Air-promoted selective hydrogenation of phenol to cyclohexanone at low temperature over Pd-based nan

来源 :Science China(Chemistry) | 被引量 : 0次 | 上传用户:williamt
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Attaining high activity with high selectivity at low temperature is challenging in the selective hydrogenation of phenol to cyclohexanone due to its high activation energy(E_a, 55–70 kJ/mol). Here we report a simple and efficient strategy for phenol hydrogenation catalyzed by Pd in aqueous phase at 30 °C by introducing air to promote the catalysis. With the assistance of air, >99% conversion and >99% selectivity were achieved over Pd(111)/Al_2O_3 with an overall turnover frequency(TOF) of621 h~(-1), ~80 times greater than that of the state-of-art Pd catalyst at 30 °C. Mechanism studies revealed that phenol was activated to generate phenoxyl radicals. The radicals were yielded from the reaction between phenol and hydroxyl radicals in the presence of hydrogen, oxygen and protic solvent on Pd. The phenoxyl pathway resulted in a low apparent E_a(8.2 kJ/mol) and thus high activity. More importantly, this strategy of activating substrate by air can be adapted to other Pd based catalysts, offering a new thinking for the rational design of cyclohexanone production in industry. Attaining high activity with high selectivity at low temperature is challenging in the selective hydrogenation of phenol to cyclohexanone due to its high activation energy (E_a, 55-70 kJ / mol). Here we report a simple and efficient strategy for phenol hydrogenation catalyzed by Pd in aqueous phase at 30 ° C by introducing air to promote the catalysis. With the assistance of air,> 99% conversion and> 99% selectivity were achieved over Pd (111) / Al_2O_3 with an overall turnover frequency (TOF) of 621 h ~ (-1), ~ 80 times greater than that of the state-of-art Pd catalyst at 30 ° C. Mechanism studies revealed that phenol was activated to generate phenoxyl radicals. The radicals were yielded from the reaction between phenol and hydroxyl radicals in The presence of hydrogen, oxygen and protic solvent on Pd. The phenoxyl pathway resulted in a low apparent E_a (8.2 kJ / mol) and thus high activity. More importantly, this strategy of activating substrate by air can be adapted to other Pd based catalysts , offering a new thinking for the rational design of cyclohexanone production in industry.
其他文献
项目学习是建构主义理论中进行合作学习的重要内容之一,通过小组设置,引导学生对其学习项目进行完成,不但可以对学生的自身探索能力进行增强,同时还可以提高学生的问题解决能
坐飞机出行的人会发现,民航机场都有贵宾厅,是专门为党政官员和国企领导设置的。这些要员每次乘机时,无需到大厅等,也不用排队,直接到这里接受特殊服务。所谓特殊,也不过是歇
据Freedonia集团于2008年10月发布的研究报告,中国需要更多的机器工具,预计从2007~2012年将年增长13%,达到6060亿元人民币(886亿美元),这将驱动对金属工作液的需求。 Accordi
目前,对于我国在高中阶段的英语课堂教学,社会各界已经普遍意识到文化教学的重要性。但是我国在高中英语的教学现状是并未进行相关的文化教学活动。也正因为如此,国内高中生
To improve their mechanical and thermal insulation properties, aluminum silicate fibrous materials with in situ synthesized K_2Ti_6O_(13) whiskers were prepared
据新华网讯近日,在南京举行的首届全国职业教育发展论坛上,教育部职业教育与成人教育司副司长刘占山表示,当前我国的职业教育呈现良好的发展态势,近两年来,职业学校招生数连
知名的资源分析专家、美国地球政策研究所负责人莱斯特·布朗前不久在一篇论文中提到,包括超过地球一半人口的18个国家在内,由于过度使用地下水,使地下水位达到了“水峰值”
Two new L-tryptophan derivatives,(S)-2-(4-acetoxybenzamido)-3-(1 H-indol-3-yl)propanoic acid(I) and(S)-2-(3-acetoxybenzamido)-3-(1H-indol-3-yl)propanoic acid(II
20 0 4年3月2 8日,黄冈职业技术学院副院长李家瑞、教务处处长甘其台应德国城市议会的邀请,与首都贸易大学、西北师范大学、河北工业大学、华南师范大学的教授一行共8人出访
编者的话:人生如歌,岁月如歌,往事亦如歌——这样的歌,有时激越,有时低沉;有时令人振奋,有时令人扼腕;有时让人一次次忆起,有时又让人不忍回想……伟人的经历令人景仰,而平凡