalate and dimethyl carbonate; separating the carbonylation products to obtain dimethyl carbonate products; subsequently adding hydrogen into dimethyl oxalate in the plate reactor to produce ethylene glycol products; conducting the coupling recovery treatment on waste acids in the esterification reaction and purge gases in the carbonylation reaction for recycling. The device system comprises an esterification reaction system, a carbonylation reaction system, a coupling recovery system for purge gases and waste acids and a hydrogenation reaction system. The technology has the characteristic that device consumption is remarkably reduced, and particularly the nitric acid waste liquid recycling and purge gas recycling technologies as well as the separation technologies thereof are highly coupled; recycling of the raw materials in reaction waste gases is realized, and the effect is remarkable.

The invention provides a supported palladium-based catalyst and a preparation method and an application thereof. The supported palladium-based catalyst comprises an active ingredient and a carrier, wherein the active ingredient is a palladium-based compound; the carrier is selected from at least one of aluminum oxide, silicon oxide, magnesium oxide, zinc oxide, zirconium oxide, titanium dioxide, metal organic framework compound, activated carbon, molecular sieve, carbon nanotube, and graphene. The supported palladium-based catalyst is applied to the reaction of methyl nitrite vapor-phase carbonylation preparing dimethyl carbonate, and has the advantages that the catalytic activity is high, the product selectivity is high, and the service life is long.

The synthesis method of methyl ethyl carbonate belongs to the technical field of organic compounds synthesized by ester exchange. Dimethyl carbonate and diethyl carbonate, or dimethyl carbonate and ethanol are used as raw materials to perform ester exchange in the presence of catalyst. The reaction mode comprises two kinds of fixed bed continuous reaction and kettle-type reaction. The catalyst issolid alkali catalyst in which the carrier is active carbon, carbon molecular sieve or mesoporous carbon and the active component is Na2O, K2O, MgO, CaO, SrO or BaO. In the process of fixed bed continuous synthesis, the catalyst is stable without inactivation after long-term use, thereby retaining the high yield of the methyl ethyl carbonate, simplifying the production process, and achieving environmental friendliness and energy conservation. In the kettle-type reaction, the catalytic efficiency is high, the catalyst can be recovered by simple filtering and re-sintering, and the target product can be obtained in short time with high yield.

A gasifying osmotic film for separating the azeotropic methanol/dimethyl carbonate solution is prepared from polyvinyl alcohol and polyacrylic acid. Its preparing process is also disclosed.

The invention provides a method for separating dimethyl carbonate and methanol through pressure-swing distillation of heat pump, and an apparatus thereof. In the dimethyl carbonate and methanol through pressure-swing distillation of the heat pump, an atmospheric azeotropic steam material obtained from the top of an atmospheric rectification tower is supercharged and heated by a heat pump compressor, and is introduced to a reboiler at the bottom of the atmospheric rectification tower as a heat source, so a liquid in the atmospheric rectification tower is heated, and the self-condensation of the atmospheric azeotropic steam material is completed. Compared with traditional atmospheric azeotropic steam material condensation through using cooling water and kettle liquid heating realized through an extra external heat source, the method in the invention properly improves the temperature and the pressure of an atmospheric azeotropic steam through the heat pump compressor to make the atmospheric azeotropic steam realize the kettle liquid heating and the reasonable and effective energy cycle as a heat source; and the cost generated by the pump heat compressor is far lower than the cost of traditional cooling water and the external heat source, so a good economic benefit is generated.

The invention relates to a technique for coproduction of dimethyl carbonate and propylene glycol, in particular to a novel technique for purifying high-quality propylene glycol in the production process of dimethyl carbonate. The technical scheme includes the steps of reactive distillation, extractive distillation, separation of the dimethyl carbonate, the recovery and refining of carbinol, primary carbonization, first filtration of sodium carbonate crystals and refining of the propylene glycol. The invention solves the problem of low recovery rate of the propylene glycol, and the recovery rate of the propylene glycol can be above 95%. Meanwhile, the propylene glycol has more stable quality, with the purity reaching 99.99% and the chroma less than 10, thereby the propylene glycol totally meets the requirements for medical auxiliary material, daily cosmetics, top grade unsaturated resin and polyether. Meanwhile, the purity of the byproduct dipropylene glycol can be above 99.50%, thus improving the benefit of the equipment.

The invention discloses a direct catalytic synthesis catalyst to prepare dimethyl carbonate from methanol and carbon dioxide and the preparation and application methods of the catalyst. The catalyst of the invention consists of transitional metal soluble salt, promoter and carrier, with the weight ration from 0.01to 0.5: 0.01to 0.1:1. The preparation method is that: (1) the carrier is impregnated into the transition metal soluble salt solution; (2) the promoter is added into the solution, which is stirred in room temperature, ultrasonically dispersed and stored stationarily in room temperature; (3) the solution is dried, sintered, reduced and activated to produce catalyst. The application method is that: the catalyst is put in high pressure reactor or micro reaction device with the temperature of the catalyst bed controlled between 90 degrees centigrade to 140 degrees centigrade and the reaction pressure between 0.6 to 3.0MPa. The catalyst is applicable in direct catalytic synthesis to prepare dimethyl carbonate from methanol and carbon dioxide. The raw material sources are rich, the cost is low, the preparation method is simple and the operation is easy. The catalyst is easily separated from the products, the reaction conditions are mild and the catalyst can be used repeatedly. The catalyst has high activity and selectivity.

The invention discloses a low-temperature type carbonic ester lithium battery electrolyte. The electrolyte mainly comprises the following components: ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate and propylene carbonate as solvents, lithium hexafluorophosphate and a low temperature additive. The four carbonic ester solvents are in the following weight ratio: EC: DMC: EMC: PC=2:3:5:1; the components are prepared into an 1 mol / L electrolyte containing LiPF6, four carbonic ester solvents, the low temperature additive; and the low temperature additive is one selected from polydimethylsiloxane, 1,3- propane sultone, and vinylene carbonate, or a combination thereof. According to the invention, optimization of composition of the carbonic ester solvents and addition of the low temperature additive are employed to increase solubility, degree of dissociation and conductivity of the electrolyte, improve structure of a solid phase interfacial film (SEI membrane) of the lithium ion battery cathode, the integral stability of the battery and battery cycling and prolong usage life. Especially, the invention provides a mainstream electrolyte for lithium ion power batteries used in a lowest temperature of -50 DEG C in most regions in northern China.

The invention relates to a preparation method for high-viscosity 107 glue. The preparation method comprises the following steps of: adding a certain amount of DMC (Dimethyl Carbonate) and 107 glue of which the viscosity is 100-1,500 cs or a certain amount of DMC into a reactor provided with a stirrer, a thermometer and a condensation reflowing pipe, starting stirring, heating to a certain temperature, and adding an alkali catalyst, wherein the alkali catalyst comprises one of potassium hydroxide, tetramethylammonium hydroxide pentahydrate, tetrabutyl phosphorus oxychloride or silicon alkoxidealkali gel of the alkalis; undergoing a balanced reaction at the temperature for certain hours, and directly neutralizing or heating for decomposing the alkali catalyst; and adding a phosphoric acid or silanol hydrochloric acid gel neutralizing agent of which the mass is equal to that of the catalyst under the condition that neutralization is performed, or directly heating for decomposing the alkali catalyst under the condition that neutralization is not performed, continuously stirring for 1 hour, and removing low-boiling-point substances. The high-viscosity 107 glue prepared with the methodhas the advantages of simple preparation process, stable viscosity, high product yield and capability of meeting production requirements.

This invention relates to lithium ion battery electrolyte with high times and discloses the main components as following: vinylene carbonate for 10 to 30 percentage; propylene carbonate for 4 to 20 percentage; dimethyl carbonate for 35 to 50 percentage; methyl carbonate for 10 t0 20 percentage; lithium salt for 12.5 to 16 percentage and B(OR)<3> with R representing carbon atoms less than 4 or crown ether of one or more function addictives for 0.1 to 5.0 percentage.

The invention discloses a dimethyl carbonate supported catalyst directly synthesized by methanol and carbon dioxide and a preparation method and a use method. The catalyst adopts diatomite as carrier, transition metal copper and nickel as main components of active components and zinc, iron, cobalt and the like as additives, wherein, the weight percent of diatomite in the catalyst is 60-95%, the weight percent of the transition metals is 5-30% and the weight percent of the additives is 0-15%. The preparation method comprises the following steps: soaking the carrier in a mixed solution of soluble transition metal salt and the additives, dispersing with ultrasound, evaporating and drying, calcining and reducting with hydrogen to obtain the supported catalyst. The use method comprises the following steps: placing the catalyst in a reaction device, adjusting the molar ratio of gas phase methanol to carbon dioxide to 2:1-3:1, and performing a reaction at 110-140 DEG C under the pressure of 0.6-3.0 MPa. The catalyst has the advantage of simple preparation steps, good stability and high catalytic efficiency and overcomes the defect that the carrier used by the existing catalyst needs be processed through complicated steps for pretreatment and has high price and instable catalytic performance.