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A lot of sources on the internet claim that mixing rubbing alcohol with chlorinated bleach produces chloroform.

Rubbing alcohol is isopropanol, and bleach is sodium hypochlorite. Neither of these look like typical reagents for the haloform reaction. So I ask, is chloroform really produced, and if so, how?

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    $\begingroup$ IIRC, dropping ethanol on calcium hypochlorite/chloride reportedly forms chloroform, not sure about isopropanol. From water treatment analysis, if water to be chlorinated contains organic substances, it frequently leads to chloroform concentration in dozens micrograms per litre, not being allowed to be distributed. $\endgroup$
    – Poutnik
    Commented Jul 12, 2022 at 13:53
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    $\begingroup$ "Rubbing alcohol" is whatever blend the manufacturer uses: some percentage water (usually between 30 and 50%), denatured ethanol, isopropanol, scent, etc. Look at the label to see if it's ethanol-base or isopropanol based. en.wikipedia.org/wiki/Rubbing_alcohol . Note that WebMD and other sources may state only isopropanol incorrectly. $\endgroup$
    – DrMoishe Pippik
    Commented Jul 12, 2022 at 17:48

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Yes, rubbing alcohol and bleach could produce chloroform when mixed, if the alcohol is isopropyl-type rubbing alcohol and the bleach is hypochlorite-type bleach. Isopropyl alcohol is indeed a substrate for the haloform reaction, according to Fuson and Bull, Chem. Rev., 15, 275 (1934) and references therein.

I can't recall the reference off the top of my head, but I believe in "dilute" solutions approaching "bleach and alcohol" the chlorination tends to continue and produces carbon tetrachloride as the main product.

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  • $\begingroup$ The mechanism suggests that the reaction does not chlorinate chloroform. [unless there is a parallel free radical reaction happening involving Cl2] $\endgroup$
    – jimchmst
    Commented Jul 14, 2022 at 4:44
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    $\begingroup$ Oh, I though it required a ketone, not an alcohol. I'm guessing the isopropanol is first oxidized to ketone and then it reacts. $\endgroup$
    – Juan Perez
    Commented Jul 14, 2022 at 14:56
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    $\begingroup$ Off the top of my head, bleach would oxidize some isopropanol in rubbing alcohol to acetone. Acetone has an acetyl group for the haloform reaction to occur. $\endgroup$
    – Kav
    Commented Nov 27 at 3:38

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