US EPA

608731 

Journal Article 

The acid catalyzed nitration of methanol: formation of methyl nitrate via aerosol chemistry 

Iraci, L; Riffel, B; Robinson, C; Michelsen, R; Stephenson, R 

2007 

Yes 

Journal of Atmospheric Chemistry
ISSN: 0167-7764
EISSN: 1573-0662 

58 

3 

253-266 

10.1007/s10874-007-9091-9 

WOS:000251874800005 

http://://WOS:000251874800005
Exit
 

The aqueous phase acid-catalyzed reaction of methanol (CH3OH) with nitric acid (HNO3) to yield methyl nitrate (CH3ONO2) under atmospheric conditions has been investigated using gas-phase infrared spectroscopy. Reactions were conducted in aqueous sulfuric acid solutions (50.5–63.6 wt.%) with [CH3OH] = 0.00005–0.005 M and [HNO3] = 0.02–0.21 M, at 278.2–328.6 K. Methyl nitrate production rates increased linearly with CH3OH and HNO3 concentrations and exponentially with sulfuric acid weight percent within the regime studied. Rates increased linearly with nitronium ion $$\left( {{\text{NO}}_2^ + } \right)$$ concentration, indicating that the reaction involves $${\text{NO}}_2^ + $$ as the nitrating agent under these conditions. At 298 K, the rate of methyl nitrate production can be calculated from k obs [CH3OH][HNO3], where k obs = 2.337 × 10^{−13}(exp(0.3198*wt.% H2SO4)) when the solubility of CH3ONO2 in acidic solution is approximated by H* for pure water. The temperature dependence of the rate coefficient is related to solution composition, with activation energies of 59 and 49 kJ/mol at 51.1 and 63.6 wt.% H2SO4, respectively, when k is calculated from rate $$\left[ {{\text{NO}}_2^ + } \right]^{ - 1} \left[ {{\text{CH}}_3 {\text{OH}}} \right]^{ - 1} $$ . The temperature dependence has also been parameterized for application to the atmosphere, but the small quantities of $${\text{NO}}_2^ + $$ present in aerosol particles will result in methyl nitrate production rates too small to be of significance under most atmospheric conditions. [ABSTRACT FROM AUTHOR] Copyright of Journal of Atmospheric Chemistry is the property of Springer Science & Business Media B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts) 

METHANOL; ENVIRONMENTAL aspects; METHYL groups; NITRATES; AEROSOLS; NITRIC acid; INFRARED spectroscopy; SULFURIC acid; CHEMICAL kinetics -- Effect of temperature on; NITRATION; Aerosol chemistry; Alcohol