在甲醇碳化条件下支持黄金的扩散增加
Alexandre Goguet1, Christopher Hardacre, Ian Harvey
1CenTACat, School of Chemistry and Chemical Engineering, Queen's University, Belfast, BT9 5AG, UK.
Journal of the American Chemical Society
|May 2, 2009
概括
金催化剂在甲醇碳化中的活性点是由较大的颗粒形成的小黄金集群. 酸甲基对于维持催化剂活性和分散至关重要.
科学领域:
- 不同质的催化剂.
- 纳米材料科学 纳米材料科学
- 有机金属化学 有机金属化学
背景情况:
- 支持黄金催化剂对于各种化学转化至关重要.
- 了解黄金催化剂的活性位点是优化其性能的关键.
- 甲醇碳化是一种重要的工业过程.
研究的目的:
- 在甲醇碳化中识别支持的黄金催化剂的活性位点.
- 研究甲基化物在催化剂分散和活性中的作用.
- 为了探索黄金催化剂反应后再分散的潜力.
主要方法:
- 使用先进的显微镜技术对黄金颗粒进行表征.
- 在现场研究,监测碳化反应期间的催化剂行为.
- 改变反应条件以评估甲基化物的影响.
主要成果:
- 活动部位被确定为由大型金颗粒 (>10纳米) 形成的黄金二元/三元体.
- 发现酸甲基对于黄金颗粒的分散和保持催化剂活性至关重要.
- 有证据表明,黄金催化剂在反应后可以重新分散.
结论:
- 甲醇碳化支持的黄金催化剂中的活性物种是小黄金集群.
- 酸甲基在这些活性位点的形成和稳定中起着至关重要的作用.
- 这些发现为再生和再利用黄金催化剂提供了新的可能性.
相关概念视频
01:33Carboxylic Acids to Methylesters: Alkylation using Diazomethane
Carboxylic acids react with diazomethane in an ether solvent via alkylation at the carboxylate oxygen atom to give methyl esters of the corresponding acid with excellent yields.
02:15Preparation of Alcohols via Addition Reactions
Overview
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...