Organotin Catalyst Composition

A large variety of organotin compounds are commercially available and registered in the toxic inventories of many countries. i Most of the catalysts used in the reaction of isocyanates are based on dimethyltin. 

---

Complexes of organotin with amidines have been found to be excellent catalysts for the preparation of polyurethane foams, which do not have the disadvantage of any amine odor and, in addition, delayed onset of the isocyanate-hydroxyl reaction An example of a mercapto-delayed organotin catalyst is 2,2,4,4-tetrakis(alkyl)- l,3,2,4-dithia-stannetane.55 Amine salts of amino acids, tertiary amino acids, and tertiary amino acid-nitrile compositions, have been found to be effective as delayed action catalysts for polyurethane synthesis. They are particularly effective when used in combination with an organometallic compound, such as an organotin. ... 

The first section, Chemical Reactions on Polymers, deals with aspects of chemical reactions occurring on polymers—aspects relating to polymer size, shape, and composition are described in detail. One of the timely fields of applications comprises the use of modified polymers as catalysts (such as the immobilization of centers for homogeneous catalysis). This topic is considered in detail in Chapters 2, 3, 8, 9, and 11 and dealt with to a lesser extent in other chapters. The use of models and neighboring group effect(s) is described in detail. The modification of polymers for chemical and physical change is also described in detail in Chapters 2 (polystyrene) 4 (polyvinyl chloride) 5 (polyacrylic acid, polyvinyl alcohol, polyethyleneimine, and polyacrylamide) 6 (polyimides) 7 (polyvinyl alcohol) 8 (polystyrene sulfonate and polyvinylphosphonate) 10 (polyacrylamide) and 12 (organotin carboxylates). 

Table 6.11 Composition, activity, selectivity and enantioselectivity in the hydrogenation of acetophenone over different Pt and Rh-based catalysts promoted with different chiral organotin compounds (PE = 1-phenylethanol ...

---