Tetrabutyltin

Tetrabutyltin

Sample of SnBu4
Names
IUPAC names Tetra-n-butylstannane Tetra-n-butyltin
Other names SnBu4 TBT Tetrabutyl tin Tetrabutylstannane
Properties
Chemical formula	C16H36Sn (C4H9)4Sn SnBu4
Molar mass	347.147 g/mol
Appearance	Colorless liquid
Odor	Faint, distinctive
Density	1.054 g/cm3 (20 °C)
Melting point	−97 °C (−143 °F; 176 K)
Boiling point	245 °C (473 °F; 518 K)
Solubility in water	0.0008 g/100 ml
Solubility	Miscible with benzene, diethyl ether, THF
Vapor pressure	0.0048 mm Hg at 20 °C
Hazards
Safety data sheet	Sigma-Aldrich
Flash point	107 °C (225 °F; 380 K)
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	2,500 mg/kg (rat, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Tetrabutyltin is the organotin compound with the formula (C₄H₉)₄Sn or SnBu₄. It is one of the few stable liquid organometallic compounds that can be handled (relative) safely without requiring special conditions.

Properties

Chemical

By the redistribution reaction with tin(IV) chloride, SnBu₄ forms tributyltin chloride and dibutyltin chloride.

TBT reacts easily with halogens, hydrogen halides and most acids.

Physical

Tetrabutyltin is a colorless liquid, with a density similar to that of water. It is not soluble in water, but it's miscible with many organic solvents. Tetrabutyltin has a boiling point of 245 °C at standard conditions, which can be lowered to 127-145 °C by lowering the air pressure to 10 mmHg. This is preferred, as the compound decomposes close to 265 °C, which is very close to its boiling point.

Tetrabutyltin has a faint distinctive smell, difficult to describe.

Availability

Can be bought from chemical suppliers.

Preparation

Tetrabutyltin can be prepared by reaction of tin(IV) chloride with the Grignard reagent of n-butyl chloride.

SnCl₄ + 4 BuMgCl → SnBu₄ + 4 MgCl₂

Tetrabutyltin can be prepared by a Wurtz reaction from tin(IV) chloride, n-butyl chloride and sodium metal. The yield of this reaction is 65%. To limit the formation of tin metal, due to the sodium reduction of stannic chloride, dibutyltin dichloride may be used instead, if available.

The classical route of obtaining tetraalkyl organometallic compounds, in this case between sodium-tin alloy and n-butyl chloride has not been studied.

Projects

• Make stabilizers for PVC
• Compound collecting

Handling

Safety

Tetrabutyltin is not very volatile, so its vapors aren't very dangerous. As a liquid it shows moderate toxicity, although consumption of this compound has been described as being "fatal". The LD50 for this compound has been given as 2,500 mg/kg for rat.

Storage

In glass vials, away from light and air.

Disposal

Can be neutralized with an acid to tin salts and butyl compounds, which can be separated and further neutralized.