Mahesh N. Varma

Effect of Chain Length of Alcohol on the Lipase-Catalyzed Esterification of Propionic Acid in Supercritical Carbon Dioxide

The esterification of propionic acid was investigated using three different alcohols, namely, isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol. The variation of conversion with time for the synthesis of isoamyl propionate was investigated in the presence of five enzymes. Novozym 435 showed the highest activity, and this was used as the enzyme for investigating the various parameters that influence the esterification reaction. The Ping-Pong Bi-Bi model with inhibition by both acid and alcohol was used to model the experimental data and determine the kinetics of the esterification reaction.

Recovery of Glutaric Acid Using Tri-N-Butyl Phosphate: Effect of Diluentsand Temperature

Reactive separation of glutaric acid with tri-n-butyl phosphate in ethyl acetate and hexanol was studied to explain the effect of temperature on the extraction. Extraction was carried out at different temperature range of 308-338 K. The reactive extraction results were discussed in terms of overall distribution coefficients (KD), degree of extraction (η%), loading ratio (φ), and equilibrium complexation constants (KE). The results showed that an increase in temperature reduced distribution coefficients and extraction efficiency for both diluent used in the organic phase. Moreover, thermodynamic function viz enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) were calculated. Reactive extraction of glutaric acid by tri-n-butyl phosphate resulted in negative values of enthalpy. Thus, the reactive extraction process is an exothermic reaction.

Ionic liquids: energy efficient novel solvent for the extractive desulphurisation of liquid fuels

A novel group of energy efficient solvent, recognised as ionic liquids, has recently been the subject of challenging research on the extractive desulphurisation of liquid fuels. The aim of this study is to explore the possible application of ionic liquids as green energy efficient solvent because of their unique physical and chemical properties. In this work, imidazolium-based 1-butyl-3-methylimidazolium hexfluorophosphate [BMIM]PF6 and 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM]BF4 were synthesised and employed as extractive agent for removal of sulphur compounds. The 1H-NMR, and 13C-NMR have been discussed for the molecular confirmation of synthesised ionic liquid. Further, conductivity, and solubility analysis of ionic liquids were carried out. The effects of reaction time, reaction temperature, partition coefficient, sulphur compounds, ultrasonication and recycling of ionic liquids without regeneration on dibenzothiophene removal of liquid fuel were presented. Also, the desulphurisation and multistage extraction of real fuels were investigated. The data and results of presented work might be provide significant insights of ionic liquids as green solvent for extractive desulphurisation of liquid fuels.