4740-85-6Relevant academic research and scientific papers
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.
HYDROPHILIC FLUORINATED MOLECULES FOR LIPOSOMAL 19F MRI PROBES WITH UNIQUE MR SIGNATURES
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Paragraph 0108, (2018/06/15)
Readily available hydrophilic and small organofluorine moieties were condensed via “click chemistry” to generate nonionic hydrophilic fluorinated molecules with unique 19F MR signatures. These were used to fabricate stable liposome formulations for imaging various tissue types. This approach was tailored to exploit the broad spectrum of organic 19F molecular species and to generate probes with distinct 19F MRI signatures for simultaneous assessment of multiple molecular targets within the same target volume.
Microwave rehydrated Mg-Al-LDH as base catalyst for the acetalization of glycerol
Prakruthi,Chandrashekara,Jai Prakash,Bhat
, p. 3667 - 3674 (2015/06/30)
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.
Clay catalysed rapid valorization of glycerol towards cyclic acetals and ketals
Pawar, Radheshyam R.,Gosai, Kalpeshgiri A.,Bhatt, Adarsh S.,Kumaresan,Lee, Seung Mok,Bajaj, Hari C.
, p. 83985 - 83996 (2015/10/28)
Biodiesel production usually results in a huge amount of glycerol, raising a critical need to transform it into high value products. The present study highlights that solvent-free, conventional thermal activation, and non-conventional microwave/ultrasonic activation in the liquid phase are able to selectively transform glycerol into cyclic acetals and ketals using an optimised acid activated clay catalyst. Several parameters for the acid activation of bentonite clay were optimized under mild reaction conditions with a high concentration of clay (6%) and varying the acid concentration in the range of 6 to 15 N. The acid-activated clay samples were characterized by XRD, FT-IR, BET, and XRF analysis. The active sites of the catalyst were examined by volumetric titration and confirmed by pyridine adsorbed FT-IR and advanced NH3-TPD analyses. The activation performed at relatively mild conditions, i.e.; 6 N H2SO4 and 6% w/v clay, reproducibly resulted in an improved surface area (180 m2 g-1) and surface acidity (23 mg KOH g-1), with superior quantitative Br?nsted and Lewis acidic sites. Moreover, the eco-friendly process involving a catalyst, microwave, or ultra-sonication were successfully utilized to achieve a commercially valuable hyacinth fragrance, in addition to furan-based fuel additive precursors exhibiting a high conversion of glycerol and excellent selectivity within much less activation time (2 min).
Room temperature acetalization of glycerol to cyclic acetals over anchored silicotungstates under solvent free conditions
Narkhede, Nilesh,Patel, Anjali
, p. 19294 - 19301 (2014/05/20)
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. the Partner Organisations 2014.
