112 results about "Dimethyl sulfate" patented technology

The present invention discloses an imidazole derivative, a preparation method thereof, and an application, belonging to the field of organic chemistry. The preparation method of the imidazole derivative of the present invention includes: adding compound 2a and dimethyl sulfate into an organic solvent, heating and reacting to obtain compound 3a; wherein, compound 2a is prepared by adding compound 1a, TrtCl, and a base reagent into a solvent, controlling the temperature at 0-10 °C, mixing evenly and reacting. The present invention also further prepares 2-(1-methylimidazol-5-yl)ethylamine (4a) by using the imidazole derivative. The present invention selects dimethyl sulfate as a methylation reagent and cooperates with a specific protecting group design to achieve the efficient preparation of 2-(1-methylimidazol-5-yl)ethylamine, with a total yield of 82.4%.

The utility model provides a reaction system for continuously synthesizing dimethyl sulfate, which comprises an absorption module I, an absorption module II, a reaction module I, a reaction module II and a pipeline module, the absorption module I and the absorption module II respectively comprise an absorption tower, a circulating tank, a circulating pump and a condenser, the reaction module I and the reaction module II respectively comprise a reaction tower, a circulating tank, a circulating pump and a condenser, and the pipeline module comprises a sulfur trioxide feeding pipeline, a dimethyl ether feeding pipeline, a crude dimethyl sulfate feeding pipeline, a tail gas conveying pipeline and a product conveying pipeline. The reaction system disclosed by the utility model realizes continuous generation of dimethyl sulfate, is simple to operate, low in device investment, high in reaction rate and high in yield, and provides a guarantee for realizing large-scale industrial production.

The invention discloses a continuous kettle type nitromethane production process, and relates to the technical field of basic chemical raw material synthesis and flow chemical reaction process control, which comprises the following steps: quantitatively and continuously pumping a temperature-regulated sodium nitrite mixed solution into a raw material mixer in a closed-loop automatic control mode through a variable-frequency feeding pump matched with a mass flow meter; synchronously, quantitatively and continuously pumping dimethyl sulfate into the raw material mixer in a closed-loop automatic control manner by matching a feeding pump with a stop valve and a mass flow meter, and uniformly mixing the two raw materials in the raw material mixer according to the stoichiometric molar ratio of the dimethyl sulfate to the sodium nitrite, according to the tandem type segmented design, each reaction kettle can be subjected to customized temperature field control and heat transfer design specially aiming at the special thermodynamic and dynamic requirements of the reaction stage where the reaction kettle is located, the heat transfer efficiency of the whole system is greatly improved, and due to the fact that reaction heat is taken away timely and accurately, the heat transfer efficiency is greatly improved. And a by-product generation path induced by local abnormal high temperature is effectively restrained.

The invention relates to the field of preparation of guanidine or derivatives thereof, and particularly discloses high-purity creatine monohydrate and a preparation method thereof. The preparation method comprises the following steps: sequentially carrying out condensation reaction, acidolysis reaction and hydrolysis reaction on dimethyl sulfate and urea, cooling, crystallizing and filtering to obtain O-methylisourea hydrogen sulfate, and then reacting a sarcosine salt aqueous solution with the O-methylisourea hydrogen sulfate under the conditions that the temperature is 45-65 DEG C and the pH value is 10-12 to obtain the sarcosine salt. And performing post-treatment to obtain the high-purity creatine monohydrate. The preparation method has the advantages of being low in raw material cost, easy to transport and store and rich in source, byproducts in the reaction process are few, danger is low, the yield and purity are high, the industrial requirement is met, and the preparation method is suitable for large-scale industrial production.

The invention relates to an L-proline heterocyclic intermediate, alpha-methyl-L-proline hydrochloride and a preparation method thereof, which comprises the following steps: step 01, cyclization upper protection: taking L-proline as a raw material, which is shown in a formula (1), to react with trichloracetic aldehyde hydrate under an acidic condition, and performing upper protection to obtain a heterocyclic intermediate as shown in a formula (2); the molar weight of chloral hydrate is 1-2.5 times of the molar weight of the L-proline shown in the formula (1), preferably 1.5 times of the molar weight of the L-proline shown in the formula (1). 02, methylation: reacting the heterocyclic intermediate as shown in the formula (2) obtained in the step 01 with lithium diisopropylamide, and after the reaction is completed, adding dimethyl sulfate for methylation to obtain an intermediate as shown in a formula (3); 03, deprotection: adding the intermediate as shown in the formula (3) obtained in the step 02 into a deprotection reagent for hydrolysis so as to obtain the alpha-methyl-L-proline hydrochloride as shown in the formula (4), so that the problems that the preparation cost of the existing alpha-methyl-L-proline hydrochloride is relatively high and the yield is relatively low can be solved.

The invention belongs to the technical field of drug synthesis, and relates to a dotenorad synthesis method, which comprises: weighing 100 g of a compound 1 as a raw material, and carrying out a substitution reaction with dimethyl sulfate to obtain a compound 2; taking the compound 2 as a raw material, and carrying out esterification reaction with methanol under an acidic condition; taking the compound 3 as a raw material, and obtaining a compound 4 after chlorination; hydrolyzing the compound 4 serving as a raw material to obtain a compound A; reacting the compound 5 serving as a raw material with a formaldehyde aqueous solution to obtain a compound 6; taking the compound 6 as a raw material, and performing thioether oxidation to obtain a compound B; taking a compound A as a raw material, and carrying out amide condensation reaction with a compound B to obtain a compound C; and 6, demethylating the compound C serving as a raw material under the action of lithium chloride to obtain a compound D, namely the final product dotenorad. According to the synthesis method of dotenorad, oxidation after condensation is not needed, generation of by-products is avoided, raw materials are low in cost and easy to obtain, and the synthesis method is suitable for industrial production.

The invention provides a method for detecting trace dimethyl sulfate in nicergoline, which comprises the following steps of: carrying out derivatization reaction on an azacyclo-compound serving as a derivatization agent and dimethyl sulfate in nicergoline to generate a derivatization product, and determining the amount of the derivatization product by using a high performance liquid chromatograph-mass spectrometer, therefore, the content of dimethyl sulfate in nicergoline is obtained. Compared with the prior art, the detection method provided by the invention has the characteristics of good specificity, high sensitivity, good reproducibility and the like, and makes up the vacancy of how to detect trace dimethyl sulfate in nicergoline in the prior art.

The invention provides a novel technology for concentrating dried waste sulfuric acid of a chloromethane synthesis device. According to a traditional sulfuric acid recovery process, waste sulfuric acid and water are mixed and hydrolyzed, then rectification and concentration are carried out, during hydrolysis, the waste sulfuric acid usually needs to be diluted to the concentration of about 50%, a large amount of introduced water needs to be removed during rectification and concentration, and steam consumption is huge. The process provided by the invention is as follows: waste sulfuric acid after drying and impurity removal in chloromethane synthesis firstly exchanges heat with concentrated high-temperature concentrated sulfuric acid and then enters a rectifying tower 1, 96% concentrated sulfuric acid is extracted from the tower bottom, most sulfuric acid in the waste sulfuric acid is recovered, and a gas phase at the tower top contains moisture, a small amount of sulfuric acid and organic matters (dimethyl sulfate and the like) and the like. The method comprises the following steps: condensing a gas phase at the top of a rectifying tower 1, mixing with a certain proportion of water, feeding into an upper tower 2 of a hydrolysis tower, hydrolyzing dimethyl sulfate and methyl hydrogen sulfate into sulfuric acid and methanol, removing part of organic matters and water through an upper tower heater, feeding the sulfuric acid in a tower kettle into a lower tower 3 of the hydrolysis tower, and concentrating to 96% through vacuum rectification.

The invention discloses an improved herbicide dicamba preparation method, and relates to the technical field of compound synthesis, the method comprises the following steps: using 2, 5-dichlorophenol as an initial raw material, heating 2, 5-dichlorophenol and a potassium hydroxide solution in an organic solvent to form salt, dehydrating and purifying, then carrying out carboxylation reaction with CO2 under the action of a catalyst, acidifying, distilling, and drying to obtain 3, 5-dichlorophenol; 2, 6-dichlorosalicylic acid is added; according to the method, 2, 3, 6-dichlorosalicylic acid and dimethyl sulfate are subjected to an etherification reaction, a hydrolysis reaction and an acidification reaction, and pure dicamba is obtained. The catalyst comprises K2CO3 and KCl, the purity of the obtained 3, 6-dichlorosalicylic acid is greatly improved, and the consumption of hydrochloric acid is remarkably reduced; according to the method, secondary reaction is adopted in the etherification process, so that 3, 6-dichlorosalicylic acid is completely converted into dicamba, and the product prepared by the method is high in yield, high in purity and relatively strong in controllability.

The present application relates to a kind of preparation method of trifluoromethyl pyrazole compound, belong to the technical field of organic synthesis.The specific method is: (1) trifluoroacetyl ethyl acetate is first with hydrazine hydrate cyclization reaction and generates compound of formula III;(2) under the catalysis of base, compound of formula III is reacted with difluoromethylation reagent and generates compound of formula II;(3) compound of formula II is reacted with methylating agent and obtains compound of formula I;The difluoromethylation reagent is difluoro-monochloromethane or sodium difluoro-monochloroacetate;The methylating agent is chloromethane, bromomethane, iodomethane, dimethyl sulfate or dimethyl carbonate.The present application is prepared by changing reaction route, and the higher-priced raw material methylhydrazine is replaced, and isomer impurity is no longer generated in the product prepared.Not only raw material cost is reduced, but also the purity of product is improved.

The invention discloses a method for detecting specific pollutants in a pesticide production plot, which can simultaneously detect six specific pollutants including three organophosphorus pesticides including isocarbophos, isofenphos-methyl and profenofos. One pesticide degradation product is dimethyl phosphate; the intermediate product of one pesticide is dimethyl phosphite, and the production raw material of the other pesticide is dimethyl sulfate. The method comprises the following steps: carrying out freeze-drying and grinding on a soil sample, and sieving with a sieve with the aperture of 0.25 mm; uniformly stirring the soil sample and diatomite, and adding a substitute and an extracting agent for extraction treatment to obtain a sample extracting solution; carrying out dehydration treatment on the sample extracting solution; and performing concentration treatment on the sample extracting solution to obtain a to-be-detected sample solution containing six target objects. The method can be used for simultaneously detecting specific pollutants of 6 pesticide production plots, and the detection rate is high; by adding an interior label, the accuracy of the method is improved; and the qualification rate of sample detection is improved by adding a substitute.

The present application relates to a kind of preparation methods of 2-methylamino-3-formylpyridine, comprising the following steps: 3-cyanopyridine and dimethyl sulfate are heated to reflux reaction in organic solvent I, then base is added, continue to react under heating reflux condition, and obtain intermediate product 2-methylamino-3-formylpyridine.The raw material used in the preparation method of the present application is cheap and easy to obtain, the preparation process has few side reactions, and is easy to purify.Only the steps of extraction and heavy crystallization are needed to achieve high purity, and strict control of anhydrous reaction conditions is not required.The yield and purity are high, and the prepared 2-methylamino-3-formylpyridine is suitable for industrial large-scale production of 2-methylamino-3-hydroxymethylpyridine, and further preparation of eslicarbazepine acetate and / or eslicarbazepine acetate sulfate.

The present invention relates to a synthetic method of 2-methyl-α-methoxyiminophenylacetic acid methyl ester, and the method flow comprises the following: Step 1: using o-methylphenylacetic acid or o-methylphenylacetamide or o-methylphenylacetic acid methyl ester as raw material, first directly oximating and esterifying with sodium nitrite in sulfuric acid in a solvent; Step 2: "one-pot method" hydrogenation of sodium hydroxide or potassium hydroxide to control pH value, and reacting with dimethyl sulfate to obtain 2-methyl-α-methoxyiminophenylacetic acid methyl ester. The present invention uses o-methylphenylacetic acid or o-methylphenylacetamide or o-methylphenylacetic acid methyl ester as raw material, and adopts safe and reliable sodium nitrite as oximation reagent, avoids using nitrite esters that are flammable and explosive, avoids using expensive methoxyamine hydrochloride, has safe and reliable reaction, low raw material cost, and adopts "one-pot method" in the operation process, has simple and smooth process, mild reaction conditions, and is suitable for industrialized amplification production.

The invention relates to a catalyst for preparing anisole through phenol methanol etherification as well as a preparation method and application of the catalyst. The catalyst takes aluminum phosphate as a carrier and is doped with zirconium oxide; on the basis of the mole number of Al, the mole ratio of P to Al is (0.05-2): 1, and the mole ratio of Zr to Al is (0.08-0.20): 1. Dropwise adding the aluminum-zirconium mixed aqueous solution into the phosphorus source aqueous solution, stirring, standing and washing to obtain a solid sample; and drying and roasting the solid sample to obtain the aluminum phosphate catalyst. Under the action of the catalyst, phenol and methanol are catalyzed to generate anisole. Compared with the prior art, the phenol conversion rate is greater than or equal to 50%, the anisole selectivity is greater than or equal to 85%, highly toxic dimethyl sulfate and a large amount of alkali are not needed, the process is green, the cost is low, separation is simple, and the method is suitable for large-scale industrial production of anisole.

The invention relates to an application of N, N-diisopropylethylamine as an organic acid binding agent in preparation of dimethyl sulfate, N, N-diisopropylethylamine is used for purifying a crude dimethyl sulfate product into a dimethyl sulfate product, N, N-diisopropylethylamine is added into the crude dimethyl sulfate product, stirring reaction is carried out, and the N, N-diisopropylethylamine is obtained. And carrying out reduced pressure distillation or reduced pressure rectification purification to obtain a dimethyl sulfate product. According to the method, N, N-diisopropylethylamine is used as an organic acid-binding agent, so that various acidic residues in the crude dimethyl sulfate product can be effectively removed, the acidity of the dimethyl sulfate product is reduced, and the product quality is correspondingly improved. And moreover, the residual liquid amount of dimethyl sulfate can be reduced, the treatment amount of three wastes is reduced, and the method is suitable for industrial production of high-purity dimethyl sulfate.

The invention discloses modified lignin as well as a preparation method and application thereof, the preparation method comprises the following steps: adding lignin into a reaction kettle, adding an organic solvent, and stirring and dispersing; the preparation method comprises the following steps: adding an alkaline agent into a reaction kettle, stirring, condensing, refluxing, heating to 80-110 DEG C, adding a modifier A which is dimethyl carbonate or dimethyl sulfate, and reacting for 3-6 hours; after the reaction is finished, a modifier B is added for continuous reaction, negative pressure distillation is performed to remove the organic solvent, modified lignin is obtained, and the modifier B is epichlorohydrin. According to the method, the polarity of the lignin is remarkably reduced through two-step modification, the compatibility and dispersity of the lignin and a rubber matrix are enhanced, meanwhile, introduced active groups can be chemically bonded with rubber molecules, and the reinforcing effect is improved. The prepared modified lignin can be used as a rubber reinforcing agent, the tensile strength and hardness of a rubber product are effectively improved, the process is environment-friendly, the solvent can be recycled, and the method is suitable for preparing a green high-performance rubber material.

The application discloses a preparation method of triclabendazole, and relates to the technical field of raw medicine synthesis. The method comprises the following steps: taking 4-chloro-5-(2,3-dichlorophenoxy)-2-nitroaniline as raw material, and sequentially performing reduction in an iron powder ethanol system, ring closure with a sulfur-containing ring closure reagent, methylation with dimethyl sulfate, and crystallization and purification in ethanol to obtain triclabendazole finished products. In the reaction process, iron mud is removed through pressure filtration, ethanol is recovered through distillation, and the ring closure intermediate is precipitated under acidic conditions. The process condition is clear, the operation is simple, the emission of hazardous waste can be reduced, the utilization rate of solvents and the purity of products can be improved, and the method is suitable for industrialized production of triclabendazole raw medicine.

The method for manufacturing an intermediate compound for shikonin synthesis of the present invention comprises the steps of: reacting 1,5-dihydroxynaphthalene with dimethyl sulfate to prepare 1,5-dimethoxynaphthalene; reacting 1,5-dimethoxynaphthalene with N-bromosuccinimide (NBS) to prepare 1,5-dibromo -4,8-dimethoxynaphthalene; introducing a methoxy group into 1,5-dibromo-4,8-dimethoxynaphthalene using copper iodide (CuI) and 1,10-phenanthroline as a catalyst to prepare 1,4,5,8-tetramethoxynaphthalene; performing formylation of 1,4,5,8-tetramethoxynaphthalene using phosphoryl chloride (POCl3) to prepare 2-formyl-1,4,5,8-tetramethoxynaphthalene; and forming a boron complex using pinacolborane (HBpin) and 3,3-dimethylallyl bromide and reacting the boron complex with 2-formyl -1,4,5,8-tetramethoxynaphthalene to prepare a prenylated shikonin intermediate. Compared to conventional synthetic methods, the method of the present invention offers milder reaction conditions, shorter reaction time, and improved yield, thereby greatly enhancing the economic feasibility of shikonin synthesis.

The invention belongs to the technical field of medicine detection, and particularly relates to a method for detecting and analyzing dimethyl sulfate in potassium sulfate serving as a raw material of a sodium potassium magnesium sulfate concentrated solution, the method adopts gas chromatography, and the chromatographic conditions are as follows: a chromatographic column is a capillary column of a non-polar stationary phase; the temperature programming control is as follows: the initial temperature of the column temperature is controlled to be 40-60 DEG C, the holding time is 2-5 minutes, the temperature is raised to 120-140 DEG C at the rate of 5-20 DEG C / min, then the temperature is raised to 230-280 DEG C at the rate of 15-25 DEG C / min, and the holding time is 5-15 minutes; the temperature of a sample inlet is 240-280 DEG C; the temperature of a detector is 250-350 DEG C. The method provided by the invention can detect the content of dimethyl sulfate in potassium sulfate, does not appear in the existing detection method, and can make up the technical blank in the field. The analysis method provided by the invention is good in specificity, high in repeatability, low in detection limit and high in accuracy.

The invention relates to a method for efficiently preparing flurbiprofen based on a Suzuki-Miyaura coupling reaction. The preparation method comprises the following steps: taking ethyl cyanoacetate as a raw material, and carrying out methylation reaction on the ethyl cyanoacetate and methyl iodide or dimethyl sulfate to prepare racemic ethyl 2-cyanopropionate; the racemic ethyl 2-cyanopropionate and 4-bromine-2-fluorobiphenyl are subjected to a similar Suzuki-Miyaura reaction under the combined action of a zero-valent palladium metal catalyst, a metal stabilizer phosphine ligand and alkali, and the racemic ethyl 2-cyano-2-(2-fluoro4-biphenyl) propionate is obtained; and carrying out hydrolysis and decarboxylation on the racemic 2-cyano-2-(2-fluoro-4-biphenyl) ethyl propionate to obtain racemic 2-(2-fluoro-4-biphenyl) propionic acid, namely, the flurbiprofen. The process route comprises three steps of reaction, materials are cheap and easy to obtain, operation is simple, aftertreatment is convenient, and the obtained product is high in purity.

The invention provides a method for continuously synthesizing dimethyl sulfate, which uses the reaction system provided by the invention to continuously synthesize dimethyl sulfate, and comprises the following steps: simultaneously and respectively dissolving and absorbing SO3 and dimethyl ether in crude dimethyl sulfate stored in a primary absorption circulating tank and a primary reaction circulating tank to form two absorption liquids; the method comprises the following steps: respectively absorbing an absorption liquid 1 for absorbing dimethyl ether and an absorption liquid 2 for absorbing SO3, then conveying the absorption liquid 2 into a primary reaction circulating tank for storing the absorption liquid 1, carrying out esterification reaction to generate dimethyl sulfate, and sequentially conveying materials which are not completely reacted into a secondary reaction circulating tank and a secondary absorption circulating tank for continuous reaction. The method is simple in process, energy consumption is reduced, cost is saved, the production problems of running, overflowing, dripping, leaking and the like are completely eradicated through the continuous production technology, and a guarantee is provided for large-scale industrial production.

The application belongs to the technical field of compound synthesis, and particularly relates to a preparation method of dipyrone with controlled content of 4-N methylene sulfonic acid sodium dipyrone impurity, which comprises the following steps: dissolving 4-formylaminoantipyrine in water, and then adding dimethyl sulfate and lye to react to obtain a methylation liquor; the obtained methylation liquor is hydrolyzed and neutralized, and then is left to stand and separate into layers, the upper 4-methylaminoantipyrine oil is cooled and crystallized to obtain 4-methylaminoantipyrine solid; the obtained 4-methylaminoantipyrine solid, ethanol, sodium pyrosulfite, activated carbon and formaldehyde are mixed to react to obtain dipyrone; the mass percentage of 4-aminoantipyrine in the 4-formylaminoantipyrine is not more than 1.5%. The content of 4-N methylene sulfonic acid sodium dipyrone (unknown impurity) in the prepared dipyrone is less than or equal to 0.05%, which meets the requirements of the European Pharmacopoeia.

The invention discloses a continuous preparation technology of O-methyl-N-nitroisourea, and belongs to the technical field of fine chemical engineering. The O-methyl-N-nitroisourea is prepared by using the continuous flow reactor, compared with the prior art, the whole reaction process is completely sealed, the phenomena of running, emitting, dripping and leaking in the reaction process can be completely eradicated, meanwhile, the dosage of dimethyl sulfate is reduced, and personnel injury caused by leakage of highly toxic dimethyl sulfate can be effectively avoided; according to the invention, all the materials are fed in a liquid phase form, the preparation process of a sulfuric acid solution and a mixed acid solution is avoided, the operation procedures are reduced, the dissolution heat of sulfuric acid is effectively utilized, and the temperature rise is accelerated; the reaction can be completed by using a relatively low amount of concentrated nitric acid, and compared with fuming nitric acid, the cost of the concentrated nitric acid is greatly reduced; the whole operation process is simple, side reactions are few, the yield is high, the method is suitable for industrial production, and compared with a traditional intermittent kettle reaction, the method has great advantages.

The present invention provides a method for preparing O-methyl-N-benzyloxycarbonyl-L-homoserine, which relates to the field of organic synthesis. The preparation method of the present invention comprises the following steps: (1) reacting compound 1, a base, and di-tert-butyl dicarbonate in a solvent to obtain compound 2; (2) reacting compound 2, a base, and dimethyl sulfate in a solvent to obtain compound 3; (3) reacting compound 3 with thionyl chloride in a solvent to obtain compound 4; (4) reacting compound 4 with benzyl chloroformate in an alkaline environment in a solvent to obtain compound 5; (5) reacting compound 5 with a base in a solvent to obtain. The raw materials used in the present invention are easily available and low-priced, the reaction conditions are mild, the intermediate reaction steps do not require purification, and column chromatography separation is not required, and the steps are simple; and the reaction steps of the present invention are safe, non-toxic, and environmentally friendly. The product obtained by the preparation method of the present invention has high purity, high yield, low cost, is suitable for scale-up production, and has broad application prospects. #imgabs0#

The invention provides a method for catalytic continuous synthesis of aryl methyl ether, and belongs to the field of aryl methyl ether. The method for catalytically and continuously synthesizing the aryl methyl ether is carried out in a manner of combining continuous reaction and continuous rectification. According to the method for catalytically and continuously synthesizing the aryl methyl ether, the continuous production of the aryl methyl ether can be realized while dimethyl sulfate is not adopted and a large amount of high-toxicity wastewater and solid wastes are prevented from being generated in the production process, and the continuous production of the aryl methyl ether is mild in reaction condition, low in requirement on production equipment, small in production risk and high in production efficiency; the yield of the aryl methyl ether prepared through large-scale production is high, and large-scale industrial production is facilitated.

The invention relates to the technical field of methyl isocyanate, in particular to a methyl isocyanate preparation method based on a dimethyl sulfate route, which comprises the following steps: raw material preparation: raw materials comprise sodium cyanate, orthodichlorobenzene and dimethyl sulfate, the mass ratio of sodium cyanate to dimethyl sulfate is 1: (0.6), and the mass of orthodichlorobenzene is 3-5 times that of sodium cyanate; the method comprises the following steps: raw material pretreatment: respectively pretreating sodium cyanate, o-dichlorobenzene and dimethyl sulfate for later use; according to the method, uniform slurry is formed through grinding, the specific surface area of sodium cyanate particles is increased, full contact between the sodium cyanate particles and dimethyl sulfate is promoted, the effect of improving the reaction efficiency is achieved, after heating and negative-pressure dehydration treatment, hydrolysis of dimethyl sulfate and hydrolysis side reaction of methyl isocyanate can be prevented through reduction of moisture, and therefore generation of impurities is reduced, and the product quality is improved. The product purity is improved, the product is prevented from being decomposed or subjected to secondary reaction at high temperature due to lower rectification temperature, and the product stability is ensured.

The present application relates to a kind of preparation methods of 3,4-dihydroxy-5-methoxybenzoic acid methyl ester, with gallic acid as raw material, it is reacted with trimethyl orthoformate or trimethyl orthoacetate, trimethyl orthoformate or trimethyl orthoacetate can realize the protection of adjacent diphenol hydroxyl on one hand, on the other hand, carboxyl esterification and 5-hydroxyl are methylated, form the methyl ester of 5-phenolic hydroxyl methylation and 3,4-orthoester protection benzoic acid shown in formula 1a or formula 1b, further by acidic solution treatment, deprotection is carried out, and the target product 3,4-dihydroxy-5-methoxybenzoic acid methyl ester is prepared.The preparation method is mild in reaction condition, process is simple, easy to operate, product yield and purity are high, solve the wastewater problem in borax protection method, and avoid using toxic dimethyl sulfate for methylation, process condition is simple, easy to operate, convenient for industrialization, with very high application value.

The invention belongs to the field of synthesis of drug intermediates, and discloses a process for industrially producing 2-allyl-3-methoxybenzaldehyde. The synthesis method comprises the following three steps: 1, alkylation reaction: reacting a raw material 3-hydroxybenzaldehyde with allyl bromide under an alkaline condition to obtain an allyl ether intermediate (3-allyl ether benzaldehyde); and 2, Claisen rearrangement reaction of the allyl ether intermediate: under a brand new flowing chemical reaction device (240 DEG C, 2MPa back pressure), dissolving the raw materials in a solvent, pumping the solvent into a microchannel, carrying out rearrangement reaction, and recrystallizing to remove an isomer, so as to obtain the intermediate 2-allyl-3-hydroxybenzaldehyde. And 3, methylation reaction: enabling the 2-allyl-3-hydroxybenzaldehyde to react with dimethyl sulfate under an alkaline condition, so as to obtain the product 2-allyl-3-methoxybenzaldehyde. The total yield of the three steps is 40%. According to the process, the raw materials are low in price and easy to obtain, the process operation is simple and convenient, and the process is suitable for industrial production of the 2-allyl-3-methoxybenzaldehyde.

The invention discloses a preparation method of N1, N2-dimethylbenzene-1, 2-diamine, and belongs to the technical field of preparation of medical intermediates. O-phenylenediamine is used as a raw material and reacts with ethyl formate, then dimethyl sulfate is adopted for a nitrogen-methylation reaction, finally formyl is removed under the action of acid, and N1, N2-dimethylbenzene-1, 2-diamine is obtained. According to the method, all the raw materials can be conveniently purchased on the market, the process of each step of reaction is simple and convenient, no expensive catalyst is used, the yield is high, and industrial production is easy.

The invention discloses a clean production process for cationic dyes. A parent substance and dimethyl sulfate undergo a methylation reaction, followed by expansion and hydrolysis. Salt and zinc chloride are added for transformation and crystallization. After crystallization, the product and mother liquor wastewater are filtered. Zinc chloride and sodium chloride are added to the mother liquor wastewater obtained after crystallization for neutralization. After nanofiltration, the concentrated solution is applied to the hydrolysis and expansion process of the next batch. The wastewater after nanofiltration enters a biochemical treatment system. The clean production process of the invention can solve the problems of generating and applying crystallization wastewater, reduce wastewater treatment costs, increase product yield, reduce wastewater generation and salt usage, and recover a small amount of cationic dye dissolved in the wastewater.