An Environmentally Benign Solid Acid Nanocatalyst for the Green Synthesis of Carboxylic Acid Ester

Abstract

Green and sustainable chemistry have gained substantial attention worldwide, and the efforts have been greatly appreciated for the substitution of Brønsted acid catalysts from homogeneous to heterogeneous phases. In this perspective, a sulfonic acid-functionalized silica nanospheres (SAFSNS) catalyst was prepared by organosilylation-sulfonation on the surface of well-ordered silica nanospheres as a heterogeneous nanocatalyst. The physicochemical properties of nanocatalyst were well characterized by powder XRD, IR, TGA, DSC, NH 3 -TPD, N 2 sorption, EDAX, and SEM techniques. The attainment of the anchoring of SO 3 H functionalization involving the Brønsted acidities was found up to 0.35 mmol H + /g. The synthesized SAFSNS nanocatalyst ascertain the replacement of the highly toxic liquid phase acids to a stable, solid acid catalyst for the green esterification of carboxylic acids under solvent-free reaction conditions, showed reasonable to excellent esters yield (63-94 %) in 3.5 hours at 100°C with five times reusability without substantial diminution in catalytic proficiency.

Copper Pyrrole‐imine Incorporated Fe3O4‐Nanocomposite: A Magnetically Separable and Reusable Catalyst for the Oxidative Amination of Aryl Aldehydes

“…Therefore, continuing our research in the development of Fe 3 O 4 -based magnetically separable heterogeneous catalysts, we discovered magnetic chitosan anchored Ag-nano catalyst for reduction of nitroarenes, [26] methyl salicylate immobilized Pd catalyst for carbon-carbon coupling, [27] silica embedded Pd-Schiff base catalyst for Suzuki, Heck, and Sonogashira coupling tractions [11b] and nano-silica functionalized acid catalyst for ester synthesis. [28] Herein, we are interested in the fabrication of a novel sustainable heterogeneous catalyst based on magnetic chitosan factionalized Cu-Schiff base nanocatalyst for amination of aldehydes with amines to corresponding amides. Only a few examples of heterogeneous catalysts such as silica supported Pd [29] and Cu, [30] MOFs immobilized Pd [31] and Ni [32] nanoparticles and MWCNT functionalized Cu 2 O or CuI [33] are found in the literature for amination of aldehydes.…”

Novel Siglec-15-Sia axis inhibitor leads to colorectal cancer cell death by targeting miR-6715b-3p and oncogenes

“…In line with the United Nations Sustainable Goals (SDGs), a suitable and recyclable heterogenous catalyst for the Mannich reaction was developed. The heterogenous nano-catalyst SAFSNS, was synthesised and characterized by our reported procedure (15).…”

“…All the starting materials, reagents, and solvents were obtained from Merck and Spectrochem. The synthesis and characterization data of the sulfonic acid-functionalized silica nanospheres (SAFSNS), an environmentally benign solid acid nano-catalyst is available in our recent publication (15). The progress of the synthesis reaction of the SHG-8 molecule was monitored by using thin-layer chromatography (TLC) on silica gel plates and the spots were visualized under ultraviolet light (UV, l254 nm).…”

β-Cyclodextrin-Functionalized Fe3O4-Supported Pd-Nanocatalyst for the Reduction of Nitroarenes in Water at Mild Conditions

“…Moreover, in recent years, using magnetically responsive materials like Fe 3 O 4 (MNs)-core which are supported on nano-structured transition metal heterogeneous catalysts is gaining a lot of attention as they are environmentally friendly and exhibit easiness of the recyclability of the catalysts. , Such systems provide dynamic flexibility through which the contact between the catalyst and reactants is enhanced, hence increasing immensely the activity of the catalysts. , These special features of Fe 3 O 4 encouraged us to pursue the development of green and sustainable Fe 3 O 4 -based heterogeneous catalysts. Recently, our research group and by others have explored Fe 3 O 4 -based heterogeneous catalysts for important organic transformations, including chemoselective N -arylation of O -alkyl primary carbamates, , domino synthesis of carbamates and unsymmetrical urea, , nitroarene reduction, C–C cross-coupling, , oxidative amination, A 3 coupling, and ester synthesis . In the continuation of our efforts, herein, we have synthesized and characterized for the first time a β-cyclodextrin-functionalized Fe 3 O 4 -supported Pd-nanocatalyst for the reduction of the toxic nitro-arenes to the corresponding aniline derivatives.…”

“…Recently, our research group and by others have explored Fe 3 O 4 -based heterogeneous catalysts for important organic transformations, including chemoselective N -arylation of O -alkyl primary carbamates, 29 , 30 domino synthesis of carbamates and unsymmetrical urea, 31 , 32 nitroarene reduction, 33 C–C cross-coupling, 34 , 35 oxidative amination, 36 A 3 coupling, 37 and ester synthesis. 38 In the continuation of our efforts, herein, we have synthesized and characterized for the first time a β-cyclodextrin-functionalized Fe 3 O 4 -supported Pd-nanocatalyst for the reduction of the toxic nitro-arenes to the corresponding aniline derivatives.…”