Title

Photooxidation of methoxyphenols on titanium dioxide surrogates.

Date of Award

5-1-2014

Document Type

Thesis

School

College of Liberal Arts

Degree Name

Bachelor in Arts

Abstract

Titanium dioxide, or rutile, while relatively uncommon in the atmosphere, has gained relevance in urban atmospheric chemistry over the past few decades due to its use in solar self-cleaning coatings for buildings and windows. Though it has not often been thought of as a component of classical aerosols, its remarkable photochemistry makes a strong case for reconsideration. Upon adsorption onto rutile aerosols or surfaces in the presence of oxygen, water, and sunlight, methoxyphenols were found to degrade via radical photo-oxidation to commodity chemicals and reactive aldehydes such as vanillin and coniferyl aldehydes. While these reactions appear often in the literature in suspension phase, heterogeneous gas-solid interface radical oxidation is markedly less common and nearly non-existent for the particular system studied. The radical oxidation processes observed form reactive species that may be active participants in browning reactions decreasing aerosol reflectivity. If this proves to be true, then photocatalytic aerosol components such as rutile must be included in atmospheric modeling to reduce the ambiguity of current models. Additionally, the reaction presented provides a far greener route to valuable commodity chemicals than currently used industry standards, reducing environmental impact of their production.