Showing papers by "Anjali Patel published in 2014"
TL;DR: In this paper, a 12-tungstophosphoric anchored to MCM-41 and zirconia was used for the esterification of glycerol, a value added byproduct from biodiesel production.
94 citations
TL;DR: In this paper, 12-Tungstophosphoric acid (TPA) supported on mesoporous molecular material (MCM-48) was synthesized, characterized and its use as a heterogeneous catalyst was explored for biodiesel production via oleic acid esterification with methanol.
72 citations
TL;DR: In this paper, the effect of different reaction parameters like % loading, catalyst amount, mole ratio, time and temperature were studied for the supreme conversion of 12-tungstosilicic acid anchored to SBA-15.
40 citations
TL;DR: In this paper, an environmentally benign oxidation of alcohols and alkenes over transition metal substituted phosphomolybdates with molecular oxygen as an oxidant and TBHP as an initiator was carried out.
32 citations
TL;DR: In this article, a solvent free green route towards valorisation of glycerol via acetalization with benzaldehyde has been proposed using heterogeneous catalysts comprising of parent Keggin type and monolacunary silicotungstate anchored to MCM-41.
Abstract: Heterogeneous catalysts comprising of parent Keggin type silicotungstate as well as monolacunary silicotungstate anchored to MCM-41 were synthesized and characterized by several physicochemical methods. A solvent free green route towards valorisation of glycerol via acetalization with benzaldehyde has been proposed. Both the catalysts showed very good activity as well as selectivity towards dioxolane derivatives within a short reaction time and at room temperature. The tuning of the acidity of the parent silicotungstate leads to an increase in the selectivity towards 1,3-dioxolane. The catalysts were also recycled up to four times without any significant loss in the conversion. The excellent performance of these mesoporous catalysts is attributed to their combination of acidity, wide pores and large specific surface area.
32 citations
TL;DR: In this article, 12-Tungstophosphoric acid anchored to mesoporous material (MCM-48) was synthesized and characterized by thermogravimetric-differential thermal analysis, Brunauer-Emmett-Teller analysis, Fourier transform infrared spectroscopy, 29Si nuclear magnetic resonance, X-ray diffraction, and transmission electron microscopy.
Abstract: 12-Tungstophosphoric acid anchored to mesoporous material (MCM-48) was synthesized and characterized by thermogravimetric–differential thermal analysis, Brunauer–Emmett–Teller analysis, Fourier transform infrared spectroscopy, 29Si nuclear magnetic resonance, X-ray diffraction, and transmission electron microscopy. The efficacy for the esterification of glycerol with acetic acid was investigated and 50% selectivity toward diacetyl and 30% for triaceyl glycerol was obtained under mild reaction conditions. The kinetic study was carried out, and it was found that esterification of glycerol follows first-order kinetics, and the rates are not mass transfer limited. As a cleaner alternative to traditional procedures, environmentally benign oxidation of glycerol was investigated with H2O2, and 40.5 and 33.6% selectivity for dihydroxyacetone and glyceraldehyde was obtained, respectively. The catalyst can be used up to four cycles without significant loss in conversion.
32 citations
TL;DR: In this paper, the bifunctional catalytic activity was evaluated for esterification as well as oxidation reactions of benzyl alcohol, showing that the reaction rate is truly governed by the chemical step.
30 citations
TL;DR: In this article, an environmentally benign oxidation of alcohols and alkenes was carried out over supported undecamolybdophosphate using molecular oxygen as an oxidant with tertiary butylhydroperoxide (TBHP) as a radical initiator under solvent free mild conditions.
30 citations
TL;DR: A new catalyst comprising monolacunary phosphomolybdate and MCM-41 was synthesized and characterized by different physicochemical techniques and showed superiority in obtaining better conversion under solvent free and aerobic conditions.
Abstract: A new catalyst comprising monolacunary phosphomolybdate and MCM-41 was synthesized and characterized by different physicochemical techniques. The catalytic activity was evaluated by carrying out solvent free aerobic oxidation of alkenes and alcohols. The catalyst showed 60% conversion of styrene and 28% conversion of benzyl alcohol. The superiority of the present catalytic system lies in obtaining better conversion under solvent free and aerobic conditions.
26 citations
TL;DR: In this paper, the authors presented a study of esterification of oleic acid as well as transesterification of soybean oil with methanol over a solid acid catalyst comprising a monolacunary silicotungstate anchored to zeolite Hβ.
Abstract: This paper presents a study of esterification of oleic acid as well as transesterification of soybean oil with methanol over a solid acid catalyst comprising a monolacunary silicotungstate anchored to zeolite Hβ. The optimization of the reaction parameters were carried out to get the maximum conversion. The 3.5 wt% catalyst charge at 60 °C showed 82% conversion of oleic acid with a 1 : 20 mole ratio of acid to alcohol in 10 h whereas the 4 wt% catalyst charge at 65 °C showed 96% conversion of soybean oil with a ratio of oil to alcohol of 1 : 4 (w/w) in 8 h. The catalyst was found to be readily reusable and exhibited consistency in activity upon reuse four times without appreciable loss in the conversion.
21 citations
TL;DR: An attempt has been made to use tetranuclear sandwich type Mn(II) substituted POMs as catalyst for solvent free liquid phase oxidation of styrene under mild reaction conditions as discussed by the authors.
TL;DR: In this paper, 12-Tungstophosphoric acid and lacunary phosphotungstate anchored to MCM-41 and ZrO2 were synthesized, characterized and used as bifunctional catalyst for oxidative esterification of benzaldehyde with methanol.
Abstract: 12-Tungstophosphoric acid and lacunary phosphotungstate anchored to MCM-41 and ZrO2 were synthesized, characterized and used as bifunctional catalyst for oxidative esterification of benzaldehyde with methanol. The different aldehyde substrates study show excellent selectivity for esters, indicating the scope of the catalysts. A tentative reaction mechanism for oxidative esterification of aldehyde is also proposed.
TL;DR: In this article, the authors used heptamolybdate coordinated transition metal (Co2+, Zn2+) complexes as catalysts and H2O2 as an oxidant at 80°C.
Abstract: Oxidation of styrene is carried out by using heptamolybdate coordinated transition metal (Co2+, Zn2+) complexes, [2-ampH]4[{Co(H2O)5}Mo7O24] ⋅9H2O (1), [3-ampH]4[{Co(H2O)5}Mo7O24] ⋅9H2O (2), [2-ampH]4[{Zn(H2O)5}Mo7O24] ⋅4H2O (3) and [3-ampH]4[{Zn(3-ampy)(H2O)4}Mo7O24] ⋅4H2O (4) as catalysts and H2O2 as an oxidant at 80°C. The leaching study has been carried out to check the quality of catalyst and it has been reused for three times with good percentage of conversion. For the first two catalysts (compounds 1 and 2), the major product obtained is benzaldehyde, and benzoic acid is the major product for next two catalysts (compounds 3 and 4). Stability of the catalysts has been analyzed by IR, UV-spectroscopy and powder X-ray crystallography.
TL;DR: In this article, a solvent free green route to carry out the Biginelli cyclocondensation reaction is described over synthesized catalysts, which provides an efficient and much improved protocol of Biginelli reaction in terms of solvent free conditions, high yields up to 98 %, very short reaction time of 15 min, and simple work-up procedure.
Abstract: Solid acids comprising 12-tungstophosphoric acid and 12-tungstosilicic acid anchored on to metal oxide (ZrO2), zeolites (Hβ and HZSM-5), and mesoporous material (MCM-41) were synthesized, characterized and used as the catalysts. A solvent free green route to carry out the Biginelli cyclocondensation reaction is described over synthesized catalysts. The method provides an efficient and much improved protocol of Biginelli reaction in terms of solvent free conditions, high yields up to 98 %, very short reaction time of 15 min, and simple work-up procedure. Based on the above study a best catalyst among all is proposed and is recycled up to four times without any significant change in % yields of the product. Another important feature of this method is survival of a variety of functional groups under the reaction conditions.
TL;DR: In this article, a μ-oxido divanadium compound with an aliphatic hydrazone ligand was synthesized for the oxidation of styrene in presence of H2O2 and appears to be easily recyclable.
TL;DR: In this article, the in-pocket Cs salt of di-manganese(II) substituted phosphotungstate was synthesized and characterized by various spectral techniques, and the use of the synthesized complex for liquid phase oxidation of styrene using the environmentally benign oxidants O 2 and H 2 O 2 was explored.