66 results about "Acetyl bromide" patented technology

The invention discloses a preparation method and use of the main ingredient of a fragrance releasing agent for tobacco with a jasmine fragrance. The method comprises: preparing benzyl-2,3,4,6-tetra-o-acetyl-beta-d-glucopyranoside by a Cohen-Kohler reaction, acetylizing glucose in the presence of a perchloric acid catalyst, reacting the product of the acetylization with bromine hydride, removing solvent, recrystallizing in diethyl ether to obtain white crystals of alpha-acetobromoglucose; and reacting the alpha-acetobromoglucose with phemethylol and silver carbonate in a ratio of 1:2:1 in a dark place, removing the solvent, purifying by silica gel chromatography column and obtaining pure benzyl-2,3,4,6-tetra-o-acetyl-beta-d-glucopyranoside. In the invention, the benzyl-2,3,4,6-tetra-o-acetyl-beta-d-glucopyranoside is used as a main precursor with the jasmine fragrance. The fragrance releasing agent for tobacco with the jasmine fragrance, which is prepared by the invention, can release target fragrance effectively. The raw materials are simple and readily available. The cost is low, and the reaction equipment is simple.

The invention discloses a synthesis method for 4, 4'-dibromo-2, 2'-dipyridyl and belongs to the field of organic synthesis. The synthesis method includes the following steps: (A) oxidizing reaction: 2, 2'-dipyridyl reacts with 30% of hydrogen under the action of a metal catalyst and a phase transfer catalyst in the medium of water, and 2, 2'-dipyridyl nitrogen oxide is obtained; (B) nitration reaction: the 2, 2'-dipyridyl nitrogen oxide and fuming sulphuric acid are heated and react with fuming nitric acid in the medium of concentrated sulfuric acid, and 4, 4'-dinitro-2, 2'-dipyridyl nitrogen oxide is obtained; and (C) bromination reaction and deoxygenation reaction: the 4, 4'-dinitro-2, 2'-dipyridyl nitrogen oxide is added into acetic acid and heated till backflow, an acetyl bromide acetic acid solution is added, reaction is finished, a reducing agent is added, and the 4, 4'-dibromo-2, 2'-dipyridyl is obtained. According to the synthesis method for the 4, 4'-dibromo-2, 2'-dipyridyl, the solvent-free environment-friendly oxidizing reaction is adopted, the dosage of acetyl bromide is reduced, other reducing agents are used to replace phosphorus tribromide for the deoxygenation reaction, the bromination and reduction are changed into a one-pot method, harmful effects in the aspects of HSE (health, safety, environment) are reduced, and the synthesis method is environment-friendly and suitable for industrial production.

The present invention relates to a process for preparing cefathiamidine, in particular a process for preparing high-purity cefathiamidine. The preparation method comprises the following steps of: adding water or an aqueous inorganic salt solution as an auxiliary solvent in or after a reaction on acetyl bromide-7ACA and N,N'-diisopropylthiourea; after the reaction, cooling the mixture, and dropwise adding a crystallization solvent into the mixture, and performing suction filtration to obtain a crude product of cefathiamidine; and purifying the crude product again,and drying the crude product in vacuum to obtain the high-purity cefathiamidine. According to the preparation method provided by the present invention, residues of impurities in the cefathiamidine can be effectively reduced, the content of acetyl bromide-7ACA and the macromolecular compound impurities can be reduced to 0.1% or less or can be completely eliminated, and other residues of impurities in the cefathiamidine can be reduced to be less than 0.2%.

The invention discloses a method for preparing tyrosol glucoside in quantities; in the method, tyrosol is taken as raw material, and tyrosol phenolic hydroxyl acetylation protection is carried out selectively to be condensed with acetyl bromide sugar substitute followed by de-protection. The invention features available raw material, less reaction steps, high yield, simple preparation technique, stable technical parameters, capability of preparing kilogram level high purity (more than 98%) tyrosol glucoside once, and application in preparing various tyrosol glucoside.

The invention relates to a crystalline cefuroxime axetil preparation method, which comprises: 1) carrying out a reaction on paraldehyde and acetyl bromide at a temperature of -10-10 DEG C under the action of a catalyst to obtain 1-bromoethyl acetate; 2) adding cefuroxime acid and a catalyst to the mixed solution of an organic solvent and water, adjusting the temperature to -20-5 DEG C, adding the1-bromoethyl acetate prepared in the step 1) to the mixed solution in a dropwise manner to obtain the crystalline cefuroxime axetil. According to the present invention, the method improves the traditional process, simplifies the process, improves the product quality, does not use the extraction solvent dichloromethane, greatly reduce the production cost, and improves the reaction efficiency and the purity of the final product.

The invention discloses a preparation method of 1-bromoethyl acetate, which comprises the following steps: under the catalysis of aluminum oxide, reacting acetyl bromide with paracetaldehyde; and then, extracting with dichloromethane/water to obtain the high-purity 1-bromoethyl acetate. According to the method, the paracetaldehyde is used instead of acetaldehyde in the traditional process, and the aluminum oxide is used for catalysis preferably, so that the method is environment-friendly, is easy to realize quantification and ensures high yield and purity of the product; and meanwhile, the process conditions of the method are mild and easy to control, thereby being suitable for industrial production.

The invention belongs to the technical field of organic chemistry, and particularly relates to a method for preparing 3,4-di-O-acetyl-L-rhamnal. The method comprises that: firstly, under the catalytic action of p-toluenesulfonic acid(perchloric acid, amido-sulfonic acid, zinc chloride and sulphuric acid), L-rhamnal reacts with acetic acid and acetic anhydride to obtain 1,2,3,4-tetra-O-acetyl-L-rhamnose; the 1,2,3,4-tetra-O-acetyl-L-rhamnose is added with acetyl bromide and methanol for reaction to generate 1-bromine-2,3,4-tri-O-acetyl-L-rhamnose; and the 1-bromine-2,3,4-tri-O-acetyl-L-rhamnose is added with ethyl acetate(acetone), an aqueous solution of disodium hydrogen phosphate(a phosphate buffer and a solution of potassium phosphate dibasic) and the zinc powder for reaction to generate the 3,4-di-O-acetyl-L-rhamnal. The method has the characteristics of easy operation, short process flow, high yield, short reaction time, low cost, little 'three wastes', little environmental pollution, easy industrialization and the like.

The invention relates to an acetyl bromide synthesis production process, and relates to the technical field of chemical engineering. According to the invention, acetyl bromide is obtained through a bromination reaction of acetic anhydride and liquid bromine. The process provided by the invention has the following advantages: preparation is convenient and simple; the process is environment-friendly and pollution-free; raw materials are easy to obtain; equipment investment is low; product purity is high; operation is convenient; the prepared acetyl bromide has good application effect; and the prepared acetyl bromide is safe and reliable.

The present invention discloses a chemical synthesis process for preparing gastrodin and similar phenolic glucoside represented by a formula (I) thereof. According to the present invention, industrial easily-available raw materials such as acetic anhydride and acetyl bromide or PHOSPHORUS TRIBROMIde or phosphorus pentabromide are used to complete the hydroxy protection of glycosyl and the bromination reaction of hemiacetal hydroxy, such that the problems that the use of red phosphorus and bromine during the gastrodin bulk drug production process causes physical and psychological harm on production workers and environment pollution and damage are solved; and the process mainly comprises two steps of key reactions, wherein the first step reaction is synthesis of bromoacetyl glycosyl compound, and the second step reaction is condensation of the bromoacetyl glycosyl compound and a phenolic compound to generate the acetyl-protected phenolic glucoside compound.

The invention discloses a preparation method of 2-methoxy-5-fluorobromoacetophenone. The method comprises the following steps: taking p-fluoroanisole as an initial raw material, and reacting with bromoacetyl bromide under the condition of Lewis acid to generate a compound I, namely 2-methoxy-5-fluorobromoacetophenone. In the one-step synthesis route process taking the p-fluoroanisole as the initial raw material, a large amount of reagents with high toxicity and high pollution are avoided, and meanwhile, the raw materials are low in price, so that the whole synthesis process is low in pollution and easy to treat.

The invention discloses a preparation method of compounds for preventing and controlling plant virus disease: glucoside-1,4-pentadiene-3-ketone compounds containing acetoxyl groups and bioactivity, namely the compounds shown in the general formula (b) and a preparation method thereof. According to the preparation method, the glucoside-1, 4-pentadiene-3-ketone compounds containing the acetoxyl groups are synthesized by taking acetone, 2 or 4-substituted hydroxybenzaldehyde, substituted arylamine and acetyl bromoglucose as raw materials, ethanol and dichloromethane as solvents, dichloromethane as a catalyst and tetrabutylammonium bromide as a phase transfer catalyst. The compounds (f6), (f8), (f10), (f26) and (f28) have relatively good inhibitory effects on tobacco mosaic virus, cucumber mosaic virus and the like. The formula is shown in the description.

The invention relates to the technical field of analysis and detection, in particular to a method for analyzing the content of acetyl bromide in cefuroxime axetil. According to the analysis method, the content of acetyl bromide in cefuroxime axetil is measured by using a triple four-stage liquid chromatograph-mass spectrometer, acetyl bromide is used as a reference substance, 2, 4-dinitrophenylhydrazine is used as a derivatization reagent, and the content of acetyl bromide in cefuroxime axetil is analyzed by using a standard curve method. According to the analysis method disclosed by the invention, the problems that acetyl bromide is extremely active, easy to hydrolyze and difficult to measure are solved through a pre-column derivatization method, and the detection method is efficient and accurate.

The invention discloses a papermaking black liquid lignin content detection method which comprises the following steps: drying papermaking black liquid lignin and grinding into fine powder to obtain alignin standard sample; taking the defined amount of the lignin standard sample, utilizing an acidized acetyl bromide method to acetylize lignin, diluting with water to a specific volume, utilizing an ultraviolet spectrophotometer to measure absorbance at the 280nm position, calculating out solution absorbance according to a formula, performing a plurality of groups of parallel experiments and taking an average value; taking the defined amount of the lignin standard sample, utilizing a KLASON method and an acid-soluble lignin detection method to detect the total content X of KLASON lignin andacid-soluble lignin and calculating out corrected absorbance; taking a lignin sample to be measured, drying, grinding into fine powder, utilizing an acidized acetyl bromide method to acetylize lignin, diluting with water to a specific volume, utilizing the ultraviolet spectrophotometer for measuring absorbance at the 280nm position and calculating out the lignin content according to the formula.When the detection method disclosed by the invention is utilized for detecting the papermaking black liquid lignin content, the detection method has the advantages of higher accuracy, good repeatability, short detection time, high efficiency and wide application range; furthermore, the detection method is suitable for detecting high-content lignin and low-content lignin.

The invention discloses a detection method for a lignin content of papermaking pre-cooking liquor. The detection method comprises the following steps: drying lignin of papermaking pre-cooking liquor and grinding the lignin into fine powder to obtain a lignin standard sample; taking the defined amount of lignin standard sample, preparing a gradient-concentration solution, utilizing an acidizing acetyl bromide method to acetylize lignin, utilizing an ultraviolet spectrophotometer to measure absorbance at the 280nm position and making a standard curve between the absorbance and the lignin concentration; taking the defined amount of the lignin standard sample, utilizing a KLASON method and an acid-soluble lignin detection method to detect contents of KLASON lignin and acid-soluble lignin and correcting the standard curve; taking a lignin sample to be detected, drying, grinding into powder, acetylizing lignin, utilizing the ultraviolet spectrophotometer to measure absorbance at the 280nm position and calculating out the lignin content according to the corrected standard curve. The detection method disclosed by the invention can be utilized for detecting the lignin content of the papermaking pre-cooking liquor and has the advantages of higher accurate rate, good repeatability, short detection time, high efficiency, wide application range and suitability for high-content and low-content lignin detection.