In nonaqueous enzymology, control of enzyme hydration is commonly approached by fixing the thermodynamic water activity of the medium. In this work, we present a strategy for evaluating the water activity in molecular dynamics simulations of proteins in water/organic solvent mixtures. The method relies on determining the water content of the bulk phase and uses a combination of Kirkwood-Buff th...

TiO2 nanoparticles/melamine Tri sulfonic acid (MTSA) supported on silica gel as an efficient catalytic system for simple, one pot, solvent-free and environmentally benign process for synthesis of dihydropyrimidines via Biginelli reaction at 110 °C is described. It was found that the catalyst is reusable and exhibited remarkable activity. The catalyst can be easily separated and reused several t...

An efficient tandem synthesis of alkyl aryl ethers, including valuable building blocks of dialdehyde and dinitro groups under microwave irradiation and solvent free conditions on potassium carbonate as a mild solid base has been developed. A series of alkyl aryl ethers were obtained from alcohols in excellent yields by following the Williamson ether synthesis protocol under practical mild condi...

TiO2 nanoparticles/melamine Tri sulfonic acid (MTSA) supported on silica gel as an efficient catalytic system for simple, one pot, solvent-free and environmentally benign process for synthesis of dihydropyrimidines via Biginelli reaction at 110 °C is described. It was found that the catalyst is reusable and exhibited remarkable activity. The catalyst can be easily separated and reused several t...

TiO2 nanoparticles/melamine Tri sulfonic acid (MTSA) supported on silica gel as an efficient catalytic system for simple, one pot, solvent-free and environmentally benign process for synthesis of dihydropyrimidines via Biginelli reaction at 110 °C is described. It was found that the catalyst is reusable and exhibited remarkable activity. The catalyst can be easily separated and reuse...

A direct approach for producing methanol from methane in a three-step, liquid phase process is reported. In the first step, methane is reacted with SO3 to form methanesulfonic acid (MSA) at 75 8C using a free-radical initiator and MSA as the solvent. Urea-H2O2 in combination with RhCl3 is found to be the most effective initiator (57% conversion of SO3; 7.2% conversion of CH4). MSA is then oxidi...

During the preparation of multi-component model membranes, a primary consideration is that compositional homogeneity should prevail throughout the suspension. Some conventional sample preparation methods pass the lipid mixture through an intermediary, solvent-free state. This is an ordered, solid state and may favor the demixing of membrane components. A new preparative method has been develope...

New examples and sources of ghost peaks in reversed-phase gradient HPLC are described and related to previous publications to give a broad perspective of ghost peak problems. In one new example the ghost peak was found to be due to mixing problems caused by a period of non-delivery of the stronger "solvent B" in a stepped gradient system. In a second example the ghost peak was due to plasticize...

The present study was designed to evaluate the antioxidant activity of 5 organic solvent extracts (petroleum ether, n-hexane, chloroform, ethyl acetate and methanol) of wheat grains, 3, 5 and 7 days old wheat seedlings. To determine the antioxidant activity of five extracts of four different samples, 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radica...