Scholarlink

Context <p>The stereo-specific production of <i>syn</i>- and <i>anti</i>-CH<sub>3</sub>CHOO conformers from the CH<sub>3</sub>CHI + O<sub>2</sub> reaction has been investigated by ab initio quantum-chemical and statistical theory studies. The results of the studies clearly indicate that the [<i>syn</i>]:[<i>anti</i>] product ratio depends on both temperature and pressure of the reaction system, and is kinetically, rather than thermodynamically, controlled. Most experimental data measured near room temperature at 2–10&#xa0;Torr He pressure agree with the predicted results in terms of either the absolute rate constants for <i>syn</i>- and <i>anti</i>-CH<sub>3</sub>CHOO production and/or the [<i>syn</i>]:[<i>anti</i>] product ratio. If the stereo-specificity of <i>syn</i>- and <i>anti</i>-CH<sub>3</sub>CHOO formation were controlled thermodynamically, one would predict [<i>syn</i>]:[<i>anti</i>] = 241:1 independent of pressure at 298&#xa0;K, instead of (80 ± 10):(20 ± 10) measured experimentally or 86:14 predicted theoretically at 5-Torr He pressure.</p> Methods <p>All calculations were performed using Gaussian 16 software. Geometry, frequency, and IRC analysis calculations were conducted at the B3LYP/Aug-cc-PVTZ level of theory. The potential energy surface of the system was computed at the CCSD(T)/Aug-cc-PVTZ//B3LYP/Aug-cc-PVTZ level. The rate constants for individual product channels in the reaction, including the direct production of IO + CH<sub>3</sub>CHO and the collisional deactivation of the excited CH<sub>3</sub>CHIO<sub>2</sub>* intermediate formed by the association of CH<sub>3</sub>CHI with O<sub>2</sub>, were predicted by statistical theory calculations using the Variflex code.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Ab initio prediction for product stereo-specificity in the CH3CHI + O2 reaction: formation of syn- vs anti-CH3CHOO

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年7月11日

查看全文
  • Hue-Phuong Trac,
  • Putikam Raghunath,
  • Ming-Chang Lin

摘要

Context

The stereo-specific production of syn- and anti-CH3CHOO conformers from the CH3CHI + O2 reaction has been investigated by ab initio quantum-chemical and statistical theory studies. The results of the studies clearly indicate that the [syn]:[anti] product ratio depends on both temperature and pressure of the reaction system, and is kinetically, rather than thermodynamically, controlled. Most experimental data measured near room temperature at 2–10 Torr He pressure agree with the predicted results in terms of either the absolute rate constants for syn- and anti-CH3CHOO production and/or the [syn]:[anti] product ratio. If the stereo-specificity of syn- and anti-CH3CHOO formation were controlled thermodynamically, one would predict [syn]:[anti] = 241:1 independent of pressure at 298 K, instead of (80 ± 10):(20 ± 10) measured experimentally or 86:14 predicted theoretically at 5-Torr He pressure.

Methods

All calculations were performed using Gaussian 16 software. Geometry, frequency, and IRC analysis calculations were conducted at the B3LYP/Aug-cc-PVTZ level of theory. The potential energy surface of the system was computed at the CCSD(T)/Aug-cc-PVTZ//B3LYP/Aug-cc-PVTZ level. The rate constants for individual product channels in the reaction, including the direct production of IO + CH3CHO and the collisional deactivation of the excited CH3CHIO2* intermediate formed by the association of CH3CHI with O2, were predicted by statistical theory calculations using the Variflex code.