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Decarboxylation is a chemical reaction that removes a carboxyl group and releases carbon dioxide (CO 2). Usually, decarboxylation refers to a reaction of carboxylic acids, removing a carbon atom from a carbon chain. The reverse process, which is the first chemical step in photosynthesis, is called carboxylation, the addition of CO 2 to a
Aromatization is a chemical reaction in which an aromatic system is formed from a single nonaromatic precursor. Typically aromatization is achieved by dehydrogenation of existing cyclic compounds, illustrated by the conversion of cyclohexane into benzene.
The mechanism involves two overlapping cycles, one using a copper halide and the other using palladium. The decarboxylation step occurs between the substituted benzoic acid and copper halide to form the intermediate aryl copper species. The palladium initially undergoes oxidative addition from the aryl halide to form a Pd(II) aryl complex.
Here decarbonylation accompanies the preparation of cyclopentadienyliron dicarbonyl dimer: 2 Fe(CO) 5 + C 10 H 12 → (η 5 −C 5 H 5) 2 Fe 2 (CO) 4 + 6 CO + H 2. Decarbonylation can be induced photochemically as well as using reagents such as trimethylamine N-oxide: Me 3 NO + L + Fe(CO) 5 → Me 3 N + CO 2 + LFe(CO) 4
The above mechanism is consistent with all available experimental evidence. [3] The equilibrium between species 1 and 2 is supported by 18 O Isotopic labeling experiments. In deuterated water , carbonyl oxygen exchange occurs much faster than the rearrangement, indicating that the first equilibrium is not the rate-determining step.
Another example is the synthesis of 2,7-dimethyl-2,7-dinitrooctane from 4-methyl-4-nitrovaleric acid: [3] The Kolbe reaction has also been occasionally used in cross-coupling reactions . In 2022, it was discovered that the Kolbe electrolysis is enhanced if an alternating square wave current is used instead of a direct current .
Dibenzyl ketone is prepared by ketonic decarboxylation of phenylacetic acid. One method is where phenylacetic acid is reacted with acetic anhydride and anhydrous potassium acetate and refluxed for two hours at 140−150 °C. The mixture is distilled slowly so that the distillate is mostly acetic acid. Carbon dioxide is released in this reaction ...
Thus, synthesis of benzaldehyde through the Friedel–Crafts pathway requires that formyl chloride be synthesized in situ. This is accomplished by the Gattermann-Koch reaction, accomplished by treating benzene with carbon monoxide and hydrogen chloride under high pressure, catalyzed by a mixture of aluminium chloride and cuprous chloride ...