Dioctyltin Oxide

Esterification, Transesterification and Polycondensation Catalyst

Dioctyltin oxide is a tin-organic compound – an amorphous, white powder that appears almost crystalline. In organic solvents it is difficult to soluble, completely insoluble in water. It is usually abbreviated as DOTO.

Dioctyltin oxide is used as a stabilizer and as a widely applicable catalyst, especially for esterification reactions, transesterification reactions and condensation reactions. It is slightly less reactive than dibutyltin oxide, but is not subject to as many regulatory restrictions, which is why it is increasingly used. Of course, there are safety standards that must be respected. Areas of application and characteristics are largely equivalent, but with slightly different processing times.

NameDioctyltin Oxide
SynonymsDi-n-octyltin oxide
Dioctyl tin oxide
Dioctyl oxo stannane

Dioctyltin Oxide in Paints and Coatings

The suitability of dioctyltin oxide for catalysis in various paints and coatings, especially in the automotive industry, is of economic importance. It is used, for example, for cathodic electro-submersible coating of components that are mass-produced or have sophisticated geometries. During the process, the surface of the workpieces is coated with a wafer-thin primer that provides protection against corrosion or damage caused by physical influences. DOTO catalysts can also be used for everyday applications such as paints or oil paints.

Dioctyltin oxide is also used as a curing catalyst in polyurethane coatings, in silicone-based systems, in polyester and alkyd resins, where it supports high-temperature transesterification reactions that occur, for example, in the production of coating resins. The use of dioctyltin oxide is also possible for many floor coatings.

DOTO in Oleochemistry

Dioctyltin oxide catalysts in oleochemistry perform a similar task: the catalysis of transesterification reactions for surfactant esters, lubricant esters or fatty acid esters. Like dibutyltin oxide, DOTO can be used widely here.

For Binders

Binders, such as fatty acid esters, (see oleochemistry) can be produced with the help of DOTO as a transesterification catalyst. They support polymer formation for a wide range of end-uses made of alkyd resins, polycarbonates, silicones and polyurethanes, which, for example, are used to produce foam plastic molded parts that are particularly found where resistant materials are required. It connects polyester systems used in glass fiber reinforced plastics, for carbon or laminates. Insulating casting resins for electronic components are another example.

Dioctyltin oxide performs these tasks as well as dibutyltin oxide, but with slightly lower activity, which allows for longer processing times before the curing of the various plastic systems. Similarly, one benefits from a comparatively lower toxicity.

Other Applications

Like the DBTL, dioctyltin oxide is extremely versatile, not only because of its catalytic effect. It is also an intermediate of the chemical industry from which other chemicals are synthesized.

As a light stabilizer for polyvinyl chlorides (PVC), it helps to make plastic products even more durable: they do not become brittle and are more resistant to weathering.

Product Variants

Dioctyltin oxide is offered in two different variants: as powder and as wet powder.

BNT Product NameProdukt VariantShort Form
BNT-CAT 510Dioctyltin oxideDOTO
BNT-CAT 515Dioctyltin oxide wetDOTO wet

Transport and Storage

BNT-CAT 510 is shipped in fiber drums lined with PE inliners. Dry rooms should serve as a storage location. If the storage is carried out in sealed original packaging, a minimum shelf life of 6 months is given without compromising the quality.