3207 results about "Acetic anhydride" patented technology

The invention relates to a process for the production of acetic acid by carbonylation of methanol, and reactive derivatives thereof, in a reaction mixture using a rhodium-based catalyst in low water conditions. The process is used to achieve reaction rates of at least 15 g mol/l/hr. The high rate reactions proceed at water concentrations of less than 2.0 wt. %. Under certain conditions, the water concentration in the reaction mixture of the process is maintained at a desired concentration by at least one process step including adding a compound such as methyl acetate, dimethyl ether, acetic anhydride, or mixtures of these compounds to the reaction system. The process step of adding the components to the reaction mixture may be combined with other process steps for controlling water concentrations in reaction mixtures for the carbonylation of methanol.

A method of removing organic iodides from non-aqueous organic media includes contacting the organic media with a silver or mercury-exchanged cationic ion exchange substrate at a temperature greater than about 50° C. The method is particularly effective for removing high molecular weight organic iodides from organic media such as acetic acid or acetic anhydride. Particular species removed include decyl iodides and dodecyl iodides from organic media such as acetic acid.

The invention relates to the hydropyridine derivatives of 2-acetoxy-5- (Alpha-cyclopropyl carbonyl-2-fluorobenzyl) -4, 5, 6, 7-tetrahydrothiophene plus [3, 2-C] pyridine and salts of the hydropyridine derivative as well as the preparation method. The invention comprises following steps: preparing two main intermediates: Alpha-cyclopropyl carbonyl-2 fluorobenzyl halogen 2 (wherein, X=F, CL, Br, I) and 2-oxygen-2, 4, 5, 6, 7, 7 Alpha-hexahydrothiophene plus [3, 2-C] pyridinium salt 3 (wherein, HA=HCL, H2SO4, HBr, HI); esterifying the product obtained through condension of the two main intermediates using acetic anhydride to get target product. The target product and the needed acid are combined to be salts via addition reaction; during the process of crystallization, necessary crystal seed is added to achieve single-morphic crystals.

The invention relates to a preparation method of abiraterone acetate. The method comprises: taking dehydroepiandrosterone as the raw material, which successively reacts with hydrazine hydrate and idoine so as to obtain 17-iodo-adrost-5, 16-diene-3beta-ol, which then undergoes a Negishi coupling reaction with 3-pyridine zinc halide to obtain abiraterone, and finally conducting esterification with acetyl chloride or acetic anhydride, thus obtaining the target product abiraterone acetate.

The invention discloses a making method of new chain-extending typed fluorenyl dimaleimide, which comprises the following steps: dissolving 9, 9-di(4-amino phenyl) fluorene into N, N-dimethyl acetamide; stirring; dripping maleic anhydride of N, N-dimethyl acetamide with the same molar weight to react for 2h; adding dianhydride directly with the same molar weight; stirring 3h; adding the compound of acetic anhydride and potassium acetate; stirring under indoor temperature to react for 4h; sedimenting in the water; obtaining the product with receiving rate over 95%.

The present invention provides, according to an aspect thereof, a novel process for the preparation of dronedarone [1] and pharmaceutically acceptable salts thereof. According to a preferred embodiment, the process comprises N-acetylating of p-anisidine or p-phenetidine with acetic anhydride, reacting of the obtained N-(4-alkoxyphenyl)acetamide with 2-bromohexanoyl chloride or bromide in the presence of aluminum chloride or bromide to obtain N-[3-(2-bromohexanoyl)-4-hydroxyphenyl]acetamide [6a], converting the compound [6a] into 2-butyl-5-benzofuranamine hydrochloride [12a] and subsequently converting [12a] into [1] or pharmaceutically acceptable salts thereof. In accordance with another aspect of this invention, there are provided novel intermediates, inter alia the novel compounds [6a] and [12a]. The novel intermediates of the present invention are stable, solid compounds, obtainable in high yields, which can be easily purified by crystallization and stored for long periods of time.

Process for the preparation of a starch ester, in particular a starch acetate, wherein a starch-based feedstock is reacted with an organic carboxylic acid anhydride in the presence of a catalyst. The reaction of the starch-based feedstock and the anhydride is performed at an excess pressure of about 0.1 to 50 bar in an essentially anhydrous medium containing 10% by weight of water at the most. As catalyst, sodium acetate, sodium hydroxide or sulphuric acid is used, and as the reaction medium, acetic acid or excess acetanhydride is used. By means of the invention, the duration of the esterification reaction can be significantly shortened, the separation of the product can be facilitated, and the recirculation of the waste solutions can be rendered more efficient.

The invention discloses a preparation method of a thermotropic liquid crystal polyarylester fiber, relates to a preparation method of thermotropic liquid crystal polyarylester, and aims to solve the problems that the existing method for preparing the thermotropic liquid crystal polyarylester is complex and the polyarylester fiber is low in tensile strength. The preparation method of the thermotropic liquid crystal polyarylester fiber comprises the following steps: step one, adding p-hydroxybenzonic acid, 2-(4-hydroxyphenyl)-5-carboxylbenzimidazole, acetic anhydride, 4-diethylaminopyridine and an antioxidant into a polymerization kettle for carrying out melt condensation polymerization to prepare a pre-polymer of thermotropic liquid crystal polyarylester; step two, putting the pre-polymer in a rotary kiln under the condition with nitrogen protection for carrying out solid phase polycondensation reaction to obtain high-molecular-weight polymer powder; step three, mixing the high-molecular-weight polymer powder, then cooling and drawing to prepare primary polyarylester fiber; and step four, carrying out heat treatment on the primary polyarylester fiber. The preparation method of the thermotropic liquid crystal polyarylester fiber is simple to operate; the tensile strength of the polyarylester fiber which is finally obtained can reach 4.0-4.5GPa.

The process of preparing water soluble chitosan includes adding chitosan into 2-8 wt% concentration acetic acid aqua to compound acetic acid solution of chitosan of 2-10 wt% concentration, adding enzyme or oxidant to degrade chitosan to polymerization degree below 1000, cooling the solution to 0-10 deg.c, adding ethanol or methanol solution of acetic anhydride, stirring first at normal temperature for 2-24 hr and then at 20-40 deg.c for another 20-40 deg.c, adding alkali to regulate pH to over 8 under stirring, adding ethanol to deposit, centrifugation to obtain solid product, soaking in alcohol solution of KOH, centrifugation, alcohol washing, and drying to obtain water soluble chitosan of acetyl degree of 45-55%. The present invention has simple preparation process, and the product is used as material for tumor resisting and immunity raising medicine and health product and as additive for cosmetics and food.

The invention relates to a solid-phase synthetic method for degarelix. The method comprises the following steps of: 1) reacting resin with Fmoc-D-Ala-OH to obtain Fmoc-D-Ala-resin, wherein the resin is amino resin; 2) sequentially connecting according to the amino acid sequence of the degarelix by adopting an Fmoc solid-phase synthetic strategy; 3) removing Fmoc from a N terminal, and acetylating by using acetic anhydride and pyridine; 4) removing a protective group X on the 6th amino acid residue -4Aph(X) from a C terminal; 5) connecting L-4,5-dihydrooroticacid to a side-chain amino group of the 6th amino acid residue -4Aph at the C terminal; 6) cutting peptide resin by using a cracking reagent, precipitating by using anhydrous ether, and centrifuging to obtain crude peptide; and 7) purifying and separating to obtain the degarelix. The method is easy to operate and slightly damages human bodies and environments; and by the process, the content of impurities is effectively reduced, and the large-scale production can be performed.

The invention discloses a lubricant preparing method, particularly relates to a method for preparing an environment-friendly polyester lubricating-oil basic oil. The invention takes use of chemical modification of vegetable oil to improve the rheologic behavior and oxidation stability. Firstly, the vegetable oil is mixed with alcohol for esterification reaction to achieve vegetable-oil monoester and introduce branched chain into the molecular structure. Subsequently, hydrogen peroxide is used to turn the double-bonds in the vegetable-oil basic oil into saturated epoxy-bonds; then, the epoxy-bonds are opened by fatty acid to achieve vegetable-oil monoether containing hydroxy groups. And finally, acetic anhydride is used to esterify the generated hydroxy groups and achieve polyether vegetable-oil ether. Compared with vegetable oil, the modified polyester vegetable-oil ether is largely improved in frictional behavior, rheologic behavior and oxidation stability.

The invention relates to a method for the reaction of sucralose esterified single solvent, characterized by: 1) DMF, sucrose and organotin acetate are subjected to negative pressure esterification in an esterification kettle while DMF is recovered to the bypass channels of earlier stage by negative pressure distillation and condensing, and the recovered DMF whose water content is larger than 0.9-1.0% ppm is to be delivered into the recovery system; 2) Negative pressure recovery of DMF continues until the water content is less than 0.6% ppm, then which is returned to the esterification kettle for the next batch of esterification reaction; 3) The esterification reaction material is added into the esterification kettle, and acetic anhydride is added dropwisely in; water is added after adding dropwisely, and sucrose 6 ester and organotin acetate are extracted and separated with cyclohexane; organic tin acetate present in the cyclohexane phase, which is produced through evaporating of the cyclohexane solvent. The advantages of the method for the reaction of sucralose esterified single solvent is shortening the production cycle, eliminating the original tin recovery process, reducing the consumption of raw materials and energy and maximizing the savings in all costs.

The invention relates to a synthesis method of amino-protecting glycine dipeptidase derivant. The amino-protecting glycine dipeptidase derivant is N-9-Fmoc glycine dipeptidase, N-Boc glycine dipeptidase and N-acetyl glycine dipeptidase. The invention has the technology that glycine dipeptidase is dissolved in 1-20% of inorganic aqueous alkali, and the organic solution of Fmoc-OSu or Boc2O or Ac2Ois dropwise added; reaction is finished within 1-12 hours, the yield of the product Fmoc-Gly-Gly-OH, Boc-Gly-Gly-OH and Ac-Gly-Gly-OH is between 80-95%, and the content of the product is above 99%. The invention has simple technology, easy industrialization and low cost. The product of the invention is the important raw material for synthesizing polypeptide compound.

The invention provides a preparation method of acetylated sodium hyaluronate. The preparation method comprises following steps: adding hyaluronic acid or hyaluronate into a mixed solvent of acetic acid and acetic anhydride; carrying out acylation reactions under the catalytic action of concentrated sulfuric acid, after reactions, adding the reaction liquid into water to carrying out precipitation,filtering, washing the precipitate to obtain acetylated hyaluronic acid, adding alkali to adjust the pH value until the solution becomes neutral; filtering to remove the impurities, and carrying outspray drying to obtain acetylated sodium hyaluronate. The preparation time is largely shortened, precipitation and washing do not need a large amount of organic solvents, the environment is protected,the cost is reduced, and the preparation method is especially suitable for industrial large scale production.

The invention discloses an oil absorption material using cellulose as a base and a preparation method thereof. The preparation method comprises the following steps: pretreating the raw material corn straws with sodium hydroxide and sodium hypochlorite to extract cellulose, and carrying out acetylation modification on the cellulose with acetic anhydride to obtain the natural high-efficiency oil absorption material. The technical scheme disclosed by the invention has efficient adsorption effect on marine oil spill; the oil absorption rate can reach more than 60 times; and the preparation method has the advantages of simple process and easy recovery.

The invention relates to a method for preparing a computed tomography (CT)/magnatic resonance imaging (MRI) bimodal imaging contrast agent based on dendrimers. The method comprises the following steps of: (1) adding DOTA-N-hydroxy succinimide (NHS) solution into the fifth generation of poly(amidoamine) (PAMAM) dendrimer solution, adding methoxy poly(ethylene glycol) (mPEG)-COOH solution which is subjected to 1-ethy 1-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) activation, reacting with stirring, and thus obtaining functionalized dendrimer solution; (2) adding chloroauric acid solution and sodium borohydride solution into the functionalized dendrimer solution, reacting with stirring, adding gadolinium nitrate solution, stirring, adding triethylamine and acetic anhydride, andreacting with stirring for 8 to 24 hours; and (3) dialyzing the solution obtained in the step (2), performing freeze drying treatment, and thus obtaining the contrast agent. The method has a simple preparation process, and experimental conditions are realized at normal temperature and under normal pressure; and the CT/MRI bimodal imaging contrast agent prepared by the method has a good CT/MRI effect, and a favorable foundation is laid for the development of a novel multifunctional contrast agent.

A process for the rapid production and stabilization of dilute aqueous peracetic acid in which acetic anhydride and hydrogen peroxide are reacted in an aqueous medium with a stoichiometric excess of hydrogen peroxide and the aqueous medium containing the peracetic acid reaction product is adjusted, as necessary, to a pH of less than about 8 to provide a stabilized dilute peracetic acid solution. The dilute peracetic acid may be produced on site or in situ for treatment of an aqueous medium requiring disinfecting, biocidal, antimicrobial or bleaching treatment.

The invention relates to a preparation method of acipimox for treating hyperlipidemia, belonging to the field of medicines. The invention provides an acipimox synthesis process which is simple and easy to operate. The preparation method comprises steps of with 2, 5-dimethylpyrazine as a raw material, carrying out nitrogen oxidation, reaction with acetic anhydride and alkaline hydrolysis to obtain 2-hydroxymethyl-5-methylpyrazine; directly oxidizing a post-treatment fluid by using 2,2,6,6-tetramethyl-1-piperidinyloxy/sodium hypochlorite/potassium bromide to obtain 5-methylpyrazine-2-carboxylic acid, wherein the post-treatment fluid is not needed to be dried and concentrated; oxidizing 5-methylpyrazine-2-carboxylic acid by using hydrogen peroxide/sodium tungstate to obtain acipimox.

The invention relates to a preparation method of pegylation modified hyperbranched poly(ethylene imine) (PEI) coated nano-gold particles, which comprises the following steps: modifying PEI by using mPEG (polyethylene glycol)-COOH, and sequentially carrying out dialysis and freeze-drying on the obtained product so as to obtain PEI-mPEG; taking the solid, dissolving the solid by using water, adding a HAuCl4 solution into the dissolved solid, stirring the obtained product, adding a NaBH4 solution into the obtained product, and carrying out reaction on the obtained mixture at room temperature; and adding triethylamine and acetic anhydride into the obtained object, and after the reaction is completed, carrying out dialysis and freezing on the obtained product so as to obtain pegylation modified hyperbranched polymine coated nano-gold particles. According to the invention, the cheap and easily-obtained PEI is taken as a carrier, so that the cost of materials is reduced; the surface of PEI is modified by using mPEG-COOH, so that the biocompatibility of materials and the colloidal stability of nano-gold particles are improved, and the nano-gold particles are successfully applied to vivo CT (computed tomography) imaging. The method disclosed by the invention is simple in design, mild in reaction conditions and easy to operate, and has an industrialized implementation prospect.

This invention relates to a synthesis method of acetylation di-starch adipate, which takes starch, acetic anhydride, hydrochloric acid, sodium hydroxide, adipic acid as raw materials in water medium, and conducts eight steps of preparing chemicals, conditioning, alkalization, neutralization, washing, drying, screening, and packaging to obtain the product, which has white powder particles, DS of 0.01~0.07, 6% paste E point viscosity of 500 ~ 3000BU. Compared with similar product on the market, the invention has good viscosity, transparency, replacement, shear resistant, heat resistant, and the produced food has good water storage, absorbent, expansion, so it is suitable for sauces and leisure food.