18 results about "Dihydroxylation" patented technology

The present invention relates to a method for preparing an isohexide-based polycarbonate copolymer. The isohexide-based polycarbonate copolymer is obtained by sequentially carrying out a transesterification reaction, a pre-polycondensation reaction, and a final polycondensation reaction on diol and dialkyl carbonate under the action of a catalyst, wherein the diol includes diol A1 and diol A2, or further includes diol A3; the diol A1 is isohexide; the molecular structural formula of the diol A2 contains a cyclic ether structure and two primary hydroxyl groups, and the primary hydroxyl groups are linked to the cyclic ether structure via a methylene group; the diol A3 is a dihydroxy compound; and during the pre-polycondensation reaction, the temperature is first gradually increased to 180-200ºC within 5-15 min, the pressure is gradually reduced to 45-55 kPa within 5 min, and finally, gradient heating and gradient pressure reduction are carried out. The copolymer prepared by the present invention has high molecular weight, high heat resistance, high strength, high toughness, and transparency, and thus has a wide range of applications.

The invention discloses a preparation method of heat-resistant bisphenol A type copolycarbonate, and belongs to the technical field of polycarbonate synthesis. Comprising the following steps: by taking bisphenol A and diester carbonate as monomers, aromatic dibasic acid, aromatic dibasic acid ester or aromatic dihydroxy compound as a copolymerization unit and imidazole ionic liquid as a catalyst, carrying out transesterification under a protective atmosphere, and then carrying out condensation polymerization under a vacuum condition to obtain the heat-resistant bisphenol A type copolycarbonate. A metal-free catalyst is used for carrying out melt polycondensation on bisphenol A type copolycarbonate, so that efficient polymerization and heat-resistant modification of polycarbonate are realized. The performance of the copolycarbonate is regulated and controlled by controlling the type and proportion of the added copolymerization units, so that the glass-transition temperature is increased while the mechanical properties and optical properties of the bisphenol A polycarbonate are retained.

This invention discloses a method for preparing a key intermediate of iodopyridine, using dimethyl malonate as a raw material, and sequentially undergoing dihydroxylation S1 → acetalization S2 → hydrolysis and acidification S3 → decarboxylation S4 to obtain iodopyridine. The raw materials of this invention are inexpensive and readily available in the market, and the reaction efficiency is high, improving the purity and yield of the product. Intermediates 1 and 2 obtained from the process do not require separation and purification operations and can be directly used in the next step of the reaction. The purification effect is significant, yielding intermediate products with a purity ≥99%, and the total yield of the five steps is as high as 65-70%, which is beneficial for large-scale production.

The present disclosure relates to a method for olefin oxygen oxidation, comprising the following steps: contacting an olefin compound with a catalyst under oxygen condition to perform an oxidation reaction; the catalyst is a composite catalytic material, the composite catalytic material comprises a framework heteroatom molecular sieve and a metal element M dispersed in the intracrystalline of the molecular sieve; the framework heteroatom molecular sieve is a molecular sieve in which at least part of silicon in a full-silicon molecular sieve framework is replaced by a heteroatom element Q, and the heteroatom element Q is selected from one of titanium, boron, zirconium, aluminum, tin, phosphorus and germanium. The method uses a metal-containing multi-level porous heteroatom molecular sieve for olefin oxygen oxidation reaction, and high conversion rate of olefin and high selectivity of ketone and dihydroxyl compound can be obtained under relatively mild conditions.

Methods for asymmetric cis-dihydroxylation ("AD") of quinones to produce cis-diols of quinones with high yield (i.e. a yield ≥ 30%) and high enantioselectivity (i.e. an enantiometric excess ≥ 30%) are disclosed. The method uses an iron-based catalyst, such as one or more Fe(II) complexes, as the catalyst, and can be performed under mild reaction conditions (e.g. a temperature ≤ 50°C at 1 atom in open air). The method generally includes: (i) maintaining a reaction mixture at a temperature for a period of time sufficient to form a product, where the reaction mixture contains a quinone, one or more iron-based catalyst (s), and a solvent, and where the product contains a chiral cis-diol. Optionally, the method also includes adding an oxidant into the reaction mixture prior to and / or during step (i), such as a hydrogen peroxide solution.

The invention relates to the field of carbonate polymerization, and discloses isosorbide polycarbonate and a preparation method thereof. The preparation method of the isosorbide polycarbonate comprises the following steps: under the action of a ketonic acid metal salt catalyst, taking a dihydroxy compound, diester carbonate and aliphatic dihydric alcohol as raw materials, and carrying out transesterification and polycondensation reaction to obtain the isosorbide polycarbonate. The keto acid metal salt is used as the catalyst for synthesizing the isosorbide polycarbonate, the catalyst is low in price and not prone to inactivation, and the isosorbide polycarbonate with high molecular weight and ideal transparency is catalytically synthesized.

The present invention provides an estetrol synthesis process, and relates to the technical field of steroid compound synthesis processes, and the method comprises the following steps: taking estrone as an initial raw material, firstly carrying out 3-site hydroxyl protection, and then carrying out an oxidative dehydrogenation reaction in the presence of a metal catalyst and in an oxygen atmosphere to prepare a key intermediate ketene, then 17-site carbonyl reduction, 17-site hydroxyl protection, 15, 16-site double bond dihydroxylation, 3-site protecting group removal and hydrolysis reaction are sequentially carried out, and finally the target product estetrol is obtained. The method adopts metal catalysis to directly oxidize to construct cycloenone, effectively avoids the problem of poor stability of partial intermediates in the prior art, has the advantages of simple process, short reaction steps, greenness, environmental protection and the like, and is suitable for industrial production.

The present invention addresses the problem of providing a composition containing a dihydroxy compound having a biphenanthrene skeleton, the composition making it possible to diminish troubles caused by metals remaining in large amounts in conventional dihydroxy compounds having a biphenanthrene skeleton. This composition contains a dihydroxy compound having a biphenanthrene skeleton, the dihydroxy compound being represented by general formula (1a) and having a total content of sodium, potassium, iron, and copper metals of 40 ppm or less. (In the formula, the R1 moieties each independently represent a C2-C4 alkylene group, the R2 moieties each independently represent a C1-C6 alkyl group, a C6-C18 aryl group, or a halogen atom, and each n independently indicates 0 or an integer of 1-4.)

This polycarbonate diol contains a structural unit (1) represented by general formula (I) and a structural unit (2) represented by general formula (II). The percentage content of the structural unit (2) in the polycarbonate diol is 4.3 mol% or less relative to the total structural units of the polycarbonate diol which is 100 mol%.　The present invention can provide: a method for producing a polycarbonate diol, in which a diol such as 1,4-butanediol is used as a raw material and a polycarbonate diol with a molecular weight close to the theoretical molecular weight in high yield can be obtained; and a polycarbonate diol that makes it possible to obtain a polyurethane having excellent mechanical properties and chemical resistance and configured to suppress variation in the mechanical properties.　In general formula (I), n is an integer of 4-6. Also, in general formula (II), m is an integer of 2-4.

A highly efficient synthesis of cis-diol compounds through cis-dihydroxylation of olefins using osmate (VI) salt as catalysts is disclosed, which has found important application in efficient large-scale preparation of, among others, α,α-cedranediol from α-cedrene.

Provided are a method for producing a modified aluminosilicate capable of highly selectively producing hydroquinones by a reaction of phenols and hydrogen peroxide under industrially advantageous conditions, a method for producing a catalyst for producing an aromatic dihydroxide compound, a catalyst containing a modified aluminosilicate, a method for producing an aromatic dihydroxide compound using the catalyst, and a modified aluminosilicate. The method for producing an aluminosilicate may include preparing a liquid in which sol-like silica containing water is contacted with a metal compound (AL) containing aluminum and oxygen to obtain an aluminosilicate having a specific range of a molar ratio of water to silica (HMR); treating the aluminosilicate with an acid; subjecting the treated product to primary calcination; and contacting the calcined product with a liquid containing one or more elements in Group 4 and Group 5 of the Periodic Table, followed by carrying out drying and secondary calcination.

The present invention relates to a process for manufacturing a polycarbonate comprising the steps of: i) melt reacting a dihydroxy compound and a carbonate, optionally in the presence of one or more transesterification catalysts, thereby forming a stream of molten polycarbonate, i ') combining the stream of molten polycarbonate obtained in step i) with 0 to 5000 ppm of water, based on the weight of polycarbonate, ii) feeding the stream of molten polycarbonate obtained in step i) or step i') to a melt mixing device, iii) combining the stream of molten polycarbonate with 0 to 5000 ppm of water, based on the weight of polycarbonate, in the melt mixing device, ii) feeding the stream of molten polycarbonate obtained in step i) to the melt mixing device, iii) combining the stream of molten polycarbonate and 0 to 5000 ppm, based on the weight of polycarbonate, of water in the melt mixing device, the total amount of water to be combined with the stream of molten being 5 to 5000 ppm, based on the weight of polycarbonate, iv) subjecting the stream obtained in step iii) at least partially to a vacuum in the range of 1 to 800 mbar, and v) passing the stream obtained in step iv) through a melt filter in order to at least partially remove water from the stream of molten polycarbonate, and v) passing the stream obtained in step iv) through the melt filter.

The invention relates to a method for producing a polycarbonate, comprising the steps of:-subjecting a dihydroxy compound and a carbonate to a melt reaction, optionally in the presence of a transesterification catalyst, thereby forming a molten polycarbonate stream, and-combining the molten polycarbonate stream with 5 to 5000 ppm of water and 50 to 10000 ppm of a siloxane compound, based on the weight of the polycarbonate.

The invention provides a preparation method of a sofosbuvir intermediate isomer as shown in a formula (I), which comprises the following steps: S4, carrying out dihydroxylation reaction on a compound 4 in the presence of a first oxidant to obtain a compound 3; s5, carrying out condensation reaction on the compound 3 and thionyl chloride in the presence of alkali; then carrying out oxidation reaction in the presence of a second oxidant to obtain a compound 2; s6, carrying out fluorination reaction on the compound 2 and a fluorinating agent in the presence of alkali; then, under an acidic condition, hydrolysis is carried out, a cyclization reaction is further carried out, and a compound 1 is obtained; s7, the compound 1 and benzoyl chloride are subjected to an esterification reaction in the presence of alkali, and the compound shown in the formula (I) is obtained. The oriented preparation of the sofosbuvir can realize accurate qualitative and quantitative analysis of isomer impurities in the medicine, and by strengthening the control of the impurities, the risk of adverse reaction of the medicine can be reduced, and the guarantee is provided for the medication safety of sofosbuvir.

The present invention relates to a process for manufacturing a polycarbonate comprising the steps of i) melt reacting a dihydroxy compound and a carbonate, optionally in the presence of a transesterification catalyst, thereby forming a stream of molten polycarbonate, ii) passing the stream of molten polycarbonate obtained in step i) through a melt filter, iii ') combining the filtered stream of molten polycarbonate obtained in step ii) with 0 to 5000 ppm of water, based on the weight of polycarbonate, iii) feeding the stream obtained in step ii) to a melt mixing device, and iv) combining the stream of molten polycarbonate obtained in the melt mixing device with 0 to 5000 ppm of water, based on the weight of polycarbonate, wherein after combining the stream of molten polycarbonate with said water, the stream is subjected to a vacuum wherein the total amount of water to be combined with the stream of molten polycarbonate in steps iii ') and iv) is from 5 to 5000 ppm based on the weight of polycarbonate.

The present invention discloses a method for preparing high-purity estragen-1,3,5(10)-triene-3,15α,16α,17β-tetrol (abbreviated as estragen-1,3,5(10),15-tetraene) using 3-hydroxy-17β-hydroxy-estragen-1,3,5(10),15-tetraene as a raw material, and preparing estragen-1 through three steps of phenolic hydroxyl protection, asymmetric dihydroxylation, and hydrolysis. In the preparation method of the present invention, 3-hydroxy-17β-hydroxy-estragen-1,3,5(10),15-tetraene is used as a raw material, alkoxy-substituted benzoyl is used to protect the 3-hydroxyl group, potassium osmate is used to catalyze oxidation to perform an asymmetric dihydroxylation reaction, and di-α-hydroxy groups are introduced at the 15,16 positions. The preparation method does not require the use of expensive chemical reagents and catalysts, the dihydroxylation has high stereoselectivity, is easy to purify and separate, has mild reaction conditions, and is simple and convenient to operate, thereby achieving efficient preparation of high-purity estragen-1,3,5(10),15-tetraene (≥99.5%).

A polycarbonate diol composition contains: a polycarbonate diol containing a structural unit (1) derived from a compound (1) represented by the following general formula (1); HO—(CH2)n—OH (1) (n is an integer of 3 to 6) and an aldehyde having 3 or more and 8 or less carbon atoms. A method for producing a polycarbonate diol composition, includes: polycondensing a carbonate compound and a dihydroxy compound composition containing a compound (1) represented by the following general formula (1) and an aldehyde having 3 or more and 8 or less carbon atoms by a transesterification reaction in the presence of a catalyst, to obtain a polycarbonate diol composition containing a polycarbonate diol. A polyurethane is obtained by using this polycarbonate diol composition.

The present invention relates to a preparation method of an isohexide-based polycarbonate copolymer, wherein diol and carbonic acid diester are subjected to ester exchange reaction, pre-polycondensation reaction, and final polycondensation reaction in sequence under the action of a catalyst to obtain an isohexide-based polycarbonate copolymer; diol includes diol A1 and diol A2, or, further includes diol A3; diol A1 is isohexide; the molecular structural formula of diol A2 contains a cyclic ether structure and two primary hydroxyl groups, and the primary hydroxyl group and the cyclic ether structure are connected by a methylene group; diol A3 is a dihydroxy compound; during the pre-polycondensation reaction, the temperature is first gradually increased to 180 200 DEG C within 5 15 min, and then the pressure is gradually reduced to 45 55 kPa within 5 min, and finally gradient heating and gradient pressure reduction are performed. The copolymer obtained by the present invention has high molecular weight, high heat resistance, high strength, high toughness and transparency, and has a wide range of applications.