Triisobutyl Phosphate, Tri-isobutyl Phosphate, TIBP, 126-71-6

Triisobutyl Phosphate, Tri-isobutyl Phosphate, TIBP, 126-71-6

Chemical Identity

• Name: Tri-isobutyl phosphate (TIBP)

• CAS Number: 126-71-6

• Molecular Formula: C12H27O4P

• Molar Mass: 266.31 g/mol

• Synonyms: Tris(2-methylpropyl) phosphate, Phosphoric acid triisobutyl ester

• InChIKey: HRKAMJBPFPHCSD-UHFFFAOYSA-N

Physical Properties

• Density: 0.965 g/mL at 20 °C

• Boiling Point: ~205 °C

• Melting Point: 150 °C

• Flash Point: 150 °C

• Auto-ignition Temperature: 430 °C (DIN 51794)

• Vapor Pressure: 0.002 hPa (20 °C)

• Water Solubility: 264 mg/L at 25 °C

• Refractive Index: n20/D 1.420

• Appearance: Transparent, colorless liquid

Uses

• Textile auxiliaries, dye auxiliaries, penetrants

• Defoamer and wetting agent

• Widely applied in inks, construction chemicals, oilfield additives

• Also used in plastics and polymer processing

Safety and Risk

• Classification: Xi – Irritant

• Risk Code: R43 – May cause sensitization by skin contact

• Safety Advice: S36/37 – Wear suitable protective clothing and gloves

• WGK (Germany): 1 (low hazard to water)

• Toxicity: LD50 oral (rabbit) > 5000 mg/kg; LD50 dermal (rabbit) > 5000 mg/kg

• Storage: Keep below 30 °C, in dry and ventilated conditions

• Hazards: Combustible under high heat or open flame; thermal decomposition releases toxic phosphorus oxides, CO, CO₂, and phosphane

Production (Simplified Process)

Isobutanol reacts with phosphorus oxychloride under controlled low temperature (<20 °C). After addition, the mixture is heated to 65–70 °C under reduced pressure for several hours. Excess alcohol and HCl are recovered by distillation. The crude product is purified by vacuum distillation, yielding >85% recovery and >99% purity.

In short: Tri-isobutyl phosphate is a versatile phosphate ester, mainly used as a defoamer and penetrant in textile, ink, construction, and oilfield applications. It is relatively low in acute toxicity but requires careful handling due to irritant properties and combustion risks.

Sectoral Suitability of Phosphate Esters (Blue Dot Scale)

• Scale meaning: 🔵 = Low suitability (1) 🔵🔵🔵 = Medium suitability (3) 🔵🔵🔵🔵🔵 = High suitability (5)

Abbreviations

• TIBP → Tri-isobutyl phosphate (Tri-izobutil fosfat)

• TBP → Tributyl phosphate (Tributil fosfat)

• TOP → Trioctyl phosphate (Trioctil fosfat)

• TEP → Triethyl phosphate (Trietil fosfat)

• TPP → Triphenyl phosphate (Trifenil fosfat)

• TEHP → Tri(2-ethylhexyl) phosphate (Tri(2-etilheksil) fosfat)

Key Takeaways

• TIBP is highly suitable for textile, ink, construction, and oilfield applications.

• TBP dominates in nuclear and metallurgy, also strong in plastics.

• TOP & TEHP are best for plastics and polymers, especially where thermal stability and flame retardancy are needed.

• TEP & TPP show medium suitability in construction and polymers, mainly as flame retardants or additives.