Efficient Process for the Production of Alkyl Esters.

This article reports a scalable process development for the production of alkyl esters through the esterification route by utilizing fly ash as a catalyst. The catalyst consisting of mixed oxides such as alumina, iron oxide, calcium oxide, magnesium oxide, and silica was employed for the esterification reaction without modification. The catalyst was evaluated for the conversion of feedstock containing variable amounts of free fatty acids, mono/dibasic acid, and alcohol/polyols into the corresponding alkyl esters. Three types of fly ash catalysts, viz., FS-1, FP-1, and FC-1, were chosen from three different industrial sources. Synthesis of dimethyl adipate was studied as a model reaction. FS-1 fly ash gave the highest yield of dimethyl adipate, whereas FC-1 gave a low yield of dimethyl adipate. The recyclability of FS-1 was evaluated for three cycles, and no loss of yield was observed. Furthermore, the catalyst FS-I was found to be capable of producing good yields for various esterification reactions with different substrates.

Studies on structure property relations of efficient decal substrates for industrial grade membrane electrode assembly development in pemfc.

Electrode fabrication and membrane electrode assembly (MEA) processes are critical steps in polymer electrolyte membrane fuel cell (PEMFC) technology. The properties of decal substrate material are important in decal coating technique for efficient transfer of catalyst layer. In the present study, MEAs are fabricated in decal method using 6 different decal substrates among which polypropylene (PP) is found ideal. Morphological, thermal, spectroscopic and sessile drop measurements are conducted for 6 decal substrates to evaluate the thermal and physicochemical properties. Studies indicate PP is thermally stable at hot-press conditions, having optimal hydrophobicity that hinders the coagulation of catalyst ink slurry cast. The pristine PP film has been identified to showcase 100% transfer yield onto the Nafion membrane without contamination and delamination of catalyst layer from membrane. The PP based MEAs are evaluated underconstant current mode in a hydrogen-oxygen fuel cell test fixture. The performance is found to be of 0.6 V at a constant current density of 1.2 A.cm-2. Besides, the cost of PP-film is only 7.5% of Kapton-film, and hence the current research work enables the high throughput electrode fabrication process for PEMFC commercialization.

Synthesis of organic-inorganic hybrid mesoporous tin oxophosphate in the presence of anionic surfactant.

Synthesis of novel mesoporous hybrid tin oxophosphate is reported from phenylphosphonic acid as the only precursor of phosphorus in the presence of anionic surfactant (SDS), which possesses a wormhole mesoporous structure and is stable even after calcination at 550 degrees C.

Microporous niobium phosphates and catalytic properties prepared by a supramolecular templating mechanism.

Microporous hexagonal niobium phosphate synthesized using neutral surfactants of molecular length, C6 to C10 hydrocarbons, by a supramolecular templating mechanism (S0I0) possesses strong hydrophilic character, which leads to high selectivity for catechol formation (95.3%) in the presence of protic solvent (MeOH) in the hydroxylation of phenol using aqueous H2O2.

Photocontrolled reversible release of guest molecules from coumarin-modified mesoporous silica.

Since the discovery of MCM-41 more than ten years ago, many investigations have explored the suitability of hexagonal mesoporous silicas for potential practical applications. These range from catalysis and optically active materials to polymerization science, separation technology and drug delivery, with recent successes in the fabrication of hybrid mesoporous organosilicas expected to open up further application possibilities. Because the pore voids of this class of materials exhibit relatively narrow pore size distributions in the range of 2-4 nm in diameter, mesoporous silicas can selectively include organic compounds and release them continuously at a later stage. The functionalization of MCM-41 pore voids with photoactive derivatives provides influence over the material's absorption behaviour, but full control over the release process remains difficult. Here we show that the uptake, storage and release of organic molecules in MCM-41 can be regulated through the photocontrolled and reversible intermolecular dimerization of coumarin derivatives attached to the pore outlets. Successful functionalization requires uncalcined MCM-41 still filled with the template molecules that directed the formation of its pores, to ensure that coumarin derivatives attach preferentially to the pore outlets, rather than their inside walls. We find that this feature and the one-dimensional, isolated nature of the individual pores allow for efficient and reversible photocontrol over guest access to the material's interior.

Synthesis of a novel mesoporous tin phosphate, SnPO4.

Novel mesoporus tin phosphates have been synthesized using alkyltrimethylammonium bromide (alkyl = C8-C18) as surfactant; the structure of the materials is stable at 500 degrees C. UV-VIS spectra show tetrahedral coordination of tin.

Synthesis of hexagonal and cubic super-microporous niobium phosphates with anion exchange capacity and catalytic properties.

Super-microporous hexagonal niobium phosphate synthesized using neutral surfactant (S0I0 mechanism) and cubic structure with cationic surfactant (S+X-I+); the hexagonal niobium phosphate possesses an excellent anion exchange capacity (6.3 mmol g-1) and high product selectivity towards 4-naphthaquinone (88.6%) in the oxidation of 1-naphthol in presence of aqueous H2O2.