Tppts
Encyclopedia
3,3′,3′′-Phosphinidynetris(benzenesulfonic acid) trisodium salt (abbreviated TPPTS when isolated and tppts as a ligand
), 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.
of triphenylphosphine
. The sulfonation occurs at one meta-position of each of the three phenyl rings. The sulfonation agent is oleum
, a solution of sulfur trioxide in sulfuric acid. The resulting trisulfonic acid is then treated with triisooctylamine and sodium hydroxide. Immediately upon dissolving in the reaction medium, the phosphine is protonated. It is the phosphonium salt that undergoes the sulfonation:
As a Lewis base, tppts is stronger than triphenylphosphine.
of propene by Ruhrchemie. Hydroformylation, also known as oxo synthesis, is the reaction of an alkene
with carbon monoxide
and hydrogen
. Traditionally, hydroformylation is catalyzed by rhodium and cobalt complexes in nonaqueous solution.
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...
), 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
Phosphine
Phosphine is the compound with the chemical formula PH3. It is a colorless, flammable, toxic gas. Pure phosphine is odourless, but technical grade samples have a highly unpleasant odor like garlic or rotting fish, due to the presence of substituted phosphine and diphosphine...
. Its complex with rhodium
Rhodium
Rhodium is a chemical element that is a rare, silvery-white, hard and chemically inert transition metal and a member of the platinum group. It has the chemical symbol Rh and atomic number 45. It is composed of only one isotope, 103Rh. Naturally occurring rhodium is found as the free metal, alloyed...
is used in the industrial production of butyraldehyde.
Synthesis
Tppts is synthesized by sulfonatingSulfonic acid
Sulfonic acid usually refers to a member of the class of organosulfur compounds with the general formula RS2–OH, where R is an alkyl or aryl. The formal part of acid, HS2–OH, are formally derivatives of the "parent" inorganic compound with the formula HSO2.-Preparation:Sulfonic acid is...
of triphenylphosphine
Triphenylphosphine
Triphenylphosphine is a common organophosphorus compound with the formula P3 - often abbreviated to PPh3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists as relatively air stable, colorless crystals at room temperature...
. The sulfonation occurs at one meta-position of each of the three phenyl rings. The sulfonation agent is oleum
Oleum
Oleum , or fuming sulfuric acid refers to a solution of various compositions of sulfur trioxide in sulfuric acid or sometimes more specifically to disulfuric acid ....
, a solution of sulfur trioxide in sulfuric acid. The resulting trisulfonic acid is then treated with triisooctylamine and sodium hydroxide. Immediately upon dissolving in the reaction medium, the phosphine is protonated. It is the phosphonium salt that undergoes the sulfonation:
- HP(C6H5)3+ + 3 SO3 → [HP(C6H4SO3H)3]+
- [HP(C6H4SO3H)3]+ + 4 N(C8H17)3 → [HN(C8H17)3]3[P(C6H4SO3)3] + [HN(C8H17)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.
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 hydroformylationHydroformylation
Hydroformylation, also known as oxo synthesis or oxo process, is an important industrial process for the production of aldehydes from alkenes. This chemical reaction entails the addition of a formyl group and a hydrogen atom to a carbon-carbon double bond...
of propene by Ruhrchemie. Hydroformylation, also known as oxo synthesis, is the reaction of an alkene
Alkene
In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...
with carbon monoxide
Carbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
and hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
. Traditionally, hydroformylation is catalyzed by rhodium and cobalt complexes in nonaqueous solution.