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Upon heating, Δ9-tetrahydrocannabinolic acid decarboxylates to give the psychoactive compound Δ9-Tetrahydrocannabinol. [13] When cannabis is heated in vacuum, the decarboxylation of tetrahydrocannabinolic acid (THCA) appears to follow first order kinetics. The log fraction of THCA present decreases steadily over time, and the rate of decrease ...
The dry distillation of calcium acetate to give acetone was reported by Charles Friedel in 1858 [3] and until World War I ketonization was the premier commercial method for its production. [4] Ketonic decarboxylation of propanoic acid over a manganese(II) oxide catalyst in a tube furnace affords 3-pentanone. [5]
[6] [5] These reactions proceed via the intermediacy of metal acyl hydrides. An example of this is the Tsuji–Wilkinson decarbonylation reaction using Wilkinson's catalyst. (Strictly speaking, the noncatalytic version of this reaction results in the formation of a rhodium carbonyl complex rather than free carbon monoxide.)
The reaction mechanism involves a two-stage radical process: electrochemical decarboxylation gives a radical intermediate, which combine to form a covalent bond. [2] As an example, electrolysis of acetic acid yields ethane and carbon dioxide: CH 3 COOH → CH 3 COO − → CH 3 COO· → CH 3 · + CO 2 2CH 3 · → CH 3 CH 3
Decarboxylation reaction reactions are typically quite thermodynamically favorable due to the entropic contribution of cleaving a single molecule into two, one of which is a gas. Conversely, we can expect carboxylation reactions to be energy-requiring, and we should not be surprised to learn ATP hydrolysis is coupled to carboxylation.
The inverse procedure is the Arndt–Eistert synthesis, where an acid is converted into acyl halide, which is then reacted with diazomethane to give one additional methylene in the aliphatic chain. Many acids undergo oxidative decarboxylation. Enzymes that catalyze these reactions are known as carboxylases (EC 6.4.1) and decarboxylases (EC 4.1.1).
Studies of decarboxylation over nickel and palladium-based catalysts were first reported by Wilhelm Maier et al., in 1982, [6] when they achieved the deoxygenation of several carboxylic acids via decarboxylation under a hydrogen atmosphere. This included the conversion of aliphatic acids (such as heptanoic and octanoic acids) to alkanes (namely ...
An example of the E1cB reaction mechanism in the degradation of a hemiketal under basic conditions. The E1cB elimination reaction is a type of elimination reaction which occurs under basic conditions, where the hydrogen to be removed is relatively acidic, while the leaving group (such as -OH or -OR) is a relatively poor one.