钙盐助剂对ZrO_2催化CO加氢合成i-C_4烃的影响

Effect of calcium salts on selective formation of i-C_4 from CO hydrogenation over ZrO_2 catalysts

考察了几种钙盐助剂对ZrO2 催化CO加氢合成i C4烃的影响。ZrO2 的制备采用普通沉淀法 ,助剂的添加采用机械混和法。CaF2 和CaSO2 表现出良好的助剂效应 ,在提高烃类产物中i C4烃的选择性的同时 ,保持着较高的反应活性。而CaCl2 ,Ca(NO3) 2 ,Ca(BO2 ) 2 等钙盐助剂却产生负效果 ,烃类产物中甲烷等低碳烃类的选择性大大增加 ,而i C4烃的选择性降低。催化剂酸碱表征结果表明 ,催化剂表面酸碱性对催化剂的催化性能有很大的影响。催化剂上适宜数量的酸碱量和酸碱比例是影响CO加氢合成i C4烃的非常重要的因素。

The promoting effects of various calcium salts on the activity and selectivity of ZrO 2 in isosynthesis were studied in this work.ZrO 2 was prepared by precipitation. The calcium salts were added into zirconia by mechanical mixing method.CaF 2 and CaSO 4 were found to be effective additives, which could remarkably enhance the iso-C 4 selectivity in total hydrocarbons meanwhile maintain the activity as pure ZrO 2. However,Ca(NO 3) 2,Ca(BO 2) 2 and CaCl 2 wholly changed the distribution of hydrocarbons to favor methanation.The results of temperature-programmed desorption (TPD) of NH 3 and CO 2 indicated that the performance of the catalysts depended on the acid-base properties of the catalysts.The appropriate amount of acid and base and the ratio of basic sites to acidic sites on the catalysts are significant for the synthesis of i-C 4 hydrocarbons from CO hydrogenation.