Vapor density : 4.21 (vs air)
Vapor pressure : 10 mmHg (132 °C)
Autoignition temp.: 1061 °F
Quality : meets analytical specification of Ph. Eur., BP, USP, FCC, E210
Total impurities :
  oxidisable substances, complies
  residual solvents, complies
  ≤ 0.0005 % heavy metals (as Pb)
  ≤ 0.03 % halogen compounds (as Cl)
  ≤ 0.7 % water (Karl Fischer)
Ign. residue : ≤ 0.05 % (as SO₄)
loss : ≤ 0.5 % loss on drying, 3 h (via H₂SO₄)
pH = 3-5 (20 °C, 0.1%)
bp = 249 °C (lit.)
mp = 121-125 °C (lit.)
Cation traces :
  As : ≤ 3 mg/kg
  Cu : ≤ 10 mg/kg
  Hg : ≤ 1 mg/kg
  Pb : ≤ 2 mg/kg
  Zn : ≤ 20 mg/kg
Suitability :
  complies for appearance of solution
  complies for reaction against H₂SO₄.