Preparation of Chlorine Gas

by Eleusis

Hey... thinking about making your own chloroform or what have you? Need some chlorine gas to do it? Well, if you survive this bit of proactive Darwinism on my part, you will get what you want.

Preparation of Chlorine Gas

*DANGER* Chlorine is nasty stuff.

Molar ratios

37g KMnO4 to 7.1mL 31.45% HCl to .41g Cl

In a round bottom ground glass joint flask of 500mL capacity, place 16g Potassium Permanganate (KMnO4) and a teflon coated stirrer magnet. Assemble either a straight adapter with gas nipple or a claisen adapter with a gas adapter (see ascii below). Connect a pressure equalized addition funnel to either (put it on the center tube if using the claisen adapter).

    ||                               ||
    /\                               /\
   |  |                             |  |
   |  |     pressure equalized      |  |
   |  |      addition funnel        |  |
    \/                               \/    ___ gas adapter
    ||__                             ||   ||--
    ||-- gas nipple                  ||___||   claisen adapter
    ||                               ||-----
    /\                               /\
   /  \     round bottom flask      /  \
  /    \                           /    \
  \  o /      stirrer magnet       \ o  /
   \__/                             \__/

In the addition funnel you will eventually run a volume of "Muriatic" Acid (31.45% HCl) 19 times the weight of the KMnO4 (304mL for this example). With the funnel stopcock in the OFF position, fill it with HCl, then stopper and wire the stopper in place. Connect a bubbler setup filled with water to remove any HCl vapor (see below) to the gas nipple using teflon, synthetic rubber or polypropylene tubing (no pvc).

inlet   outlet
    ||  ||
  | ||     |
  | ||     |  Erlenmeyer flask with two-hole rubber stopper
  | ||     |  and two glass tubes, or similar, filled 3/4's
  |        |  full with water.

Obviously, whatever the chlorine gas is to be used for should be setup and connected to the outlet tube of the bubbler. At this point, start dropping the HCl from the addition funnel into the flask below at a slow enough rate such that 1-2 bubbles a second pass through the bubbler. After half the total volume of HCl has been added, turn on the magnetic stirrer to help maintain the gas flow (it will slow down otherwise). The total volume of Chlorine gas produced will be .25 moles of the normal diatomic form (Cl2), or .5 moles monoatomic.

- - Chlorine Gas Preparation Doc - 09/13/95 -