Carbon Monoxide - Organic and Main Group Chemistry

Organic and Main Group Chemistry

In the presence of strong acids and water, carbon monoxide reacts with alkenes to form carboxylic acids in a process known as the Koch–Haaf reaction. In the Gattermann-Koch reaction, arenes are converted to benzaldehyde derivatives in the presence of AlCl₃ and HCl. Organolithium compounds (e.g. butyl lithium) react with carbon monoxide, but these reactions have little scientific use.

Although CO reacts with carbocations and carbanions, it is relatively nonreactive toward organic compounds without the intervention of metal catalysts.

With main group reagents, CO undergoes several noteworthy reactions. Chlorination of CO is the industrial route to the important compound phosgene. With borane CO forms an adduct, H₃BCO, which is isoelectronic with the acylium cation +. CO reacts with sodium to give products resulting from C-C coupling such as sodium acetylenediolate 2Na+·C₂O2−
2. It reacts with molten potassium to give a mixture of an organometallic compound, potassium acetylenediolate 2K+·C₂O2−
2, potassium benzenehexolate 6K+ C₆O6−
6, and potassium rhodizonate 2K+·C₆O2−
6.

The compounds cyclohexanehexone or triquinoyl (C₆O₆) and cyclopentanepentone or leuconic acid (C₅O₅), which so far have been obtained only in trace amounts, can be regarded as polymers of carbon monoxide.

At pressures of over 5 gigapascals, carbon monoxide disproportionates into carbon dioxide (CO₂) and a solid polymer of carbon and oxygen, in 3:2 atomic ratio.