- Ruthenium-Catalyzed Selective Hydrogenation of Epoxides to Secondary Alcohols
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A ruthenium(II)-catalyzed highly selective Markovnikov hydrogenation of terminal epoxides to secondary alcohols is reported. Diverse substitutions on the aryl ring of styrene oxides are tolerated. Benzylic, glycidyl, and aliphatic epoxides as well as diepoxides also underwent facile hydrogenation to provide secondary alcohols with exclusive selectivity. Metal-ligand cooperation-mediated ruthenium trans-dihydride formation and its reaction involving oxygen and the less substituted terminal carbon of the epoxide is envisaged for the origin of the observed selectivity.
- Thiyagarajan, Subramanian,Gunanathan, Chidambaram
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supporting information
p. 9774 - 9778
(2019/12/02)
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- Compositions And Methods For Bioactive Dental Composites
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Described herein are compositions and methods which produce hydrolytically stable resin monomers, bioactive fillers, phosphorus coupling agent and surface coating method, which can be combined to produce new generation dental composites; compositions comprising the same, as well as methods of making and using the same are also described.
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Paragraph 0111
(2016/05/24)
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- Synthesis and flame retardant potential of polyols based on bisphenol-S
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Polyether polyols based on bisphenol-S were prepared by alkoxylation and compared with analogs based on bisphenol-A, as well as standard aromatic polyester, and polyether polyols for viscosity and temperature stability. Thermo-oxidative stability was determined by thermo-gravimetric analysis, pyrolysis gas chromatography/mass spectroscopy, and evolved gas analysis mass spectroscopy. Incorporation of the sulfone moiety was found to dramatically improve the thermo-oxidative stability of the neat polyol. Significant char formation was observed with gas phase evolution of flame retardant SO2 and aromatic sulfone only apparent at about 600 °C.
- Sonnenschein, Mark F.,Virgili, Justin M.,Babb, David A.,Bell, Bruce M.,Nickless, Brian C.
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p. 2102 - 2108
(2016/06/14)
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- One-pot alkoxylation of phenols with urea and 1,2-glycols
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A one-pot epoxide-free alkoxylation process has been developed for phenolic compounds. The process involves heating phenols and urea in 1,2-glycols at 170-190 °C using Na2CO3/ZnO as co-catalysts under atmospheric conditions. During the course of this new alkoxylation reaction, a five-membered ring cyclic carbonate intermediate, ethylene carbonate (EC) or propylene carbonate (PPC), was produced in-transit as the key intermediate and was subsequently consumed by phenols to form alkoxylated ether alcohols as final products in excellent yields. For instance, phenol, bisphenol A (BPA), hydroquinone and resorcinol were converted into their respective mono-alkoxylated ether alcohols on each of their phenolic groups in 80-95% isolated yields. In propoxylation of phenols, this approach shows great product selectivity favoring production of high secondary alcohols over primary alcohols in isomeric ratios of nearing 95/5. Since ammonia (NH3) and carbon dioxide (CO2) evolving from the reaction can be re-combined in theory into urea for re-use, the overall net-alkoxylation by this approach can be regarded as a simple condensation reaction of phenols with 1,2-glycols giving off water as its by-product. This one-pot process is simple, safe and environmentally friendlier than the conventional alkoxylated processes based on ethylene oxide (EO) or propylene oxide (PO). Moreover, this process is particularly well-suited for making short chain-length alkoxyether alcohols of phenols.
- Lin, Hsing-Yo,Dai, Shenghong A.
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experimental part
p. 167 - 173
(2011/04/19)
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- Aromatic ethers and process for producing aromatic ethers
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According to a production process, aromatic ethers are producible by reacting phenols with an oxirane compound with use of an anion exchange resin as a catalyst. According to another production process, aromatic ethers having an alcoholic hydroxyl group are producible by a crystallization-purification step of using a solvent having a solubility parameter ranging from 7.5 to 12.5 for purification by crystallization. Further, according to still another production process, producible are aromatic ethers having an alcoholic hydroxyl group, wherein the content of a metal in the aromatic ethers is less than 100 ppm by mass, and the content of a halogen element in the aromatic ethers is less than 100 ppm by mass.
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