Dibutyltin Oxide Properties&Applications

Dibutyltin Oxide Properties&Applications

CAS No.: 818-08-6

Molecular Formula: C8H18OSn

Molecular Weight: 248.91

I. Physicochemical Properties

1. Physical Properties

Appearance: White crystalline powder or colorless to slightly yellow crystals at room temperature

Melting Point: 108-112℃

Boiling Point: Decomposes above 200℃, no definite boiling point

Density: Approximately 1.45 g/cm³ (25℃)

Solubility: Insoluble in water, soluble in most organic solvents such as benzene, toluene, ethanol, and ether, and also soluble in dilute acids and strong alkali solutions.

Stability: Stable in a dry environment at room temperature, slowly hydrolyzes in the presence of water to form dibutyltin hydroxide, and easily decomposes at high temperatures to produce toxic tin compounds and hydrocarbon gases.

2. Chemical Properties

Reactivity: Reacts with organic acids and anhydrides to form the corresponding dibutyltin carboxylate salts; can participate in transesterification and condensation reactions, acting as a catalyst.

Coordination Properties: The tin atom in the molecule has empty orbitals and can form coordination compounds with compounds containing lone pairs of electrons (such as amines and ethers).

Thermal Decomposition: Gradually decomposes at temperatures above 200℃, releasing butyl radicals and tin oxide, and produces toxic fumes when burned.

II. Industrial Applications

Dibutyltin oxide is an important organotin intermediate and functional additive, widely used in various fine chemical fields, specifically as follows:

Polyurethane Synthesis Catalyst

As an efficient gel catalyst, it can catalyze the reaction of isocyanates with polyols, used in the production of polyurethane soft foams, rigid foams, elastomers, and coatings. Compared with other tin catalysts, its catalytic efficiency is moderate, effectively controlling the reaction rate and improving the mechanical properties and weather resistance of the products. Silicone Resin Curing Accelerator

Used in the curing system of condensation-type silicone resins and silicone rubber, it accelerates the condensation reaction between silanol and alkoxy groups, shortens curing time, and improves the hardness, adhesion, and high-temperature resistance of the cured product. It is suitable for the production of high-temperature resistant silicone coatings and sealants.

PVC Heat Stabilizer

It can be used as an auxiliary heat stabilizer in PVC processing, synergistically working with main stabilizers (such as calcium-zinc stabilizers and organotin stabilizers) to inhibit the degradation of PVC during high-temperature processing, improving the heat resistance and anti-yellowing properties of the product. It is commonly used in the production of PVC pipes, profiles, and films.

Transesterification and Condensation Reaction Catalyst

In organic synthesis, it catalyzes the transesterification reaction between esters and alcohols, as well as the polycondensation reaction of polymers such as polyesters and polycarbonates. It features high catalytic activity and good selectivity, improving product yield and purity.

Antifungal and Antibacterial Agent

It possesses certain antifungal and antibacterial activity and can be used in products such as coatings, wood preservatives, and leather treatment agents to inhibit the growth and reproduction of mold and bacteria, extending the service life of materials.

Organotin Compound Synthesis Intermediate

As a raw material for the preparation of other functional organotin compounds (such as dibutyltin carboxylate and dibutyltin thiolates), it is widely used in the synthesis of products in fields such as catalysts, stabilizers, and pesticides.