Laser synthesis kinetics

The examples given above represent only a few of the many demonstrated photochemical appHcations of lasers. To summarize the situation regarding laser photochemistry as of the early 1990s, it is an extremely versatile tool for research and diagnosis, providing information about reaction kinetics and the dynamics of chemical reactions. It remains difficult, however, to identify specific processes of practical economic importance in which lasers have been appHed in chemical processing. The widespread use of laser technology for chemical synthesis and the selective control of chemical reactions remains to be realized in the future. 

The first metallofullerenes, La C2 , were discovered by Smalley et al.18,23 after laser vaporization of composite targets made of graphite and lanthanum oxide or chloride. Because of their low-yield synthesis, laborious purification, and often air sensitivity and kinetic instability, studying the physical properties and chemical reactivity of these fascinating compounds was a serious challenge. Fortunately, the high sensitivity of the electrochemical methods was well adapted to study the microgram quantities in which these materials were usually available. The series of M C82... 

This chapter discusses four methods of gas phase ceramic powder synthesis by flames, fiunaces, lasers, and plasmas. In each case, the reaction thermodynamics and kinetics are similar, but the reactor design is different. To account for the particle size distribution produced in a gas phase synthesis reactor, the population balance must account for nudeation, atomistic growth (also called vapor condensation) and particle—particle segregation. These gas phase reactors are real life examples of idealized plug flow reactors that are modeled by the dispersion model for plve flow. To obtain narrow size distribution ceramic powders by gas phase synthesis, dispersion must be minimized because it leads to a broadening of the particle size distribution. Finally the gas must be quickly quenched or cooled to freeze the ceramic particles, which are often liquid at the reaction temperature, and thus prevent further aggregation. 

Among different coumarin derivatives used, 7-Amino-4-trifluoromethylcoumarin (ATFMC) revealed the most promising characteristics as an efficient fluorescent emitter. AFTMC is used in the synthesis of a substrate for fluorimetric assay of proteolytic enzymes and for use as a laser dye. We have recently investigated the chemiluminescence reactions of some peroxyoxalate esters, hydrogen peroxide and AFTMC. In this paper we report the solvent effects on the kinetics of the chemiluminescence process of the peroxyoxalate chemiluminescence in the presence of AFTMC. 

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