40results about How to "Fewer reaction by-products" patented technology

This invention provides a method for preparing trans-4-acetoxy-2-methyl-2-crotonaldehyde. The method comprises: reacting isoprene and tert-butyl hypochlorite in acetic anhydride solution to obtain chlorine-containing ester, reacting with urotropine, and hydrolyzing to obtain trans-4-acetoxy-2-methyl-2-crotonaldehyde. The method has such advantages as few reaction procedures, easy operation, high isoprene conversion rate, high yield (40-56%), no need for DMSO during the oxidation process, no byproduct, low raw material cost, easy recovery of solvent, little environmental pollution and low cost, and is suitable for industrial production.

The invention belongs to the technical field of medicine preparation, and relates to a preparation method for production of a starch-based capsule. The preparation method specifically comprises the following steps of starch etherifying, glue digestion, defoaming, impurity removal, glue dipping and forming, and the like. The prepared hydroxypropyl starch-based capsule has the advantages that the surface is smooth, the transparency is high, the disintegration time is short, the production technology is simplified, the production cost is reduced, and the hydroxypropyl starch-based capsule is suitable for industrial production.

The invention discloses a synthetic method of 3,3'-binitro-5,5'-di-1,2,4-triazole. The structural formula of 3,3'-binitro-5,5'-di-1,2,4-triazole is as follows: as shown in the description. The synthetic method disclosed by the invention comprises the following steps: taking 5,5'-diamido-3,3'-di-1,2,4-triazole as a raw material, dissolving 5,5'-diamido-3,3'-di-1,2,4-triazole in organic sulfonic acid to prepare a salt solution, at normal temperature, dripping the salt solution in a sodium nitride aqueous solution, heating in water bath, when the gas is released completely, cooling to the room temperature, filtering, washing with water and drying the solution to obtain the target product 3,3'-binitro-5,5'-di-1,2,4-triazole. The synthetic method disclosed by the invention is easy in operation, few in side reactions and high in reaction yield, and can be mainly applied to synthesis of 3,3'-binitro-5,5'-di-1,2,4-triazole.

The invention discloses a preparation method of polyfluoro aliphatic carboxylic acid, which comprises the following concrete steps: oxidizing polyfluoro aliphatic alcohol by potassium permanganate to obtain polyfluoro carboxylic acid potassium salt, purifying intermediate products of fluorine-containing potassium carboxylate, namely washing for removing unreacted raw materials, and then, acidizing for releasing polyfluoro carboxylic acid. By utilizing the characteristic that the polyfluoro aliphatic alcohol is oxidized by the potassium permanganate to obtain the polyfluoro carboxylic acid, but the acidity of the polyfluoro carboxylic acid is further stronger than the acidity of acetic acid, so that the generated polyfluoro carboxylic acid is neutralized with potassium hydroxide released by the potassium permanganate in the reaction process to obtain the fluorine-containing carboxylic acid potassium salt, the invention adopts the method of firstly washing the fluorine-containing potassium carboxylate and then acidizing for releasing the polyfluoro carboxylic acid, thereby solving the problem that the polyfluoro aliphatic alcohol and the polyfluoro aliphatic carboxylic acid can not be rectified and separated easily. The polyfluoro aliphatic alcohol which is used as a raw material in the invention is prepared by telomerization of tetrafluoroethylene and belongs to an industrialized raw material. The process for preparing the polyfluoro aliphatic carboxylic acid by oxidizing the polyfluoro aliphatic alcohol has mild conditions and is suitable for industrialized production.

The invention discloses a biosynthesis method of borneol, which comprises the following steps: selecting and separating microbial strains for synthesizing the borneol from the nature, collecting cells after fermentation, taking the cells as a bio-catalyst to be subjected to the hydrolysis reaction of borneol ester in an organic solvent-buffer salt system, and obtaining a borneol product with the borneol content of over 75 percent after separation and refining. The bornrol product is close to the composition of natural borneol, and the method is a novel method for preparing the borneol.

The present invention relates to a process for preparing orthoformate by taking advantage of hydrocyanic acid, as by-product in production of acrylic nitrile, and apparatus therefore. The hydrocyanic acid, as by-product in production of acrylic nitrile, is adopted as a starting raw material and, together with alkyl alcohol and halogen hydride, is dissolved in an indifferent solvent; then after halogenation, salt forming and alcoholysis reactions, crystal separation and distillation rectification, the orthoformate is obtained. By adopting a reactor equipped with stirring, built-in plastics bundled tubes or metal dish tube heat interchanger to resolve the heat exchange problem existing in the aggregation exothermic halogenation and salt forming reactions, the present invention prevents blasting boiling and exploding accident states from appearing during the course of reaction, facilitates placidity and controllability of the reaction temperature, and achieves the requirement for safe reactions.

The invention discloses application of a heat-resistant alpha-glucuronidase polypeptide fusion body in preparation of glucuronic acid. An amino acid sequence of the fusion body is as shown in SEQ ID NO.1. According to the invention, seven amino acid residues are fused at the C end of heat-resistant alpha-glucuronidase protein to form a brand-new polypeptide fusion body, the specific activity of the obtained polypeptide fusion body is improved by 297% compared with that of wild type enzyme TmAguA, the Kcat and Kcat/Km of a corresponding hydrolyzed 4-O-methyl glucuronic acid xylo-oligosaccharidesubstrate are improved by 356% and 363% respectively, and the stability is improved by 21.1%-65.7% compared with that of the wild type enzyme; the fusion body is used for preparing the glucuronic acid, and compared with the wild type enzyme, the fusion body has the advantage that the yield of the glucuronic acid prepared by converting beechwood xylan through the polypeptide fusion body is increased by 21.6-60.3%; and the fusion body has the advantages of high conversion efficiency, few reaction byproducts, high yield and purity, easiness in separation and purification, less chemical pollutionand the like.

The invention discloses a method for preparing durene from carbon monoxide and methanol. The method comprises the following steps: contacting a raw material containing carbon monoxide and methanol with a catalyst in a reactor, and reacting to obtain the durene, wherein the catalyst is prepared by modifying a material containing a molecular sieve, and the modification treatment is selected from atleast one of oxide modification, water vapor treatment and acid treatment. According to the method provided by the invention, the defects of a traditional durene process route are overcome, and the method for preparing durene by coupling carbon monoxide and methanol is a new process technology for producing durene. The preparation of durene by using carbon monoxide and methanol as raw materials isnot restricted by the raw materials, the device is easy to realize large-scale production, and the methodhas good economy, and has good industrial application prospect.

The invention discloses a modified synthetic method of dicyclopropyl ketone, comprising: first, in the presence of reaction inert organic solvent and solid sodium alcoholate, subjecting gamma-butyrrolactone to inter-molecular dehydration condensation to generate an intermediate; second, adding concentrated hydrochloric acid into a reaction system and generating 1,7-dichloro-4-heptanone crude product by decarboxylation; third, closing loop under the action of a strong base to generate the dicyclopropyl ketone. The invention has the advantages that the inert organic solvent and solid sodium alcoholate are used, there is no need for recycling alcohols, reaction controllability is greatly improved, reaction byproducts are decreased, product yield is 15-20% as high as that of a conventional technique, production cost is lowered, environment protection burden is lowered, and product quality is improved.

The invention relates to a simple preparation method of a 9-hydroxyfluorene-9-carboxylate compound. The method comprises the following step: with a benzoyl formate compound I and an iodobenzene compound II as raw materials, under the catalysis of Pd(OAc)2 and trifluoroacetic acid, carrying out a cyclization reaction by using silver trifluoroacetate as an oxidant and 2-fluoro-5-trifluoromethylaniline as a ligand to obtain the 9-hydroxyfluorene-9-carboxylate compound. Compared with an existing method, the method of the invention has the advantages that reaction raw materials are easy to synthesize through a classical reaction; 2, the reaction is simple and convenient, operation is easy, a target product can be obtained in one step, few reaction byproducts are produced, little waste is discharged, the product is directly purified by using column chromatography, strong acid or strong base is not needed for aftertreatment, pressure on the environment is greatly reduced, purification effectis good, and yield can reach 60-90%; and 3, reaction expansibility is strong, a novel method for synthesizing the 9-hydroxyfluorene-9-carboxylate compound is provided, and the compound which is not synthesized before can be synthesized.

The invention relates to a synthesis method of alpha,gamma,gamma,gamma-tetrachlorobutyrate. The synthesis method comprises the following steps: stirring and mixing carbon tetrachloride and acrylate with a copper salt and/or cuprous salt main catalyst, an organic amine or imidazole cocatalyst and a polar inert organic solvent at room temperature, sealing a reaction kettle, conducting heating for anaddition reaction, preforming cooling to room temperature, carrying out filtering, distilling a filtrate under normal pressure to recover carbon tetrachloride, and performing rectifying under reducedpressure to obtain alpha,gamma,gamma,gamma-tetrachlorobutyrate. The purity of the alpha,gamma,gamma,gamma-tetrachlorobutyrate obtained by using the method is up to 99.5%, one-way reaction yield is upto 96.1%, a product is easy to separate, reaction byproducts are few, the catalytic effect of the catalysts and the ligand is excellent, the raw materials and the catalysts are cheap and easy to obtain, and the solvent and the catalysts are easy to recycle; and the method is mild in reaction condition, simple in technological operation, low in production cost, good in economic benefit and suitable for industrial production.

Belonging to the technical field of chemical synthesis, the invention specifically relates to a preparation method of 1-bromonaphthalene. The method includes: (1) dissolving naphthalene fully in dichloroethane, and adding hydrobromic acid under stirring to form a mixed solution; (2) adding sodium hypochlorite into the mixed solution dropwise at 25-30DEG C, and conducting heat preservation stirring; (3) carrying out standing layering, taking the oil phase layer, and performing washing; and (4) conducting drying, and performing reduced pressure fractionation, thus obtaining 1-bromonaphthalene. The synthesis process adopted by the invention has the advantages of simple reaction device, few by-product, high yield, high utilization rate of bromine compared with other processes, low pollution ofthree wastes, low production energy consumption, high safety of the reaction process, and conforms to the green chemistry concept.

The invention relates to a preparation method of (S)-3-methylamino-1-(2-thienyl)-1-propanol. (S)-3-dimethylamino-1-(2-thienyl)-1-propanol is used as a raw material to be treated by the following stepsof (1) performing hydroxy group protective reaction on the (S)-3-dimethylamino-1-(2-thienyl)-1-propanol; (2) performing demethylation reaction; (3) performing hydroxy removal reaction protection. Thepreparation method has the advantages that the reaction byproducts are few; the purity is high; the reaction speed is high; the yield is high.