- Microwave-assisted acid-induced formation of linker vacancies within Zr-based metal organic frameworks with enhanced heterogeneous catalysis
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Herein, we report a microwave-assisted acid-induced post-treatment method for the formation of linker vacancies within Zr-based metal organic frameworks (Zr-MOFs). The number of linker vacancies can be easily regulated with this method by changing the concentration of the HCl solution and the duration of microwave irradiation. The optimized defective UiO-66 showed higher linker defects with a higher specific surface area and thermal stability. The results of the catalytic cyclization of citronella showed that the Zr-MOFs with more defects exhibited enhanced catalytic performance. This work may provide a new method for the creation of defective MOFs with high activity and stability.
- Liang, Yu,Li, Chenhui,Chen, Lanjun,Huo, Jia,Loubidi, Mohammed,Zhou, Yangyang,Liu, Yanbo
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- KINETICS AND MECHANISM OF THE HYDRATION OF THE EQUILIBRIUM MIXTURE OF 3-METHYL-1-BUTEN-3-OL AND 3-METHYL-2-BUTEN-1-OL WITH ISOPRENE IN AQUEOUS SOLUTIONS OF SULFURIC ACID
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The kinetic relationships of the hydration of an equilibrium mixture of 3-methyl-1-buten-1-ol (dimethylvinylcarbinol, DMVC) and 3-methyl-2-buten-1-ol (dimethylallyl alcohol, DMAA) with isoprene (C5H8) were investigated in aqueous solutions of sulfuric acid from 24.9 to 49.7percent at 25 deg C.Data were obtained on the mechanism of hydration of the equilibrium mixture of DMVC and DMAA with isoprene.Key words: Kinetic relationships, hydration mechanism, equilibrium mixture.
- Ryabova, R. S.,Osipova, G. F.,Vinnik, M. I.
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- Conversion of Isobutene and Formaldehyde to Diol using Praseodymium-Doped CeO2 Catalyst
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Conversion of low-carbon olefins to higher alcohols or olefins via the formation of C-C bonds is an increasingly important topic. We herein report an example of converting isobutene and formaldehyde (38 wt % aqueous solution) to 3-methyl-1,3-butanediol (MBD), a precursor for isoprene. The reaction occurs through a Prins condensation-hydrolysis reaction over a praseodymium (Pr)-doped CeO2 catalyst. The best MBD yield (70%) is achieved over the Pr-doped CeO2 catalyst. Catalyst characterizations with high-angle annular dark field transmission electron microscopy (HAADF-TEM), pyridine adsorption infrared (IR) and Raman spectroscopy, and density functional theory (DFT) calculations show that the doped Pr is uniformly and highly dispersed in the CeO2 crystalline phase. In addition, the Pr doping creates more oxygen vacancy sites on CeO2 and thus enhances the Lewis acidity of the catalyst, which is responsible for the catalytic performance of the Pr-CeO2 catalyst. (Chemical Equation Presented).
- Zhang, Zhixin,Wang, Yehong,Lu, Jianmin,Zhang, Chaofeng,Wang, Min,Li, Mingrun,Liu, Xuebin,Wang, Feng
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- The experimental detection of a retro-Prince reaction exemplified by a homogeneous acid-catalyzed decomposition of isopentenols
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The occurence of the retro-Prince reaction in the transformations of an equilibrium mixture of 2-methyl-3-buten-2-ol and 3-methyl-2-buten-1-ol in 24.9percent-49percent aqueous sulfuric acid at 25 deg C has been experimentally proved. - Key words: acid catalysis; equilibrium mixture; isopentenols; Prince reaction.
- Ryabova, R. S.,Osipova, G. F.
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- Preparation method 3 -methyl -1-3 -butanediol
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The present invention relates to a preparation method of 3-methyl-1,3-butanediol. The method comprises the steps of mixing isobutene, a formaldehyde aqueous solution and a Pr-doped ceria catalyst, putting the mixture into a pressure-resistant container for sealing, and stirring for reacting to prepare the 3-methyl-1,3-butanediol by Prins condensation and hydrolysis. The separation process has theadvantages that the product and the catalyst are simple to separate, the catalyst can be recycled, the reaction process is simple, controllable and easy to operate, and the yield of the 3-methyl-1,3-butanediol is up to 98%.
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Paragraph 0038; 0040-0041; 0043-0044; 0046-0047; 0049; ...
(2021/06/02)
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- Method for preparing 3 - methyl -1 and 3 - butanediol
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The present invention relates to a preparation method of 3-methyl-1,3-butanediol. The 3-methyl-1,3-butanediol is prepared from isobutylene and a formaldehyde aqueous solution as reaction substrates byPrins condensation and hydrolysis process under the action of a doped ceria catalyst. A specific reaction process is as follows: a certain amount of the isobutylene, the formaldehyde aqueous solutionwith a certain concentration and a certain amount of the doped ceria catalyst are mixed and put into a container for sealing, stirring at temperature not lower than 60DEG C for reacting for 0.5h or more, and separating to obtain the 3-methyl-1,3-butanediol. The preparation method has the advantages that the product and the catalyst are simple to separate, the catalyst can be recycled, the reaction process is simple, controllable and easy to operate, and the yield of the 3-methyl-1,3-butanediol is up to 95%.
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Paragraph 0037; 0039; 0040; 0042; 0043; 0045; 0046; ...
(2021/06/02)
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- Rapid Deoxyfluorination of Alcohols with N-Tosyl-4-chlorobenzenesulfonimidoyl Fluoride (SulfoxFluor) at Room Temperature
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The deoxyfluorination of alcohols is a fundamentally important approach to access alkyl fluorides, and thus the development of shelf-stable, easy-to-handle, fluorine-economical, and highly selective deoxyfluorination reagents is highly desired. This work describes the development of a crystalline compound, N-tosyl-4-chlorobenzenesulfonimidoyl fluoride (SulfoxFluor), as a novel deoxyfluorination reagent that possesses all of the aforementioned merits, which is rare in the arena of deoxyfluorination. Endowed by the multi-dimensional modulating ability of the sulfonimidoyl group, SulfoxFluor is superior to 2-pyridinesulfonyl fluoride (PyFluor) in fluorination rate, and is also superior to perfluorobutanesulfonyl fluoride (PBSF) in fluorine-economy. Its reaction with alcohols not only tolerates a wide range of functionalities including the more sterically hindered alcoholic hydroxyl groups, but also exhibits high fluorination/elimination selectivity. Because SulfoxFluor can be easily prepared from inexpensive materials and can be safely handled without special techniques, it promises to serve as a practical deoxyfluorination reagent for the synthesis of various alkyl fluorides.
- Guo, Junkai,Kuang, Cuiwen,Rong, Jian,Li, Lingchun,Ni, Chuanfa,Hu, Jinbo
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supporting information
p. 7259 - 7264
(2019/05/10)
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- The in situ transformation of the co-product formaldehyde in the reversible hydrolysis of 1,3-dixoane to obtain 1,3-propanediol efficiently
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Herein, a strategy is developed for efficient production of l,3-propanediol via the hydrolysis of 1,3-dioxane by the in situ transformation of the co-product formaldehyde (HCHO) in the presence of Eu(OH)3. The reversible hydrolysis reaction is promoted to yield 98% conversion and 99% 1,3-propanediol selectivity. Furthermore, HCHO is converted to formic acid (HCOOH) which could act as an acidic catalyst in the hydrolysis of 1,3-dioxane. The combination of FT-IR and control experiments demonstrates that HCOOH is generated via the hydrolysis of formate species which formed on the surface of Eu(OH)3.
- Wang, Yehong,Zhang, Jian,Zhang, Zhixin,Hou, Tingting,Zhang, Chaofeng,An, Jinghua,Wang, Feng
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supporting information
p. 1455 - 1458
(2018/04/12)
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- Hydrogenation of CO2-Derived Carbonates and Polycarbonates to Methanol and Diols by Metal–Ligand Cooperative Manganese Catalysis
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The first base-metal-catalysed hydrogenation of CO2-derived carbonates to alcohols is presented. The reaction proceeds under mild conditions in the presence of a well-defined manganese complex with a loading as low as 0.25 mol %. The non-precious-metal homogenous catalytic system provides an indirect route for the conversion of CO2 into methanol with the co-production of value-added (vicinal) diols in yields of up to 99 %. Experimental and computational studies indicate a metal–ligand cooperative catalysis mechanism.
- Zubar, Viktoriia,Lebedev, Yury,Azofra, Luis Miguel,Cavallo, Luigi,El-Sepelgy, Osama,Rueping, Magnus
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supporting information
p. 13439 - 13443
(2018/09/21)
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- METHOD FOR PRODUCING CONJUGATED DIENE
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A method for producing a conjugated diene, including a step A of allowing an α-olefin and formaldehyde to react with each other to produce a γ,δ-unsaturated alcohol in the presence of an alcohol; and a step B of subjecting the γ,δ-unsaturated alcohol to a dehydration reaction at 135 to 210° C. in the presence of an aqueous solution of an acidic catalyst.
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Paragraph 0069-0074
(2018/10/30)
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- 3 - methyl - 1, 3 - butanediol production
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PROBLEM TO BE SOLVED: To provide a method for producing 3-methyl-1, 3-butanediol of extremely high quality which has an extremely low odor and can be used for cosmetics.SOLUTION: There is provided a method for producing 3-methyl-1, 3-butanediol which comprises a step of performing distillation purification while supplying 3-methyl-1, 3-butanediol and water and/or steam.
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Paragraph 0021
(2017/06/02)
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- Method used for preparing 1,3-dihydric alcohol via Prins condensation reaction
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The invention relates to a method used for preparing a 1,3-dihydric alcohol via Prins condensation reaction. According to the method, an olefin and a formaldehyde aqueous solution are taken as reaction substrates, and direct preparation of the 1,3-dihydric alcohol is carried out under catalytic effect of an acidic composite metal oxide. The reaction process comprises following steps: the formaldehyde aqueous solution is mixed with a catalyst, and an obtained mixture is delivered into a pressure vessel for sealing; the olefin gas is added, stirring is carried out, and reaction is carried out for more than 2h at a temperature higher than 80 DEG C. After reaction, the catalyst is easily collected via separation from a reaction system, and can be recycled for a plurality of time, and the highest yield of the 1,3-dihydric alcohol is 90%.
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Paragraph 0018; 0019
(2016/10/10)
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- NOVEL RUTHENIUM COMPLEX AND METHOD FOR PREPARING METHANOL AND DIOL
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Provided is a method for preparing methanol and diol from cyclic carbonate, comprising: under a hydrogen atmosphere, in an organic solvent, and with the presence of a ruthenium complex (Ru(L)XYY') and an alkali, conducting a hydrogenation reduction reaction on the cyclic carbonate or polycarbonate to obtaib methanol and diol. Also provided is a ruthenium complex prepared from ruthenium and a tridentate amido diphosphine ligand. Also provided is a deuterated methanol and deuterated diol preparation method by substituting the hydrogen and ruthenium complex with deuterium.
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Paragraph 0095
(2015/09/23)
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- Mild and selective deprotection of tert -butyl(dimethyl)silyl ethers with catalytic amounts of sodium tetrachloroaurate(III) dihydrate
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A simple and mild method for the removal of tert-butyl(dimethyl)silyl (TBS) protecting groups with catalytic amounts of sodium tetrachloroaurate(III) dihydrate is described. The procedure permits selective deprotection of aliphatic TBS ethers in good to excellent yields in the presence of aromatic TBS ethers, aliphatic triisopropylsilyl ethers, aliphatic tert-butyl(diphenyl)silyl ethers, or sterically hindered aliphatic TBS ethers. Additionally, TBS ethers can also be transformed into 4-methoxybenzyl ethers or methyl ethers in one pot by using larger quantities of the catalyst and a higher reaction temperature.
- Zhang, Qi,Kang, Xiuqin,Long, Lei,Zhu, Lijuan,Chai, Yonghai
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- A new approach to the synthesis of 1-oxaspiro[4.n]alkanes and tetrahydrofurans by the 1,5-CH insertion reaction of magnesium carbenoids
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1-Alkoxy-1-[2-chloro-2-(p-tolylsulfinyl)ethyl]cycloalkanes were prepared from various cyclic ketones in good overall yields. Treatment of these cycloalkanes bearing a sulfinyl group with i-PrMgCl resulted in the formation of 1-oxaspiro[4.n]alkanes in high to quantitative yields via the 1,5-CH insertion reaction of generated magnesium carbenoid intermediates. When this procedure was commenced with acyclic ketones, multi-substituted tetrahydrofurans were obtained in up to a 96% yield. This procedure provides a new and good way for the synthesis of 1-oxaspiro[4.n]alkanes and tetrahydrofurans with the formation of a carbon-carbon bond between a carbenoid carbon and a non-activated carbon in high yields. The oxygen atom in the magnesium carbenoid intermediates was proved to act very important roles in the 1,5-CH insertion reaction.
- Satoh, Tsuyoshi,Yasoshima, Tsukasa,Momochi, Hitoshi
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scheme or table
p. 2074 - 2077
(2012/07/14)
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- Synthesis of isoprene from formaldehyde and isobutene over phosphate catalysts
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Vapor phase Prins condensation of isobutene with formaldehyde has been studied over boron (BP), aluminum (AlP), titanium (TiP), zirconium (ZrP) and niobium (NbP) phosphates. The catalysts were characterized by elemental analysis, X-ray diffraction, low-te
- Sushkevich,Ordomsky,Ivanova
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- Mutation and inhibition studies of mevalonate 5-diphosphate decarboxylase
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Mevalonate 5-diphosphate decarboxylase plays an important role in regulating cholesterol biosynthesis, which was studied through incubation with various synthetic substrate analogs and characterization of mutated enzymes. The results are potentially useful for further developing inhibitors that block the mevalonate pathway which is a drug target for treating cardiovascular disease and cancer.
- Qiu, Yongge,Gao, Jinbo,Guo, Fei,Qiao, Yuqin,Li, Ding
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p. 6164 - 6168
(2008/04/03)
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- Synthesis and biological activities of new 1α,25-dihydroxy-19-norvitamin D3 analogs with modifications in both the A-ring and the side chain
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In a series of studies on structure-activity relationships of 2-substituted 19-norvitamin D analogs, we found that 1α,25-dihydroxy-19-norvitamin D3 analogs with 2β-hydroxyethoxy or 2E-hydroxyethylidene moieties show strong binding affinity for the vitamin D receptor (VDR) as well as marked transcriptional activity. To further examine the effects of side chain structure on the activity of 2-substituted 19-norvitamin D analogs, we have synthesized new 19-norvitamin D3 analogs with modifications in both the A-ring at the C(2) position and the side chain. The side chains of these analogs contained a double bond between C(22) and C(23) or an oxygen atom at C(22). The biological activity of the analogs was evaluated in vitro. All the side chain-modified analogs were less active than 1α,25-dihydroxyvitamin D3 1e and the parent compounds 3-6e possessing a natural 20R-configuration in binding to the VDR, but, except for the (20R)-22-oxa analogs 3-6d, were significantly more potent in transcriptional activity. Of the side-chain-modified analogs 4 and 5, the 2β-hydroxyethoxy- and 2E-hydroxyethylidene-22,24-diene-24a,26a,27a-trihomo analogs showed markedly higher transcriptional activity (25- and 17.5-fold, respectively) compared with 1e. Elongation of the side chain at the C-24, C-26, and C-27 positions and introduction of a 22,24-diene moiety strongly increased transcriptional activity, as seen in the 20-epi analogs 3-6f.
- Shimizu, Masato,Miyamoto, Yukiko,Kobayashi, Emi,Shimazaki, Mika,Yamamoto, Keiko,Reischl, Wolfgang,Yamada, Sachiko
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p. 4277 - 4294
(2007/10/03)
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- Kinetic scheme of homogeneous acid-catalyzed transformation of isopentenols
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The reactions occurring in an equilibrium mixture of 3-methyl-1-buten-3-ol and 3-methyl-2-buten-1-ol in 24-49 percent aqueous solutions of H2SO4 yield isoprene, 3-methyl-3-buten-1-ol, isobutylene, formaldehyde, 3-methylbutane-1,3-diol.Isobutylene is rapidly hydrated to give 2-methylpropan-2-ol.The presence of formaldehyde in the reaction mixture indicates that the transformations involve the reverse Prins reaction.On the basis of experimental and literature data, two most probable reactions were suggested.
- Ryabova, R. S.,Osipova, G. F.,Travin, S. O.
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p. 840 - 843
(2007/10/02)
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- Cyclic Ether Formation in Superacid Media
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The formation of ethers in superacids by interaction of a primary hydroxy group with a carbocation centre has been investigated by a study of cyclisation of suitable substrates, mainly 1-(2-hydroxyethyl)cyclohexanols to give hydrobenzofurans.Cyclisation traps thermodynamically stable ionic species, with rates of reaction dependent upon the size of the ether ring formed.Three- and four-membered ether rings were not formed, five-membered ether rings formed readily, the reaction being comparable in rate with a 1,2-methyl shift.Six-membered rings formed a little less readily and seven-membered rings less readily still, though a yield of 34 percent from a suitable substrate has been recorded.An unexpected feature of the reactions was their stereospecificity; in one case, this is believed to result from a methyl shift concerted with attack of the primary hydroxy group, the reaction proceeding through hindered transition state, in which methyl loss, probably as CH3+, competes with a 1,2-methyl shift.
- Carr, Graham,Whittaker, David
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p. 359 - 366
(2007/10/02)
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- MECHANISM OF HYDROLYSIS OF 4,4-DIMETHYL-1,3-DIOXANE
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The hydrolysis of 4,4-dimethyl-1,3-dioxane in aqueous solutions of sulfuric acid (4-40 wt. percent) and p-toluenesulfonic acid (3-50 wt. percent) was investigated at various temperatures.According to the proposed hydrolysis mechanism, the directions which determine the process rate are the monomolecular dissociation of the protonated molecules of the 1,3-dioxane and the dissociation of the intermediate particles consisting of the protonated molecules of 1,3-dioxane and the anions of the acid.The true values of the rate constants for each of the paths and their temperature dependence were determined.It was concluded that the variation of the effective activation energy with variation of the sulfuric acid concentration may be criterion for the occurence of the reaction in several directions, i.e., catalysis by several types of acid particles.
- Zakoshanskii, V. M.,Rybkina, L. A.,Gankin, V. Yu.,Idlis, G. S.
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p. 1727 - 1732
(2007/10/02)
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- HYDROLYSIS OF 4,4-DIMETHYL-1,3-DIOXANE IN WATER-ALCOHOL SOLUTIONS
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The kinetics of the hydrolysis of 4,4-dimethyl-1,3-dioxane in a water-alcohol medium (0-40 wt. percent) were investigated.The alcohols can be arranged in the following order according to their reducing effect on the rate constant: tert-butyl > isopropyl > ethyl > methyl.The effect of C1 - C4 alcohols in the investigated range of variation in the composition of the binary solvent is similar to that observed in the hydrolysis of 4,4-dimethyl-1,3-dioxane in the water-1,4-dioxane system.With increase in the concentration of alcohol in the binary solvent the equilibrium of the hydrolysis reaction is shifted toward 4,4-dimethyl-1,3-dioxane.
- Ryvkina, L. A.,Gankin, V. Yu.,Sinitsyn, A. V.,Polyakova, M. A.
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p. 1718 - 1722
(2007/10/02)
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- 2-Oxo-1,3,2-dioxathianes. I. Preparation of the Alkyl-substituted Derivatives
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2-Oxo-1,3,2-dioxathiane, all methyl- and several other alkyl-substituted 2-oxo-1,3,2-dioxathianes have been synthesized by condensing 1,3-alkanediols and thionyl chloride.The amount of the S==O-axial and S==O-equatorial isomers can be controlled by adding pyridine to the reaction mixture.
- Virtanen, Terttu,Nikander, Hannu
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p. 113 - 116
(2007/10/02)
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- COCONDENSATION OF ISOBUTYLENE WITH FORMALDEHYDE AND ACETALDEHYDE
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2,4,4-Trimethyl-1,3-dioxane is formed preferentially in the reaction of isobutylene, formaldehyde, and acetaldehyde in the presence of an acidic catalyst.In addition, 4-dimethyl- and 2,4,4,6-tetramethyl-1,3-dioxanes, 4-methyl-2,4-pentanediol and 3-methyl-1,3-butanediol were found in the reaction mass.The possibility of mutual transformations between the cyclic acetals and formal through the stage of the formation of consecutive-parallel reactions is proposed.
- Safarov, M. G.,Ogorodnikov, S. K.,Ibatullin, U.G.,Idlis, G. S.,Nigmatullin, N. G.
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p. 805 - 809
(2007/10/02)
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