【作者】 季德春；

【导师】 王清遐； 徐龙伢；

【作者基本信息】 中国科学院研究生院（大连化学物理研究所） ， 化学工程， 2003， 博士

【摘要】 一氧化碳水合制低碳醇过程为工业CO的利用提供了新途径。该方法不仅节省了氢源，而且用普通的过渡元素和主族元素催化剂，避免了对贵金属的依赖。 本文首先通过对溶剂及活性组份的筛选，发现PbTiO₃催化剂具有较佳的催化反应性。考察了碱金属碳酸盐类助剂和溶剂对反应活性的影响。结果表明，碱金属碳酸盐类助剂作用随溶解度的增加而明显增强，总的甲醇和乙醇的收率顺序为K₂CO₃＞Na₂CO₃＞Li₂CO₃。溶剂的作用与其碱性有密切关系，强碱性的有机多胺能够有效促进该反应，相对于非极性溶剂的2.0mg．g^-1.h^-1，在碱性溶剂中相同催化剂活性最高可达到23.1mg.g^-1.h^-1。提出在碱金属碳酸盐K₂CO₃的作用下可能遵循两步循环反应的反应机理。 超细催化剂的特殊表面结构和性质也为CO水合制低碳醇反应活性的提高提供了可能。本文首次发现溶胶-凝胶法制备的超细TiO₂催化剂表现出较好的活性。分别用三种不同方法制备了超细TiO₂催化剂，结合TG-DTA、IR、XRD、TEM、XPS等表征技术，对不同方法制备的超细TiO₂催化剂进行了比较。另外还发现TiO₂催化剂的热处理温度对反应的CO转化率影响不明显，但是甲、乙醇的收率却随热处理温度的上升而增加明显，1023K金红石与锐钛矿质量比为9：2的混晶条件下，醇产物达到最高。 在此基础上首次用溶胶—凝胶法合成组分单一的PbTiO₃超细粒子。催化剂粒子分散性良好，颗粒分布均匀，经统计平均计算的1：1催化剂的样品平均粒径为31.2nm。实验结果表明利用TiO₂调变PbO催化剂，能够使醇产物中乙醇比例上升，副产物CO₂选择性下降。 对于PbTiO₃催化剂，在反应的还原性气氛中，仍存在催化剂的部分还原，另外还存在K₂CO₃在催化剂表面的聚集，因此必须经过空气焙烧和水洗两步处一氧化碳水合制低碳醉过程研究理才能使Pb五03催化剂的反应性能得到较好恢复。实验数据还表明，这两种处理方式次序对催化剂最终性能没有明显影响。同样对于五伍催化剂，经过水洗处理，催化剂的反应活性就可以得到较好恢复。更多还原

【Abstract】 Catalytic conversion of CO and PfcO to alcohols (methanol and ethanol) is a new promising route for the utilization of CO in industry process. Not only the hydrogen energy is saved, but also the catalyst is composed of transition element. So that this rout is independent of the noble metal.In the present paper, performance of the solvents and the active composition was studies at first and the PbTiO3 catalyst was found to be the best. Moreover, the effects of alkali metal carbonate promoters and the solvents were investigated at the same time. Experimental results showed that with the increase of the solubility of the alkali carbonate (K2CO3 > Na2CO3 > Li2CO3), the subsequent production of alcohols ranged from 2.0 mg.g-1.h-1 to 23.1 mg.g-1.h-1. The results also suggested that the effect of the solvents on PbTiOs catalyst for catalytic conversion of CO and H2O to alcohols was very sensitive. The catalytic activity was found to increase with the alkalescence of solvents. So the two-step reaction mechanism of direct catalytic conversion of CO and H2O to alcohols is presented that the combination of the carbonate recycle and formate catalytic decomposition results in the final alcohols synthesis.Ultrafine catalyst make it possible for the promotion of catalytic activity of alcohols synthesis from catalytic conversion of CO and H2O. For the first tune, it is reported that the ultrafine TiO2 catalyst prepared by sol-gel method has the stable activity. By means of TG-DTA> IR, XRTK TEM and XPS techniques for the characterization of catalysts, different preparation methods were compared.Moreover, the influence of calcining temperature on the reaction performance of the was also investigated. It was found that the STY of MeOH and EtOH increasedwith the calcining temperature and it reached the maximum 1.82mg.m-2.h-1 as the ratio of rutile to anatase is 9:2, while the corresponding conversion of CO did not be effected remarkably.On this basis, the ultrafine PbTiOs particles was prepared by the same method (sol-gel). The dispersion and the distribution of particles is very well, the average particles size is 31.2nm. It is found that with the addition of the TiO2, the proportion of ethanol increases and the CO conversion decreases at the same time.In the present paper, a new process for the regeneration of catalyst in catalytic conversion of CO and H2O was put forward. For the PbTiO3 catalyst, because of the reduction of catalyst in part and the assembling of K2CO3 on the surface of catalyst, the regeneration process includes two steps: oxidation hi air and washing with water. Experimental results show that the order of the two steps has no effect on the performance of regenerated PbTiO3 catalyst. As for the TiO2, only one washing step is required.更多还原