All early preparations used variations of the haloform reaction.
From the en.wikipedia.org
This conversion is called the haloform reaction.
From the en.wikipedia.org
Well, I know the haloform reaction is the theoretical method, and I myself was investigating possibilities of producing bromine or hypobromite with electrolysis.
From the en.wikipedia.org
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Compounds with the formula CHX3, where X is a halogen atom
Trihalomethanes (THMs) are chemical compounds in which three of the four hydrogen atoms of methane (CH4) are replaced by halogen atoms. Many trihalomethanes find uses in industry as solvents or refrigerants. THMs are also environmental pollutants, and many are considered carcinogenic. ...