- Transesterification of dimethyl carbonate with phenol using Br?nsted and Lewis acidic ionic liquids
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Transesterification reaction of dimethyl carbonate with phenol to methylphenyl carbonate and diphenyl carbonate using dibutyltin oxide catalyst in conjunction with Br?nsted and Lewis acidic ionic liquids was studied. It was observed that the use of ionic liquids significantly enhances the yield of diphenyl carbonate. The ionic liquid having p-toluenesulfonate as anion and metal halide (e.g. ZnCl2) as Lewis acid precursor exhibited higher activity and selectivity for diphenyl carbonate formation. Furthermore, the Br?nsted and Lewis acidity of ionic liquids was measured by IR spectroscopy using pyridine as a probe and their Lewis acidity order was also determined.
- Deshmukh, Krishna M.,Qureshi, Ziyauddin S.,Dhake, Kishor P.,Bhanage, Bhalchandra M.
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experimental part
p. 207 - 211
(2011/09/12)
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- Synthesis of diphenyl carbonate from CO2, phenoxide, and CCl4 with ZnCl2 as catalyst
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Direct synthesis of diphenyl carbonate (DPC) from phenoxide, CO2 and CCl4 in one pot was realized with ZnCl2 as catalyst. Trichloromethyl cation may act on potassium phenyl carbonate, which brings the carbonyl more easily attached on by the phenoxide. Onium salts promote the reaction greatly, especially with phenol and potassium carbonate instead of phenoxide as reactants. Moreover, the substituent on the aromatic ring has significant effects on the selectivity and yield of carbonate. Copyright
- Li, Zhenhuan,Qin, Zhangfeng,Zhu, Huaqing,Wang, Jianguo
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p. 784 - 785
(2007/10/03)
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- The reactions of difluorodiiodomethane with nucleophiles
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Treatment of difluorodiiodomethane with phenoxides (ArO-) in DMF at room temperature gives ArOCF2I in 7-15%, the carbonates (ArOCO2Ar) being the major products, while with thiophenoxides affords difluoromethylene derivativ
- Guo, Yong,Chen, Qing-Yun
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p. 105 - 109
(2007/10/03)
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- Continuous production of aromatic carbonates
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A process for continuously producing aromatic carbonates comprising continuously feeding a dialkyl carbonate, an aromatic hydroxy compound, and a catalyst to a reactor equipped with a distillation tower, continuously distilling off a by-produced aliphatic alcohol from the distillation tower so as to keep the aliphatic alcohol concentration in the reactor at 2% by weight or less, and continuously withdrawing produced alkylaryl carbonate and/or diaryl carbonate and the catalyst from the reactor; and a process for continuously producing a diaryl carbonate comprising continuously feeding an alkylaryl carbonate and a catalyst to a reactor equipped with a distillation tower, continuously distilling off a by-produced dialkyl carbonate from the distillation tower so as to keep the dialkylcarbonate concentration in the reactor at 2% by weight or less, and continuously withdrawing the produced diaryl carbonate and the catalyst from the reactor are disclosed. Continuous production of aromatic carbonates can be performed in a stable manner without being accompanied by clogging of a distillation tower.
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- Metal Template ortho-Acylation of Phenols. Direct Synthesis of Salicylic Acid Chlorides and Derivatives
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A direct synthesis of salicylic acid chlorides is achieved via "metal-driven" intracomplex acylation of bromomagnesium and aluminum phenoxides with phosgene.Salicylic acids 5 and some derivatives 6, 7 can be obtained by quenching the reaction mixture with convenient reagents.Moreover the reaction of lithium phenylacetylide with 3 provides a new convenient approach to ortho-hydroxyaryl alkynyl ketones like 8.The oriented complex 2, involving the metal phenoxide and phosgene is proposed to account for the ortho-regioselective control of the reaction.
- Sartori, Giovanni,Casnati, Giuseppe,Bigi, Franca,Bonini, Giovanni
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p. 763 - 766
(2007/10/02)
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