氨基甲醇脱水：理论研究

Aminomethanol water elimination: theoretical examination.

作者信息

Feldmann Michael T, Widicus Susanna L, Blake Geoffrey A, Kent David R, Goddard William A

机构信息

Center for Advanced Computing Research, MC 158-79, California Institute of Technology, Pasadena, 91125, USA.

出版信息

J Chem Phys. 2005 Jul 15;123(3):34304. doi: 10.1063/1.1935510.

DOI:10.1063/1.1935510

PMID:16080734

Abstract

The mechanism for the formation of hexamethylenetetraamine predicts the formation of aminomethanol from the addition of ammonia to formaldehyde. This molecule subsequently undergoes unimolecular decomposition to form methanimine and water. Aminomethanol is the predicted precursor to interstellar glycine, and is therefore of great interest for laboratory spectroscopic study, which would serve as the basis for observational searches. The height of the water loss barrier is therefore useful in the determination of an appropriate experimental approach for spectroscopic characterization of aminomethanol. We have determined the height of this barrier to be 55 kcalmol at ambient temperatures. In addition, we have determined the infinite-pressure Rice-Ramsperger-Kassel-Marcus unimolecular decomposition rate to be <10(-25) s(-1) at 300 K, indicating gas-phase kinetic stability for typical laboratory and hot core temperatures. Therefore, spectroscopic characterization of and observational searches for this molecule should be straightforward provided an efficient formation mechanism can be found.

摘要

六亚甲基四胺的形成机制预示着氨与甲醛加成会生成氨基甲醇。该分子随后发生单分子分解，形成亚甲基亚胺和水。氨基甲醇是星际甘氨酸的预测前体，因此对于实验室光谱研究极具意义，这将为观测搜索提供基础。因此，失水势垒的高度对于确定用于氨基甲醇光谱表征的合适实验方法很有用。我们已确定在环境温度下该势垒的高度为55千卡/摩尔。此外，我们已确定在300 K时无限压力下的赖斯-拉姆齐格-卡塞尔-马库斯单分子分解速率小于10^(-25) 秒^(-1)，这表明在典型的实验室温度和热核温度下，该分子在气相中具有动力学稳定性。因此，只要能找到有效的形成机制，对该分子进行光谱表征和观测搜索应该很简单。