CAJ | 학술논문

以电化学改性和化学改性的碳纤维(CF)为载体制备了负载铱催化剂,通过考察催化剂在甲醇低压羰基化合成醋酸反应中的催化性能,研究了 CF 表面处理条件对负载铱催化剂性能的影响.XPS测试结果表明,阳极氧化后碳纤维表面出现 O、N 元素,氧化时间由2 min增加到5 min,O/N原子比例提高,在随后的负载铱催化剂中,铱的负载量由2．17％增加到4．88％,且双齿配位铱的比例较单齿配位铱增加,对醋酸的选择性由20％提高到30％.对阳极氧化后的CF,分别通过表面羟基缩合引入具有配位基团的 N-(β-氨乙基)-γ-氨丙基甲基二甲氧基硅烷后,由于配位基团数量的增加,铱的负载量分别提高到4．49％和6．43％,同时,单齿配位铱/双齿配位铱的比例增大,由于其分子链结构的柔性,明显改善了固载铱的化学微环境,催化剂对醋酸的选择性分别提高到72．5％和77．8％,表现出良好的催化活性和选择性.
이전화학개성화화학개성적탄섬유(CF)위재체제비료부재의최화제,통과고찰최화제재갑순저압탄기화합성작산반응중적최화성능,연구료 CF 표면처리조건대부재의최화제성능적영향.XPS측시결과표명,양겁양화후탄섬유표면출현 O、N 원소,양화시간유2 min증가도5 min,O/N원자비례제고,재수후적부재의최화제중,의적부재량유2．17％증가도4．88％,차쌍치배위의적비례교단치배위의증가,대작산적선택성유20％제고도30％.대양겁양화후적CF,분별통과표면간기축합인입구유배위기단적 N-(β-안을기)-γ-안병기갑기이갑양기규완후,유우배위기단수량적증가,의적부재량분별제고도4．49％화6．43％,동시,단치배위의/쌍치배위의적비례증대,유우기분자련결구적유성,명현개선료고재의적화학미배경,최화제대작산적선택성분별제고도72．5％화77．8％,표현출량호적최화활성화선택성.
Carbon fiber (CF)modified by anodizing (CF-Ox)and silanization (CF-Si)were applied for supported iridium catalyst.The effects of CF modification condition on the performances of the supported iridium catalysts were investigated by studying its catalytic activities in the methanol carbonylation reaction.The loading amount of Ir on CF-Ox was 2.17% and 4.88% for anodizing time of 2 and 5 min respectively,the X-ray photoelectron spectroscopy results indicated that oxygen and nitrogen were introduced to CF surface after anodizing (CF-ox). The oxygen/nitrogen atomic ratio enhanced as the anodizing time from 2 to 5 min,subsequently,the loading amount of Ir increased from 2.17% to 4.88% in the supported iridium catalyst.Comparing to the monodentate ligand iridium,the proportion of bidentate ligand iridium was increased,and resulted in the increase of acetic acid selectivity from 20% to 30%.For the 2 and 5 min anodized CF,after introducing N-(β-aminoethyl)-γ-am-monia propyl methyl dimethoxy silane(CF-Si)which have coordinating groups by the surface hydroxyl conden-sation respectively,the loading amount of Ir increased to 4.49% and 6.43% respectively,while the ratio of mo-nodentated iridium/bidentate iridium increased.The grafted silane molecular provids CF surface with a soluble soft chain of coordination sites,which contributed to the increase of Ir loading amount and improving the chemi-cal environment for coordinated iridium.Consequently,acetic acid selectivity increased to 72.5% and 77.8%.