Trihexylphosphine

Trihexylphosphine (THP) (CAS 4168-73-4) is a high-molecular-weight tertiary alkylphosphine valued in specialized synthetic and industrial applications. It is a colorless to pale yellow, slightly viscous liquid with the characteristic strong, pungent, garlic-like odor common to phosphines. THP possesses a unique combination of high electron richness (due to the alkyl groups) and enhanced lipophilicity (due to the long hexyl chains). This lipophilic character makes THP an excellent phase-transfer catalyst and a superb ligand for non-polar solvent systems, often preferred over shorter-chain phosphines like tributylphosphine due to its lower volatility and higher thermal stability.

Basic Information of THP

CAS No.:	4168-73-4
EC No.:	224-025-3
Linear Formula:	C18H39P
Molecular Weight:	286.48
Appearance:	Colorless to pale yellow, slightly viscous liquid
Odor:	Strong, highly pungent, garlic-like
Melting Point:	20℃
Boiling Point:	227 °C / 50mmHg
Density:	0,83 g/cm3
Solubility:	Insoluble in water; highly soluble in organic solvents, oils, and non-polar media.
RIDADR:	UN 3254 4.2 PG I
Chemical Structure:

Application Overview

Trihexylphosphine's high lipophilicity and low volatility distinguish it, making it crucial for processes requiring specialized solubility or high temperatures:

• Phase-Transfer Catalysis (PTC): The long alkyl chains enable THP to efficiently mediate reactions between aqueous and organic phases, acting as an effective phase-transfer catalyst or co-catalyst in two-phase systems, where it solubilizes metal complexes in non-polar media.

• High-Temperature Catalysis: Due to its high boiling point and thermal stability, THP is the preferred phosphine ligand for demanding metal-catalyzed cross-coupling reactions (e.g., Suzuki, Heck) that must be run at elevated temperatures where shorter-chain phosphines would boil off or degrade.

• Nanomaterials Synthesis: It is frequently used as a capping ligand or solvent in the high-temperature synthesis of quantum dots and metal nanoparticles. The long alkyl chains facilitate control over particle size and surface passivation.

• Pharmaceutical Intermediates: Employed in the synthesis of complex organic molecules where its strong reducing power (e.g., in Mitsunobu or Staudinger-type reactions) and excellent solvent compatibility are leveraged.

• Guaranteed Low Phosphine Oxide (THPO): We strictly monitor and guarantee an oxidation product (THPO) content below 0.1%. This ensures the maximum available concentration of the active phosphine ligand, which is paramount for catalytic efficiency and minimizing reagent waste.

• Customized Low-Volatility Packaging: Given its sensitivity to oxygen and its high boiling point, we ship THP in precision-cleaned, inert gas-blanketed containers with seals rated for high-temperature use. This preserves the reagent's purity and maximizes its shelf life in challenging industrial environments.

Hazards Classification

• GHS Classification: Flammable Liquid (GHS02), Acute Toxicity Oral (GHS06), Skin Irritation (GHS07), Eye Irritation (GHS07)

• Hazard Statements: Flammable liquid and vapor; Harmful if swallowed; Causes skin irritation; Causes serious eye irritation.

• UN Number: UN 3254

• Hazard Class: 4.2 (Pyrophoric liquids)

• Packing Group: I