No abstract

No abstract

Partial degradations of 4-methoxyresorcinol and p-anisyl 1-neopentyl alcohol were carried out with the PC series of photocatalysts from Millenium chemicals and with Degussa P25. The PC series of anatase catalysts varies only in the degree of sintering, and thus particle size and type of crystal defects. The initial product distributions were not substantially sensitive to catalyst, implying that none of the major products depended on particular binding sites that could be annealed away. Rate constants varied from catalyst to catalyst, but not dramatically, on a weight-to-volume basis. Thus there was also not a direct connection between available surface area and the rate of degradation. The product distribution as a function of suspension pH is also discussed.

The selectivity of hydroxylation of the distal rings of 4‐phenylbenzoic acid, 4‐phenylsalicylic acid, and 5‐phenylsalicylic acid were determined using partial TiO2‐mediated photocatalytic degradation and photo‐Fenton conditions. This separation of the binding site from the phenyl group being hydroxylated allows a less‐biased evaluation. The hydroxylation regiochemistry behaves as qualitatively expected for an electrophilic reaction, given the assumption that 4‐carboxyphenyl is a slightly electron‐withdrawing substituent. Selectivity for hydroxylation of the distal phenyl in 4‐ and 5‐phenylsalicylic acid is reversed, due to the reversal of the electronic demand, while adsorption to the TiO2 surface is assumed to be analogous for the two structures. Copyright © 2011 John Wiley & Sons, Ltd.

ProQuest Information and Learning Company. 1.5. References Chapter 2. Particle size effects on the mechanism and kinetics of degradation of organic molecules using titanium dioxide photocatalysis 2.1. Abstract 2.2. Introduction 2.3. Experimental 2.4. Results and Discussion 2.4.1. MRC Degradation Products 2.4.2. ANP Degradation Products 2.4.3. Trends Across the pH Spectrum for MRC Degradation 2.4.4. Trends Across the pH Spectrum for ANP Degradation 2.4.5. Comparison of MRC and ANP Degradations 2.4.6. Reaction Kinetics 2.4.6.1. Kinetic trends over the pH range 2.4.6.2. Kinetic trends between titania catalysts iii 2.4.6.3. Dark adsorption studies 2.5. Conclusion 2.6. References Chapter 3. General Conclusion 3.1. Conclusions 3.2. References CHAPTER 1 General Introduction