Unimolecular Decomposition Reactions of Propylamine and Protonated Propylamine

Mansour H Almatarneh; Ismael A Elayan; Mazen Al-Sulaibi; Ahmad Al Khawaldeh; Sedeeqa O W Saber; Mahmood Al-Qaralleh; Mohammednoor Altarawneh

doi:10.1021/acsomega.8b02792

Unimolecular Decomposition Reactions of Propylamine and Protonated Propylamine

ACS Omega. 2019 Feb 14;4(2):3306-3313. doi: 10.1021/acsomega.8b02792. eCollection 2019 Feb 28.

Authors

Mansour H Almatarneh^{1

2}, Ismael A Elayan¹, Mazen Al-Sulaibi¹, Ahmad Al Khawaldeh¹, Sedeeqa O W Saber^{1

2

3

4}, Mahmood Al-Qaralleh¹, Mohammednoor Altarawneh^{3

4}

Affiliations

¹ Department of Chemistry, University of Jordan, Amman 11942, Jordan.
² Chemistry Department, Memorial University, St. John's, Newfoundland and Labrador A1B 3X7, Canada.
³ School of Engineering and Information Technology, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia.
⁴ Chemical Engineering Department, Al-Hussein Bin Talal University, Ma'an 71111, Jordan.

Abstract

A detailed computational study of the decomposition reaction mechanisms of cis-propylamine (cis-PA), trans-propylamine (trans-PA), and the cis-isomer of its protonated form (cis-HPA) has been carried out. Fourteen major pathways with their kinetic and thermodynamic parameters are reported. All reported reactions have been located with a concerted transition state, leading to significant products that agree with previous theoretical and experimental studies. Among six decomposition pathways of trans-PA, the formation of propene and NH₃ is the significant one, kinetically and thermodynamically, with an activation energy barrier of 281 kJ mol^-1. The production of two carbenes is found via two different transition states, where the reactions are thermodynamically controlled and reversible. Furthermore, five decomposition pathways of cis-PA have been considered where the formation of ethene, methylimine, and H₂ is the most plausible one with an activation energy barrier of 334 kJ mol^-1. The results show that the formation of propene and NH₄ ⁺ from the decomposition of cis-HPA is the most favorable reaction with an activation barrier of 184 kJ mol^-1, that is, the lowest activation energy calculated for all decomposition pathways.