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Organic Reactions and Nanoparticle Preparation in CO 2 ‐Induced Water/P104/ p ‐Xylene Microemulsions
Author(s) -
Zhang Rui,
Liu Jun,
He Jun,
Han Buxing,
Wu Weize,
Jiang Tao,
Liu Zhimin,
Du Jimin
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200204496
Subject(s) - microemulsion , chemistry , propylene oxide , inorganic chemistry , micelle , reaction rate constant , hydrolysis , nanoparticle , ethylene oxide , pulmonary surfactant , nuclear chemistry , aqueous solution , chemical engineering , organic chemistry , kinetics , copolymer , engineering , biochemistry , physics , quantum mechanics , polymer
Nanometer‐sized gold particles are synthesized by the reduction of HAuCl 4 with KBH 4 in the CO 2 ‐induced microemulsion of (EO) 27 (PO) 61 (EO) 27 (P104; EO=ethylene oxide, PO=propylene oxide)/ p ‐xylene/CO 2 /H 2 O. The recovery of gold particles from the microemulsion can be easily accomplished by the venting of CO 2 , while the surfactant remains in the organic phase. The effect of the molar ratio of the reductant to HAuCl 4 , the concentration of the reactants, and the molar ratio of water to EO segments (W 0 ) in the reverse micelles on the size of the gold particles is studied. The hydrolysis of benzoyl chloride (BzCl) and p ‐nitrophenyl chloroformate (NPhCl) has also been carried out in the microemulsion. The results show that the observed rate constants k obs of both substrates increase significantly with W 0 , and that W 0 has a larger influence on the hydrolysis of BzCl. The different extents of the influence of W 0 on the two reactions can be ascribed to the different reaction mechanisms and the expected changes in nucleophilicity and polarity of water in the reverse micelles.