Дийодтрифенилфосфоран

Substance identification

Diiodotriphenylphosphorane is a complex of triphenylphosphine with molecular iodine, triphenylphosphonium diiodide. English name Diiodotriphenylphosphorane, formula C18H15I2P, section “Phosphines”. Synonyms: Phosphoran, diiodotriphenyl-; Triphenylphosphine diiodide. The supplier card contains a numeric identifier 1642315, which does not correspond to the standard CAS number format (a different number appears in the literature for this substance, probably an internal database code).

Basic Attributes

• Formula: C18H15I2P
• Molecular weight: 516.09; exact weight 516.09
• DSSTox ID: DTXSID70213802
• PSA: 0; XLogP3: 5.2162

Physico-chemical characteristics

• Appearance: yellow to orange powder
• Melting point: 171–172 °C
• Storage conditions: 2–8 °C

Substance class and application

Diiodotriphenylphosphorane is a product of the addition of molecular iodine to triphenylphosphine, an analogue of the more well-known bromide reagent (Appel's reagent) with iodine instead of bromine. The phosphorus atom in the complex exhibits a high affinity for oxygen, which makes the compound an effective reagent for the conversion of alcohols, thiols and phenols into the corresponding iodoalkanes through an intermediate alkoxyphosphonium compound - triphenylphosphine oxide, while acting as the thermodynamic driving force of the reaction. The reagent is used for the preparation of iodoalkanes from a wide range of alcohols under mild conditions, the synthesis of β-iodo-α,β-unsaturated ketones from cyclic β-diketones in the presence of triethylamine, the preparation of alkyl nitrates from alcohols, the Beckmann rearrangement of cycloalkanone oximes to lactams, as well as for the preparation of esters of aromatic and aliphatic carboxylic acids in the presence of N,N-dimethylaminopyridine. Compared to the more common bromide analogue, the iodide salt provides higher nucleophilicity of the released halide ion, which accelerates the substitution reaction at the primary and secondary carbon centers.

Safety Information

• Hazard category: 8
• Transport code: UN 2923
• WGK Germany: 3
• Hazard class code: 34-42/43-62
• Safety instructions: 26-36/37/39-45
• RTECS number: TB6100000
• Label: C
• Hazard statements: H314, H317, H334, H361
• Precautions: P261, P280, P305+P351+P338, P310

Storage and transportation

Store at 2–8 °C, in an airtight container, protected from moisture and light - phosphoranes of this type are sensitive to hydrolysis with the release of hydrogen iodide. Transport under UN code 2923, hazard category 8 (corrosive substances). Wear gloves and safety glasses; the reagent causes severe skin burns and eye damage, irritates the respiratory tract and may cause allergic reactions if inhaled. The powder is hygroscopic and gradually decomposes in the light, so the container should be immediately and tightly closed after collecting the reagent.