Process for the preparation of liquid tin(II) alkoxides

摘要

A synthetic process of producing liquid tin(II) alkoxides for use as either catalysts in the synthesis of lactide or as initiators in the polymerization of cyclic ester monomers to yield biodegradable polyesters is described. The synthetic process employs anhydrous tin(II) chloride dissolved in n-heptane mixed with dry diethylamine. Alcohols, ROH, in which the R groups are n-C4H9, n-C6H13, and n-C8H17 are added to the reaction mixture and stirred for 12 hours. The reaction mixture is then filtered under nitrogen or argon before being evaporated to dryness to yield the three tin(II) alkoxides, namely: tin(II) n-butoxide, tin(II) n-hexoxide, and tin(II) n-octoxide. All three tin(II) alkoxides are viscous, dark yellow liquids which are highly soluble in most common organic solvents. Furthermore, they can all be stored under an inert atmosphere for long periods without any significant change in their reactivity and, therefore, in their effectiveness as catalysts/initiators.

主权项

1. A process for producing a tin(II) alkoxide, comprising steps of:
adding one mole equivalent of anhydrous tin(ll) chloride to a reaction vessel; adding 2 to 3 mole equivalents of an amine to the reaction vessel of the anhydrous tin(ll) chloride in a nonpolar, aprotic solvent; further adding 2 to 3 mole equivalents of anhydrous alcohol ROH to the reaction vessel to provide a reaction mixture such that a newly produced tin(ll) alkoxide Sn(OR)2 does not undergo self-aggregation; stirring the reaction mixture for at least 3 hours in a temperature range of 25- 38° C. to provide a tin(ll) alkoxide Sn(OR)2, wherein the R group is selected from the group comprising CH3, C2H5, nC3H7, nC4H9, nC5H11, nC6H13, nC7H15, and nC8H17 and the steps are carried out under inert atmosphere; wherein the amine is selected from the group consisting of dimethylamine, diethylamine and diisopropylamine.