ONE-STEP HYDROTHERMAL CATALYTIC CONVERSION OF CASSAVA RESIDUE INTO DIOLS

摘要

As high-value chemicals with a very large market demand, ethylene glycol (EG) and 1,2-propylene glycol (1,2-PG) are widely used in the synthesis of a broad range of materials, including polyester, anti-freezing agents, and chemical intermediates, which are mainly synthesized using non-renewable fossil resources. With the increasing levels of energy consumption and the ever-diminishing reserves of fossil energy resources, the supply of diols will be affected. Fortunately, renewable biomass can be used to synthesize bulk chemicals such as EG and 1,2-PG, which could lessen the dependence on fossil resources and contribute to the sustainable development of the world economy. Hence, in order to promote the utilization value of biomass waste and achieve the sustainable production of high value-added chemicals, cassava residues were used as a raw material in experiment, which have not been properly used as a resource duo to its relatively low economic value. The chemical compositions and the contents of cassava residues were detected by chemical and advanced instrumental analytical methods, then several mixed catalysts consisting of activated carbon supported Ru (Ru/AC) and a tungsten compound were used for one-step hydrothermal catalytic conversion of cassava residue into diols. Besides, the effects of various reaction conditions on the catalytic performance were investigated. The results showed that cassava residue was an excellent material for conversion into idols on account of containing a high content of carbohydrates (85.1%) and a low amount of lignin (5.7%). The tungsten species exerted a significant effect on the catalytic performance, when the reaction was carried out at 245°C for 60 min, the Ru/AC-H_2WO_4 mixed catalyst showed the best catalytic performance with total diols yield of above 58.1%. However, increasing the recycling time of RU/AC-H_2WO_4 mixed catalyst, the yield of diols reduced slowly because inorganic impurities in cassava residue reacted with H_2WO_4 during the reaction and produced CaWO_4 and FeWO_4.