TY - JOUR
T1 - Cosolvent effect on enhancement of reaction rate constant in near-critical region
AU - Aizawa, Takafumi
AU - Janttarakeeree, Siriporn
AU - Ikushima, Yutaka
AU - Saitoh, Norio
AU - Arai, Kunio
AU - Smith, Richard L.
N1 - Funding Information:
This research was supported in part by Industrial Technology Research Grant Program in 2000 from the New Energy and Industrial Technology Development Organization (NEDO) of Japan and Core Research for Evolutional Science and Technology (CREST) from Japan Science and Technology Corporation (JST).
PY - 2003/12
Y1 - 2003/12
N2 - Triplet-triplet annihilation of anthracene in supercritical carbon dioxide with and without acetonitrile cosolvent was studied with a transient absorption technique. In pure CO2, enhancement of the reaction rate was observed. Extinction coefficients and quantum yields of triplet state anthracene in the near-critical region sharply increased and decreased, respectively. In the presence of cosolvent, however, the enhancement of the reaction rate constant in the near-critical region decreased with increasing amounts of cosolvent. Under these conditions, both the extinction coefficients and quantum yields of triplet state anthracene showed less variation providing strong evidence that the cosolvent shields specific interactions between solute and the CO2 solvent.
AB - Triplet-triplet annihilation of anthracene in supercritical carbon dioxide with and without acetonitrile cosolvent was studied with a transient absorption technique. In pure CO2, enhancement of the reaction rate was observed. Extinction coefficients and quantum yields of triplet state anthracene in the near-critical region sharply increased and decreased, respectively. In the presence of cosolvent, however, the enhancement of the reaction rate constant in the near-critical region decreased with increasing amounts of cosolvent. Under these conditions, both the extinction coefficients and quantum yields of triplet state anthracene showed less variation providing strong evidence that the cosolvent shields specific interactions between solute and the CO2 solvent.
KW - Acetonitrile
KW - Anthracene
KW - Cosolvent
KW - Supercritical carbon dioxide
KW - Transient absorption
UR - http://www.scopus.com/inward/record.url?scp=0242386511&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0242386511&partnerID=8YFLogxK
U2 - 10.1016/S0896-8446(02)00243-7
DO - 10.1016/S0896-8446(02)00243-7
M3 - Article
AN - SCOPUS:0242386511
VL - 27
SP - 247
EP - 253
JO - Journal of Supercritical Fluids
JF - Journal of Supercritical Fluids
SN - 0896-8446
IS - 3
ER -