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通过改变溶液中偏钨酸铵的浓度以化学还原法制备了一系列NiWB催化剂,并用于微晶纤维素的催化加氢。用物理吸附(BET)和透射电镜(TEM)等手段对催化剂进行了表征,探讨了催化剂中Ni和W的不同配比对催化剂性能的影响,同时研究了反应条件对纤维素催化加氢性能的影响。BET结果表明,随着W含量的增加,催化剂比表面积增加;TEM结果表明,催化剂为纳米颗粒,分散均匀;SAED结果表明,催化剂具有非晶态结构。适宜的反应条件为:反应温度245℃、反应时间2 h、H2压力6 MPa,此时微晶纤维素转化率可达100%,乙二醇的收率在43%以上,而六元醇的收率在5%左右。
A series of NiWB catalysts were prepared by chemical reduction method by changing the concentration of ammonium metatungstate in solution and used for the catalytic hydrogenation of microcrystalline cellulose. The catalysts were characterized by means of physical adsorption (BET) and transmission electron microscopy (TEM). The effects of different proportions of Ni and W on the catalyst performance were discussed. Meanwhile, the effects of reaction conditions on the catalytic hydrogenation of cellulose influences. The BET results showed that the specific surface area of the catalyst increased with the increase of W content. The TEM results showed that the catalyst was nano-particles and dispersed uniformly. The SAED results showed that the catalyst had an amorphous structure. The suitable reaction conditions are as follows: the reaction temperature is 245 ℃, the reaction time is 2 h, the pressure of H2 is 6 MPa, the conversion rate of microcrystalline cellulose can reach 100%, the yield of ethylene glycol is above 43% The yield is about 5%.