Choline Chloride-based Deep Eutectic Solvents for Degradation of Waste Cotton Fibrics to 5-Hydroxymethylfurfural

The preparation of value-added products is an effective way to reuse waste cotton fabrics (WCFs). Seven kinds of choline chloride (ChCl)-based deep eutectic solvents (DESs) were rapidly formed and characterized. Performances of these ChCl-based DESs were evaluated in terms of degradation of WCFs to 5-hydroxymethylfurfural (5-HMF) without any additional catalyst. The degradation was characterized by high-performance liquid chromatography (HPLC) and scanning electron microscopy (SEM) method. The results showed that the DESs formed by ChCl and p -toluene sulfonic acid ( p -TSA) had the best effect in converting WCFs. Moreover, the stability of 5-HMF in the as-obtained DESs was also investigated. The highest 5-HMF yield was 10.20 % at 100 °C, with a reaction time of 90 min, and the molar ratio of hydrogen bond acceptor (HBA) to hydrogen bond donor (HBD) was 1:1.3 in ChCl/ p -TSA DESs system without a catalyst. The investigated DESs system offers a good alternative compared to the available WCFs degradation methods, considering its cost-efficiency, environmental, and operability aspects. Therefore, the green and environmentally friendly synthesis of 5-HMF from cellulose materials (WCFs) could be an effective method to realize the high-value utilization of waste textiles, having an important theoretical significance and practical value.