- Preparation method of terephthalic acid and diester thereof
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The invention discloses a preparation method of terephthalic acid and diester thereof. Specifically, under the action of a supported metal catalyst, 2-cyclohexene-1,4-dicarboxylic acid undergoes catalytic dehydro-aromatization in a polar solvent or a nonpolar solvent so as to prepare terephthalic acid and diester. The polar solvent is water, methanol, ethanol, n-propanol, isopropanol, n-butanol, glycol dimethyl ether and diglyme. The nonpolar solvent is one or more than two components selected from a group consisting of n-hexane, n-heptane, normal octane, cyclohexane, benzene and toluene. A metal active component of the supported metal catalyst is non-noble metal and/or noble metal. A carrier for the supported metal catalyst is one or more than two components selected from a group consisting of a carbon carrier, nanoscale metal oxide, nanometer nonmetal oxide and a molecular sieve. When conversion rate of 2-cyclohexene-1,4-dicarboxylic acid is 95% and above, selectivity of terephthalic acid or diester of terephthalic acid can reach 90%.
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Paragraph 0036; 0038
(2017/06/23)
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- Primary coloured electrochromism of aromatic oxygen and sulfur diesters
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Eleven aromatic diesters and thioic S,S′-diesters were synthesized and investigated using electrochemical (cyclic voltammetry and controlled potential electrolysis) and UV-vis spectroscopic techniques over a range of temperatures. Nine of the compounds exhibited vibrant colour changes from a colourless state in their neutral forms to brightly coloured upon one-electron electrochemical reduction in acetonitrile. The compounds were found to display either red, green or blue colours in their one-electron reduced states. The electrochromic properties of 3 of the compounds that displayed the most vibrant colour changes were examined in solution using a gold micro-mesh electrode laminated inside a polymer film.
- Xu, Xiuhui,Webster, Richard D.
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p. 18100 - 18107
(2014/05/20)
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- Preparation of monoalkyl terephthalates: An overview
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Terephthalic acid can be readily converted to the corresponding monoalkyl terephthalate in high yield, via a two-step procedure. This method is advantageously compared to the more representative methods described in the literature. The purification of the expected monoester, a crucial problem for this synthetic pathway, is discussed, and an original procedure has been developed. Copyright Taylor & Francis Group, LLC.
- Chenot, Elodie-Denise,Bernardi, Dan,Comel, Alain,Kirsch, Gilbert
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p. 483 - 490
(2007/10/03)
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- The methoxycarbonylation of aryl chlorides catalysed by palladium complexes of bis(di-tert-butylphosphinomethyl)benzene
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A catalyst system based on palladium-1,2-bis-(di-tert-butylphosphinomethyl) benzene (BDTBPMB) shows good activity for the methoxycarbonylation of strongly activated aryl chlorides, like 4-chloromethylbenzoate or 4-chlorocyanobenzene. Surprisingly, the use of less activated aryl chlorides, like 4-chloroacetophenone, leads to the formation of dimethyl terephthalate amongst other products arising from organic reactions of methoxide ion and/or CO. Less nucleophilic alcohols such as 2,2,2-trifluoroethanol promote the formation of carbonylation products even from 4-chloroacetophenone and chlorobenzene. Labelling studies involving CD3OH, CD3OD or 13CO give information on the origin of many of the products. The Royal Society of Chemistry 2005.
- Jimenez-Rodriguez, Cristina,Eastham, Graham R.,Cole-Hamilton, David J.
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p. 1826 - 1830
(2007/10/03)
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- Unsymmetrical dicarboxylic esters as bleach precursors
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A bleach precursor compound, its peroxygen derivative, and detergent compositions containing these materials are disclosed herein. The bleach precursors structurally comprise a pair of different diesters, one ester containing an electrically-charged functional group. Perhydrolysis of the precursor in the presence of hydrogen peroxide and a basic aqueous media generates a peroxycarboxylic acid.
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