| Abstrakt: |
Oxidation of glycerol to lactic and glycolic acids is one of the most sought-after upgrades for this waste product in the biodiesel industry. These renewable glycerol-based hydroxy—carboxylic acid products are valuable monomers for the synthesis of new generation biodegradable polymers. In this work, a practically no-cost catalyst was prepared by using electrode coatings in 18,650 type Li-ion cells found in a spent DELL laptop battery. The combined cathode and anode coatings collected from Li-ion cells were pyrolyzed at 600 °C in air for 30 min. to prepare the catalyst with formula LiNi0.03Mn0.02Co0.11O0.85/C. Oxidation of glycerol using 25 mg/mmol catalyst in 0.50 M aqueous NaOH, under 3.4 atm. O2, 230 °C, 4 h. gave the highest yields of lactic and glycolic acids, 54 and 41%, respectively. Next, this hydroxy acid mixture was directly polymerized using p-toluene sulfonic acid—SnCl2 catalyst in refluxing xylene to give poly(lactic-co-glycolic acid) with Mw = 8017, Mw/Mn = 1.435, Tg = 41 °C, Tm = 182 °C and in 74% yield. [ABSTRACT FROM AUTHOR] |
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