Atmospheric chemistry of ethyl propionate

Vibeke Friis Andersen; Kristian Ørnsø; Solvejg Jørgensen; Ole John Nielsen; Matthew Stanley Johnson

doi:10.1021/jp300897t

Atmospheric chemistry of ethyl propionate

Vibeke Friis Andersen, Kristian Ørnsø, Solvejg Jørgensen, Ole John Nielsen, Matthew Stanley Johnson

Kemisk Institut

20 Citationer (Scopus)

Abstract

Ethyl propionate is a model for fatty acid ethyl esters used as first-generation biodiesel. The atmospheric chemistry of ethyl propionate was investigated at 980 mbar total pressure. Relative rate measurements in 980 mbar N ₂ at 293 ± 0.5 K were used to determine rate constants of k(C ₂H ₅C(O)OC ₂H ₅ + Cl) = (3.11 ± 0.35) × 10 ^-11, k(CH ₃CHClC(O)OC ₂H ₅ + Cl) = (7.43 ± 0.83) × 10 ^-12, and k(C ₂H ₅C(O)OC ₂H ₅ + OH) = (2.14 ± 0.21) × 10 ^-12 cm ³ molecule ^-1 s ^-1. At 273-313 K, a negative Arrhenius activation energy of -3 kJ mol ^-1 is observed. The chlorine atom-initiated oxidation of ethyl propionate in 980 mbar N ₂ gave the following products (stoichiometric yields): ClCH ₂CH ₂C(O)OC ₂H ₅ (0.204 ± 0.031), CH ₃CHClC(O)OC ₂H ₅ (0.251 ± 0.040), and C ₂H ₅C(O)OCHClCH ₃ (0.481 ± 0.088). The chlorine atom-initiated oxidation of ethyl propionate in 980 mbar of N ₂/O ₂ (with and without NO _x) gave the following products: ethyl pyruvate (CH ₃C(O)C(O)OC ₂H ₅), propionic acid (C ₂H ₅C(O)OH), formaldehyde (HCHO), and, in the presence of NO _x, PAN (CH ₃C(O)OONO ₂). The lack of acetaldehyde as a product suggests that the CH ₃CH(O)C(O)OC ₂H ₅ radical favors isomerization over decomposition. From the observed product yields, we conclude that H-abstraction by chlorine atoms from ethyl propionate occurs 20.4 ± 3.1%, 25.1 ± 4.0%, and 48.1 ± 8.8% from the CH ₃-, -CH ₂-, and -OCH ₂- groups, respectively. The rate constant and branching ratios for the reaction between ethyl propionate and the OH radical were investigated theoretically using quantum mechanical calculations and transition state theory. The stationary points along the reaction path were optimized using the CCSD(T)-F12/VDZ-F12//BH&HLYP/aug-cc- pVTZ level of theory; this model showed that OH radicals abstract hydrogen atoms primarily from the -OCH ₂- group (80%).

Originalsprog	Engelsk
Tidsskrift	Journal of Physical Chemistry A
Vol/bind	116
Udgave nummer	21
Sider (fra-til)	5164-5179
Antal sider	16
ISSN	1089-5639
DOI	https://doi.org/10.1021/jp300897t
Status	Udgivet - 31 maj 2012

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10.1021/jp300897t

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@article{fceb98170c124bc0a500f7744011de75,

title = "Atmospheric chemistry of ethyl propionate",

abstract = "Ethyl propionate is a model for fatty acid ethyl esters used as first-generation biodiesel. The atmospheric chemistry of ethyl propionate was investigated at 980 mbar total pressure. Relative rate measurements in 980 mbar N 2 at 293 ± 0.5 K were used to determine rate constants of k(C 2H 5C(O)OC 2H 5 + Cl) = (3.11 ± 0.35) × 10 -11, k(CH 3CHClC(O)OC 2H 5 + Cl) = (7.43 ± 0.83) × 10 -12, and k(C 2H 5C(O)OC 2H 5 + OH) = (2.14 ± 0.21) × 10 -12 cm 3 molecule -1 s -1. At 273-313 K, a negative Arrhenius activation energy of -3 kJ mol -1 is observed. The chlorine atom-initiated oxidation of ethyl propionate in 980 mbar N 2 gave the following products (stoichiometric yields): ClCH 2CH 2C(O)OC 2H 5 (0.204 ± 0.031), CH 3CHClC(O)OC 2H 5 (0.251 ± 0.040), and C 2H 5C(O)OCHClCH 3 (0.481 ± 0.088). The chlorine atom-initiated oxidation of ethyl propionate in 980 mbar of N 2/O 2 (with and without NO x) gave the following products: ethyl pyruvate (CH 3C(O)C(O)OC 2H 5), propionic acid (C 2H 5C(O)OH), formaldehyde (HCHO), and, in the presence of NO x, PAN (CH 3C(O)OONO 2). The lack of acetaldehyde as a product suggests that the CH 3CH(O)C(O)OC 2H 5 radical favors isomerization over decomposition. From the observed product yields, we conclude that H-abstraction by chlorine atoms from ethyl propionate occurs 20.4 ± 3.1%, 25.1 ± 4.0%, and 48.1 ± 8.8% from the CH 3-, -CH 2-, and -OCH 2- groups, respectively. The rate constant and branching ratios for the reaction between ethyl propionate and the OH radical were investigated theoretically using quantum mechanical calculations and transition state theory. The stationary points along the reaction path were optimized using the CCSD(T)-F12/VDZ-F12//BH&HLYP/aug-cc- pVTZ level of theory; this model showed that OH radicals abstract hydrogen atoms primarily from the -OCH 2- group (80%).",

author = "Andersen, {Vibeke Friis} and Kristian {\O}rns{\o} and Solvejg J{\o}rgensen and Nielsen, {Ole John} and Johnson, {Matthew Stanley}",

year = "2012",

month = may,

day = "31",

doi = "10.1021/jp300897t",

language = "English",

volume = "116",

pages = "5164--5179",

journal = "Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory",

issn = "1089-5639",

publisher = "American Chemical Society",

number = "21",

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TY - JOUR

T1 - Atmospheric chemistry of ethyl propionate

AU - Andersen, Vibeke Friis

AU - Ørnsø, Kristian

AU - Jørgensen, Solvejg

AU - Nielsen, Ole John

AU - Johnson, Matthew Stanley

PY - 2012/5/31

Y1 - 2012/5/31

N2 - Ethyl propionate is a model for fatty acid ethyl esters used as first-generation biodiesel. The atmospheric chemistry of ethyl propionate was investigated at 980 mbar total pressure. Relative rate measurements in 980 mbar N 2 at 293 ± 0.5 K were used to determine rate constants of k(C 2H 5C(O)OC 2H 5 + Cl) = (3.11 ± 0.35) × 10 -11, k(CH 3CHClC(O)OC 2H 5 + Cl) = (7.43 ± 0.83) × 10 -12, and k(C 2H 5C(O)OC 2H 5 + OH) = (2.14 ± 0.21) × 10 -12 cm 3 molecule -1 s -1. At 273-313 K, a negative Arrhenius activation energy of -3 kJ mol -1 is observed. The chlorine atom-initiated oxidation of ethyl propionate in 980 mbar N 2 gave the following products (stoichiometric yields): ClCH 2CH 2C(O)OC 2H 5 (0.204 ± 0.031), CH 3CHClC(O)OC 2H 5 (0.251 ± 0.040), and C 2H 5C(O)OCHClCH 3 (0.481 ± 0.088). The chlorine atom-initiated oxidation of ethyl propionate in 980 mbar of N 2/O 2 (with and without NO x) gave the following products: ethyl pyruvate (CH 3C(O)C(O)OC 2H 5), propionic acid (C 2H 5C(O)OH), formaldehyde (HCHO), and, in the presence of NO x, PAN (CH 3C(O)OONO 2). The lack of acetaldehyde as a product suggests that the CH 3CH(O)C(O)OC 2H 5 radical favors isomerization over decomposition. From the observed product yields, we conclude that H-abstraction by chlorine atoms from ethyl propionate occurs 20.4 ± 3.1%, 25.1 ± 4.0%, and 48.1 ± 8.8% from the CH 3-, -CH 2-, and -OCH 2- groups, respectively. The rate constant and branching ratios for the reaction between ethyl propionate and the OH radical were investigated theoretically using quantum mechanical calculations and transition state theory. The stationary points along the reaction path were optimized using the CCSD(T)-F12/VDZ-F12//BH&HLYP/aug-cc- pVTZ level of theory; this model showed that OH radicals abstract hydrogen atoms primarily from the -OCH 2- group (80%).

AB - Ethyl propionate is a model for fatty acid ethyl esters used as first-generation biodiesel. The atmospheric chemistry of ethyl propionate was investigated at 980 mbar total pressure. Relative rate measurements in 980 mbar N 2 at 293 ± 0.5 K were used to determine rate constants of k(C 2H 5C(O)OC 2H 5 + Cl) = (3.11 ± 0.35) × 10 -11, k(CH 3CHClC(O)OC 2H 5 + Cl) = (7.43 ± 0.83) × 10 -12, and k(C 2H 5C(O)OC 2H 5 + OH) = (2.14 ± 0.21) × 10 -12 cm 3 molecule -1 s -1. At 273-313 K, a negative Arrhenius activation energy of -3 kJ mol -1 is observed. The chlorine atom-initiated oxidation of ethyl propionate in 980 mbar N 2 gave the following products (stoichiometric yields): ClCH 2CH 2C(O)OC 2H 5 (0.204 ± 0.031), CH 3CHClC(O)OC 2H 5 (0.251 ± 0.040), and C 2H 5C(O)OCHClCH 3 (0.481 ± 0.088). The chlorine atom-initiated oxidation of ethyl propionate in 980 mbar of N 2/O 2 (with and without NO x) gave the following products: ethyl pyruvate (CH 3C(O)C(O)OC 2H 5), propionic acid (C 2H 5C(O)OH), formaldehyde (HCHO), and, in the presence of NO x, PAN (CH 3C(O)OONO 2). The lack of acetaldehyde as a product suggests that the CH 3CH(O)C(O)OC 2H 5 radical favors isomerization over decomposition. From the observed product yields, we conclude that H-abstraction by chlorine atoms from ethyl propionate occurs 20.4 ± 3.1%, 25.1 ± 4.0%, and 48.1 ± 8.8% from the CH 3-, -CH 2-, and -OCH 2- groups, respectively. The rate constant and branching ratios for the reaction between ethyl propionate and the OH radical were investigated theoretically using quantum mechanical calculations and transition state theory. The stationary points along the reaction path were optimized using the CCSD(T)-F12/VDZ-F12//BH&HLYP/aug-cc- pVTZ level of theory; this model showed that OH radicals abstract hydrogen atoms primarily from the -OCH 2- group (80%).

U2 - 10.1021/jp300897t

DO - 10.1021/jp300897t

M3 - Journal article

C2 - 22524192

SN - 1089-5639

VL - 116

SP - 5164

EP - 5179

JO - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory

JF - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory

IS - 21

ER -

Atmospheric chemistry of ethyl propionate

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