Photochemistry - Applications

Applications

Many important processes involve photochemistry. The premier example is photosynthesis, in which most plants use solar energy to convert carbon dioxide and water into glucose, disposing of oxygen as a side-product. Humans rely on photochemistry for the formation of vitamin D. In fireflies, an enzyme in the abdomen catalyzes a reaction that results in bioluminescence.

Photochemistry can also be highly destructive. Medicine bottles are often made with darkened glass to prevent the drugs from photodegradation. A pervasive reaction is the generation of singlet oxygen by photosensitized reactions of triplet oxygen. Typical photosensitizers include tetraphenylporphyrin and methylene blue. The resulting singlet oxygen is an aggressive oxidant, capable of converting C-H bonds into C-OH groups.In photodynamic therapy, light is used to destroy tumors by the action of singlet oxygen.

Many polymerizations are started by photoinitiatiors, which decompose upon absorbing light to produce the free radicals for Radical polymerization.

In the area of photochemistry, a photochemical reaction is a chemical reaction that is induced by light. Photochemical reactions are valuable in organic and inorganic chemistry because they proceed differently than thermal reactions. Photochemical reactions are not only very useful but also can be a serious nuisance, as in the photodegradation of many materials, e.g. polyvinyl chloride and Fp. A large-scale application of photochemistry is photoresist technology, used in the production of microelectronic components. Vision is initiated by a photochemical reaction of rhodopsin.