Chemistry of a Mist of Bleach in Air/CO2 Good Disinfectant But Safe?
Here is the chemistry as to why airborne mist of Chlorine Bleach exposed to CO2 in air, is likely an excellent disinfecting agent.
First, I note that the action of CO2 gas on aqueous hypochlorite:
OCl- (aq) + CO2 (g) + H2O (l) = HOCl (aq) + HCO3- (aq)
forming hypochlorous acid (source: see https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC2199... ) which is reportedly 80 times more powerful than hypochlorite (reference: see,
for example, the discussion presented here https://www.cleanroomtechnology.com/news/article_page/The_sc... ). And even further, with the introduced amphoteric bicarbonate, even more HOCl:
OCl- (aq) + HCO3- (aq) = HOCl (aq) + CO3(2-) (aq)
Interestingly, reported by Watt’s in his Dictionary of Chemistry, page 16, to quote:
“Properties:- An aqueous solution of HClO smells like Cl2O.”
as:
Cl2O + H2O = 2 HOCl
where I suspect that Watt knows full well the difference in smell between chlorine and dichlorine monoxide. I note this as there are many websites
claiming (see, for example, https://www.oakgov.com/homelandsecurity/Documents/Bleach%20F...), in alkaline conditions of hypochlorite bleach, the creation of free chlorine,
which even if created by some path (like via sunlight forming HCl from the HOCl and then, HCl + HOCl creates H2O releasing Cl2), the action of
chlorine on aqueous NaOCl is a cited path to again HOCl.
So, as a possible explanation of this strange chemistry, I cite other known properties of Cl2O, which per Wikipedia (https://en.wikipedia.org/wiki/Dichlorine_monoxide) includes, to quote:
“At room temperature it exists as a brownish-yellow gas which is soluble in both water and organic solvents. Chemically, it is a member of the
chlorine oxide family of compounds, as well as being the anhydride of hypochlorous acid. It is a strong oxidiser and chlorinating agent.”
So, the good solubility in organics and strong chlorinating abilities of Cl2O would seem to imply that food products, like butter, in proximity to
chlorine monoxide gas, could in time be expected to become tainted. There was even an anecdotal report made on another forum to this effect when eggs
washed in bleach, likely exposed to CO2, liberated Cl2O and tainted the butter, cake and other content of the refrigerator. This is in accord with
another source (https://pubchem.ncbi.nlm.nih.gov/compound/Chlorine-monoxide#...), to quote:
“Dichlorine monoxide has been used as an intermediate in the manufacture of calcium hypochlorite and in sterilization for space applications. Its
use in the preparation of chlorinated solvents and chloroisocyanurates has been described. Dichlorine monoxide has been shown to be effective in
bleaching of pulp (qv) and textiles.”
So, while HOCl/Cl2O have powerful disinfecting abilites, they are not likely safe to inhale. In the lungs, HOCl can promote a fenton-type reaction, in
the presence of transition rich dust particles, as follows (reference, see https://www.sciencedirect.com/topics/chemistry/hypochlorous-... and relatedly in fenton conditions, for example, "Generation of Hydroxyl Radicals
from Dissolved Transition Metals in Surrogate Lung Fluid Solutions" by Edgar Vidrio, et al at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2626252/ .):
Fe(2+)/Cu(+) + HOCl → Fe(3+) + •OH + Cl- (at pH >5)
Fe(2+)/Cu(+) + HOCl → Fe(3+) + •Cl + OH- (at pH <5)
where problematic radical creation can lead to cancer and other lung issues. This is a possible explanation as to why some sites argue questionable
chemistry (to escape liability for toxic fumes?).
So, bottom line, using H2O/NaOCl/CO2 is fine for disinfecting, but not likely safe, in my estimation (and also others, see https://learn.compactappliance.com/cleaning-with-bleach/), in the presence of humans (and apparently small animals) owing to the potential of
immediate and even more serious longer-term disease issues.
[Edited on 29-6-2020 by AJKOER]
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