Organotin amines reactions

Fio. 5. Some reactions of the tin-nitrogen bond in organotin amines. 

Some syntheses of the organotin amines are outlined in equation form below, and some of the extensive reactions o of this class are illustrated in Fig. 5. It is obvious from Fig. 5 that the organotin amines are available as powerful synthetic intermediates for a number of important reactions i. S2, 53. 

The structures of organotin amines and alkoxides are tetrahedral, as expected. Organotin alkoxides and phenoxides are prepared from reaction with alcohols and alkali metal alkoxides or phenoxides with the organotin halide. Most of the published reactions occur in the liquid phase. For instance, the dimethoxide is formed from reaction of dibutyltin dichloride in methanol at 0°C in 98% yield. ... 

The reaction is of practical importance in the vulcanization of siUcone mbbers (see Rubber compounding). Linear hydroxy-terrninated polydimethyl siloxanes are conveniently cross-linked by reaction with methyldiethoxysilane or triethoxysilane [998-30-1]. Catalysts are amines, carboxyflc acid salts of divalent metals such as Zn, Sn, Pb, Fe, Ba, and Ca, and organotin compounds. Hydroxy-terrninated polysiloxanes react with Si—H-containing polysiloxanes to... 

In the single-stage production of polyurethanes, di-, tri-, or polyisocyanates are mixed directly with molecules containing two or more reactive hydrogen atoms, such as diols, diamines, and dicarboxylic acids. We typically increase the reaction rate by adding amine or organotin based catalysts. The reaction normally occurs rapidly, evolving much heat. In order to ensure... 

Catalysts Catalysts are widely used for PU manufacture. Sometimes a combination of two or three catalysts is required to obtain the desired balance of reaction rates between compounds of differing active hydrogen activity. Metal compounds, especially organotin compounds, are much more efficient catalysts than tertiary amines for the -OH/NCO reaction. In addition to more commonly used dibutyltin(IV) dilaurate, dibutyltin(IV) diacetate, dialkyltin(IV) oxide or salts of divalent fin with a variety of carboxylic acids such as stannous octoate, hexoate and naphthenate etc. are available for this purpose. Combination of tin catalysts with tertiary amines has been reported to lead to a synergistic increase in catalytic activity. 

The elimination of amines may also be accomplished by using the reactions of organotin amides and transition-metal hydrides, or transition-metal amides and tin hydrides4. Neither route has attracted much attention recently. 

While tertiary amines are adequate catalysts for many reactions, a variety of metal catalysts has been found to be far more powerful. Organotin compounds are now used commercially in many polyurethane processes. The discovery of these catalysts was made independently by Hostettler and Cox [145] and by Britain and Gemeinhardt [146], all of whom were searching for more effective catalysts for foam formation. 

The reaction of organotin halides with metal or ammonium carboxylates (equation 13-4 M = Na, K, Tl, Ag, or R3NH+) can be carried out in a solvent such as acetone or carbon tetrachloride, but it is more convenient to prepare the salt in situ by adding the acid to a solution of sodium in an alcohol.10 The sodium carboxylate is formed in a finely-divided form, and then reacts readily with the equivalent amount of the organotin chloride. Alternatively the reaction can be carried out by slowly adding a tertiary amine to a solution of the acid and tin chloride in a solvent such as benzene.10... 

S tanny lphosphincs can be prepared by treating an organotin halide with a metallo-phosphine, or with a hydridophosphine in the presence of a tertiary amine, or by acidoly-sis of a stannylamine with a phosphine. Some examples of these reactions are given in equations 16-70,67 16-71,68 and 16-72.69 Stannylphosphines containing a PH group, like the corresponding amines, disproportionate unless they are stabilised by steric hindrance. 

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