The synthesis of zeolites with special morphologies has attracted much attention,because the morphologies influence the efficiency of catalysis,applications as the hosts for micro-devices,and so on. Silicalite-1 with chain-like morphology (0.576.33 m) were synthesized successfully with poly(diallyldimethylammonium chloride) (PDDA) as an additive and was characterized by XRD and SEM. The PDDA as the additive in the synthesis system was the real key for the formation of the chain-like morphology of the products. The length and the diameter of the material can be tuned through adjusting the molar ratios of PDDA and TPAOH. The straight channels of materials are longer and their openings are much fewer than those of the traditional slicalite-1 crystals,because of the crystal stacking along the b axis.
It is of great significance and challenge to achieve direct conversion of cellulose to specific polyols,e.g.,ethylene glycol and propylene glycol.For such selective conversion,a novel one-pot approach was studied by combination of alkaline hydrolysis and hydrogenation on supported Ru catalysts.A wide range of bases including solid bases,e.g.,Ca(OH)2 and La2O3,and phosphate buffers were examined in the cellulose reaction in water,and the cellulose conversions and polyol products depended largely on the basicity or pH values in the aqueous solutions.Ethylene glycol,1,2-propanediol,and especially 1,2,5-pentanetriol were obtained with selectivities of 15%,14% and 22%,respectively,at 38% cellulose conversion at pH 8 in phosphate buffer solution.These preliminary results provide potentials for efficient conversion of cellulose to targeted polyols by using the advantages of bases.
DENG TianYin,SUN JiYing & LIU HaiChao Beijing National Laboratory for Molecular Sciences,State Key Laboratory for Structural Chemistry of Stable and Unstable Species
