| Research Abstract |
The absorbance of the Soret and Q-bands of free-base tetraphenylporphyrin (TPPH_2) is reversibly sensitive to ppm levels of HCl. The replacement of the hydrogen para to the phenyl group with an -OH group enhances the sensitivity of the Soret and the Q-band region. 1) While both response and recovery times of tetra 4-OH substituted tetraphenyl-porphyrin (TP(OH)PH_2) is considerably longer than that of TPPH_2, the replacing the hydrogen meta to the phenyl group with tert-butyl group is effective to improve both response and recovery times. 2) The replacement of the hydrogen para to the phenyl group with an alkoxyl group(-OR)(TP(OR)PH_2) improves both response and recovery times of TP(OH)PH_2, i.e., their recovery times reduce from sevral days for TP(OH)PH_2 to 10 minimutes or one hour for TP(OR)PH_2. 3)A short recovery time and high sensitivity to sub-ppm levels of HCl was achieved using the TP(OC_4H_9)PH_2-BuMA composite films. On the other hand, The response behaviours of the composite films of TPPH_2 derivatives-various polymer matrices were affected by glass transition temperature (Tg) of polymer matrices. When Tg is lower than working temperature (318K), the sensitivity increases with increasing Tg, and achieve the maximum for Tg=269K, and then decrease at higher Tg. These results can be explained by free volume for HCl diffusion and molecular vibration.
Polymerization of vinyl monomers, such as vinyl acetate (VAc), acrylonitrile (AN), methylmethacrylate (MMA) and styrene (St), were carried out in water-ethyl acetate twophase system, by the use of Na_2S_2O_4 and CCl_4 as redox initiator, tetrabutylammonium chloride(TBA^+Cl^-) as a phasetransfer-catalyst. VAc was polymerized most speedy, but St was not polymerized. AN was polymerized speedy at first stage, but the conversion-time relation showed a dead-end polymerization. MMA was polymerized moderately.
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