Applications
What is the importance of efficient reactions?
Chemical reaction
Reactions on surfaces Reuben Leon Kahn Anaplerotic reactions Diethyl azodicarboxylate Photooxygenation
Reactions_on_surfaces-Abstract Reuben_Leon_Kahn-Abstract Anaplerotic_reactions-Abstract Diethyl_azodicarboxylate-Other_reactions Photooxygenation-Types_of_Photooxygenation
Reactions on surfaces are reactions in which at least one of the steps of the reaction mechanism is the adsorption of one or more reactants. The mechanisms for these reactions, and the rate equations are of extreme importance for heterogeneous catalysis. 
Reuben Leon Kahn (July 26, 1887 in Kovno, Lithuania – July 22, 1979 in Miami) was an American immunologist. He is best known for his investigations of blood reactions, like the Kahn test, an efficient test for syphilis. 
Anaplerotic reactions (from the Greek ἀνά= 'up' and πληρόω= 'to fill') are those that form intermediates of a metabolic pathway. Examples of such are found in the Tricarboxylic acid (TCA) Cycle (also called the Krebs or citric acid cycle). In normal function of this cycle for respiration, concentrations of TCA intermediates remain constant; however, many biosynthetic reactions also use these molecules as a substrate. Anaplerosis is the act of replenishing TCA cycle intermediates that have been extracted for biosynthesis (in what are called cataplerotic reactions). The TCA Cycle is a hub of metabolism, with central importance in both energy production and biosynthesis. Therefore, it is crucial for the cell to regulate concentrations of TCA Cycle metabolites in the mitochondria. Anaplerotic flux must balance cataplerotic flux in order to retain homeostasis of cellular metabolism. 
DEAD is an efficient component in Diels-Alder reactions and in click chemistry, for example the synthesis of bicyclo[2.1.0]pentane, which originates from Otto Diels. It has also been used to generate aza-Baylis-Hillman adducts with acrylates.DEAD can be used for synthesis of heterocyclic compounds. Thus, pyrazoline derivatives convert by condensation to α,β-unsaturated ketones:Another application is the use of DEAD as enophile in Ene reactions: 
The three types of photooxygenation reactions are distinguished by the mechanisms that they proceed through, as they are capable of yielding different or similar products depending on environmental conditions. Type I and II reactions proceed through neutral intermediates, while type III reactions proceed through charged species. The absence or presence of 1O2 is what distinguishes type I and type II reactions, respectively. 