CAJ | 학술논문

乙二醇是重要的化工原料，广泛应用于阻冻剂、燃料电池和聚酯工业等领域。传统制备乙二醇路线有基于石油路线的环氧乙烷水合法以及基于煤和天然气路线的C1合成法。C1路线合成乙二醇是CO氧化偶联生成草酸二甲酯，草酸二甲酯再催化加氢合成乙二醇。设计和制备高效草酸二甲酯加氢催化剂是实现煤制乙二醇工业化关键。草酸二甲酯加氢催化剂主要有Ru基均相催化剂和Cu基非均相催化剂，其中，无Cr的Cu基催化剂（ Cu/SiO2）是研究重点。影响Cu/SiO2催化性能的主要有载体、制备方法和助剂。载体类型不仅影响活性物种与载体之间的相互作用，而且影响活性物种分散度，具有高表面积和有序介孔结构的载体能够提高Cu物种分散度，从而显著提高催化剂活性。制备Cu/SiO2催化剂的方法有蒸氨法、浸渍法、沉积沉淀法、离子交换法和溶胶-凝胶法等。蒸氨法制备的Cu/SiO2形成铜氨络合离子，使Cu物种得到很好分散，还原后催化剂表面Cu+含量较高。Mo、Co、Ni和B等助剂的添加可以调变Cu物种的价态和分散度，提高催化剂性能。添加助剂时，要综合考虑助剂的引入对催化剂酸碱性质、活性物种分散度和载体孔径结构等的影响。研究认为，草酸二甲酯加氢机理是Cu0与Cu+的协同作用，Cu0是催化剂上的活性位点，活化H2；Cu+起亲电子的L酸作用，激化CO键提高草酸二甲酯中酯基的反应。催化剂失活的主要原因是产物乙醇酸甲酯在催化剂表面较难脱附以及反应过程中催化剂烧结。Cu/SiO2催化剂存在热稳定性差等缺陷，制备高稳定Cu基催化剂是今后发展方向。
을이순시중요적화공원료，엄범응용우조동제、연료전지화취지공업등영역。전통제비을이순로선유기우석유로선적배양을완수합법이급기우매화천연기로선적C1합성법。C1로선합성을이순시CO양화우련생성초산이갑지，초산이갑지재최화가경합성을이순。설계화제비고효초산이갑지가경최화제시실현매제을이순공업화관건。초산이갑지가경최화제주요유Ru기균상최화제화Cu기비균상최화제，기중，무Cr적Cu기최화제（ Cu/SiO2）시연구중점。영향Cu/SiO2최화성능적주요유재체、제비방법화조제。재체류형불부영향활성물충여재체지간적상호작용，이차영향활성물충분산도，구유고표면적화유서개공결구적재체능구제고Cu물충분산도，종이현저제고최화제활성。제비Cu/SiO2최화제적방법유증안법、침지법、침적침정법、리자교환법화용효-응효법등。증안법제비적Cu/SiO2형성동안락합리자，사Cu물충득도흔호분산，환원후최화제표면Cu+함량교고。Mo、Co、Ni화B등조제적첨가가이조변Cu물충적개태화분산도，제고최화제성능。첨가조제시，요종합고필조제적인입대최화제산감성질、활성물충분산도화재체공경결구등적영향。연구인위，초산이갑지가경궤리시Cu0여Cu+적협동작용，Cu0시최화제상적활성위점，활화H2；Cu+기친전자적L산작용，격화CO건제고초산이갑지중지기적반응。최화제실활적주요원인시산물을순산갑지재최화제표면교난탈부이급반응과정중최화제소결。Cu/SiO2최화제존재열은정성차등결함，제비고은정Cu기최화제시금후발전방향。
Ethylene glycol( EG)is an important fine intermediate,which is conventionally used in the fields of antifreeze,fuel cell and polyester manufacture,etc. There are two kinds of synthetic routes of ethylene glycol:the hydration of ethylene oxide depended on the petroleum resource and the hydrogenation of oxalate based on the syngas route from the coal or natural gas. The latter route is suitable for the situation of China, and is the focus of this review. During the indirect synthesis of EG from syngas,dimethyl oxalates( DMO) are firstly synthesized via the coupling of CO with nitrite esters,and then are catalytically hydrogenated to EG. The designment and preparation of highly active catalysts for DMO hydrogenation are the key to realize the industrialization of coal to EG. The catalysts for DMO hydrogenation to EG mainly include homogeneous ruthenium-based catalysts and homogeneous copper-based catalysts. Cu/SiO2 catalysts,non-chromium Cu-based catalysts,are nowadays research focus of DMO hydrogenation catalysts. Three key factors affecting the catalytic performance of Cu/SiO2 catalysts are supports,assistants and preparation methods. The types of supports can affect not only the interaction between the active species and supports,but also the dispersion of copper species. Supports with large surface areas and ordered mesoporous structure can improve the dispersion of copper species,and then greatly promote the activity and stability of Cu catalysts. The preparation methods of Cu/SiO2 catalysts include impregnation,deposition-precipitation,ammonia evapo-ration,and sol-gel method,etc. When Cu/SiO2 catalysts were prepared by ammonia evaporation method, copper-ammonia complex ions formed on the catalysts,which resulted in well dispersion of Cu species,and Cu+ contents on the surface of Cu/SiO2 catalysts after reduction were higher. The promoters,such as Mo, Co,Ni and B,etc,could modulate the valence and dispersion of Cu species greatly,and then improve the performance of the catalysts. The catalytic mechanism over Cu/SiO2 catalysts should be related to the cooperation of Cu0 and Cu+ in DMO hydronation to EG. Cu0 was as the active site for the activation of H2 ,and Cu+ was as Lewis acid for the activation of CO bond. The main reasons for the deactivation of copper-based catalysts were that the product of methyl glycolate on the surface of the catalyst was difficult to desorption,and the catalysts were sintered during the reaction. Nowadays,poor thermal stability of Cu/SiO2 catalysts becomes the bottleneck for the industrial manufacture of EG via the syngas route, therefore,Cu catalyst with high stability is the future development direction.