Hexamethylphosphoramide

Hexamethylphosphoramide, often abbreviated as HMPA, is a phosphoramide compound with the formula (CH3)2NPO(NCH3)2. This colorless liquid is a useful polar aprotic solvent and additive in organic synthesis.

Structure and Bonding

Hexamethylphosphoramide, or HMPA, is a phosphoramide (a compound containing phosphorus, nitrogen and oxygen) with a tetrahedral phosphorus center. The phosphorus atom is bonded to three nitrogen atoms and one oxygen atom. The nitrogen atoms are each bonded to two methyl groups, giving the molecule its hexamethyl name.

Properties

HMPA is a colorless, hygroscopic liquid at room temperature. It has a high boiling point (232 °C) due to its polar nature and the ability to form hydrogen bonds. It is miscible with water and most organic solvents.

Uses

HMPA is primarily used as a solvent in organic synthesis. Its strong donor properties enhance the reactivity of many organic compounds, making it a valuable tool in the synthesis of pharmaceuticals and fine chemicals. It is also used in the production of high performance polymers.

Safety

HMPA is classified as a carcinogen and has been linked to bladder cancer in laboratory animals. It is also a skin and eye irritant. Proper safety precautions should be taken when handling this compound.

See also

• Phosphoramide
• Polar aprotic solvent
• Organic synthesis