The hydration of sodium bis(2-ethyl-l-hexyl) sulfosuccinate (AOT) reversed micelles has been studied by three independent methods: differential scanning calorimetry, ESR spin labeling, and 2H NMR. A consistent picture is evolving although the actual hydration numbers differ from method to method. This difference is most likely due to differences in the principles underlying these methods. From both calorimetry and 2H NMR it is concluded that two water molecules are tightly bound to one AOT-Na+ molecule whereas ESR spin labeling identifies four strongly bound water molecules. Our calorimetric study benefited greatly from a comparison of the thermal behavior of AOT reversed micelles and AOT smectic (lamellar) phases. Calorimetry reveals that six water molecules are unfreezable in AOT reversed micelles. This is also the case for AOT smectic (lamellar) phases; however, these six water molecules can be frozen by cooling the sample to -40 °C. The difference in the two AOT systems is attributed to supercooling that takes place in the submicroscopic droplets of AOT reversed micelles. 2H NMR gives further insight into AOT hydration. A total number of 13 water molecules are affected and structurally perturbed by 1 AOT molecule. These 13 water molecules consist of three types of water differing in the affinity for AOT-Na+. Two out of these 13 water molecules are more strongly bound; the remaining 11 water molecules appear to be weakly associated with AOT-Na+.

Sustainable process and efficient heterogeneous acid catalyst for the preparation of platform chemicals like 5-hydroxymethyl furfural (5-HMF) from renewable source is much in demand in the context of heterogeneous catalysis. Commercially available solid acid catalyst, H-USY zeolite was modified by treating with aqueous solution of H3PO4 and H2SO4 (10–30 wt %). Modified H-USY was completely characterized by XRD, NH3-TPD, energy dispersive analysis X-ray (EDAX), FT-IR, pyridine-IR, and NMR. Its catalytic performance was evaluated for the fructose conversion to 5-HMF in methyl isobutyl ketone (MIBK)–water system. Modified H-USY zeolite was identified to have potential in enhancement of 5-HMF yield up to 65% from 32% (parent H-USY) with minimum formation of furfural (8%). H-USY modified with 10 wt % H3PO4 (10P–Y) was found to be the best compared to other studied catalysts, namely, H-USY modified with 20 and 30 wt % H3PO4 (20 and 30P–Y) or 10–30 wt % H2SO4 (10- to 30S–Y). Best performance of 10P–Y is associated with the optimum combination of moderate acidity (both weak as well as strong), moderate dealumination of Al from extra-framework sites as well as from framework sites of H-USY, formation of new Al–O–P bonds between framework Al and elemental monomeric phosphorus, presence of Brønsted as well as Lewis acidity, and creation of mesopores. This gives new insight on a potential heterogeneous acid catalyst for the synthesis of 5-HMF.

Response surface methodology (RSM) with Box–Behnken experimental design (BBD) demonstrated Hierarchical-HZ-5 as potential catalyst for ethanolysis of renewable furfuryl alcohol to ethyl levulinate biofuel with 99% FAL conversion and 73% EL yield.

Ethanolysis of biomass derived furfuryl alcohol (FA) produces ethyl levulinate (EL), a biofuel additive and precursor for γ‐valerolactone synthesis. The present study is devoted to develop an efficient and an environmentally benign catalytic system for one‐pot conversion of FA to EL biofuel, by revealing an insight of the catalytic mechanism. The catalytic activity of H‐ZSM‐5, Meso‐HZ‐5 (desilicated H‐ZSM‐5) and different percentage H3PW12O40(HPW) anchored to Meso‐HZ‐5 catalysts have been evaluated for the FA ethanolysis. As per our knowledge, this is the first research reporting the application of HPW anchored to Meso‐HZ‐5 catalysts for the conversion of FA into EL in biomass utilization. These catalysts were synthesized and characterized by Powder X‐ray diffraction (XRD), N2 physisorption and temperature programmed NH3 desorption (TPAD). Products of FA ethanolysis viz., 4,5,5‐triethoxypentan‐2‐one (TEP), ethoxy‐methyl‐ furan (EMF), diethyl ether (DEE), EL were identified by Gas Chromatography‐Mass Spectroscopy (GC‐MS) and quantified by flame ionization detector (GC‐FID). The physicochemical properties of catalysts were found to correlate to the product distribution matrix. Moreover, influences of several process parameters such as catalyst amount, reactant molar ratio, temperature and time on the extent of FA ethanolysis were systematically investigated. Under optimized conditions, 15% (w/w) HPW/Meso‐HZ‐5 exhibited a remarkable catalytic performance with complete FA conversion (100%) along with 97% yield of EL, these activity values are superior than the previously reported studies. The present study provides an insight of the catalytic mechanism along with a potential environmental benign and the economic catalyst for the efficient synthesis of EL biofuel from the biomass‐derived FA. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1736–1742, 2018

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