Tin Catalysts

ViaCat dibutyltin and monobutyltin compounds act as esterification catalysts for making organic esters and polyesters. Examples of simple organic esters are plasticizers, lubricants, and heat-transfer fluids. Polyesters made with organotin compounds serve as binders for industrial coatings. When modified with fatty acids, they work as binders for air-drying coatings used in decorative and protective applications.

Dibutyltin compounds also catalyze transesterification and polycondensation of dimethyl terephthalate into polyethylene terephthalate or in making high molecular weight copolyester elastomers. These materials are used in packaging and engineering plastics. ViaCat organotin compounds require temperatures above 200°C for esterification reactions, higher than those with strong acid catalysts like p-toluenesulfonic acid.

However, several advantages justify using organotin catalysts. They minimize side reactions, resulting in better color and odor properties for the end products, with fewer by-products. There is no need to refine to remove catalyst residues, and equipment corrosion is eliminated. Typical tin catalyst levels are 0.05–0.3 wt % based on total reactants.