1994 Fiscal Year Final Research Report Summary
Control of Reactivity and Selectivity through Elucidiation of Activation Mechanisms of Sonochemical Reactions
Grant-in-Aid for General Scientific Research (B)
|Allocation Type||Single-year Grants |
|Research Institution||SHIGA UNIVERSITY OF MEDICAL SCIENCE |
ANDO Takashi SHIGA UNIVERSITY OF MEDICAL SCIENCE,DEPARTMENT OF CHEMISTRY,PROFESSOR, 医学部, 教授 (70029867)
FUJITA Mitsue SHIGA UNIVERSITY OF MEDICAL SCIENCE,DEPARTMENT OF CHEMISTRY,RESEARCH ASSISTANT, 医学部, 教務職員 (40175576)
SOHMIYA Hajime SHIGA UNIVERSITY OF MEDICAL SCIENCE,DEPARTMENT OF CHEMISTRY,ASSOCIATE, 医学部, 助手 (80211324)
KIMURA Takahide SHIGA UNIVERSITY OF MEDICAL SCIENCE,DEPARTMENT OF CHEMISTRY,RESEARCH ASSOCIATE P, 医学部, 助教授 (70167378)
|Project Period (FY)
1992 – 1994
|Keywords||Sonochemistry / Ultrasound / Lead Tetraacetate / Photochemistry|
Mechanisms of sonochemical activation in several reactions were studied in order to establish it as the novel and general method of controlling the reactivity and selectivity of chemical reactions. Results are summarized below :
1. In several reactions of lead tetraacetate, we found that : (1) stirenes whose reaction courses become more radical at higher temperatures showed the acceleration in their rates with more radical products under ultrasonic irradiation ; (2) a triarylmethane which reacts by increasing ionic mechanisms at higher temperatures showed no definite results ; and (3) 2-octanol whose reactivity does not change at higher temperatures does not show any clear effect of ultrasound. The results showed that the effect of ultrasound originates from the thermal effect.
2. Thermodynamic study on the reaction of lead tetraacetate with trans-beta-methylylstirene indicated that the chain propagation step involving methyl radical occurs at a temperature only slightly higher than that
determined by a thermocouple. The result indicated that the cite of the reaction is not in the interface but in the bulk liquid.
3. Catalytic reactions of active manganese dioxide with mixtures of different classes of compounds showed the characteristic selectivity based of the adsorption on the surface.
4. Sonochemical switching from aliphatic nucleophilic substitution to aromatic electrophilic substitution by selective poisoning of the basic cites on the alumina surface with acidic salts by accelerating solid-solid interaction with ultrasonic irradiation was tried in the mixtures of organic halides, salts, and alumina in aromatic solvents without much success.
5. Simultaneous irradiation of a tetrahydrofuran solution of benzophebnone with ultrasound and UV light gave tetrahydrofuran hydroperoxide, while their separate of sequential irradiation did not. The mechanisms are not clear yet.
6. Standardization of the power of ultrasound was studied by using calorimetry and the Weissler reaction. Less
Research Products (16 results)