In this work, optimization of supercritical methanol extraction and transesterification for the production of biodiesel was investigated using Jatropha curcas L. seeds. Several important process parameters including heat pre-treatment (45°C-105°C for 12 and 24 hours), particle size (0.5 mm-2.0 mm) and temperature (200°C-300°C) were being studied by varying one factor at a time. The experiment w...

Conventional solvent-based methods are still the most practical approaches for recovery of polyhydroxyalkanoate (PHA) polymer from cellular biomass, even though potential alternatives exist, including chemical, mechanical, and enzymatic methods. It is still necessary, however, to avoid dangerous and environmentally unfriendly solvents (e.g., chloroform and dichloromethane) in the polymer recove...

In this work we investigate the circular dichroism (CD) spectrum of [Co(en)3]3+ in water, using the discrete solvent reaction field (DRF) model. The DRF model is a polarizable quantum mechanics/molecular mechanics (QM/MM) model. The implementation of the DRF model for CD spectra calculations based on time-dependent density functional theory (TDDFT) is presented. The combination of DRF with TDDF...

Reactions of (η-RC5H4)Fe(CO)2I (R = H, Me) complexes with phosphine ligands PR′3 (R′ = Ph, m-Tol, p-C6H4OMe, p-C6H4Cl, p-C6H4F) have been performed under solvent-free conditions in the melt phase and generally yielded the ionic products [(η5-RC5H4)Fe(CO)2PR′3]I rather than the CO substituted products (η5-RC5H4)Fe(CO)(PR′3)I. The complexes have been characterised by IR, NMR and MS techniques. By...

Recent developments of NMR methods for characterization of lignocellulosic biomass allow improved understanding of plant cell-wall structures with minimal deconstruction and modification of biomass. This study introduces a new NMR solvent system composed of dimethylsulfoxide (DMSO-d6 ) and hexamethylphosphoramide (HMPA-d18 ). HMPA as a co-solvent enhanced swelling and mobility of the biomass sa...

The main objective of the present study was to investigate the effect of solvent type and ratio as well as the extraction techniques (i.e. supercritical fluid extraction (SFE) and conventional solvent extraction) on betacyanins and antioxidant activity of the peel and fresh extract from the red pitaya (Hylocereus polyrhizus). The peel and flesh extracts obtained by SFE at 25MPa pressure and 10%...

A solvent-extraction system comprising toluene/ter-butanol (ter-BuOH) mixed solvent as the organic phase was developed to selectively extract Cr(VI) from acidic chloride media in the presence of divalent metals, namely Cd(II), Co(II), Cu(II), Ni(II) and Zn(II) under 5 M CaCl2 salting-out conditions. Chromium(VI) was selectively extracted as a solvated ion-pair of [ter-BuOH2+ x CrO3Cl-] at ter-B...

anufacturing industries have traditionally relied on chloM rofluorocarbons (CFCs) and other halogenated solvents for precision cleaning of metals, plastics, composites, ceramics, electronic components, and other materials. In 1991, for example, the Environmental Protection Agency estimated that approximately 170 million pounds of CFC-113 and methyl chloroform were used by US . industries for va...

Large porphyrinoids with three Rh(CO)2 groups at their dipyrrin units shows two-step metal transposition through the macrocycle in solution and the equilibrium between the C3v-isomer and the Cs-isomer depends on the solvent polarity.

National Institute of Standards and Technology Boulder, CO 80303 Sample injection in supercritical fluid chromatography (SFC) is usually performed using a combination of apparatus from liquid chromatography and capillary gas chromatography. The device most often consists of an injection valve (of the type used in liquid chromatography) followed by a flow splitter controlled by a restrictor. It ...