Benzoyl Peroxide
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Dibutyltin and
monobutyltin compounds are used as esterification
catalysts for the manufacture of organic esters and/or
polyesters. Examples of simple organic esters include plasticizers,
lubricants, and heat-transfer fluids. Polyesters produced by the use of
organotin compounds are used as binders for formulating coatings for
industrial use, or when modified with fatty acids they are used as
binders for air drying coatings for decorative and protective
applications. Dibutyltin compounds are also used as catalysts for
transesterification and polycondensation of dimethyl terephthalate into
polyethylene terephthalate or manufacturing of high molecular weight
copolyester elastomers. The use of these materials is either in
packaging applications or engineering plastics.
The esterification
reactions catalyzed by organotin compounds require temperatures above
200°C, which is much higher than those involving strong acid
catalysts, such as p-toluenesulfonic acid. Though, number of advantages
justifies the use of organotin catalysts. The side reactions are
minimized so the end products have better color and odor properties
because fewer by-products are formed, there is no need for refining to
remove the catalyst residues and the equipment corrosion is eliminated.
Usual levels of tin catalysts are 0.05–0.3 wt % based on the
total reactants charged. |
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