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The conversion of CO 2 to high value-added chemicals in water using environment-friendly and cost-effective catalysts is a very significant topic. In this work, a green method for the conversion of CO 2 catalyzed by alcohol amines has been developed. Alcohol amines showed considerable activating ability to CO 2 in the cyclization with 2-aminobenzonitrile to quinazoline-2,4(1 H ,3 H )-dione in water. Notably, when diethanolamine (DEA) was used as the catalyst, 94% yield of quinazoline-2,4-(1 H ,3 H )-dione could be achieved. A plausible mechanism has been proposed based on the 1 H NMR, FT-IR analysis and DFT calculation. The excellent catalytic performance is attributed to the combined effect of both the secondary amine and hydroxyl groups on alcohol amines with the assistance of water in the formation of carbamate. Water plays a bi-functional role of solvent and co-catalyst in this catalytic process. Catalysts can be easily recovered and reused five times without significant loss of activity., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The production of biofuels and chemicals by hydrogenation of furfural has attracted much attention recently. Herein the effect of Na + doping on the catalytic performance of Pd/SiO 2 in hydrogenation and reductive-etherification of furfural in ethanol was systematically studied. Two Pd/SiO 2 catalysts with and without the modification by Na + were prepared by impregnation and calcination. Their catalytic properties were compared for the hydrogenation of furfural and furfural diethyl acetal under mild conditions. The silanol groups on Pd/SiO 2 catalysed the acetalization of furfural and alcohol and the resulted acetal underwent hydrogenolysis on Pd nanoparticles (NPs) with an average particle size of 8 nm, leading to a moderate yield (∼58%) of furfuryl ethyl ether. Doping Na + on Pd/SiO 2 led to the diminishing of silanol groups as well as strong interaction between Na + and Pd NPs. No acetalization occurred on Na + modified Pd/SiO 2 due to the exchange of H + of Si-OH with Na + , thus the reductive etherification of C[double bond, length as m-dash]O group in furfural was completely inhibited. Meanwhile the hydrogenation of furan-ring over Na + coordinated Pd NPs could proceed with very high selectivity (>90%) forming tetrahydrofurfural in high yield. Kinetics study on the hydrogenation of furfural diethyl acetal over Pd/SiO 2 and Na + doped Pd/SiO 2 suggested that the Na + greatly impeded the hydrogenolysis of C-O-C bond of acetal, while the hydrogenation of the furan ring took place selectively., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)