TY - JOUR
T1 - The aqueous phase nitration of phenol and benzoic acid studied through flow-gated capillary electrophoresis
AU - Tang, Hao
AU - Wei, Yiyi
AU - Thompson, Jonathan E.
N1 - Funding Information:
The authors would like to thank the State of Texas/Texas Tech University for financial support of this project through new faculty start-up funding. The University of Illinois MS facility provided rapid analysis of the samples and helpful discussions. The authors would also recognize the contributions of the late Professor Dennis Shelly whose laboratory provided capillary tubing for completion of this work. Hao Tang performed most experiments, analyzed and reported data, and contributed to authoring the manuscript. Yiyi Wei performed UV-VIS experiments. Jon Thompson provided guidance and assisted authoring and editing the manuscript.
PY - 2013/10
Y1 - 2013/10
N2 - The aqueous phase nitration of benzoic acid and phenol was investigated via on-line capillary electrophoresis (CE). The presence of nitrated benzoic acid and phenol was supported through appearance of corresponding molecular ion peaks in ESI-MS measurements, and speciation of the nitrated isomers is achieved via the on-line CE method. The nitrated isomers produced in both reactions were successfully separated in <4 min by addition of 15 mM β-cyclodextrin to the electrophoresis buffer. Sequential separations (on-line analysis) allowed the reaction kinetics to be described. For benzoic acid, reaction yields were low (2-3%) however, results suggest both 3- and 2-nitrobenzoic acid form in a 1-1.4 concentration ratio. In addition, 3-hydroxybenzoic acid also forms in significant quantity under our reaction conditions. For the nitration of phenol, the reaction occurred more rapidly with observed yields between ≈10-30% for individual isomers. The yield of 2-nitrophenol was higher than 4-nitrophenol by a ratio of ≈ 1.7-2, but 3-nitrophenol was not detected. For both reactions, nitrated and hydroxylated aromatics were the major products and formation of higher molecular weight oligomers was not observed.
AB - The aqueous phase nitration of benzoic acid and phenol was investigated via on-line capillary electrophoresis (CE). The presence of nitrated benzoic acid and phenol was supported through appearance of corresponding molecular ion peaks in ESI-MS measurements, and speciation of the nitrated isomers is achieved via the on-line CE method. The nitrated isomers produced in both reactions were successfully separated in <4 min by addition of 15 mM β-cyclodextrin to the electrophoresis buffer. Sequential separations (on-line analysis) allowed the reaction kinetics to be described. For benzoic acid, reaction yields were low (2-3%) however, results suggest both 3- and 2-nitrobenzoic acid form in a 1-1.4 concentration ratio. In addition, 3-hydroxybenzoic acid also forms in significant quantity under our reaction conditions. For the nitration of phenol, the reaction occurred more rapidly with observed yields between ≈10-30% for individual isomers. The yield of 2-nitrophenol was higher than 4-nitrophenol by a ratio of ≈ 1.7-2, but 3-nitrophenol was not detected. For both reactions, nitrated and hydroxylated aromatics were the major products and formation of higher molecular weight oligomers was not observed.
KW - aqueous organic aerosol
KW - capillary electrophoresis
KW - chemical kinetics
KW - nitration reactions
KW - secondary organic aerosol
UR - http://www.scopus.com/inward/record.url?scp=84886391582&partnerID=8YFLogxK
U2 - 10.1080/03067319.2012.746323
DO - 10.1080/03067319.2012.746323
M3 - Article
AN - SCOPUS:84886391582
SN - 0306-7319
VL - 93
SP - 1329
EP - 1341
JO - International Journal of Environmental Analytical Chemistry
JF - International Journal of Environmental Analytical Chemistry
IS - 12
ER -