Homochirality, an interesting phenomenon of life, is mainly an unresolved problem and was thought to be a property of living matter. Herein, we show that artificial β-peptides have the tendency toward homochiral diastereoselective chain elongation. Chain-length-dependent stereochemical discrimination was investigated in the synthesis of foldamers with various side chains and secondary structure...

The present study deals with the selective hydrogenation of menthone to menthol in a Parr reactor. The reactions are carried out in the temperature range of 100-200°C, pressure range of 5-20 kg/cm, 100 mL solvent and catalyst to substrate ratio ranging from 0-10% for a reaction time of 4-5 h. The samples are then analyzed using a gas chromatograph for determining the conversion and then selecti...

Vanadium phosphorous oxide (VPO) is traditionally manufactured from solid vanadium oxides by synthesizing VOHPO4·0.5H2O (the precursor) followed by in situ activation to produce (VO)2P2O7 (the active phase). This paper discusses an alternative synthesis method based on sol-gel techniques. Vanadium (V) triisopropoxide oxide was reacted with ortho-phosphoric acid in an aprotic solvent. The produc...

Reaction kinetics were studied to quantify the effects of polar aprotic organic solvents on the acid-catalyzed conversion of xylose into furfural. A solvent of particular importance is γ-valerolactone (GVL), which leads to significant increases in reaction rates compared to water in addition to increased product selectivity. GVL has similar effects on the kinetics for the dehydration of 1,2-pro...

A b as well as methanol selectivity (~90%) were achieved with a mass space velocity of 2700 L/h.kg-cat. at 433 K and 5.0 MPa via ethyl formate in slurry phase. This study investigated the influences of co-precipitation PH value of copper magnesium catalyst, types of alkali compounds as carbonylation promoters and impregnation agents, alcohol solvent on the reaction performances. It was also fou...

At atmospheric pressure and at 130-160 degrees C, primary aromatic amines (p-XC6H4NH2, X = H, Cl, NO2) are mono-N-alkylated in a single step, with symmetrical and asymmetrical dialkyl carbonates [ROCOOR', R = Me, R' = MeO(CH2)2O(CH2)2; R = R' = Et; R = R' = benzyl; R = R' = allyl; R = Et, R' = MeO(CH2)2O(CH2)2], in the presence of a commercially available NaY faujasite. No solvents are required...

Fractionation is considered to be one promising strategy to utilize raw biomass to its fullest and produce chemicals with high selectivity. Herein, ethanol/H2O (1/1, v/v) co-solvent with 0.050 M oxalic acid is used to simultaneously fractionate 88.0 wt% of hemicellulose and 89.2 wt% of lignin in corn stover, while cellulose is not obviously degraded. H2O dissolves hemicellulose, G unit and thos...

The conventional concept of selective complexation of actinides with soft donor ligands (either S or N donor) has been modified here through exploiting the concept, "intra-ligand synergism", where a hard donor atom, such as oxygen preferentially binds to trivalent actinides [An(iii)] as compared to the valence iso-electronic trivalent lanthanides [Ln(iii)] in presence of another soft donor cent...

The effects of two valerian extracts (aqueous and hydroalcoholic) were investigated through [(3)H]Glutamate ([(3)H]Glu) and [(3)H]Fluorowillardine ([(3)H]FW) receptor binding assays using rat synaptic membranes in presence of different receptor ligands. In addition, the extract stability was monitored spectrophotometrically. Both extracts demonstrated interaction with ionotropic glutamate recep...

The preference of large protein ion channels for cations or anions is mainly determined by the electrostatic interactions of mobile ions with charged residues of the protein. Here we discuss the widely spread paradigm that the charges determining the channel selectivity are only those that can be considered solvent-accessible because of their location near the permeation pathways of ions and wa...