- Nano-SO42-/TiO2catalyzed eco-friendly esterification of dicarboxylic acids
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Nano-SO42-/TiO2 was prepared by wet impregnation method. The structure and properties of the prepared nano-SO42-/TiO2catalyst was characterized by XRD, SEM, TEM and BET analysis. The catalytic activities of the catalysts were tested by the esterification of sebacic acid with 2-ethyl hexanol and a series of other dicarboxylic acid. The influence factors on the reaction, such as the catalyst calcination temperature, reaction temperature/time and the molar ratio of acid to alcohol were extensively explored. Nano-SO42-/TiO2prepared exhibited much higher catalytic activity in esterification reactions. By applying the optimized reaction condition, i.e. 160 C, 2 h, 5 wt % nano-SO42-/TiO2with a 1:3 molar ratio of sebacic acid to 2-ethyl hexanol, higher than 99 % isolated of the desired ester could be obtained.
- Ji, Xianbing,Chen, Yinxia,Shen, Zuoyuan
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- Exceptionally active and reusable nanobiocatalyst comprising lipase non-covalently immobilized on multi-wall carbon nanotubes for the synthesis of diester plasticizers
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A new method for the synthesis of dicarboxylic acid esters in the presence of a new heterogeneous nanobiocatalyst consisting of Candida antarctica lipase B immobilized on multi-walled carbon nanotubes (MWCNTs) has been developed. Selection and characterization of the support for Candida antarctica lipase B (CALB) was initially performed. Pristine and modified MWCNTs of different geometries, morphologies and surface/core modifications were tested as a lipase carrier and determining that the CheapTubes MWCNTs nanobiocatalyst with a 15.7 wt.% CALB loading was the most active nanobiocatalyst. The model reaction of succinic acid with n-butanol was carried out with a 4-molar excess of alcohol and 150 mg of nanobiocatalyst per 1 mmol of succinic acid at 45 °C in cyclohexane. The di-n-butyl succinate was obtained with 95% yield after 3 h. The activities of the new nanobiocatalysts were compared with the benchmark Novozyme-435 and other acidic catalysts. Recycling studies demonstrated the possibility of utilizing the most active MWCNTs-lipase biocatalyst six times without any significant loss of activity. The main advantage of this study is the superior activity of the new nanobiocatalyst, which resulted in a significant reduction of reaction times as compared to those reported in the literature.
- Szelwicka, Anna,Boncel, S?awomir,Jurczyk, Sebastian,Chrobok, Anna
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- Micro-flow nanocatalysis: synergic effect of TfOH@SPIONs and micro-flow technology as an efficient and robust catalytic system for the synthesis of plasticizers
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The combination of continuous flow technology with immobilizing of only 0.13?mol% of triflic acid (TfOH) on silica-encapsulated superparamagnetic iron oxide nanoparticles (SPIONs) under solvent-free conditions successfully provided a powerful, efficient, and eco-friendly route for the synthesis of plasticizers. The turnover frequency value in micro-flow conditions varied in the range of 948.7 to 7384.6 h?1 compared to 403.8 to 3099 h?1 for in-flask. This technique works efficiently, encouraging future applications of micro-flow nano-catalysis in green chemistry.
- Tashi, Maryam,Shafiee, Behnaz,Sakamaki, Yoshie,Hu, Ji-Yun,Heidrick, Zachary,Khosropour, Ahmad R.,Beyzavi, M. Hassan
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- Oxidation of cyclohexanone and/or cyclohexanol catalyzed by Dawson-type polyoxometalates using hydrogen peroxide
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The oxidation of cyclohexanone, cyclohexanol or cyclohexanone/cyclohexanol mixture using as catalyst, Dawson-type polyoxometalates (POMs) of formula, α- and β-K6P2W18O62, α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62 and hydrogen peroxide, carried out at 90 °C with a reaction time of 20 h, led to a high number of mono- and di-acids which were identified by GC-MS. Levulinic, 6-hydroxyhexanoic, adipic, glutaric and succinic acids, major products were evaluated by HPLC. Regardless of the substrate nature, all POMs exhibited high catalytic activity with 94–99% of conversion, whereas the formation of the different products is sensitively related to both the composition and symmetry of the POMs and the substrate nature. The main products are adipic acid in the presence of α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62, levulinic acid in the presence of α1-K7P2Mo5VW12O62 and β-K6P2W18O62 and 6-hydroxyhexanoic acid in the presence of α- and β-K6P2W18O62. Graphical abstract: High catalytic activity was observed with?α- and?β-K6P2W18O62, α-K6P2Mo6W12O62 and α1-K7P2Mo5VW12O62 Dawson-type for the oxidation of cyclohexanone, cyclohexanol or cyclohexanone/cyclohexanol mixture, in the hydrogen peroxide presence, to several oxygenated products. Adipic, levulinic and 6-hydroxyhexanoic acids are the main products. The peroxo- species formed in situ could be the active sites.[Figure not available: see fulltext.]
- Dermeche, Leila,Idrissou, Yasmina,Mazari, Tassadit,Moudjahed, Mohammed,Rabia, Cherifa
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- Lubricant base oil and ester compounds
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[Problem] To provide: an ester compound having low viscosity, excellent fluidity even at low temperatures, and a high viscosity index; and a lubricating oil base oil that blends said compound therein. [Solution] The present invention provides an ester compound indicated by formula (I). Formula (I) (in formula (I), R1 indicates a C1–35 hydrocarbon group and at least one hydrogen in the hydrocarbon group can be independently substituted for a group indicated by formula (II)). Formula (II) (in formula (II), R2 indicates a C1–30 linear alkyl or a C3–30 branched alkyl.)
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Paragraph 0079; 0099; 0100
(2019/06/29)
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- Treatment of skin conditions by use of PPAR alpha activators
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Disorders of the skin and mucous membrane that have a disrupted or dysfunctional epidermal barrier are treated or prevented by topical application of compounds that are either activators of the farnesoid X receptor, activators of the peroxisome proliferator-activated receptor alpha , and oxysterol activators of the LXR alpha receptor. The same compounds are also effective in treating disorders of epidermal differentiation and proliferation.
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