Deep Eutectic Solvents as pretreatment for viscose production

Abstract

Viscose from dissolving pulp is one of the most used fabrics in the world. However, its production involves a very hazardous compound: CS2. Therefore, reducing its consumption is of utmost importance. In this sense, dissolving pulp can be pretreated, increasing the reactivity of the cellulose and reducing the CS2. Deep eutectic solvents have been used in biomass pretreatment as delignifying agents since their selectivity towards lignin is high. The ones used with lignocellulosic biomass usually comprise a quaternary ammonium and an organic acid. In previous studies, the formed by choline chloride and lactic acid has excellent results among different DES. However, the optimal conditions of the treatment have not been found, which is the aim of this study. This study showed that no harsh conditions are needed to increase reactivity since temperatures below 100 ºC and time below 120 min could be used. Additionally, the study of the influence of the operating conditions led to the mathematical model of reactivity to find the optimal conditions. At the best conditions, reactivity increased to 97.97%, with a CS2 consumption reduction of more than 16%.