废旧尼龙6纺织品的磷钨酸催化亚临界水解研究

Study on phosphotungstic acid catalyzed hydrolysis of waste nylon 6 textiles in subcritical water

为研究废旧尼龙6纺织品在亚临界水中的催化水解反应,以磷钨酸(HPW)作为催化剂,对解聚后的固相剩余物和液相产物进行表征与分析,阐述了水解产物的组成和水解机理,并研究了反应温度及催化剂HPW对废旧尼龙6纺织品水解效果的影响。结果表明:水解产物主要有固相剩余物即未完全分解的尼龙6与液相产物即己内酰胺(CPL),以及—(CH_(2))_(5)—NH—CO—链段的重复数目为1~5的环状、线型低聚物;在水解反应中,提高温度和添加HPW都有利于解聚程度的提高,其中在260~270℃时加入HPW可以大幅度提高尼龙6的解聚度和CPL产率,使整个体系反应温度降低了10℃,缓和了反应条件。

To study the catalytic hydrolysis of waste nylon 6 textiles in subcritical water,phosphotungstic acid(HPW)was used as a catalyst to characterize and analyze the solid-phase residues and liquid-phase products after depolymerization.The composition and hydrolysis mechanism of the hydrolysates were described,and the effects of reaction temperature and catalyst HPW on the hydrolysis of waste nylon 6 textiles were studied.The results show that the hydrolysates mainly consist of the not completely decomposed nylon 6 solid residues,and the liquid product caprolactam(CPL)and its cyclic or linear oligomers with 1 to 5 repeat—(CH_(2))_(5)—NH—CO—segment.In the hydrolysis reaction,increasing the temperature and adding HPW is conducive to the improvement of depolymerization degree.At the temperature from 260℃to 270℃adding HPW can greatly improve the depolymerization degree and CPL yield of nylon 6,which reduces the reaction temperature of the whole system by 10℃and ease the reaction conditions.