14 results about "Ethyl chloroformate" patented technology

This invention relates to the field of spray system technology, and more particularly to an alkaline spray system for the production of ethyl chloroformate, comprising the following steps: S1, adding tetramethylammonium hydroxide to water, heating to room temperature, stirring until completely dissolved, adding modified sodium metasilicate, disodium ethylenediaminetetraacetate, and sodium lignosulfonate, controlling the temperature and stirring, filtering to obtain an alkaline solution; S2, turning on the power to the control system, ensuring the control system operates normally, setting the operating parameters of the spray system, starting the alkaline solution pump, drawing the alkaline solution from the storage tank, conveying it through pipelines to the spray heads, adjusting the pump's output flow rate, and starting intermittent, uniform spraying of the alkaline solution. The waste liquid after spraying flows through pipelines into a sedimentation tank for post-treatment. The alkaline spray system of this invention can significantly improve the purification efficiency of acidic gases, heavy metal ions, and organic pollutants in waste gas.

The invention relates to a synthetic method of 2-diphenylmethyl pyrrolidine or an acid salt of 2-diphenylmethyl pyrrolidine. In order to solve the problems of easy ring opening and low yield in the prior art, the invention provides a synthetic method of 2-diphenylmethyl pyrrolidine or an acid salt thereof, which comprises the following steps: in the presence of an alkaline reagent, performing amidation and esterification reaction on a compound pyrrole-2-formic acid as shown in a formula II and ethyl chloroformate in an ROH solvent to obtain a compound as shown in a formula III; r in the ROH solvent is alkyl; performing Grignard reaction with phenyl magnesium bromide to obtain a compound as shown in a formula IV; carrying out reduction reaction on the compound shown in the formula IV under the catalytic action of trifluoroacetic acid and triethyl silane to obtain a compound shown in a formula V; and carrying out hydrolysis reaction on the compound in the formula V under an alkaline condition to obtain the compound 2-diphenylmethylpyrrolidine in the formula I or the acid salt thereof. According to the method, ring-opening impurities can be effectively avoided, the yield is increased to 95% or above, and the purity reaches 99% or above.

The invention discloses a preparation method of L-2, 4-diaminobutyric acid dihydrochloride, which comprises the following steps: (1) taking L-homoserine as an initial raw material, and reacting with concentrated hydrochloric acid in the presence of a zinc chloride / ferrous chloride synergistic catalyst to prepare L-2-amino-4-chlorobutyric acid hydrochloride; (2) after neutralization, carrying out an acylation reaction with ethyl chloroformate to generate N-ethoxycarbonyl-L-4-chlorobutyric acid; (3) carrying out esterification with ethanol so as to obtain N-ethoxycarbonyl-L-4-chlorobutyl amino acid ethyl ester; (4) under the catalysis of sodium iodide, carrying out nucleophilic substitution reaction with phthalimide potassium salt, and cooling, crystallizing and purifying the key intermediate by dropwise adding water to obtain L-2-[(ethoxycarbonyl) amino]-4-phthalimide ethyl butyrate; and (5) finally, hydrolyzing for deprotection, and concentrating and crystallizing to obtain the L-2, 4-diaminobutyric acid dihydrochloride. The method has the advantages of mild reaction conditions, simplicity and convenience in operation, high total yield and the like, and is suitable for large-scale industrial production.

The application relates to the technical field of tail gas treatment, in particular to a tail gas capturing and treating system applied to ethyl chloroformate synthesis, which comprises the following steps: S1, condenser pretreatment of tail gas; S2, falling film absorption, to obtain concentrated hydrochloric acid and tail gas after falling film absorption; S3, catalytic decomposition of phosgene, to obtain dilute hydrochloric acid and tail gas after catalytic decomposition; and S4, secondary series alkaline washing is carried out, and the dilute lye is used for circular spraying and is discharged through an induced draft fan. In the application, ethanol, ethyl chloroformate and other low-boiling-point substances in the tail gas are recovered through condenser pretreatment, the condensate is returned to a production system for recycling, raw material waste is reduced, and production cost is lowered. Hydrogen chloride is efficiently absorbed and converted into concentrated hydrochloric acid and dilute hydrochloric acid, which are used in the next section for recycling or external sale, resource reuse is realized, and harmful gas emission is reduced.

The application discloses a spiromesifen derivative, belongs to the field of crop disease and pest control, and has the structure shown in the following formula 1001, a preparation method thereof is as follows: under the protection of inert gas, 3-(2, 4, 6-trimethylphenyl)-2-oxo-1-oxaspiro[4, 5]-non-3-ene-4-ol and dichloromethane are stirred and cooled to 0-5 DEG C, then triethylamine is added, fluorine ethyl chloroformate is added dropwise, after dropwise addition is completed, the reaction is continued after being raised to room temperature, and then purification is conducted, and the spiromesifen derivative is obtained; the spiromesifen derivative has higher safety for citrus, watermelon and Chinese rose and has better pest control activity than that of spiromesifen.

The present invention relates to an intermediate of monepantel and a preparation method thereof, and belongs to the field of medicine and chemical technology. The present invention provides a preparation method of a monepantel intermediate 1B, which is reacted as follows: wherein R1 is selected from benzyl or substituted benzyl, and the substituted benzyl is a benzyl arbitrarily substituted by 1 4 groups selected from the following groups on a phenyl ring: C1 4 alkyl, C1 4 alkoxy, nitro, cyano, trifluoromethyl, trifluoromethoxy; comprising the following steps: step A: a compound of formula 1A is subjected to an acylating agent and an aminating agent to obtain a compound of formula 1B; the method provided by the present invention avoids the use of ethyl chloroformate and trifluoroacetic anhydride and the generation of esterification impurities, avoids nitration and diazotization reactions, makes the preparation process of monepantel easier and simpler, and is suitable for industrial production.

The application discloses a preparation method of cardolan, and comprises the following steps: 1) adding 2-hydroxybenzamide and an inorganic base into water as a solvent to react; and 2) adding ethyl chloroformate, heating and ring closing to obtain cardolan. The application has the advantages that water is used as the solvent, which is beneficial to an environment-friendly reaction, ethyl chloroformate is added at room temperature, and the operation is simple and the energy consumption is low; meanwhile, the product with high quality and high yield is prepared in one step.

The application provides a new synthesis method of esacioxin intermediate. The method comprises the following steps: (1) reacting raw material 2-(trifluoromethyl) phenylacetic acid with ethyl chloroformate or isobutyl chloroformate in an inert solvent in the presence of a base to generate a mixed anhydride, and then reacting with ammonia to obtain a corresponding amide compound formula II; (2) preparing an isonitrile compound formula III through a dehydration reaction of the amide compound formula II obtained in the step (1) in the presence of a dehydrating agent and an acid binding agent; (3) cyclizing the isonitrile compound formula III obtained in the step (2) with 2-butynoic acid ethyl ester in the presence of a base and a metal catalyst to form a pyrrole ring compound formula IV; and the reaction formula is shown in the following formula: compared with the prior art, the technical scheme of the application has the advantages of high yield, simple post-treatment, low cost and easy industrialization.

The application belongs to the technical field of medicine synthesis, and particularly relates to a synthesis method of empagliflozin. The application uses cobalt dibromide complex and zinc powder as a catalyst, and realizes carbon-carbon bond construction of aryl bromide by using ethyl chloroformate as a bridge, so as to realize synthesis of an important intermediate II of empagliflozin. The intermediate is further reduced and deprotected to obtain empagliflozin. The process can solve the use of n-butyl lithium, the whole synthesis route is short, operation is simple, and the process is more suitable for industrial mass production.

This invention discloses a method for synthesizing and applying propyl 4-{[(1R)-1-phenylethyl]amino}-5-(methoxycarbonyl)-1,2,3,6-tetrahydropyridine-1-carboxylate, belonging to the field of pharmaceutical preparation technology. Specifically, the method involves: removing the tert-butyloxycarbonyl group from 1-tert-butyl 4-oxopiperidinium-1,3-dicarboxylate methyl ester under oxaloyl chloride conditions; reacting the obtained intermediate with ethyl chloroformate in dichloromethane solvent to prepare compound 2; and then reacting compound 2 with the amino group of (R)-(+)-1-phenylethylamine via a nucleophilic substitution reaction to prepare propyl 4-{[(1R)-1-phenylethyl]amino}-5-(methoxycarbonyl)-1,2,3,6-tetrahydropyridine-1-carboxylate. The compound exhibits good lipid-lowering activity and can be used as a potential lipid-lowering drug for the treatment of related diseases. Furthermore, the synthesis method is simple, efficient, and low-cost, and the prepared product has high purity, making it easy to achieve large-scale industrial production.

The present application relates to tail gas treatment technical field, especially to a kind of ethyl chloroformate production containing light tail gas absorption treatment process, comprising the following steps: S1, pretreatment: collecting each workshop tail gas is filtered into bag filter, and pretreatment tail gas is obtained;S2, falling film absorption treatment: pretreatment tail gas temperature is reduced to ≤40 ℃, then it is imported into falling film absorption tower, and packing layer is equipped with the light gas absorbent with concentration of 20-30%, and falling film absorption tail gas is obtained;S3, three-stage destruction tower treatment: falling film absorption tail gas is imported into three-stage destruction tower in series, and by-product salt solution and destruction tail gas are obtained, and the salt generated is collected to storage tank, and destruction tail gas is discharged after detection reaches standard.The light gas absorbent prepared by the present application shows higher light gas and ethyl chloroformate decomposition efficiency in the absorption treatment of ethyl chloroformate production containing light tail gas.

The application belongs to the technical field of herbicides, and provides a preparation method of the herbicide cycloxaprid, which comprises the following steps: 1, mixing and stirring monocyanamide and ethyl chloroformate, cooling to 0-2 DEG C, adding liquid alkali dropwise, controlling pH and temperature, and carrying out incubation reaction to obtain a product GH520-1; 2, adding dimethyl sulfate and benzyl triethylammonium chloride to the product GH520-1, carrying out warming reaction, and after the reaction is completed, standing and layering to obtain a product GH520-2; 3, adding dimethylamine hydrochloride and liquid alkali to the product GH520-2, supplementing toluene, carrying out warming reaction, cooling to room temperature, standing and layering to obtain a product GH520-3; 4, dissolving the product GH520-3 in toluene, adding cyclohexyl isocyanate, and controlling the reaction temperature to obtain a product GH520-4; and 5, adding sodium methoxide and dimethylamine aqueous solution to the product GH520-4, controlling the reaction temperature, and obtaining a product GH520.

The application discloses a coumarin derivative containing an amide bond and a preparation method and application thereof, and has the characteristics that the specific compound structure of the coumarin derivative is 4-methyl-7-acetylamino coumarin, and the preparation method steps are as follows: 1) 3-hydroxyphenyl ethyl carbamate is prepared by amidation reaction of m-aminophenol and ethyl chloroformate; 2) 4-methyl-7-ethoxycarbonylamino coumarin is prepared by esterification reaction of 3-hydroxyphenyl ethyl carbamate and ethyl acetoacetate; 3) 4-methyl-7-aminocoumarin is prepared by esterolysis reaction of 4-methyl-7-ethoxycarbonylamino coumarin and a mixture of glacial acetic acid and concentrated sulfuric acid; and 4) 4-methyl-7-acetylamino coumarin is prepared by esterification reaction of 4-methyl-7-aminocoumarin, pyridine and acetic anhydride, and the advantages are that the compound has good antiviral and killing effects on white spot syndrome virus, the synthesis method is simple, and the conversion rate is high.

The application discloses a preparation method of L-2,4-diaminobutyric acid dihydrochloride, which comprises the following steps: (1) taking L-homoserine as a starting material, and reacting with concentrated hydrochloric acid in the presence of a zinc chloride / ferrous chloride synergistic catalyst to prepare L-2-amino-4-chlorobutyric acid hydrochloride; (2) after neutralization, acylation reaction is carried out with ethyl chloroformate to generate N-ethoxycarbonyl-L-4-chlorobutyramic acid; (3) esterification is carried out with ethanol to obtain N-ethoxycarbonyl-L-4-chlorobutyramic acid ethyl ester; (4) under the catalysis of sodium iodide, nucleophilic substitution reaction is carried out with phthalimide potassium salt, a key intermediate is purified by dropping water to reduce temperature and crystallize, and L-2-[(ethoxycarbonyl)amino]-4-phthalimidobutyric acid ethyl ester is obtained; and (5) finally, hydrolysis and deprotection are carried out, concentration and crystallization are carried out to obtain L-2,4-diaminobutyric acid dihydrochloride. The application has the advantages of mild reaction condition, simple operation, high total yield and the like, and is suitable for large-scale industrial production.