Depolymerization of Nylon-66 by Hydrolysis Using Hydrophilic and Hydrophobic Ionic Liquid

Ionic liquids have demonstrated potential efficiency as a catalyst in the hydrolysis technique for depolymerizing waste nylon-66. This research article involves the use of hydrophilic 1-butyl-3-methylimidazoliumtetrafloroborate [bmim]BF4 and hydrophobic 1-butyl-3-methylimidazolium hexafluorophospate [bmim]PF6 ionic liquids for the breakdown of waste nylon-66. Hydrophilic ionic liquid has been demonstrated to be more efficient at catalyzing the hydrolysis of waste nylon-66 into monomers than hydrophobic ionic liquid. In experimental work, 0.2g of waste nylon-66, 20 ml of 5 N HCl, and .01 mole ionic liquid were refluxed in the range of 100-140 0C for several hours. After cooling, the reaction mixture was neutralized with 5N NaOH to make a slightly alkaline solution. The addition of benzoyl chloride to the alkaline solution gives the dibenzoyl derivative of hexamethylene diammine (DBHMD). The filtrate was extracted multiple times with ethyl acetate to obtain adipic acid. The ionic liquid was recovered at the end of the reaction under reduced pressure.