1708-39-0Relevant articles and documents
Microwave rehydrated Mg-Al-LDH as base catalyst for the acetalization of glycerol
Prakruthi,Chandrashekara,Jai Prakash,Bhat
, p. 3667 - 3674 (2015)
Acetalization of glycerol with aldehydes to form cyclic acetals is an industrially important reaction and is generally carried out using acid catalysts. Base catalysts such as LDH can bring about microwave-assisted acetalization of glycerol and aldehydes to form 5-membered and 6-membered cyclic acetals. Among the different LDHs used, Mg-Al-LDH was found to exhibit maximum conversion of glycerol into 5-membered cyclic acetal. Modification of Mg-Al-LDH involving calcination at 450°C and subsequent microwave-assisted rehydration showed improved glycerol conversion rate under similar reaction conditions. Rehydration of calcined Mg-Al-LDH by microwave irradiation was found to result in LDH regaining its layered structure with higher basicity possibly exposing more hydroxyl ions responsible for basicity. Multiple use of methanol washed spent catalyst showed good repeatability for conversion up to three cycles which subsequently showed a marginal decrease in the conversion. Further dehydration followed by rehydration of the spent LDH catalyst under microwave irradiation was found to rejuvenate the catalytic activity to its initial level.
Sustainable valorisation of glycerol via acetalization as well as carboxylation reactions over silicotungstates anchored to zeolite Hβ
Narkhede, Nilesh,Patel, Anjali
, p. 154 - 163 (2016)
A simple, green and effective pathway towards valorisation of glycerol to value added products has been demonstrated. In this context, catalysts comprising parent as well as lacunary silicotungstates anchored to large pore zeolite Hβ have been synthesized and characterized by various physicochemical methods. Parent silicotungstic acid based catalyst proved to be better catalyst in terms of conversion of glycerol showing 73% conversion for carboxylation reaction and 97% conversion of glycerol towards acetalization reaction. The better activity of the catalyst was correlated with its strong acidic character. It was observed that by tuning the acidity of parent silicotungstate by formation of lacunary silicotungstate leads to the increase in the selectivity of 5-membered dioxolane from 68% to 78% and selectivity of glycerol carbonate from 72% to 75%. Both the catalysts were reusable up to four cycles under the investigated reaction conditions. The probable mechanisms for both the reactions are also discussed.
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Piantadosi,C. et al.
, p. 242 - 243 (1963)
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Low temperature synthesis of bio-fuel additives via valorisation of glycerol with benzaldehyde as well as furfural over a novel sustainable catalyst, 12-tungstosilicic acid anchored to ordered cubic nano-porous MCM-48
Patel, Anjali,Pithadia, Dhruvi
, (2020)
The present article demonstrates designing of novel catalyst, 12-tungstosilicic acid (TSA) anchored to ordered nano-porous MCM-48 (nMCM-48); TSA/nMCM-48, characterization and evaluation for synthesis of bio-fuel additives via glycerol valorisation with aromatic aldehydes. The nanopores of support were confirmed by BET and TEM while the interaction between TSA and nMCM-48 was confirmed by decrease in the surface area and pore volume of the catalysts. Assessment of vital reaction parameters (% loading of active species, mole ratio of reactants, catalyst amount, temperature and time) were performed to achieve maximum conversion of glycerol. The catalyst showed noteworthy performance at 30 °C towards conversion (>85 %) and thermodynamically stable dioxane derivative (>60 %) with remarkable TON (5945 for benzaldehyde and 7355 for furfural). The catalyst was regenerated and used for successive four catalytic runs with almost same activity. The superiority of novel catalyst is because of its geometry and nano porosity.
Modified boehmite: A choice of catalyst for the selective conversion of glycerol to five-membered dioxolane
Barik, Manas,Chinnaraja, Eswaran,Dabas, Shilpa,Mishra, Jyotiranjan,Subramanian, Palani S.,Subramanian, Saravanan
, p. 695 - 703 (2022/01/22)
The choice of the active site and support matrix decides the activity of a catalyst. Any modifications on these will have a significant impact on the reactivity and selectivity of the catalyst. Here, we have synthesised WO3-loaded boehmite and applied it for the acetalization of a biomass-derived bulk chemical, glycerol. The well-characterized acid catalyst exhibits a selective acetalization of glycerol with good conversions into a five-membered dioxolane product. The cyclability of the catalyst up to six times along with the retention of the catalytic activity ensures the heterogeneity of the material.
High-efficacy glycerol acetalization with silica gel immobilized Br?nsted acid ionic liquid catalysts - Preparation and comprehending the counter-anion effect on the catalytic activity
Shashni, Shalini,Singh, Vasundhara,Toor, Amrit Pal
, p. 21807 - 21823 (2021/12/09)
Imidazolium sulfonate zwitterions (ZIs) with unconventional counter-anions were used to fabricate a series of mesoporous silica-gel-immobilized Br?nsted acid ionic liquid (SG@BAIL) nanocatalysts. In comparison to traditional heterogeneous catalysts, these immobilised heterogeneous catalysts have the advantage of ionic-liquid acidic sites and the advantage of solid silica gel as a support, increasing their catalytic activities. The catalysts were analysed using a series of physicochemical techniques and their catalytic efficiencies were evaluated during the acetalization of glycerol (G) with benzaldehyde (B). The influence of the counter-anions present in the SG@BAIL catalysts was initially investigated in terms of the percentage conversion vs. the reaction time at a particular temperature. Furthermore, different parametric studies relating to the acetalization reaction were carried out based on the catalyst with the maximum activity. SG-[C3ImC3SO3H][OTf] was observed to have the highest catalytic performance and durability during ecofriendly acetal synthesis, with the highest selectivity for 1,3-dioxane. Parametric studies of the acetalization reaction were carried out, and the catalyst showed noteworthy performance at 90 °C, showing 94% conversion in an equimolar reactant mixture under solvent-free conditions with 0.03 wt% catalyst loading in a short time span of 75 min. In addition, kinetics modelling was performed using reversible second-order kinetics to calculate the forward rate constants at various temperatures. The activation energy of the reaction was determined using the Arrhenius equation, and the overall activation energy was 69.33 kJ mol-1. These investigations have demonstrated the excellent potential of SG@BAIL catalysts for practical application in the glycerol acetalization process.
