Hydrochloric acid

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Legality: DEA Listed Chemicals

Production of this substance may be illegal in some jurisdictions under certain circumstances.

21CFR1310.02 a & b

In 1995/6, two lists were created "List I" and "List II", for which commercial manufacturers and distributors must register, and for which possession with the intent to manufacture illegal substances (such as methamphetamine, ecstasy, etc) is illegal. On these a few dozen "precursor" compounds commonly used in the manufacture of illegal drugs. [1] [2]

Bottom line: Do not produce this chemical without checking to make sure that you may do so legally.

 
 
Hydrochloric acid
DEA LIST I/II SUBSTANCE
Chemical formula HCl(aq)
Water azeotrope(%w/w) 20.2% 
Water azeotrope bp(°C) 110
NFPA 704
NFPA704.png
0
3
1
ACID


Hydrochloric acid is a solution of hydrogen chloride dissolved in water.

Uses

  • Industrial chemical
  • Chlorination
  • Feedstock for aqua regia

Natural occurrence

  • Hydrochloric acid is produced in the human stomach.

Hazards

  • Extremely corrosive, reactive with many metals.

Character

Concentration Density Acidity Viscosity Specific
heat
Vapor
pressure
Boiling
point
Melting
point
Molarity %w/w g/L Baumé sg. pH pKa mPa·s kJ/(kg·K) kPa °C °C
2.87 10% 104.80 6.6 1.048 −0.5 1.16 3.47 1.95 103 −18
6.02 20% 219.60 13 1.098 −0.8 1.37 2.99 1.40 108 −59
20.2% (az) 110
9.45 30% 344.70 19 1.149 −1.0 1.70 2.60 2.13 90 −52
10.17 32% 370.88 20 1.159 −1.0 1.80 2.55 3.73 84 −43
10.90 34% 397.46 21 1.169 −1.0 1.90 2.50 7.24 71 −36
11.64 36% 424.44 22 1.179 −1.1 1.99 2.46 14.5 61 −30
12.39 38% 451.82 23 1.189 −1.1 2.10 2.43 28.3 48 −26
The reference temperature and pressure for the above table are 20 °C and 101.325 kPa.
Vapor pressure values are taken from the International Critical Tables and refer to the total vapor pressure of the solution.

Production

Synthesis

via sulfuric acid

Combine concentrated sulfuric acid with salt, yielding hydrogen chloride and sodium bisulfate and/or sodium sulfate. The first is favored energetically, so if the chemicals are available in (near) that ratio, the bisulfate will be produced.

H2SO4 + NaCl NaHSO4 + HCl
H2SO4 + 2 NaCl Na2SO4 + 2 HCl

via sodium bisulfate

Dry distill sodium bisulfate and salt, producing sodium sulfate and hydrogen chloride gas

NaHSO4(s) + NaCl(s)
{
heat}
Na2SO4(s) + HCl(g)

Testing

Purification

Azeotropic distillation at 108.6°C, giving 20.2%w/w HCl. This azeotrope is removed completely by adding 25% by weight calcium chloride, allowing the HCl to be boiled off the water in its entirety. The remaining water can be boiled dry to recycle the CuCl2.

Storage

Disposal

Neutralize with sodium carbonate or calcium carbonate

Na2CO3 + 2 HCl 2 NaCl + CO2 + H2O
CaCO3 + 2 HCl CaCl2 + CO2 + H2O

See Also

References

  1. "Emphasizing the "Control" in controlled substances"
    United States Drug Enforcement Agency
    link last accessed 11 September 2012.
  2. "Controlled Substances Act; Title 21; Chapter 13; Subchapter I"
    United States Food & Drug Administration
    link last accessed 11 September 2012.