- Kinetic resolutions concentrate the minor enantiomer and aid measurement of high enantiomeric purity
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Although many methods can measure enantiomeric purity, only a few can measure high enantiomeric purity, >98% ee, because in most methods the signal for the major enantiomer overwhelms the signal for the minor enantiomer. We use a kinetic resolution to concentrate the minor enantiomer into the product and thereby extend the ability of all existing techniques to measure high enantiomeric purity. The original enantiomeric purity is calculated using the enantioselectivity of the kinetic resolution and the extent of conversion. We verified this method with samples of (1S)-menthol using an acetylation with vinyl acetate catalyzed by lipase from Candida rugosa. The enantiomeric purities determined by capillary gas chromatography directly and after kinetic resolution agreed for samples with 90-99.9% ee. Error analysis suggests that the usual accuracies for conversion and enantiomeric ratio are sufficient for accurate determination of enantiomeric purity with this method. In another example, we used a kinetic resolution followed by a simple optical rotation measurement to accurately quantify 98.5% ee for a commercial sample of (S)-(+)-6-methoxy-α-methyl-2-naphthaleneacetic acid (naproxen). Thus, this kinetic resolution method allows simple techniques such as optical rotation to measure high enantiomeric purity.
- Caron,Tseng,Kazlauskas
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Read Online
- High yield synthesis of cyclic phosphites, phosphates, sulphites and sulphates of catechol and glycol mediated by hypervalent silicon centres
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Room temperature reactions of both tris(catecholato)silicate, M2[Si(o-C6H4O2)3] {M=Na, Et3NH} and glycolato silicate, K2[Si2(O2C2H4)5] with PCl3, POCl3, SOCl2 and SO2Cl2 proceed exothermally and afford easy isolation of the corresponding cyclic derivatives of catechol/glycol (1-8) in high yield, exemplifying the merit of hypervalent silicon centres in synthesis. (Et3NH)2[Si(o-C6H4O2)3] afford near quantitative conversions.
- Kingston,Sudheendra Rao
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Read Online
- Preparation method of cyclic sulfate
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The invention discloses a preparation method of cyclic sulfate, which is used for preparing cyclic sulfate by a one-step method, and has the beneficial effects that an epoxy compound is used as a rawmaterial to react with sulfamic acid or sulfuric acid in one step under the participation of anhydride to prepare cyclic sulfate, and noble metal catalysis is not needed in the preparation process; corrosive gas production is achieved, the product is high in purity and low in chromaticity (less than 20Hazen), the moisture content is less than or equal to 20ppm, and the acid value is less than or equal to 10ppm, and the influence of moisture and acid value in the electrolyte on the cycle performance and storage stability of the battery is effectively changed.
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Paragraph 0014; 0019-0020
(2021/01/29)
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- Preparation method of ethylene sulfate derivative
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The invention belongs to the technical field of organic synthetic chemistry, and particularly relates to a preparation method of an ethylene sulfate derivative, which comprises the following steps: ina mixed solvent composed of an organic solvent and water, in the presence of alkali and quaternary ammonium salt, by using ruthenium trichloride as a catalyst, reacting to obtain the ethylene sulfatederivative. The ethylene sulfite derivative shown in the general formula A and trichloroisocyanuric acid shown in the formula TCCA are subjected to an oxidation reaction to obtain the ethylene sulfate derivative, and the reaction route is as follows: R1 to R4 are independently a hydrogen atom or an alkyl group of C1-3; the ethylene sulfate derivative is synthesized with high efficiency and low cost, and the yield and purity of the product are improved.
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Paragraph 0027-0028; 0029-0030; 0031-0032; 0035-0040
(2021/01/25)
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- Synthesis method of ethylene sulfate
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The invention discloses a synthesis method of ethylene sulfate. The synthesis method comprises the following steps: mixing ethylene sulfite, a first organic solvent, an oxidant calcium hypochlorite solid and a catalyst ruthenium trichloride, adding the mixture into a reaction kettle, and cooling the reaction system to -15 DEG C to 10 DEG C; slowly dropwise adding a certain amount of cold water in a violent stirring state, continuously reacting for 6-10h at the temperature of -10 DEG C to -5 DEG C after dropwise adding is finished, carrying out suction filtration, separating filtrate, washing an organic phase twice by using a small amount of ice water, adding a molecular sieve, performing drying to remove water, performing filtering, performing concentrating, and performing recrystallizing and centrifugal drying to obtain an ethylene sulfate finished product. According to the invention, the synthesis yield of ethylene sulfite is improved; because the common oxidant sodium hypochlorite solution is easy to decompose after being stored at normal temperature, the calcium hypochlorite solid is convenient to store and can be used immediately after being prepared, and the catalyst is less in dosage and low in cost in the oxidation process of ethylene sulfate.
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Paragraph 0031; 0033-0044
(2021/04/21)
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- Synthesis process of ethylene sulfate
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The invention discloses a synthesis process of ethylene sulfate. The synthesis process comprises the following steps: dissolving ethylene glycol in an organic solvent, dropwisely adding thionyl chloride, reacting at 5-10 DEG C for 1-1.5 hours while keeping the temperature, adding a sodium carbonate solution to regulate the pH value to 7-8, and standing to stratify to obtain an ethylene sulfite-containing mixed solution; adding a catalyst into the mixed solution containing ethylene sulfite, dropwise adding a 70% tert-butyl hydroperoxide aqueous solution for 0.5-1 hour, reacting at 30-40 DEG C for 1-3 hours after dropwise adding, then adding a sodium sulfite solution, standing for layering, carrying out aqueous phase extraction, combining organic phases, carrying out reduced pressure concentration, and recrystallizing to obtain ethylene sulfate. The mixed solution containing the ethylene sulfite is directly subjected to oxidation reaction, so that the technological process is simplified;70% tert-butyl hydroperoxide aqueous solution and copper chloride are adopted, so that the cost is further reduced; and the obtained ethylene sulfate has high yield and purity.
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Paragraph 0019; 0021-0022; 0024-0025; 0027-0028; 0030-0031
(2021/02/20)
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- Ethylene sulfate preparation method
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The invention relates to an ethylene sulfate preparation method, which comprises: dissolving ethylene glycol in an aprotic organic solvent, adding an aprotic organic alkali, introducing sulfuryl fluoride, stirring while reacting, filtering after the reaction is completed, and carrying out evaporating concentrating and drying on the filtrate to obtain ethylene sulfate. According to the invention, the ethylene sulfate prepared by the method has extremely high purity of more than 99.9%, low moisture content of less than or equal to 20 ppm and low acid value of less than or equal to 10 ppm, and effectively changes the influence of the moisture and the acid value in an electrolytic solution on the cycle performance and the storage stability of a battery.
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Paragraph 0017-0019
(2020/03/02)
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- Iodine-Catalyzed Selective Functionalization of Ethane in Oleum: Toward a Direct Process for the Production of Ethylene Glycol from Shale Gas
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Direct valorization of ethane, a substantial component of shale gas deposits, at mild conditions remains a significant challenge, both from an industrial and an academic point of view. Herein, we report iodine as an efficient and selective catalyst for the functionalization of ethane in oleum at low temperatures and pressures. A thorough study of relevant reaction parameters revealed iodine to be remarkably more active than the previously reported Periana/Catalytica catalyst under optimized conditions. As a result of a fundamentally different catalytic cycle, iodine yields the bis-bisulfate ester of ethylene glycol (HO3SO-CH2-CH2-OSO3H, EBS), whereas for state-of-the-art platinum-based catalysts ethionic acid (HO3S-CH2-CH2-OSO3H, ETA) is obtained as the main product. Our findings open up an attractive route for the direct conversion of ethane toward ethylene glycol.
- Bilke, Marius,Zimmermann, Tobias,Schüth, Ferdi
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supporting information
p. 21712 - 21719
(2021/01/13)
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- Preparation method and application of cyclic sulfate compound
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The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method and application of a cyclic sulfate compound. One embodiment of the invention provides a preparation method of a cyclic sulfate compound. The cyclic sulfate compound is prepared from a compound A and sulfur-containing oxide, wherein the structural formula of the compound A is shown in the specification, R is selected from one of H, alkyl, alkenyl, substituted alkyl, aryl and halogen, X is C or S, and Y is-CH2-CH2-or-CH = C-. The compound A and sulfur trioxide are reliable in source, low in price, mild in reaction condition, easy to operate, free of waste water in the reaction process, few in three wastes, good in product quality, suitable for large-scale production, capable of obtaining the high-purity battery-grade ethylene sulfate compound, and relatively high in implementation value and social and economic benefits.
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Paragraph 0051-0056
(2020/09/23)
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- METHOD OF OXIDIZING USING CALCIUM HYPOCHLORIDE AND MANUFACTURING FOR SULFONE OR SULFIDE
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Is a process for preparing a sulphone or sulfate compound using calcium hypochlorite, and, wherein the method comprises introducing, sulfoxide or sulfite compound in an organic solvent and adding calcium hypochlorite in a solid state to an organic solvent in which the compound is introduced to oxidize the compound. (by machine translation)
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Paragraph 0111-0114; 0131
(2020/06/11)
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- Method for preparing cyclic sulfate by directly oxidizing hydrogen peroxide
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The method comprises the following steps: dropwise adding hydrogen peroxide into a mixture of cyclic sulfite, an organic solvent and a solid catalyst to carry out catalytic oxidation reaction, filtering out the solid catalyst after the reaction is finished, standing filtrate for layering, taking an organic layer, and performing distilling and concentrating to obtain a cyclic sulfate product. Cheaphydrogen peroxide is used for directly catalyzing and oxidizing cyclic sulfite to prepare cyclic sulfate, so that on one hand, the reaction is mild and easy to control, and the reaction conversion rate is high; on the other hand, no waste salt is generated, the evaporation capacity of water is small, energy consumption is low, generated waste water is little, and the production process is more environmentally friendly; the used solid catalyst contains an active component, an active auxiliary agent and an oxide carrier, and can be recycled, so that the consumption of noble metals is reduced, and the production cost is greatly reduced; the cyclic sulfate prepared by the method is few in impurities, high in purity and wide in market prospect.
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Paragraph 0045-0047
(2020/11/23)
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- Process for preparation of ethylene sulphate
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The present invention relates to a process for preparation of ethylene sulfate, the process comprises the following steps: (1) providing a mixture of an oxidizing agent and an organic solvent, whereinthe oxidizing agent comprises calcium hypochlorite; and (2) adding ethylene sulfite to the mixture to form the ethylene sulfate. According to the method for preparing the ethylene sulfate, a water system heterogeneous oxidation reaction mode adopted in the prior art is avoided. According to the method, the reaction is directly carried out in an organic solvent, so that the practical problem thatthe ethylene sulfate is decomposed in water is solved from the source, the moisture residue and the free acid residue in the product are remarkably reduced, the reaction yield of the ethylene sulfateis improved, and the purity of the product is improved.
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Paragraph 0074; 0078-0081; 0085-0088; 0092-0095; 0099-0101
(2020/11/05)
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- Synthesis method of ethylene sulfate
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The invention discloses a synthesis method of ethylene sulfate. The synthesis method comprises the following steps: adding ethylene glycol into a reaction kettle, and cooling the kettle to 35 DEG C orbelow; adding thionyl chloride into the reaction kettle; raising the temperature of the kettle to 45-60 DEG C, and continuously keeping the temperature for 1-3 hours; when the kettle temperature is 30 to 60 DEG C, vacuumizing to -0.05 MPa to-0.1 MPa; recovering the kettle pressure to the normal pressure, dropwise adding alkali liquor into the reaction kettle when the kettle temperature is 10-40 DEG C, and adjusting the pH value of the kettle liquid to 7.5-8; separating out a lower-layer solution to obtain a finished product of ethylene sulfite; adding a sodium hypochlorite solution into the reaction kettle; dissolving the ethylene sulfate crude product in an organic solvent, and adding ice water into the solution; adding a dehydrating agent into the ethylene sulfate organic solution; concentrating and crystallizing the obtained ethylene sulfate organic solution, and drying the obtained solid; dissolving the primary crystal substance in the organic solvent again, and filtering to obtain a white filter cake. The synthesis method has the advantages of high product yield and high product purity.
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Paragraph 0047; 0049; 0050; 0052; 0053; 0055; 0056; 0058
(2020/11/25)
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- A sulfuric acid preparation of vinyl method (by machine translation)
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The invention relates to a preparation method of the sulfuric acid vinyl acetate, comprising the following steps: S1. The nucleophilic substitution reaction: to glycol and chloride as the starting material, to chloroform as solvent, the nucleophilic substitution reaction be sulfuric acid ethylene [...]; S2. The refined purification: will be S1 obtained sulfuric acid ethylene [...] soluble in chloroform, under the protection of nitrogen, heating to reflux the sulfuric acid ethylene [...] is completely dissolved, then lower the temperature recrystallization, filtering, filters the cake to pass through reduced-pressure drying, to obtain. Compared with the prior art, the beneficial effects of the present invention is: to glycol and chloride as the raw material, the catalyst is not required, one-step reaction to obtain the sulfuric acid vinyl ester, the reaction route is short, mild reaction conditions, synthetic process is simple, easy to operate, high safety, the raw materials used are simple and easy to obtain, the cost is low, few by-products, the preparation of the product has high purity, low water content, product low acid value, applicable to industrial production. (by machine translation)
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Paragraph 0020-0025; 0029-0037
(2019/05/29)
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- Method for preparing ethylene sulfate
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The invention relates to a method for preparing ethylene sulfate. According to the technical scheme, the method comprises the following steps: firstly, taking sulfoxide chloride and ethylene glycol asreactive raw materials to carry out a substitution reaction; secondly, adding a catalyst and a buffer agent into the reaction product, and oxidizing with sodium hypochlorite; and thirdly, centrifuging the reactant in the previous step, re-crystallizing, filtering, refining, and drying, thereby obtaining the finished product. The method disclosed by the invention has the beneficial effects that the method has the characteristics of being readily available in reactive raw materials, low in preparation cost, high in molar yield, high in purity of the prepared product and low in moisture content,the reaction can be rapidly and efficiently carried out by the catalyst adopted in the invention, the oxidation time is reduced, and hydrolysis of the ethylene sulfate is reduced. In addition, the mixed aqueous solution of ammonium di-hydrogen phosphate and borax is adopted as a buffer agent needed by oxidation, the oxidative pH value can be effectively controlled to be 6-7, and stable oxidationis promoted. Moreover, by taking magnesium sulfate as a water removal agent, the moisture of the product is controlled to be 50ppm or less.
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Paragraph 0019; 0020; 0021
(2019/04/09)
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- Synthetic method of cyclosulphate
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The invention discloses a synthetic method of cyclosulphate. A peroxysulfate solution is pre-synthesized through sulfuric acid and hydrogen peroxide, then under existence of an organic solvent, a metal inorganic compound and a catalyst, the peroxysulfate solution is dropwise added to generate a catalytic oxidation reaction with cyclosulfite, after the reaction is completed, salt residue is filtered out, still standing for layering is conducted, an organic layer is taken to be distilled, concentrated and purified, and a cyclosulphate high-quality product is obtained. According to the syntheticmethod of the cyclosulphate, the cheap sulfuric acid and hydrogen peroxide are used as the raw materials, the peroxysulfate solution is prepared to conduct catalytic oxidation on the cyclosulfite, onthe one hand, the reaction is mild, control is easy, and the reaction conversion rate is high; on the other hand, the evaporation capacity of water is small, energy consumption is low, generated wastewater is less, and a synthetic process is more environmentally friendly; and the prepared cyclosulphate is few in impurity, high in purity and wide in market prospect.
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Paragraph 0055; 0056; 0057
(2019/11/13)
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- Preparation method of cyclic sulfate
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The invention relates to the field of organic synthesis, in particular to a preparation method of cyclic sulfate. The structural formula of cyclic sulfate is shown as formula I. The preparation methodof cyclic sulfate comprises the following step: cyclic sulfate in the formula I is prepared from a compound in formula II and sulfuryl fluoride by reacting in the presence of an acid binding agent and a catalyst. The preparation method of cyclic sulfate adopts short reaction step, cyclic sulfate can be prepared with the one-step reaction, cost of raw and auxiliary materials is low, and expensiveraw materials and oxidizing agent are not used.
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Paragraph 0071; 0072; 0073; 0074; 0075; 0076; 0077; 0091
(2018/03/28)
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- Sulfate preparation method
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The invention relates to the field of organic synthesis, and especially relates to a sulfate preparation method. The invention provides a sulfate preparation method. According to the preparation method, a compound represented by a formula (II) reacts with sulfuryl fluoride in the presence of a reaction solvent to prepare a compound represented by a formula (I). During the sulfate preparation process, the introduction of water and chlorine ions is avoided effectively, the situation that the product is degraded and the chlorine ion content is high is avoided therefore; moreover, the steps of thepreparation method are simple and short, the raw material are common chemical products on the market, the kinds of raw materials and the side reactions are few, and the yield is high. The manufacturing cost is low, only recyclable organic solvents are used, the reaction byproduct is a single inorganic salt solid and can be easily recovered, no wastewater is generated, the environment is better protected, and the sulfate preparation method is green and environmentally friendly and is suitable for industrial large scale production.
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Paragraph 0072; 0073; 0084; 0085; 0086; 0087
(2018/09/11)
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- Cyclic sulphate preparation method
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The invention relates to the field of organic synthesis and especially relates to a cyclic sulphate preparation method. The sulphate preparation method disclosed by the invention comprises the step ofreacting a compound shown in formula II with sulfuryl chloride under the reaction solvent existence condition to prepare and obtain a compound shown in formula I. The sulphate preparation method disclosed by the invention has the characteristics of brief steps, small side reaction, simpleness in aftertreatment, small three wastes, low manufacturing cost, suitability for industrial large-scale production and the like.
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Paragraph 0069-0077
(2018/09/11)
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- Method for synthesizing ethylene sulfate
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The invention relates to a method for synthesizing ethylene sulfate, and belongs to the technical field of chemical power supplies. The method comprises the following steps: A, carrying out a contactreaction on sulfur dioxide with ethylene oxide in the presence of a composite catalyst, controlling the reaction temperature to be 120-160 DEG C, introducing sulfur dioxide gas to keep the pressure ofthe reaction system at 5-12 MPa, and controlling the reaction time at 1-2.5 hours to obtain ethylene sulfite for standby use; B, adding an aqueous solution of sodium hydrogen carbonate into the ethylene sulfite obtained in the step A, carrying out cooling to a temperature ranging from -5 DEG C to 5 DEG C, dropwise adding a mixed solution of sodium periodate and ruthenium trichloride under a condition with a temperature ranging from -5 DEG C to 5 DEG C, keeping the temperature for 1-1.5 hours after the adding is completed so as to obtain a reaction solution with co-existed water phase and organic phase, carrying out standing for layering, and separating out the water phase to obtain the organic phase, namely a crude product of the ethylene sulfate; and C, carrying out molecular distillation on the crude product of the ethylene sulfate obtained in the step B under the condition with a temperature of 70-80 DEG C to obtain the ethylene sulfate. The ethylene sulfate prepared by the methodhas high purity and high yield, and when the ethylene sulfate is added into a battery, the performance of the battery is better.
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Paragraph 0023; 0024; 0025; 0026; 0027; 0028; 0029; 0031
(2018/11/03)
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- Preparation method and application of ethylene sulfate
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The invention relates to a preparation method and an application of ethylene sulfate. Ethylene sulfate is prepared through a catalytic oxidation reaction with glycol sulfite as a raw material, water as a reaction medium, metal and/or metal oxide as a catalyst and ozone as an oxidizing agent. The method has the characteristics that the yield is high, operation is convenient, aftertreatment is simple, no pollution is caused to the environment and the like.
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Paragraph 0017-0028
(2018/11/27)
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- Preparation method of ethylene sulfate
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The invention relates to a preparation method of ethylene sulfate. The preparation method comprises the steps that the temperature is controlled at 0 DEG C-50 DEG C, thionyl chloride is dropwise added into ethylene glycol, and a glycol sulfite intermediate is prepared through an esterification reaction; the temperature is controlled to be lower than 30 DEG C, heat-preservation stirring is performed for 1-3 h, the temperature is controlled at minus 10 DEG C-10 DEG C, and an aqueous sodium bicarbonate solution is added to adjust the pH value of the system to 7-8; a ruthenium trichloride catalyst is added, the temperature is controlled at 0 DEG C-10 DEG C, a sodium hypochlorite solution with the mass concentration of 13% is dropwise added, dropwise adding is finished after 1-3 h, and heat preservation is performed for 1-2 h at the temperature of 0 DEG C-10 DEG C; the ethylene sulfate is prepared through oxidization, wherein after it is monitored that no glycol sulfite intermediate exists through a TLC, the temperature is controlled at 0 DEG C-10 DEG C, an aqueous sodium hydrogen sulfite solution with the mass concentration of 5%-10% is added, stirring is performed for 10 minutes, filtering is performed by controlling the temperature at 0 DEG C-5 DEG C, the crude ethylene sulfate is obtained, and recrystallization and purification are performed to obtain the ethylene sulfate. According to the preparation method, the ethylene sulfate is prepared by adopting the solvent-free conditions through a one-pot method, the washing, extracting and concentrating processes in a two-step reaction are avoided, operation is simplified, and the product yield is increased while the single-batch yield is increased.
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Paragraph 0022; 0038; 0039; 0040; 0041
(2016/11/09)
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- Sulfuric acid preparation of vinyl method (by machine translation)
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The invention disclosed sulfuric acid preparation of vinyl method, preparation steps are as follows: (1) the substitution reaction: to thionyl chloride and ethylene glycol as the raw material for the substitution reaction, then the use of deionized water the reaction liquid washing to neutral, then standing, layered separating the sulfurous acid vinyl ester; (2) oxidation reaction: to the sulfurous acid vinyl ester is added in methylene chloride and ferric sulfate solution, then cooling to 0 - 5 °C, then dropwise sodium percarbonate solution, the aqueous phase and the organic phase may be coexistence of the reaction liquid, the reaction fluid settlement, layered separating the aqueous phase, then the organic subtracted pressure distillation, get sulfuric acid ethylene the ester is thick product; (3) refining: sulfuric acid ethylene the ester is thick using dichloromethane to recrystallize the product, to obtain high purity sulfuric acid vinyl ester. The above preparation method has the high molar yield, the product has high purity, low water content, low acid value, preparation and low cost, wherein: molar yield can reach 85% or more, can achieve the purity of 99% or more, the water content ≤ 60 ppm, acid value ≤ 60 ppm. (by machine translation)
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Paragraph 0016
(2017/01/17)
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- Lewis Acid Catalyzed Synthesis of α-Trifluoromethyl Esters and Lactones by Electrophilic Trifluoromethylation
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An electrophilic trifluoromethylation of ketene silyl acetals (KSAs) by hypervalent iodine reagents 1 and 2 has been developed. The reaction proceeds under very mild conditions in the presence of a catalytic amount of trimethylsilyl bis(trifluoromethanesulfonyl)imide (up to 2.5 mol %) as a Lewis acid providing a direct access to a variety of secondary, tertiary, and quaternary α-trifluoromethyl esters and lactones in high yield (up to 98%).
- Katayev, Dmitry,Matou?ek, Václav,Koller, Raffael,Togni, Antonio
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supporting information
p. 5898 - 5901
(2015/12/11)
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- Potent ketoamide inhibitors of HCV NS3 protease derived from quaternized P1 groups
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Blood borne hepatitis C infections are the primary cause for liver cirrhosis and hepatocellular carcinoma. HCV NS3 protease, a pivotal enzyme in the replication cycle of HCV virus has been the primary target for development of new drug candidates. Boceprevir and telaprevir are two novel ketoamide derived inhibitors that are currently undergoing phase-III clinical trials. These inhibitors include ketoamide functionality as serine trap and have an acidic alpha-ketoamide center that undergoes epimerization under physiological conditions. Our initial attempts to arrest this epimerization by introducing quaternary amino acids at P1 had resulted in significantly diminished activity. In this manuscript we describe alpha quaternized P1 group that result in potent inhibitors in the enzyme assay and demonstrate cellular activity comparable to boceprevir.
- Venkatraman, Srikanth,Velazquez, Francisco,Wu, Wanli,Blackman, Melissa,Madison, Vincent,Njoroge, F. George
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scheme or table
p. 2151 - 2155
(2010/06/19)
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- Palladium catalysed alkyne hydrogenation and oligomerisation: A parahydrogen based NMR investigation
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The role phosphine ligands play in the palladium(ii)-bis-phosphine-hydride cation catalysed hydrogenation of diphenylacetylene is explored through a PHIP (parahydrogen induced polarization) NMR study. The precursors Pd(LL′)(OTf)2 (1a-e) [LL′ = dcpe (PCy2CH 2CH2PCy2), dppe, dppm, dppp, cppe (PCy 2CH2CH2PPh2)] are used. Alkyl palladium intermediates of the type [Pd(LL′)(CHPhCH2Ph)](OTf) (2 and 3) are detected and demonstrated to play an active role in hydrogenation catalysis. Magnetization transfer experiments reveal chemical exchange from the α-H of the alkyl ligand of 2a (LL′ = dcpe) and linkage isomer 2e′ (LL′ = cppe) into trans-stilbene on the NMR timescale. Activation parameters (ΔH≠ and ΔS≠) for this transformation have been determined. These experiments, coupled with GC/MS data, indicate that the catalytic activity is greater in methanol, where it follows the order: dcpe > cppe > dppp > dppe > dppm, than in CD 2Cl2. All five of the phosphine systems described are less active than those based on bcope [where bcope is (C8H 14)PCH2-CH2P(C8H14)] and tbucope [where tbucope is (C8H 14)PC6H4CH2P(tBu) 2]. cis, cis-1,2,3,4-Tetraphenyl-buta-1,3-diene is detected as a minor reaction product with Pd(LL′)(PhCH-CHPh-CPh=CHPh)+ (4) also being shown to play a role in the alkyne dimerisation step.
- Lopez-Serrano, Joaquin,Duckett, Simon B.,Dunne, John P.,Godard, Cyril,Whitwood, Adrian C.
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supporting information; body text
p. 4270 - 4281
(2009/02/03)
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- Synthesis of hydroxy sulfonate surfactants
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The selective synthesis of sulfonate surfactants with side chains containing ether- and hydroxy groups was carried out using cyclic sulfates as epoxide analogues. The main chain was elaborated from 1,2-dodecane sulfate by the addition of various hydroxy/alkoxysulfonates. Ethyleneoxy- and 1,2-propyleneoxy- groups were introduced using ethylene sulfate and 1,2-propylene sulfate, respectively.
- Rist, ystein,Carlsen, Per H. J.
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p. 1169 - 1178
(2007/10/03)
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- Selective synthesis of aliphatic ethylene glycol sulfonate surfactants
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The selective synthesis of a series of components in a commercial surfactant mixture was studied. The general structure of the surfactant was a glycerol-based double chain monosulfonate molecule, with a C8-Guerbert alcohol, 2-ethylhexanol, at C-1, a pentyloxy group at C-3 and a 3-oxypropane-1-sulfonic acid or an ethoxylated 3-oxypropane-1-sulfonic acid side chain at the C-2 position. The main chain alcohol was obtained by a base catalyzed reaction of 2-ethylhexyl glycidyl ether with a pentyl alcohol. High C-3 selectivity was obtained. Two methods were used for the construction of the ethoxylated side chain at the C-2. A sequence consisting of O-allylation followed by ozonolysis and sodium borohydride work-up gave good yields of the desired ethoxylated homologs. A shorter, more efficient method involved the reaction with 1,2-ethylene sulfate. This method gave the ethoxylated bomologs with high selectivity and in high yields. O-Propane sulfonation was accomplished by the reaction of the appropriate alkoxides with 1,3-propane sulfone. The pure sodium sulfonates were isolated in good overall yields by continuous extraction with hexane or diethyl ether. Acta Chemica Scandinavica 1996.
- Gautun, Odd R.,Carlsen, Per H.J.,Maldal, Trygve,Vikane, Olav,Gilje, Eimund
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p. 170 - 177
(2007/10/03)
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- The stereospecific synthesis of (2S,3R) 3-carboxyproline and (2S,3R) 3-aminoproline
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Stereospecific syntheses of (2S,3R) 3-carboxyproline and (2S,3R) 3-aminoproline are reported which make use of the stereospecific alkylation of (4S)-N-(t-butyldimethylsilyl)azetidin-2-one 4-carboxylic acid with the cyclic sulfate derived from ethylene glycol.
- Baldwin, Jack E.,Adlington, Robert M.,Gollins, David W.,Godfrey, Christopher R. A.
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p. 5169 - 5180
(2007/10/02)
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- Process for the preparation of cyclic sulphates
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STR1 A method for preparing cyclic sulphates having general formula (I), wherein sulphuric anhydride and an alkylene oxide are simultaneously added to the dioxane. In general formula (I), R1, R2, R3 and R4 are the same or different and are a hydrogen atom of a C1-4 alkyl radical optionally substituted by a halogen atom.
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- Process for the preparation of cyclic sulphates
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Cyclic sulphates of formula: STR1 are prepared by oxidation of a cyclic sulphite of formula: STR2 with a hypohalite of an alkali or alkaline-earth metal and a catalytic quantity of a ruthernium derivative (RuO2, RuCl3). In formulae (I) and (II), R1, R2, R3, R4, R5 and R6 are identical or different and each represents hydrogen, halogen, alkyl, alkoxy, aryl, aryloxy or alkoxycarbonyl.
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- Process for the preparation of cyclic sulphates
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Cyclic sulphates of formula STR1 in which R1, R2, R3, R4, R5, and R6, which are identical or different, each denote hydrogen, halogen, alkyl, alkoxy, aryloxy or alkoxycarbonyl and n is 0 or 1, are prepared by rapid reaction, at a temperature of 150° to 250° C., of concentrated sulphuric acid with a glycol of formula STR2
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- NOVEL REAGENTS CONTAINING HYPERVALENT IODINE AND THEIR USE FOR ELECTROPHILIC ADDITIONS TO OLEFINS
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A series of novel I(III) containing reagents have been developed and their electrophilic reactions with olefins giving vic-disubstituted derivatives (including vic-ditriflates) are described.
- Zefirov, Nikolai S.,Zhdankin, Viktor V.,Dan'kov, Yu. V.,Caple, Ronald,Berglund, Bruce A.
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p. 3971 - 3974
(2007/10/02)
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- Application of a Lanthanide Shift Reagent in 17O N.M.R. Spectroscopy to determine the Stereochemical Course of Oxidation of Cyclic Sulphite Diesters to Cyclic Sulphate Diesters with Ruthenium Tetroxide
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Cyclic sulphite diesters are rapidly oxidized to cyclic sulphate diesters with ruthenium tetroxide in good yield; diastereotopically labelled cyclic sulphate diesters obtained by oxidation of diastereoisomeric cyclic sulphite diesters with ruthenium tetroxide are shown, by the effect of a lanthanide shift reagent on their 17O n.m.r. signals, to be formed with retention of configuration at sulphur.
- Lowe, Gordon,Salamone, Salvatore J.
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p. 1392 - 1394
(2007/10/02)
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