Computational Investigation of Radical- and Catalyst-Assisted Decomposition of CH2NO• to HCN
1Kalinga Institute of Industrial Technology Deemed to be University, School of Applied Sciences, INDIA.
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Summary
A new atmospheric pathway for hydrogen cyanide (HCN) production is identified, involving methane photolysis products and novel CH2NOX intermediates. Sulfuric acid significantly accelerates HCN formation from CH2NOCH3 decomposition.
Area of Science:
- Atmospheric Chemistry
- Astrobiology
- Quantum Chemistry
Background:
- Hydrogen cyanide (HCN) is crucial for prebiotic chemistry and present in planetary atmospheres.
- Previous models suggested HCN formation from methane photolysis products and nitrogen species.
- An unexplored atmospheric route for HCN production requires investigation.
Purpose of the Study:
- To introduce and investigate a novel atmospheric pathway for hydrogen cyanide (HCN) formation.
- To explore the decomposition mechanisms of CH2NOX intermediates leading to HCN.
- To assess the influence of catalysts on HCN production rates.
Main Methods:
- High-level quantum chemical calculations (CCSD(T)//M06-2X/6311++G(3df,3pd)) were employed.
- Reaction mechanisms for CH2NOX decomposition were studied.
- Kinetic analysis using transition state theory evaluated catalyzed and uncatalyzed pathways.
Main Results:
- A new route involving CH2NOX intermediate decomposition to HCN was identified.
- CH2NOCH3 decomposition is rapid, especially when catalyzed by sulfuric acid (H2SO4).
- H2SO4-catalyzed CH2NOCH3 decomposition shows the highest rate enhancement.
Conclusions:
- CH2NO• is identified as a novel intermediate in atmospheric nitrogen chemistry.
- Methane photolysis products (CH3•) and H2SO4 play key roles in efficient HCN production.
- This pathway is relevant for both early and modern Earth atmospheric conditions.