Tppts

Chembox new
ImageFile = TPPTS.png Name = 3,3′,3′′-Phosphinidynetris(benzenesulfonic acid) trisodium salt
OtherNames = Tris(3-sulfophenyl)phosphine trisodium salt
Section1 = Chembox Identifiers
CASNo = 63995-70-0
Section2 = Chembox Properties
Formula = P(C₆H₄SO₃Na)₃
MolarMass = 568.42 g/mol
Appearance = White microcrystalline solid
Solubility = Soluble in water
Section3 = Chembox Hazards
RPhrases = R36/37/38
SPhrases = S26

3,3′,3′′-Phosphinidynetris(benzenesulfonic acid) trisodium salt (tppts), is an organic compound that is also known as sodium triphenylphosphine trisulfonate. The compound has the formula P(C₆H₄SO₃Na)₃. This white microcrystalline solid is an unusual example of a water-soluble phosphine. Its complex with rhodium is used in the industrial production of butyraldehyde. [cite journal | author = Herrmann, W.A.; Kohlpaintner, C.W. | year = 1998 | title = Synthesis of Water-Soluble Phosphines and Their Transition Metal Complexes | journal = Inorganic Syntheses | volume = 32 | pages = 8 - 25 | ISBN = 0-471-24921-1]

ynthesis

Tppts is synthesized by sulfonating the three phenyl groups of triphenylphosphine. The sulfonation occurs at the meta-positions of the phenyl rings. The sulfonation agent is oleum, a solution of sulfur trioxide in a concentrated sulfuric acid. The resulting trisulfonic acid is then treated with triisooctylamine and sodium hydroxide:

:P(C₆H₅)₃ + 3 SO₃ → P(C₆H₄SO₃H)₃:P(C₆H₄SO₃H)₃ + 3 N(C₈H₁₇)₃ → [HN(C₈H₁₇)₃] ₃ [P(C₆H₄SO₃)₃] : [HN(C₈H₁₇)₃] ₃ [P(C₆H₄SO₃)₃] + 3 NaOH → P(C₆H₄SO₃Na)₃ + 3 N(C₈H₁₇)₃ + 3 H₂O

As a lewis base, tppts is stronger than triphenylphosphine, which is why when tppts is allowed to react with sulfonic acid (highly acidic and fully miscible in water) reactions are favorable for hydroformylation.

Uses in hydroformylation

Complexes of tppts are very soluble in water, which is the basis of its industrial application. Tppts-based rhodium catalysts were introduced in 1984 for a two-phase hydroformylation of propene by Ruhrchemie. Hydroformylation, also known as oxo synthesis, is the reaction of carbon monooxide and hydrogen with an alkene and is typically catalyzed by rhodium and cobalt. [cite journal | author = Cornils, B.; Fischer, R.W.; Kohlpaintner, C. | year = 2000 | title = Butanals | journal = Ullmann’s Encyclopedia of Industrial Chemistry | doi: = 10.1002/14356007.a04_447] Tppts is utilized in the conversion of propylene of butyraldehyde. Rhodium complexes of tppts are water-soluble, and this property is key to the separation of butyraldehyde from the catalyst.

References