Reaction mechanism of methyl nitrite dissociation during co catalytic coupling to dimethyl oxalate：A density functional theory study

Dissociation of methyl nitrite is the first step during CO catalytic coupling to dimethyl oxalate followed by hydrogenation to ethyl glycol in a typical coal to liquid process. In this work, the first-principle calculations based on density functional theory were performed to explore the reaction me...

Full description

Saved in:
Bibliographic Details
Published inChinese journal of chemical engineering Vol. 24; no. 1; pp. 132 - 139
Main Authors Fan, Chen, Luo, Man, Xiao, Wende
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.01.2016
Subjects
Catalytic
Density functional theory
Dissociation
Methyl nitrite
Non-catalytic
一氧化碳
亚硝酸钠
催化偶联反应
反应机理
密度泛函理论
第一原理计算
草酸二甲酯
解离
Catalytic
Density functional theory
Non-catalytic
Dissociation
Methyl nitrite
Online AccessGet full text

Cover

More Information
Summary:Dissociation of methyl nitrite is the first step during CO catalytic coupling to dimethyl oxalate followed by hydrogenation to ethyl glycol in a typical coal to liquid process. In this work, the first-principle calculations based on density functional theory were performed to explore the reaction mechanism for the non-catalytic dissociation of methyl nitrite in the gas phase and the catalytic dissociation of methyl nitrite on Pd（111） surface since palladium supported on alpha-alumina is the most effective catalyst for the coupling. For the non-catalytic case, the calculated results show that the CH_3O–NO bond will break with a bond energy of 1.91 eV, and the produced CH_3O radicals easily decompose to formaldehyde, while the further dissociation of formaldehyde in the gas phase is difficult due to the strong C–H bond. On the other hand, the catalytic dissociation of methyl nitrite on Pd（111） to the adsorbed CH_3O and NO takes place with a small energy barrier of 0.03 eV. The calculated activation energies along the proposed reaction pathways indicate that（i） at low coverage, a successive dehydrogenation of the adsorbed CH_3O to CO and H is favored while（ii） at high coverage, hydrogenation of CH_3O to methanol and carbonylation of CH_3O to methyl formate are more preferred. On the basis of the proposed reaction mechanism,two meaningful ways are proposed to suppress the dissociation of methyl nitrate during the CO catalytic coupling to dimethyl oxalate.
Bibliography:11-3270/TQ
Methyl nitrite Catalytic Non-catalytic Dissociation Density functional theory
Dissociation of methyl nitrite is the first step during CO catalytic coupling to dimethyl oxalate followed by hydrogenation to ethyl glycol in a typical coal to liquid process. In this work, the first-principle calculations based on density functional theory were performed to explore the reaction mechanism for the non-catalytic dissociation of methyl nitrite in the gas phase and the catalytic dissociation of methyl nitrite on Pd（111） surface since palladium supported on alpha-alumina is the most effective catalyst for the coupling. For the non-catalytic case, the calculated results show that the CH_3O–NO bond will break with a bond energy of 1.91 eV, and the produced CH_3O radicals easily decompose to formaldehyde, while the further dissociation of formaldehyde in the gas phase is difficult due to the strong C–H bond. On the other hand, the catalytic dissociation of methyl nitrite on Pd（111） to the adsorbed CH_3O and NO takes place with a small energy barrier of 0.03 eV. The calculated activation energies along the proposed reaction pathways indicate that（i） at low coverage, a successive dehydrogenation of the adsorbed CH_3O to CO and H is favored while（ii） at high coverage, hydrogenation of CH_3O to methanol and carbonylation of CH_3O to methyl formate are more preferred. On the basis of the proposed reaction mechanism,two meaningful ways are proposed to suppress the dissociation of methyl nitrate during the CO catalytic coupling to dimethyl oxalate.
ISSN:1004-9541
2210-321X
DOI:10.1016/j.cjche.2015.06.007