Debromination of hexabromobenzene by its co-grinding with CaO
Résumé
A hexabromobenzene (HBB, C 6 Br 6) powder was subjected to co-grinding with excess CaO powder in air using a planetary ball mill to investigate mechanochemical debromination of the HBB sample. The reaction proceeds smoothly with an increase in both grinding time and molar ratio of CaO addition. The co-grinding enables us to debrominate HBB, forming CaBr 2 , C and CaCO 3 besides excess CaO in the product. CaBr 2 in the product tends to absorb moisture from the atmosphere to form CaBr 2 Á nH 2 O. The reaction yield is quantitatively evaluated by measuring the amount of water-soluble bromide through water washing and the amount of unreacted HBB through toluene washing. It is found that almost 100% of debromination is achieved by 6 h grinding with the molar ratio kept constant at 2:1. Radicals are detected in the ground products, possibly due to rupture in the covalent bonds of C–C and C–Br in HBB.
Origine : Fichiers produits par l'(les) auteur(s)
Loading...