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CYPHOS® IL – Phosphonium Ionic Liquid Phase Transfer Catalysts (PTC)

Pushing the boundaries of performance

Phase transfer catalysts are employed in many commercial applications, such as polyester production and alkylation reactions. A Phase Transfer Catalyst (PTC) facilitates the migration of a reactant from one phase into another phase where reaction occurs. Advantages of PTC include faster reactions, no need for expensive (or harmful) chemicals and less waste. Via its CYPHOS® IL range, Solvay offers a wide variety of phosphonium ionic liquids to facilitate PTC, such as CYPHOS® IL 101 (Strem Catalog # 15-6382), CYPHOS® IL 253 (Strem Catalog # 15-7575) and CYPHOS® IL 356 (Strem Catalog # 15-7590).


CYPHOS® IL range available from Solvay (commercial scale) &
 Strem (commercial sampling and research quantities)

Traditionally, the area of PTC has been dominated by the use of ammonium salts and aryl phosphonium salts. However, tetraalkylphosphonium salts offer higher thermal stability and superior chemical stability than both of these chemical categories. The tetraalkylphosphonium systems are also highly tunable to accommodate a range of solubility and acidity needs.

Phosphonium salts such as CYPHOS® IL 101 (Strem Catalog # 15-6382), CYPHOS® IL 120W (Strem Catalog # 15-7570) and CYPHOS® IL 356 (Strem Catalog # 15-7590) can be tailored by exchange of the anion to modify and improve reactivity. Simple reactions such as the addition of aluminum trichloride increase the Lewis acidity of the system. 


These PTCs can then be employed in industrial processes such as the alkylation of paraffins with olefins to produce octanes (used in fuels) (1).


Current processes for alkylation chemistry employ hydrofluoric and hydrosulfuric acid. The use of a PTC represents a significant safety improvement in production.

One of the most famous applications of PTC is the OMEGA process (2-4),  developed by Shell, this catalytic system produces monoethlyene glycol (MEG). The advantages of this process include high conversion efficiency (99% vs. 90% associated with traditional methods) and the use of less steam during production.



For phase transfer catalysis, phosphonium ionic liquids offer excellent performance benefits and are recoverable and reusable.

CYPHOS® ILs are readily available, high-purity ionic liquids.   With high thermal stability, large liquid ranges, ultra-low vapor pressure, nonflammability and tunability, these salts can be employed in many PTC applications. To learn more about other ligands for catalysis, please refer to the Solvay offering at Strem.


  1.    US Patent 20130345482, June 26, 2012.
  2.    US Patent 7728164, June 1, 2010.
  3.    US Patent 8735607, May 27, 2014.
  4.    WO Patent 2007104730, September 20, 2007.


Featured Products:

15-6382 Trihexyl(tetradecyl)phosphonium chloride, min. 95% CYPHOS IL 101
CAS Number: 258864-54-9

15-7575 Tributyl(octyl)phosphonium chloride, min. 93%, CYPHOS® IL 253
CAS Number: 56315-19-6

15-7590 Trihexyl(octyl)phosphonium chloride, min. 95%, CYPHOS® IL 356
CAS Number: 850134-85-9

97-1579 Tetrabutyphosphonium bromide (75% in water), CYPHOS® 442
CAS Number: 3115-68-2

15-7570 Tributylmethylphosphoniump-toluenesulfonate, min. 95% (45-55% in water), CYPHOS® IL 120W
CAS Number: 55767-12-9

15-7590 Trihexyl(octyl)phosphonium chloride, min. 95%, CYPHOS® IL 356
CAS Number: 850134-85-9

Related Products:

CYTOP Products

Phosphorus Ligands and Compounds Booklet

All products sold in collaboration with Solvay

Ionic Liquids



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