82 results about "Methyl propionate" patented technology

The invention relates to a method for controlling wheat septospora which is resistant to a C14-demethylase inhibitor fungicide. The present invention relates to a method for controlling wheat septospora on a cereal plant, which wheat septospora comprises at least one mutation in the CYP51 gene and is resistant to a C14-demethylase (in sterol biosynthesis) inhibitor fungicide (DMI fungicide), the method comprises applying to these plants, seeds or soil of the plants a fungicidally effective amount of (I) methyl 2-[2-chloro-4-(4-chlorophenoxy) phenyl]-2-hydroxy-3-(1, 2, 4-triazol-1-yl) propionate or (II) 2-[2-chloro-4-(4-chlorophenoxy) phenyl]-2-hydroxy-3-(1, 2, 4-triazol-1-yl) propionic acid.

The present application relates to a system for preparing high-purity MMA, comprising a diethyl ketone separation unit for separating diethyl ketone from ethylene carbonylation products; a condensation reaction unit arranged downstream of the diethyl ketone separation unit, for performing condensation reaction on the product separated by the diethyl ketone separation unit to generate MMA; and a rectification separation unit arranged downstream of the condensation reaction unit, for separating the product of the condensation reaction unit to obtain high-purity MMA. After the synthesis of methyl propionate by ethylene carbonylation, the byproduct DEK is first separated and removed by the diethyl ketone separation unit, and the methyl propionate and methanol material containing the diethyl ketone after removal are subjected to condensation reaction with formaldehyde to generate MMA, effectively avoiding the problem of difficult separation of diethyl ketone DEK and MMA with very similar boiling points, and then high-purity MMA is easily obtained by separation.

The invention belongs to the technical field of lithium batteries, and relates to a lithium ion battery, in particular to a phosphate battery with both battery rate capability and safety performance. The lithium ion battery comprises a positive plate, a negative plate, a diaphragm and a non-aqueous electrolyte, the positive plate comprises a positive electrode material layer containing a phosphate material; the organic solvent comprises a first solvent, and the first solvent is selected from at least one of methyl acetate, ethyl acetate and methyl propionate; the lithium salt comprises LiPF6 and LiFSI; the first additive comprises a compound as shown in a structural formula 1; the lithium ion battery satisfies 0.02 < = 10c / a + e < = 1.8, 40 < = a < = 60, 1.1 < = b < = 1.5, 0 < e < = 1.5, and 0.05 < = c < = 2. According to the lithium ion battery provided by the invention, high-concentration LiPF6, low-content LiFSI and high-content carboxylic ester are matched with one another, so that the compatibility of rate capability and safety performance of a phosphate battery is realized.

This invention discloses a method for preparing 1,3-propanediol by hydrogenation of methyl 3-hydroxypropionate. Using manganese-doped layered copper silicate prepared by deposition precipitation as a precursor, a highly dispersed and stable copper-based catalyst is obtained through reduction. The manganese doping and layered copper silicate species enhance the interaction between copper and the support, improving the dispersion of active copper species. Simultaneously, the layered copper silicate increases the difficulty of copper species reduction, thereby improving the Cu content of the catalyst. + / Cu 0 The strong metal-support interaction and the dispersing effect of manganese can effectively inhibit the migration and aggregation of active copper species during the reaction, thus improving the stability of the catalyst. The copper-based catalyst prepared in this invention exhibits high conversion and 1,3-propanediol selectivity in the hydrogenation reaction of methyl 3-hydroxypropionate, with high catalytic activity and stability, and few byproducts, showing good prospects for industrial application.

The application designs a method for preparing optically active methyl fluoropropionate by using diethylamine sulfur trifluoride, comprising the following steps: fluorination reaction: under the protection of nitrogen, methyl S-lactate is added to a dry reaction kettle as raw material, the kettle temperature is cooled to a first reaction temperature, diethylamine sulfur trifluoride is added dropwise into the reaction kettle, after dropping, the reaction kettle is heated to a second reaction temperature, after the reaction is completed, the reaction mixture is added dropwise into saturated sodium / potassium bicarbonate aqueous solution to obtain R-2-fluoropropionic acid methyl ester; the molar ratio of diethylamine sulfur trifluoride to methyl S-lactate is 1-1.5:1, the method is high in efficiency, low in three-waste amount, short in reaction path, suitable for industrial production, and has economic value.

The application discloses a mineral tackifier special for shotcrete and a preparation method thereof, and relates to the technical field of tackifiers. The mineral tackifier is obtained through graft copolymerization reaction of 1-vinyl-2-pyrrolidone, acrylic acid, xanthan gum and hyperbranched borate under the action of an initiator; the hyperbranched borate is generated through reaction of a hyperbranched product and 1,4-benzenediboronic acid under the catalysis of anhydrous magnesium sulfate; and the hyperbranched product is prepared through esterification reaction of 3-(bis(2-hydroxyethyl)amino)propionic acid methyl ester and 2-methyl-2-propenoic acid-2,3-dihydroxypropyl ester. The mineral tackifier prepared by the application has good compressive strength and short setting time.

The application discloses a bubble column reactor for preparing methyl propionate, a reaction system and a method. The reactor comprises a bubble column body, a gas distributor and a sieve plate. The application divides the inner cavity of the reactor into multiple spaces through multiple sieve plates, and performs CO segmented feeding on the reaction of synthesizing methyl propionate from a carbonyl group through multiple gas distributors, so that the partial pressure ratio of CO and ethylene in the reactor is reduced, the gas-liquid ratio is obviously reduced, and the reaction conversion rate is obviously improved.

Fungicidal compositions comprising carboxamides The present invention relates to fungicidal compositions comprising at least one compound selected from the group consisting (I-1) N-[1,3-dimethyl-1-(phenylmethyl)butyl]-8-fluoro-3- quinolinecarboxamide, (I-2) N-[(1R)-1-benzyl-1,3-dimethyl-butyl]-8-fluoro-quinoline-3- carboxamide, (I-3) N-[(1S)-1-benzyl-1,3-dimethyl-butyl]-8-fluoro-quinoline-3-carboxamide, as active component 2) at least one compound, or an N-oxide, or an agriculturally useful salt thereof, selected from the group consisting of (II-1) methyl 2-[2-chloro-4-(4- chlorophenoxy)phenyl]-2-hydroxy-3-(1,2,4-triazol-1-yl)propanoate, (II-2) fluoxytioconazole, (II-3) flumetylsulfurim, (II-4) pyrapropoyne, wherein the weight ratio of compound I to compound II is from 10:1 to 1:10. The invention also relates to an agrochemical composition comprising the composition and a solvent of solid carrier. Further, the invention relates to a non-therapeutic use of the inventive compositions controlling phytopathogenic harmful fungi.

The application discloses a preparation method of 3-methyl mercaptopropionate, and belongs to the technical field of pesticide intermediate preparation. The application takes di-tert-butyl disulfide and methyl acrylate as raw materials, generates 3-tert-butyl mercaptopropionate under the action of lithium borohydride, then generates 3-methyl mercaptopropionate and 5-tert-butyl-1,3-dimethoxybenzene under the action of tri (pentafluorophenyl) boron while isobutene is removed and isobutene reacts with m-dimethoxybenzene, and 3-methyl mercaptopropionate is obtained after rectification. In the method, the route is good in operability, low in three wastes and cost, and provides a reference for the preparation of the compound.

The present disclosure relates to a method for preparing methyl propionate from ethylene or C2 mixed gas, comprising the following steps: mixing a heterogeneous catalyst with a liquid acid to obtain a mixed catalyst; the heterogeneous catalyst comprises a Pd precursor, a phosphine ligand and an acidic molecular sieve; the pH of the liquid acid is greater than or equal to 4; the content of the liquid acid in the mixed catalyst is 500-3000 ppm; pure ethylene or C2 mixed gas, CO and methanol are contacted with the mixed catalyst to carry out the reaction of ethylene alkoxycarbonylation to prepare methyl propionate, to obtain a liquid phase mixed product containing methyl propionate and an optional gas phase product containing ethane; wherein the C2 mixed gas comprises ethylene and ethane. The present disclosure replaces the homogeneous catalyst with the heterogeneous catalyst, develops a process for preparing high-value-added methyl propionate from widely available ethylene and low-cost C2 mixed gas, and can realize large-scale industrial production.

The present invention relates to a method for efficiently producing a compound derived from the commercially available and readily available 3-((3S)-7-bromo-2-((2-hydroxypropyl)amino)-5-(pyridin-2-yl)-3H-benzo[e][1,4]diazepine-3-yl)propionate methyl ester, namely, the compound 3-[(4S)-8-bromo-1-methyl-6-(2-pyridinyl)-4H-imidazo[1,2-a][1,4]benzodiazepine-4-yl]propionate methyl ester benzenesulfonate (remimazolam besylate).

The invention discloses a formaldehyde probe as well as a preparation method and application thereof, and belongs to the technical field of fluorescent probe preparation. Dissolving benzylamine and potassium carbonate in anhydrous acetonitrile, adding 2-bromo-2-methyl propionate, and reacting to obtain a compound 3; dissolving the compound 3 and lithium hydroxide in a mixed solution of tetrahydrofuran and water, reacting for a period of time, and quenching the reaction with hydrochloric acid to obtain a carboxylic acid intermediate 4; and dissolving the carboxylic acid intermediate 4 in dichloromethane, then adding CDM, EDCI and DMAP, and carrying out a reaction to obtain the target product DPM. The DPM is a formaldehyde regeneration type fluorescent probe and can realize formaldehyde detection in a mode of disturbing an endogenous steady state to the minimum extent. The DPM is a steady-state maintenance type formaldehyde probe successfully applied to a spinal cord injury (SCI) model for the first time, and can realize visual monitoring on formaldehyde rise of a diseased region based on a non-invasive living imaging system (IVIS).

The application discloses a heptadecyl imidazole type efficient corrosion inhibitor, a preparation method and application thereof, and belongs to the technical field of corrosion inhibitors for steel in an acidic environment. The efficient corrosion inhibitor is methyl 3-(2-heptadecyl imidazole)-2-methyl propionate, and a chemical structural formula is as follows: the efficient corrosion inhibitor is prepared through an addition reaction of 2-heptadecyl imidazole and methyl methacrylate; the application has the advantages of low drug dosage, simple synthesis method, high efficiency, safety and environmental protection; the application is used in an acidic environment such as industrial pickling and oil and gas well acidification, and compared with a conventional imidazole type corrosion inhibitor, a lower drug dosage can achieve high corrosion inhibition efficiency; in particular, in a 1 M HCl solution, when the drug dosage is 300 mg / L, the corrosion inhibition efficiency on Q235 steel reaches 98.11%.

The invention provides a method for preparing methyl propionate in one step by taking ethylene, carbon monoxide and methanol as raw materials. According to the method, cobalt salt or a cobalt compound and a pyridyl-containing organic compound form a catalytic system, and ethylene can be effectively catalyzed to be converted into methyl propionate at the temperature of 80-180 DEG C and the pressure of 0.5-8 Mpa. The mechanism for realizing the method is that divalent cobalt is promoted to be converted into key active species Co2 (CO) 8 and HCo (CO) 4 by utilizing the alkalinity and coordination capability of a pyridyl organic matter in a CO atmosphere with enough pressure, and a characteristic peak of a key intermediate HCo (CO) 4 is captured through electrospray ionization mass spectrometry (figure 4). Compared with the prior art, the methyl propionate synthesis method has the advantages that carbonyl esterification of ethylene can be realized under relatively mild conditions without using noble metals and acidic auxiliaries, unreacted gas can be recycled, the catalyst can be recycled through rectification, and the methyl propionate synthesis method is green and economical.

This invention relates to a method for preparing methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, a raw material for synthesizing antioxidants 1010 and 1076. Specifically, this invention uses 2,6-di-tert-butylphenol and methyl 3-bromopropionate as reactants, adds an organic solvent, and reacts them in a reaction system under light and in the presence of a palladium catalyst to obtain methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; furthermore, the reaction system also includes an alkaline additive. This invention provides a novel method for preparing methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. By activating the C-H bond at the 4-position of the benzene ring of 2,6-di-tert-butylphenol, a methyl propionate group is directly attached to the 4-position of the benzene ring. Compared to existing technologies, this method does not require strong bases or highly toxic reagents and has a lower reaction temperature. This method has the potential to be an alternative to existing methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate preparation processes and a new route for obtaining synthetic raw materials for antioxidants 1010 and 1076.

The utility model discloses a storage device for methyl 3-hydroxypropionate production, and relates to the technical field of methyl 3-hydroxypropionate storage, the storage device comprises a heat preservation box, a storage box is installed in the heat preservation box, and a plurality of partition plates are fixedly connected to the inner side wall of the heat preservation box from top to bottom at equal intervals. During use, the space between the outer side face of the storage box and the inner side wall of the heat preservation box is divided into the multiple cavities through the multiple partition plates, temperature sensors are installed in the multiple cavities, and then the multiple first temperature adjusting assemblies located in the multiple cavities are matched, so that when the local temperature is abnormal, the first temperature adjusting assemblies can adjust the temperature of the heat preservation box. According to the storage device, the temperature of the chamber where the temperature is abnormal can be independently adjusted, so that local temperature adjustment work can be rapidly and accurately completed, the reliability of temperature adjustment of the storage device is improved, energy consumption generated by temperature adjustment can be reduced, and the economical efficiency and practicability of the storage device are improved.

The invention discloses a synthetic method of (S)-2-(N-t-butyloxycarboryl)-3-(4-bromine-2-thiazolyl) methyl propionate, which is characterized in that (R)-N-t-butyloxycarbonyl-3-iodo-alanine methyl ester and 2, 4-dibromothiazole are used as reactants, a reducing agent, a catalyst and a cocatalyst are added into a reaction solvent, and the (S)-2-(N-t-butyloxycarboryl)-3-(4-bromine-2-thiazolyl) methyl propionate is synthesized through one-step reaction. According to the invention, cheap reagents are adopted, the reaction can be completed in one step, the defects of use of an expensive noble metal catalyst, harsh reaction conditions and complex operation in the existing synthesis method are overcome, the yield is higher, and the method can be suitable for industrial production and has good economic value.

The invention discloses a method for preparing a chiral indazole intermediate (R)-2-amino-3-(7-methyl-1H-indazole-5-yl) methyl propionate of zavazepam, which comprises the following steps of: taking zavazepam as a raw material; the preparation method comprises the following steps: by taking methyl pyruvate as a raw material, generating an enol silyl ether compound of formula IV in situ under the action of a hydrogen pulling reagent and a silicon etherification reagent; coupling the alpha-keto ester compound with a halogenated indazole compound V under the action of a palladium catalyst to obtain an alpha-keto ester compound VI; and finally, carrying out stereoselective transaminase reaction on the compound shown in the formula VI by utilizing specific modified transaminase, so as to efficiently prepare the target chiral intermediate. According to the method, chemical synthesis and biological catalysis are creatively combined, the route only needs three steps, the process is remarkably simplified, the total yield is high, the reaction condition is mild, an expensive chiral catalyst does not need to be used, the yield is remarkably improved by introducing a reaction aid into key steps, and the whole process is easy to amplify and suitable for industrial production.

The invention relates to a catalyst for preparing 1, 3-propylene glycol through hydrogenation of methyl 3-hydroxypropionate and a preparation method of the catalyst, and mainly solves the problems that the activity of the catalyst is reduced due to agglomeration of an active component Cu, and the selectivity of the 1, 3-propylene glycol is low. The preparation method comprises the following steps: (1) forming an ammonia complex ion solution from a main active component Cu and one or more of assistants Zn, Ni, Co, Cr, Pt and Ag, and forming composite nanoparticles under the action of a reducing agent; (2) adding a silicon source and one or more of carrier assistants Zr, La, Ce, Ga, Ti and Al into the solution containing the composite nanoparticles, and forming a silicon dioxide supported composite catalyst under a hydrothermal condition; and (3) carrying out suction filtration, washing, drying and roasting to obtain the catalyst. According to the present invention, the active auxiliary agent and the main active component Cu effectively form the composite particles, and the composite particles and SiO2 are organically combined under the hydrothermal condition so as to improve the dispersity of Cu, such that the activity and the stability of the catalyst are improved;

According to the preparation method, indene amine and dicyandiamide are used as reactants, magnesium-aluminum hydrotalcite is used as a catalyst, a biguanide intermediate is obtained through a reaction in an organic solvent, the Mg / Al molar ratio of the magnesium-aluminum hydrotalcite is 3: 1-4: 1, and the magnesium-aluminum hydrotalcite is roasted and activated at the temperature of 400-500 DEG C; and reacting the biguanide intermediate with R-2-methyl fluoropropionate, so as to generate the indaziflam. According to the present invention, the activated magnesium-aluminum hydrotalcite is adopted as the catalyst to prepare the indaziflam, such that the aluminum-containing wastewater can be avoided, the property of the biguanide intermediate generated through the reaction is stable, and the purity and the yield of the prepared indaziflam are high.

The application relates to a sodium ion battery wide-temperature electrolyte and a preparation method and application thereof, relates to the technical field of battery electrolytes, and solves the core problems of poor wide-temperature domain adaptability, low low-temperature ion conductivity and insufficient cycle stability of existing sodium ion battery electrolytes. The electrolyte comprises a sodium salt, a composite organic solvent and a functional additive; the composite organic solvent is a mixture of ethylene carbonate, methyl ethyl carbonate and methyl propionate; the functional additive is a mixture of vinylene carbonate and sodium difluoro oxalate borate; in an argon glove box with water oxygen content of less than or equal to 0.1 ppm, ethylene carbonate, methyl ethyl carbonate and methyl propionate are added into a preparation container, and are uniformly stirred at room temperature to obtain the composite organic solvent; sodium hexafluorophosphate is added in batches, and is stirred until completely dissolved to obtain a basic electrolyte; the functional additive is added into the basic electrolyte, and is uniformly stirred at room temperature to obtain the wide-temperature electrolyte. The application can meet the application requirements in the fields of extreme environment special power sources and the like.

The invention relates to a method for separating a C2 mixed gas, which comprises the following steps: contacting the C2 mixed gas, CO and methanol with a heterogeneous catalyst, and carrying out a reaction for preparing methyl propionate by alkoxycarbonylation of ethylene to obtain a liquid-phase mixed product and a gas-phase product, wherein the C2 mixed gas comprises ethylene and ethane; the heterogeneous catalyst comprises a Pd precursor, a phosphine ligand and an acidic molecular sieve. According to the invention, ethylene can be efficiently utilized to form a chemical product methyl propionate with high added value, and the chemical product methyl propionate is separated from ethane, so that an industrial route with high economic feasibility is provided for the utilization of concentrated ethylene of enterprises.

The invention discloses a synthesis method of an alcohol amine polymer emulsifier for emulsion explosives, which comprises the following steps: (1) carrying out 1, 4 addition reaction on methyl acrylate and acetyl bromide to obtain methyl 3-bromopropionate, and reacting with diethanol amine to generate methyl N, N-dihydroxyethyl-3-aminopropionate; and (2) carrying out esterification reaction on the N, N-dihydroxyethyl-3-amino methyl propionate and polyisobutylene succinic anhydride to prepare the polyisobutylene succinic anhydride-N, N-dihydroxyethyl-3-amino methyl propionate. And (3) carrying out esterification reaction on the polyisobutylene succinic anhydride-N, N-dihydroxyethyl-3-amino methyl propionate and triethanolamine to prepare the alcohol amine polymer emulsifier. According to the invention, the problem of poor product singleness caused by complex molecular configuration of polyalkenyl ester polymer emulsifiers of polyhydric alcohols and polyhydric alcohol amines can be solved, and the problem of large quality fluctuation of the product in industrial production can be controlled. By adopting the new method, the high-quality alcohol amine polymer emulsifier can be continuously and quickly produced, and the produced emulsifier has the characteristics of good emulsifying capacity, high emulsion forming speed and the like.

The invention relates to the field of a medicine Zaveshift for treating migraine, in particular to a preparation method of (R)-2-amino-3-(7-methylindazole-5-yl) methyl propionate. Comprising the following steps: 1, preparing 2-hydroxy-3-methyl-5-chloromethyl benzaldehyde; step 2, preparing 7-methyl-5-chloromethylindazole; (3) preparing 7-methyl-5-hydroxymethyl indazole; step 4, preparing 7-methylindazole-5-formaldehyde; step 5, preparing 2-nitro-3-(7-methyl indazole-5-yl)-methyl acrylate; and step 6, preparing the 2-nitro-3-(7-methyl indazole-5-yl Step 6, preparing 2-amino-3-(7-methylindazole-5-yl)-methyl acrylate; and step 6, preparing 2-amino-3-(7-methylindazole-5-yl) And step seven, preparing the (R) 2-amino-3-(7-methylindazole-5-yl) methyl propionate. The raw materials are low in price, easy to obtain and low in price, the process is easy to industrialize and suitable for industrial production, the obtained final product is high in purity, and the method belongs to a dangerous process and is simple in equipment and novel in route.

The invention is applicable to the field of chemical industry, and provides a continuous catalytic reaction separation method for preparing methyl propionate, which comprises the following steps: firstly, adding a fixed solution phase consisting of high-boiling-point alkane, nickel / cobalt and organic phosphine oxide into a bubbling reactor T3, and then sequentially introducing methanol, ethylene and carbon monoxide, and maintaining the temperature of the system at 140-220 DEG C and the total pressure at 6-12 MPa for reaction. Allowing a gas phase volatilized in the reactor to enter a condenser T4 for partial condensation, and returning non-condensable gas to the bubbling reactor for mechanical application; condensed liquid enters a pressurized rectifying tower T6 through a collecting tank T5, tower top distillate returns to the bubbling reactor for mechanical application, and a fraction obtained at the tower bottom is a methanol solution of methyl propionate. Compared with the prior art, precious metal such as palladium does not need to be used, protonic acid does not need to be added into reaction liquid, the catalyst system has the advantages of being good in stability in the carbon monoxide atmosphere and continuous in technological process, and the method has high production efficiency and is a green, economical and efficient methyl propionate preparation and separation method.

The application discloses a local high-concentration lithium metal battery electrolyte and a preparation method and application thereof. The electrolyte comprises a lithium salt, an organic solvent, an additive and a diluent; the organic solvent comprises at least one of methyl formate, methyl acetate, methyl propionate, methyl butyrate, ethyl propionate, ethyl acetate, ethyl butyrate, methyl trifluoroacetate and ethyl trifluoroacetate; the additive comprises at least one of fluoroethylene carbonate, lithium difluorobisoxalate phosphate and lithium difluorophosphate; and the diluent is a fluorine-containing ether compound. The local high-concentration electrolyte has the advantages of high-voltage resistance of high-concentration electrolyte and inhibition of corrosion of sulfonimide-based electrolyte on aluminum foil, meanwhile, the problems of high viscosity, low conductivity and poor impregnation with a separator of high-concentration electrolyte are overcome, the cycle performance and low-temperature performance of the lithium metal battery are significantly improved, and the local high-concentration electrolyte is particularly suitable for application in a low-temperature high-voltage lithium battery. The preparation method is simple, the cost is low, and the method is suitable for industrial production.

The invention provides a water-resistant silicon-based antioxidant as well as a preparation method and application thereof, and belongs to the technical field of wood-plastic composite material preparation aids. The invention discloses a preparation method of 3-(3, 4-dichlorophenyl)- The preparation method comprises the following steps: carrying out aminolysis reaction on 2, 5-di-tert-butyl-4-hydroxyphenyl) methyl propionate and diisopropanolamine, and then carrying out grafting reaction on methyl phenyl dichlorosilane and hydroxyl of the aminolysis product to introduce an organic silicon chain segment; finally, the reaction intermediate of dichlorodiethylsilane and N-methyl-3-aminopropyltrimethoxysilane participates in chain segment polymerization, and a coupling agent chain segment is introduced. A chain segment of a final product contains amide, amino, trimethoxy and ethyoxyl groups, so that wood flour, inorganic filler and the like are favorably combined with plastic, and an organic silicon-based antioxidant product with antioxidant and coupling functions is obtained. The product is used in wood-plastic composite material processing, and has the effects of enhancing the water boiling resistance and water boiling loss resistance of the wood-plastic surface.

An electrolyte comprising: - a solvent mixture including methyl propionate, at least one cyclic carbonate and / or at least one linear carbonate, - vinylene carbonate or ethylene monofluorocarbonate or a mixture thereof, ethylene sulfate and lithium difluorophosphate, - one or more lithium salts other than lithium difluorophosphate. Methyl propionate, ethylene sulfate and lithium difluorophosphate interact to limit the growth of the passivation layer on the surface of the negative electrode and thus limit the increase in the internal resistance of the electrochemical element. Abbreviated figure: Figure 1

The application discloses a fluorine-18 labeled indole propionic acid and a preparation method thereof, and takes 1-(2-p-toluenesulfonic acid oxyethyl)-indole propionic acid methyl ester as a precursor, which is subjected to fluorination reaction with 18 F － to obtain an intermediate 1-[ 18 F] fluorinated ethyl-indole propionic acid methyl ester. The intermediate is hydrolyzed by NaOH to obtain a target compound 1-[ 18 F] fluorinated ethyl-indole propionic acid. The compound has good chemical stability, simple preparation, good biological performance, high chemical purity, and can be used as a new PET / CT positive electron tumor imaging agent for development and popularization and application.

The present application relates to a purification process of methyl methacrylate, and provides a purification method of methyl methacrylate, which can remove water in the crude product containing formaldehyde, solvent, water, methyl propionate and methyl methacrylate through a first membrane separation membrane, so that the first concentrated liquid retains the product methyl methacrylate, unreacted raw material methyl propionate and formaldehyde, and solvent such as methanol; the second membrane separation is used for removing small molecules such as methanol and formaldehyde in the first concentrated liquid, and methyl propionate and methyl methacrylate are obtained. The system for preparing methyl methacrylate provided by the present application uses the membrane separation technology and the rectification technology, realizes the repeated recycling of unreacted raw materials and the purification, separation and recycling of methyl methacrylate by effective combination, has the advantages of simple process operation, small equipment investment, high separation efficiency and low energy consumption of recycling, improves the economic benefit, the recovery rate of methyl methacrylate is greater than or equal to 99%, and the purity is greater than or equal to 99.9%.