Homogeneous ionic liquid microextraction was developed for the simultaneceus extraction of dimetho- morph, mefenacet, isoprothiolane and oxadiazon from soil. 1-Butyl-3-methylimidazolium tetrafluoroborate was used as extraction solvent, and ammonium hexafluorophosphate was used as ion-pairing agent. High-performance liquid chromatography（HPLC） was employed for separation and determination of the analytes. The calibration curves show good linear relationship（r〉0.9988）. The recoveries are between 74.2% and 97.9% with relative standard devia- tions（RSDs） lower than 5.97%. The present method is free of volatile organic solvents, and expenditures of sample, extraction time and solvent are lower, compared with ultrasonic and Soxhlet extraction. There was no obvious diffe- rence in the extraction recoveries of pesticides obtained by the three extraction methods.
YAN RuiSHAO Ming-yuanLIANG Zhen-fenZHANG Han-qiYU Ai-min
α-Hydroxy carboxylic esters and their derivatives are key substructures in a variety of biologically active natural products and numerous pharmaceuticals[1-3].A variety of methods for the synthesis of α-hydroxyesters via homologation of aldehydes or ketones have been developed and frequently used in organic synthesis[4-14].These approaches are generally based on the following routes（Scheme 1）.
YANG JianxinYIN YunxingHE ZhenminMA LiLI XinZHANG ZhiliuLIN XiaojuanMA Rujian
A dissipative particle dynamics simulation technique was used to investigate the effect of molecular architecture of star-block copolymer on the patterned structure in a nanodroplet. With increasing the ratio of solvophilic to block length to solvophobic block length（RwT）, solvophobic sphere, ordered hexagonal phase, onion phase, perforated onion phase and flocculent phase are formed, respectively. Since onion phase has potential application in controlled drug release, it has received wide attention experimentally and theoretically. Our simulation indicates onion phase forms at a certain RH/T（close to but less than 1）. A star-block copolymer molecule has two conformations in onion phase： either fully located in a shell or shared by two neighboring shells. Central structure affects onion＇s final shape. The molecular number of the copolymer in each shell is a quadratic function of the shell＇s radius. The arm number of star-block copolymer has little influence on onion＇s structure, but slightly affects the solvent content. Additionally, we studied the influence of arm length on onion＇s structure.
We report the first trifluoroacetic anhydride- and trifluoroacetic acid-promoted cascade reaction with phtoroglucinoltribenzyl ether and carboxylic acid as starting materials. By simply varying the temperature of systems containing the same starting materials, different products were produced in high yields. A three-step consecutive reaction process was also proposed.
