- Ionic Immobilization of Silicotungstic Acid on Amine-Functionalized Zirconia: A Mesoporous Catalyst for Esterification of Maleic Acid
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Silicotungstic acid (H4SiW12O40) has been immobilized onto the mesopores of amine-functionalized zirconia by exploitation of electrostatic interactions. The ionic grafting of silicotungstic acid was confirmed by XPS, FTIR, UV/Vis-DRS and TGA analysis. The mesoporosity of the material was confirmed through N2 adsorption/desorption analysis. The morphology of the material was established by TEM analysis. The immobilized silicotungstate material was found to be an efficient heterogeneous catalyst for selective esterification of maleic acid with butan-1-ol. A 98 % level of conversion of maleic acid and 82 % selectivity for dibutyl maleate within 5 h at 95 °C was achieved. The catalyst could be reused thrice without loss of activity.
- Ramalingam, Meenakshi,Manickam, Sundar,Srinivasalu, Kutti Rani,Ismail, Mohammed Bilal,Deivanayagam, Easwaramoorthy
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p. 1697 - 1705
(2016/04/26)
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- AMINO AND HYDROXYL FUNCTIONAL POLYESTERS
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The invention relates to amino and hydroxy-functional polyesters, wherein the amine is in the form of aspartic acid esters functionality, and wherein the amino and hydroxy-functional polyester has (a) a molecular weight (Mn) of at least about 500, (b) an acid value of about 5 or less, (c) a hydroxyl value of about 30 or more, and (d) an amine value of about 30 or more, and (e) an amine functionality of less than 1.8. Preferably, the compound includes molecules having on the average: at least 1 secondary amino group as an aspartate, and/or at least 1 hydroxy group, and an average total functionality of about 1.8 or higher. More preferably, the molecular weight of the amino and hydroxy-functional polyesters is between 204 and 10,000 and preferably between 482 and 5000.
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Page/Page column 9
(2012/09/11)
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- Ring-opening of cyclic anhydrides using ionic liquids
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Four novel Bronsted acidic ionic liquids with two different acid sites on the imidazolium cations were synthesised and employed as catalysts and solvents for the ring-opening of cyclic anhydrides to synthesise half-esters. The results showed that these novel Bronsted acidic ionic liquids were efficient and recyclable. Good yields, short reaction times and mild reaction conditions were achieved.
- Jiang, Dong,Wang, Yuan Yuan,Xu, Yan Nan,Dai, Li Yi
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experimental part
p. 167 - 169
(2009/10/15)
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- β-Carbonyl substituted glutathione conjugates as inhibitors of O. volvulus GST2
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A series of β-carbonyl substituted glutathione conjugates were prepared and evaluated as inhibitors of OvGST2. Their specificity for the parasite derived protein was assessed through comparison with their inhibition of human πGST. Inhibition of OvGST2 has been demonstrated at low micromolar concentrations for these conjugates and selectivity for OvGST2 over human π-GST of greater than 10-fold has been achieved. (C) 2000 Elsevier Science Ltd. All rights reserved.
- Brophy, Peter M.,Campbell, Alison M.,Van Eldik, Annamaria J.,Teesdale-Spittle, Paul H.,Liebau, Eva,Wang, Meng F.
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p. 979 - 981
(2007/10/03)
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- Selective monoesterification of dicarboxylic acids catalysed by ion-exchange resins
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Symmetrical dicarboxylic acids with 4-14 carbon atoms gave selectively the corresponding monoesters in high yields in the transesterification catalysed by strongly acidic ion-exchange resins in ester-hydrocarbon mixtures. It was found that the rate of the esterification of the dicarboxylic acids is much higher than that of the monocarboxylic acids formed. This result can explain the high selectivity for the monoester formation and can also be explained by the existence of an aqueous layer on the surface of the resins. This method of selective esterification is quite simple and practical. The Royal Society of Chemistry 1999.
- Nishiguchi, Takeshi,Ishii, Yasuhiro,Fujisaki, Shizuo
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p. 3023 - 3027
(2007/10/03)
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