Chlorobenzene: Chlorine into Cold Benzene over an Iron Catalyst, Rabinovitz 1916

Chlorine bubbled into benzene does little on its own; with a pinch of iron catalyst it is taken up completely, swapping one hydrogen for chlorine and giving off hydrogen chloride. Louis Rabinovitz kept it at 10 to 15 °C so that tars and higher chlorides stay low, and made the catalyst from reduced iron and crystallised ferric chloride. Chlorine is a poison gas and benzene causes cancer: closed apparatus, outdoors or under a hood. Source: L. Rabinovitz, US 1,189,736 (1916). The gram example, washing and drying agents, chlorine drying, cooling and the boiling point are ours. Picture drawn by Youblob.