Vinyl Acetate → N,N'-Dicyclohexylurea

Participants

Reaction Steps

40g of poly (vinyl butyral) containing 74% by weight of vinyl butyral units, 2% by weight of vinyl acetate units and 24% by weight of vinyl alcohol units and having an approximate average molecular weight of 30,000, were dissolved in 500 cm3 of anhydrous methyl acetate at 40° C. To this solution, 28.5g of p-toluene sulphonyl isocyanate (TSI) dissolved in 40 cm3 of methyl acetate were added over the course of 15 minutes at 40° C. The reaction was allowed to continue for a further hour at 40° C. with stirring. 13.0g of 4-azidobenzylidene-α-cyano acetic acid were added followed by 12.46g of 1,3-dicyclo hexyl carbodiimide (DCC) dissolved in 40 cm3 of methyl acetate and finally 0.1g of 4-dimethylamino pyridine (DMAP). The reaction mixture was then refluxed for 3 hours and then cooled to ambient temperature whilst being stirred. The insoluble 1,3-dicyclo hexyl urea produced was removed by filtration and the filtrate was sprayed into 5 litres of water to isolate the product. The resulting fibrous precipitate was filtered off, washed with 3 litres of aqueous 1% w/w potassium carbonate solution to remove any free acid and then re-slurried into water 3 times. The final product was dried at 35° C. to constant weight.

Provenance & Evidence