Catalytic conversion of cellulose to ethylene glycol over a low-cost binary catalyst of Raney Ni and tungstic acid.

Following our previous report on the selective transformation of cellulose to ethylene glycol (EG) over a binary catalyst composed of tungstic acid and Ru/C, we herein report a new low-cost but more effective binary catalyst by using Raney nickel in place of Ru/C (Raney Ni+H(2 WO(4) ). In addition to tungstic acid, other W compounds were also investigated in combination with Raney Ni. The results showed that the EG yield depended on the W compound: H(4)SiW(12)O(40) <H(3 PW(12)O(40) <WO(3) <H(2)WO(4) , but all the investigated W compounds were selective towards EG. Moreover, both WO(3) and H2 WO(4) were dissolved partially under the reaction conditions and transformed into Hx WO(3) , which is the genuinely active species for the C-C bond breakage of cellulose. This result further confirmed that the reaction that involves the selective breakage of the C-C bonds of cellulose with W species is homogenous. Among various binary catalysts, the combination of Raney Ni and H(2)WO(4) gave the highest yield of EG (65 %), which could be attributed to the high activity of Raney Ni for hydrogenation and its inertness for the further degradation of EG. Moreover, Raney Ni+H(2)WO(4) showed good reusability; it could be reused at least 17 times without any decay in the EG yield, which shows its great potential for industrial applications.