Differences in the reactivity of ammonium salts with methylamine
Item
Title (Dublin Core)
Differences in the reactivity of ammonium salts with methylamine
Description (Dublin Core)
The heterogeneous uptake of methylamine (MA) onto (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>, NH<sub>4</sub>HSO<sub>4</sub>, NH<sub>4</sub>NO<sub>3</sub> and NH<sub>4</sub>Cl was investigated using a Knudsen cell reactor coupled to a quadrupole mass spectrometer, in situ Raman spectrometer and theoretical calculations. Exchange reactions were observed between MA and NH<sub>4</sub>NO<sub>3</sub>, (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>, and NH<sub>4</sub>Cl were observed at 298 K. Simple acid-base reaction for MA was found taking place on NH<sub>4</sub>HSO<sub>4</sub>. CH<sub>3</sub>NH<sub>3</sub>NO<sub>3</sub> and CH<sub>3</sub>NH<sub>3</sub>Cl are not stable at low pressure and have higher dissociation vapor pressure than methylammonium sulfate. The observed uptake coefficients of MA on (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>, NH<sub>4</sub>HSO<sub>4</sub>, NH<sub>4</sub>NO<sub>3</sub> and NH<sub>4</sub>Cl at 298 K were measured to be 6.30±1.03×10<sup>−3</sup>, 1.78±0.36×10<sup>−2</sup>, 8.79±1.99×10<sup>−3</sup> and 2.29±0.28×10<sup>−3</sup>, respectively. A linear free energy relationship was found for the heterogeneous reactions between MA and NH<sub>4</sub>Cl, (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> and NH<sub>4</sub>NO<sub>3</sub>. Namely, the natural logarithm of uptake coefficients of MA on these ammonium salts is linearly related to the electrostatic potential of the H atom in the NH<sub>4</sub><sup>+</sup> group.
Creator (Dublin Core)
Liu, Y.
Han, C.
Liu, C.
Ma, J.
Ma, Q.
He, H.
Date (Dublin Core)
2018-01-15
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acp-12-4855-2012
https://acp.copernicus.org/articles/12/4855/2012/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
