Ultrasound-assisted extraction and derivatization of sterols and fatty alcohols from olive leaves and drupes prior to determination by gas chromatography–tandem mass spectrometry

A method for simultaneous determination of sterols and fatty alcohols in olive leaves and drupes based on ultrasound-assisted extraction and derivatization prior to individual identification–quantitation by chromatographic separation and mass spectrometry detection (single ion monitoring mode) is reported here. The sample preparation procedure involves the following steps: (i) leaching of the raw material accelerated by ultrasound; (ii) saponification of the leachate, also accelerated by ultrasound, and separation of the unsaponifiable matter; (iii) cleaning of the extract by solid-phase extraction; (iv) silylation of the target analytes—also assisted by ultrasound; (v) injection into the gas chromatograph for identification–simultaneous quantitation of the two families of compounds. Individual separation–determination of the fatty alcohols and sterols provide limits of detection (LOD) in the range 9.8 × 10⁻² to 2 μg/l and 5.0–6.0 μg/l, respectively. The LOQs range from 0.3 to 0.9 μg/l and 17.0 to 21.0 μg/l, and the linear dynamic ranges are between LOQ and 25.0 μg/ml. The between-day precision, expressed as relative standard deviation (RSD), ranges between 3.6 and 6.1% and the within-laboratory reproducibility, also expressed as RSD, between 6.4 and 9.2%. Within the study of the metabolomic profile of the unsaponifiable fraction in olive tree, the method has been applied to the determination of the target analytes in different varieties of olive trees cultivated in the same zone, so that differences in this unsaponifiable fraction can be attributed to characteristics of the target varieties. As compared with its European Union counterpart, the method is endowed with similar analytical characteristics and drastic shortening of the operational time.     

A dicationic ionic liquid-modified phosphotungstate hybrid catalyst for the heterogeneous oxidation of alcohols with H2O2

An ionic hybrid catalyst 1,1’-(butane-1,4-diyl)-bis(3-methylimidazolium) phosphotungstate(abbreviated [Dmim] 1.5 PW) has been prepared by anion-exchange of the divalent ionic liquid(IL) 1,1’-(butane-1,4-diyl)-bis(3-methylimidazolium) di(bromide) with the Keggin phosphotungstic acid H 3 PW 12 O 40,and characterized by IR,1 H NMR,13 C NMR,ESI-MS,TG,SEM,XRD,BET surface area measurements,elemental analysis,and melting point.The hybrid material was evaluated as a catalyst for the oxidation of alcohols with aqueous hydrogen peroxide under various conditions.The catalytic performance of [Dmim] 1.5 PW was also compared with related catalysts bearing other cations or anions.The new hybrid [Dmim] 1.5 PW proved to be an efficient liquid-solid heterogeneous catalyst for H2O2-based oxidation of alcohols,with the advantages of high conversion and selectivity,easy recovery,and quite good reusability.     

Influence of Periodic Nitrogen Functionality on the Selective Oxidation of Alcohols

An enhancement in catalytic alcohol oxidation activity is attributed to the presence of nitrogen heteroatoms on the external surface of a support material. The same Pd particles (3.1–3.2 nm) were supported on polymeric carbon–nitrogen supports and used as catalysts to selectively oxidize benzyl alcohol. The polymeric carbon–nitrogen materials include covalent triazine frameworks (CTF) and carbon nitride (C₃N₄) materials with nitrogen content varying from 9 to 58 atomic percent. With comparable metal exposure, estimated by X‐ray photoelectron spectroscopy, the activity of these catalysts correlates with the concentration of nitrogen species on the surface. Because the catalysts showed comparable acidic/basic properties, this enhancement cannot be ascribed to the Lewis basicity but most probably to the nature of N‐containing groups that govern the adsorption sites of the Pd nanoparticles.     

Synthesis and application of bimetallic chiral [Co(salen)]‐type complexes: a new catalytic approach to synthesis of optically pure β‐blockers via kinetic resolution of epichlorohydrin

A series of bimetallic chiral [Co(salen)]‐type complexes were successfully applied for the synthesis of optically pure β‐blockers via phenolic kinetic resolution (PKR) of racemic epichlorohydrin [2‐(chloromethyl)oxirane; ( ± )ECH]. The reaction proceeded readily at room temperature and consequently provided enantiomerically enriched corresponding α‐aryloxy alcohols with excellent enantioselectivities of up to 98% ee. The PKR method described in this work is highly efficient and straightforward strategy for the synthesis of chiral building blocks. Copyright © 2008 John Wiley & Sons, Ltd.