Technological watch

A method for recycling polyethylene terephthalate (PET) to produce bis(2-hydroxyethyl) terephthalate (BHET) comprises the steps of (a) depolymerising PET in the presence of ethylene glycol and a catalyst system in a series of preferably two depolymerisation reactors to form a depolymerised mixture comprising BHET; (b) crystallising a precipitate comprising BHET from the depolymerised mixture; (c) dissolving the precipitate in a protic solvent, preferably water, but also optionally methanol, to form a solution comprising BHET; (d) removing impurities from the solution to form a purified solution comprising BHET; and (e) crystallising a purified product comprising BHET from the purified solution. Suitable apparatus for such a method, and the use of urea in a catalyst system therefor, are also provided.