SBA-15-functionalized sulfonic acid confined acidic ionic liquid: a powerful and water-tolerant catalyst for solvent-free esterifications

Incorporating a hydrophobic Br?nsted acid ionic liquid (HBAIL) inside the nanospaces of SBA-15-Pr-SO(3)H led to a hydrophobic super Br?nsted acid catalyst, which showed excellent catalytic performance in direct esterification of alcohols and carboxylic acids at ambient temperature under solvent-free conditions.     

2-Chloro-1-methylpyridinium iodide,an efficient reagent for the conversion of alcohols into alkyl thiocyanates both under solvent and solvent-free conditions

A new application of the Mukaiyama reagent for the simple phosphine-free conversion of alcohols into the corresponding alkyl thiocyanates is described. This transformation can be achieved either in acetonitrile or under solvent-free conditions and the products obtained in good to excellent yields. The solvent-free procedure described here is the first report on the solvent-free thiocyanation of alcohols.     

Anchoring effect on switching dynamics of a nematic liquid crystal intensity modulator

The director reorientation relaxation time of a novel nematic liquid crystal is measured through fitting the decay curve of intensity modulation by Ericksen–Leslie equation. Application of the so-called hard anchoring condition results in simplifying the mentioned equation as well as ignoring the reorientation of boundary molecules in switching procedure. This paper investigates the hardness of 1294-1b nematic liquid crystal's anchoring on rubbed PVA and the effect of boundary molecules on response time and viscoelastic coefficient calculation by experimentally obtaining the decay times of different sample thicknesses.     

Solvent‐ and catalyst‐free reaction of (aminomethyl)phosphonates with epoxides: Synthesis of novel {[(2‐hydroxyethyl)amino]methyl}phosphonates

Uncatalyzed reaction of epoxides with (aminomethyl)phosphonates for the synthesis of novel {[(2‐hydroxyethyl)amino]methyl}phosphonates is described. Treatment of (aminomethyl)phosphonates with epoxides without any catalyst and under solvent‐free conditions gives novel {[(2‐hydroxyethyl)amino]methyl}phosphonates. Using this method, a series of {[(2‐hydroxyethyl)amino]methyl}phosphonates was synthesized in good yields. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:284–289, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20615     

A peptide bromoiodinane approach for asymmetric bromolactonization

A series of 37 peptides containing an iodo-aryl amide active site were generated by means of both solid phase and conventional synthesis. These peptides were screened for asymmetric induction in the bromolactonization of 4-phenyl-4-pentenoic acid based on the generation of chiral bromoiodinane bromenium sources. The study culminated in the discovery of a tri-peptide iodo-aryl amide that effected the desired bromolactonization in quantitative conversion with 24% ee. The experiments disclosed herein provided valuable insight that ultimately facilitated the development of more synthetically useful enantioselective halocyclization methodology.     

Resolution of enantiomers of [α-hydroxy-(o-chlorophenyl)methyl]phosphinic acid via diastereomeric salt formation with enantiopure 1-phenylethylamines

The resolution of racemic α-hydroxy-H-phosphinic acid with enantiopure 1-phenylethylamines via diastereomeric salt formation was investigated. X-Ray crystallographic analysis of the salt revealed that (R)-1-phenylethylamine to be efficient resolving agent for obtaining a single enantiomer of [α-hydroxy-(o-chlorophenyl)methyl]phosphinic acid. Resolving racemic α-hydroxy-H-phosphinic acid with (S)-2-phenylethylamine also gave access to (S)-α-hydroxyalkylphosphinic acid in good yield.     

Calcium manganese(IV) oxides: biomimetic and efficient catalysts for water oxidation

CaMnO(3) and Ca(2)Mn(3)O(8) were synthesized and characterized by SEM, XRD, FTIR and BET. Both oxides showed oxygen evolution activity in the presence of oxone, cerium(IV) ammonium nitrate and H(2)O(2). Oxygen evolution from water during irradiation with visible light (λ > 400 nm) was also observed upon adding these manganese oxides to an aqueous solution containing tris(2,2'-bipyridyl) ruthenium(II), as photosensitizer, and chloro pentaammine cobalt(III) chloride, as electron acceptor, in an acetate buffer. The amounts of dissolved manganese and calcium from CaMnO(3) and Ca(2)Mn(3)O(8) in the oxygen evolving reactions were reported and compared with other (calcium) manganese oxides. Proposed mechanisms of oxygen evolution and proposed roles for the calcium ions are also considered.     

Investigation of Aqueous Diethanolamine Performance in Prediction of Hydrogen Sulfide and Carbonyl Sulfide Removal from Liquefied Propane

Journal of Solution Chemistry - Hydrogen sulfide and carbonyl sulfide represent undesirable impurities in a variety of industrial gas streams such as natural gas, liquefied natural gas and...