Method for evaluating brominated flame retarders

A process for the upgrading of brominated flame retardants comprising the stages of:

• a) provision of a plastic comprising a flame retardant A comprising a carbon-based chain substituted by at least two bromine atoms;
• b) recovery of a composition comprising said flame retardant A;
• c) bringing said composition comprising said flame retardant A into contact, in an organic solvent, with a compound A′ selected from the group consisting of Na2S2, K2S2, a potassium or sodium alkyl xanthate, and a compound of formula Y—SH in which Y is an alkali metal, an alkaline earth metal, a metal selected from rare earth metals, a —C(NH2)═NH unit or a —C(NR1R2)═NR3 unit with R1, R2 and R3 being, independently of one another, H or C1-C10 alkyl, provided that R1, R2 and R3 are not simultaneously H;
• in order to form a mixture C comprising a compound B comprising a carbon-based chain substituted by at least two —SH functional groups;
• and
• d) purification of the mixture C obtained and recovery of said compound B.