Photochemistry of Stilbene Adsorbed on Silica Gel and NaX Zeolite. A Diffuse Reflectance Laser Flash Photolysis Study

1994 ◽  
Vol 98 (44) ◽  
pp. 11444-11451 ◽  
Author(s):  
I. K. Lednev ◽  
N. Mathivanan ◽  
L. J. Johnston
Keyword(s):  
Silica Gel ◽  
Diffuse Reflectance ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Zeolite A ◽  
Nax Zeolite

Intrazeolite photochemistry. VI. Diffuse reflectance laser flash photolysis and product studies of diphenylmethyl radicals on solid supports

1990 ◽  
Vol 68 (6) ◽  
pp. 812-819 ◽  
Author(s):  
Graeme Kelly ◽  
C. J. Willsher ◽  
F. Wilkinson ◽  
J. C. Netto-Ferreira ◽  
A. Olea ◽  
...  
Keyword(s):  
Silica Gel ◽  
Time Scales ◽  
Diffuse Reflectance ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Decay Kinetics ◽  
Narrow Channels ◽  
Wide Range ◽  
Loading Effects

Diphenylmethyl radicals have been generated by 266 nm laser excitation of 1,1,3,3-tetraphenylacetone adsorbed on silica gel and included in NaX and Silicalite zeolites and have been studied using diffuse reflectance laser flash photolysis techniques. The spectrum for the radical shows λmax at ~335 nm in all three supports and is similar to that in solution. The radicals decay over time scales that vary from hundreds of nanoseconds to minutes and there are indications that some radicals may be decaying on shorter time scales than we can monitor. The efficiency of oxygen quenching increases in going from Silicalite to NaX to silica gel, consistent with the greater accessibility of oxygen to silica gel pores as compared to the narrow channels in Silicalite. Laser dose and ketone loading effects were also examined for the various supports. Potential applications of a kinetic treatment of the data based on dispersive reaction kinetics are also discussed as a means of dealing with the problem of decay kinetics that occur over a wide range of time scales. Keywords: zeolites, kinetics, diphenylmethyl radicals, laser photolysis.

Ketone photochemistry on solid silica. A diffuse reflectance laser flash photolysis study

1985 ◽  
Vol 119 (6) ◽  
pp. 484-488 ◽  
Author(s):  
Nicholas J. Turro ◽  
Ian R. Gould ◽  
Matthew B. Zimmt ◽  
Chen-Chih Cheng
Keyword(s):  
Diffuse Reflectance ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash
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