TABLE OF CONTENTS Udris [53] has described two schemes, based on chromatography and infrared spectroscopy, for the identification, in PVC extracts of:
dialkyltin dialkylthioglycollates:
dialkyltin dilauryl mercaptides:
R, R ?, R ? = alkyl stabilisers in which the dialkyltin group is combined with both thiol and carboxyl groups.
dialkyltin maleates
dialkyltin dialkyl maleates
dialkyltin dilaurates
It is first of all necessary to prepare an extract of the PVC in which the organotin stabiliser is quantitatively recovered.
For the extraction of the first set of compounds, i) the polymer is refluxed with acetone and the silver salts precipitated by the addition of aqueous silver nitrate. After drying the residue is examined by infrared spectroscopy to identify alcohols, thioacids, thiols, and alkyl groups attached to tin. For the extraction of the second set of compounds ii) the polymer is refluxed with 10% aqueous sodium hydroxide prior to the identification of alcohols by gas chromatography then the alkyl groups attached to tin and carboxylic acids are identified.
Udris [53] examined methods for the recovery and identification of tin stabilisers in excess plasticiser (90 to 95%). The plasticisers included diisooctyl phthalate and mixtures of diisooctyl phthalate and tritolyl phosphate in various proportions.
Good samples of dialkyltin dichlorides were isolated by this method from mixtures of tin stabilisers with diisooctyl phthalate and tritolyl phosphate; the dialkyltin groups have been identified in dibutyl tin dinonylmaleate, dioctyltin dilaurate, dibutyltin dinonylthioglycollate and dioctyltin thioglycollate.
Renier and co-workers [54] give...
