5‑(Chloromethyl)furfural from Polycotton Waste Textile in a Biphasic System: Different Process Designs

Due to underdeveloped waste management technologies for textile waste, 85 wt % ends up in either incineration plants or landfills. With our process, we are able to fully valorize polycotton waste, the largest fraction of textile waste, by separating both components. Cotton is converted into 5-(chloromethyl)-furfural (CMF) through a one-step batch process, using a biphasic system containing superconcentrated hydrochloric acid (HCl) (44 wt %) and chlorobenzene. The reaction temperature, reaction time, stirring speed, effective cotton loading, and volume of the organic layer of the biphasic system were first optimized using a central composite design, rendering 91 °C, 1 h, effective 8.3 mg of cotton/mL HCl, and 4 mL of organic layer/mL HCl to be the (apparent) optimal reaction conditions, leading to a CMF yield of 62.6%, which was in line with the predicted outcome of the model. The effect of adjustments on process design in regard to process structure (one-step vs two-step) and process type (batch vs semicontinuous) was investigated. This resulted in a final CMF yield of 73.3% in the two-step semicontinuous process, a method suitable for large-scale textile valorization.