Inorganic and organo- tin compounds have found industrial use as catalysts in a very wide range of applications, from heterogeneous oxidation catalysts based on tin(IV) oxide (as employed, for example, in commercial gas sensor devices) to homogeneous catalysts for industrial organic and polymeric reactions.
Although many of these applications now represent mature markets, growth is evident in certain areas and, as a generic group, catalysts (sometimes referred to as 'process additives') represent the second largest application for tin chemicals after PVC stabilisers.
Manufacture of polyurethane (PU) foam is by far the most important catalytic use in terms of tin tonnage. Tin(II) 2-ethylhexanoate (also commonly referred to as 'stannous octoate') is the most important tin chemical used in PU production, although several organotin compounds, including dibutyltin diacetate and dibutyltin dilaurate, have also featured over the years. Although traditionally mainly used in flexible foam production, recent demand for rigid insulation foams in 'green' buildings has greatly increased usage in this sector and it is believed that this application will be one of the most likely growth areas for tin chemicals generally.
Apart from the well-established uses of tin catalysts in polyurethanes, RTV silicones and esterification reactions, new developments have included their use in synthetic vitamin E production, and potential uses in synthetic crude oil generation from oil sand bitumen and in the manufacture of certain novel polymeric materials. Although these are interesting developments, it is expected that tin tonnage in such applications is likely to be limited, at least in the short term.