Hydrogen Chloride Gas Generators

[WillD]

HCl gas is obtained by mixing sulfuric acid (e.g., commercial drain cleaner) or hydrochloric acid (muriatic acid) and salt (e.g., rock or table salt) in a reaction container, referred to as an HCl generator.

HCl's generators encountered in the field have included:
• propane tanks
• plastic gasoline containers
• 2 liter pop bottles
• soda syrup cylinders
• medical oxygen cylinders
• freon and helium cylinders
• ketchup dispensers
• ziploc or plastic bags
• glass vacuum flasks
• fire extinguisher bottles
• acetylene cylinders
• dive bottles
• self-contained breathing apparatus bottles
• baby bottles
• various other containers

Types of generators encountered:
As observed at clandestine labs, an HCl generator typically has the following operational design elements:
1. ability to add acid and salt together in small quantities, then be sealed
2. ability to contain pressurized HCl gas
3. ability to valve off the generator
4. ability to transfer the HCl gas through a hose
5. portability
6. inexpensive
7. considered by the clandestine lab operator to be disposable
8. ability to disguise as a common household item (e.g. propane tank, etc.)

A dip tube, which aids in filling, may be present. It typically extends 4 inches down from the propane valve into the tank. When properly filled, a valve is opened, allowing gas to escape up through this dip tube. When the liquid level in the tank reaches the dip tube level, liquid will begin escaping the dip tube opening, indicating the tank is full.

Tanks used as HCl generators typically do not have a properly-rated valve installed. They often have a home-made arrangement of brass, galvanized copper and stainless steel fittings. Stainless steel valves may be rated for HCl.

Standard propane tank valves have a pressure-relief valve that actuates at about 375 psi. At that pressure, it is designed to automatically open, decreasing the pressure in the tank.

Additional types of HCl generators:

Chemistry of HCl generators:

H2SO4 (aq) + 2NaCl (s) ---> 2 HCl (g)+ Na2SO4 (s)
(sulfuric acid + sodium chloride ---> hydrogen chloride gas + sodium sulfate)

This reaction generates heat and pressure as the HCl is produced. Warm up the contents of their generator to produce additional HCl gas after the pressure has dropped and the reaction neared completion. Higher temperatures of any gas typically result in higher pressures.

 

[ch3wbacca]

Some of that is misleading.

Among other places... but to the point. Hydrochloric acid does not produce hydrogen chloride when mixed with sodium chloride. Sodium chloride is a neutral salt and not react with hydrochloric acid.

Sodium chloride does react with sulphuric acid to produce hydrogen chloride, however this occurs bc it is a dehydration reaction. There is considerable amount of heat produced and thus steam is released also. Which is troublesome for our purposes. We want dry hydrogen chloride.

There is a better method. Dripping sulphuric acid onto hydrochloric acid produces fairly dry hydrogen chloride, especially if you pass the gas through a drying tube or another container of highly concentrated sulphuric acid it will result in very dry gas suitable for most any purpose.

My preferred method is calcium chloride and hydrochloric acid. It is a slower less violent reaction. Less heat and less moisture is generated. I can usually use it as is if I'm in a pinch, but if time and cirucmstances allow I also pass it through a drying tube of either more calcium chloride or container of sulphuric acid, magnesium sulphate has also been used for drying but there are better purposes for it.

 

[WillD]

Thank u for the comment. We will fix it.

 

[WillD]

It's a typo. It was about the interaction of muriatic acid with a concentrated sulfuric acid, to obtain a dry gaseous hydrogen chloride. Using this method excludes the problem of hard solid precipitate. The method with the use of calcium chloride as a source and how the dryer is also good, we consider any available options and definitely indicate it. Only there is a question, how do you deal with calcium sulfate sediment?

 

[Osmosis Vanderwaal]

A topic of debate previously was the reaction of muriatic acid and aluminium (foil) my impression was aluminium chloride is the by-product and hydrogen gas was the main product but since that conversation here, I have seen in a chemistry book, the claim that this reaction produces HCl gas. If so it has advantages. Doesn't require heat, less conspicuous, less caustic chemicals to keep around. They didn't offer any mechanism or balanced equation, so what IS the product of this reaction?

 

[Osmosis Vanderwaal]

Ok, 30 different sites say aluminium chloride and hydrogen gas.

 

[zaners]

Does it need to be pure muriatic acid?

 

[SoldadoDeDrogas]

@zaners, for the purpose of creating HCl gas, no.
@FritBuchner you are correct, aluminum chloride and hydrogen gas are produced. I've seen those claims aswell and had to look into it myself, it is even mentioned in my favorite 'red p cook 101' demonstration, I don't understand why. In the video, for example, it says required items: sulfuric acid and table salt or muriatic acid and aluminum foil, implying that you create the HCl gas this way. Perhaps there are slight amounts produced or a chain reaction will occur if left in the same vessel?

 

[Osmosis Vanderwaal]

It would take a strong base to strip that chloride ion. NaOH,+ AlCl= aluminium hydroxide,(AlOH) and sodium chloride (NaCl)