Kinetics and products of the aqueous-phase oxidation of β-caryophyllonic acid by hydroxyl radicals

Aqueous-Phase Photooxidation of Vanillic Acid: A Potential Source of Humic-Like Substances (HULIS)

“…The m / z 153.07 ion can be converted to a quinone compound, which can also undergo esterification pathways in the presence of CH 3 OH. These pathways are often observed in photochemical processes. ,, Clearly, the VA + OH reaction might result in formation of other products, but they are most likely not detected here due to the limitations of the LC-MS instrument and its separation column.…”

“…Therefore, the relative rate technique was used to investigate the rate constant of the reaction of VA with OH radicals in this study. Though for kinetic and product experiments, the same , or different light sources , were used, in this study we used the same lamp in all experiments. This method relies on the assumption that VA and the reference compounds are removed solely by reacting with OH radicals.…”

“…Therefore, no pH dependence of the rate constant was observed for the reactions of carboxylic acids in previous studies. 26,30 Although VA is an aromatic compound, it is also a carboxylic acid compound and will show different forms under acidic and basic conditions. It is difficult to estimate the pH dependence on the rate constant of the VA + OH reaction.…”

One-year measurements of secondary organic aerosol (SOA) markers in the Paris region (France): Concentrations, gas/particle partitioning and SOA source apportionment

“…They are usually based on empirical calculations (Nozière et al, 2015) and experimental values are only available for a few of them (e.g. cis-pinonic acid  2.1-3.3 days (Lai et al, 2015;Witkowski and Gierczak, 2017); β-caryophyllonic acid  1.5 h in gaseous phase (Witkowski et al, 2019) and MBTCA  1.2 days (Kostenidou et al, 2018). SOA markers are typically semi-volatile compounds but their gas/particle partitioning (GPP) is still poorly documented (Al Naiema and Stone, 2017;Bao et al, 2012;Isaacman-VanWertz et al, 2016;Lutz et al, 2019;Thompson et al, 2017;Xie et al, 2014;Yatavelli et al, 2014) but this parameter is essential for the understanding of their atmospheric fate and is furthermore needed in PM source apportionment.…”

Supplementary material to "Aqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism and light absorptivity"

“…The photooxidation reaction was carried out in a custom-made quartz, jacketed reaction vessel with the internal volume of 100 ml. The reaction vessel was closed with a glass stopper and placed inside the photochemical reactor that is described in more detail elsewhere (Witkowski et al, 2019).…”