Section 1: Properties of Bromine

Reference Source:- Kirk Othmer Encyclopaedia of Chemical Technology 3rd Edition 1978 (Except where otherwise stated).

  • Boiling Point:        58.8°C
  • Freezing Point:    -7.25°C
  • Molecular weight: 159.8
Density of Liquid Bromine (g/ml)
15°C3.1396
20°C3.1226
25°C3.1055
  • Viscosity, 20°C, Centistokes: 0.31 (1)
  • Vapour Density (air = 1) at Boiling Point: 5.5 (2)
  • Vol Coeff of Expansion (20 – 30°C) 0.0011 per °C
  • Vapour Pressure, 175 mmHg (20°C)
  • Latent Heat of Vaporisation (Boiling Point) 187 kJ/kg  (44.8 cal/g)
  • Specific Heat of Liquid (25°C): 0.473 Kj/kg/°C (2) (0.113 cal/g/°C; 18.09 cal/mole/°C)
  • Solubility in water at 20°C: 3.41g/100g
  • Solubility of water in bromine at 20°C: 34 mg/100g
  • Entropy, liquid, cal/mole °K, 25°C: 36.4 (1)
  • Dielectric Constant, 10^5 freq., 25°C: 3.33 (1)
  • Surface tension, dynes/cm, 58.6°C: 36 (1)
  • Flash point: none
  • Fire point: none
  • Refractive index, 15°C/D: 1.661 (1)
  • Compressibility, saturated vapours, PV/RT, 25°C: 0.991 (1)

Two physical properties of bromine can be exploited to reduce evolution of fumes from a spillage, namely its density and its limited solubility in water. Laboratory tests carried out by ICI have indicated that evolution of fumes from liquid bromine caught in a water filled bund or contained and covered by a layer of water from a drenching system is suppressed by 99%.

Additional References

  1. Bromine Handling Manual, Albemarle 1995
  2. Occupational Health Guidelines for Bromine. US Dept of Labour 1978.
  3. Hildebrand et al.; Journal American Chemical Society 80, 4129 (1958).

Bromine is highly reactive and a strong oxidising agent. It will react vigorously with reducing agents and many organic materials, including solvents. Although bromine is not itself combustible, the heat of reaction is sufficient to initiate combustion when in contact with phosphorus or sulphur. Dry loose flammable material such as paper and wood shavings can be similarly ignited, and liquid bromine will attack some plastics and rubber.

Dry bromine will react violently with aluminium, titanium, mercury and alkali metals apart from sodium, but is not generally reactive with other metals. Reactivity is, however, markedly increased by traces of water or some organic impurities. Relatively few metals are resistant to moist bromine.

Bromine is very hygroscopic. Dry bromine rapidly absorbs water from the atmosphere. It is therefore advisable, except under well defined circumstances, to treat all bromine as being moist.

The information summarised below provides guidance on the selection of materials of construction. The user should consult a reputable materials supplier and the bromine supplier to satisfy himself that it will give the required performance under the actual conditions of use including temperature, pressure and presence of moisture.
Wet (1) Dry (Below 30 mg/kg)
Gas Liquid Gas Liquid
Metals
Lead (2) (3) (4) at 25°C G up to 50°C
Tantalum (3) G up to 200°C G up to 200°C
Mild Steel, Cast Iron U U U U
Aluminium/Adluminium Alloys U U U U
Stainless Steels (Austenitic) U U S(5) S(5)
Nickel, Monel U U G G
Inconel U U
Hastelloy “C” U U G G
Copper, Brass U U U U
Bronze U U
Silver U U
Titanium [S(5)] U U U
Niobium and Niobium/Tantalum Alloy
Ceramics
Stoneware, Porcelain, Glass (6) G G G G
Plastics
PTFE, PCTFE, PVDF, FEP (7) G G G G
Ebonite U U U U
CPVC, PVC U U U U
Polyethylene, Polypropylene U U U U
Notes
  • The resistance to wet bromine depends upon the water content and temperature. Bromine in contact with air of 80% relative humidity can pick up 300 mg of water per litre.
  • Chemical Lead, BS 334: 1983 (type A).
  • Data refer to gas or liquid.
  • Tin-free flux should be used for lead burning.
  • Only if found satisfactory after specific trials. Evidence on titanium is conflicting and it should be contemplated for use only with wet bromine gas and then with caution.
  • Upper temperature limit is determined by factors other than corrosion. Avoid mechanical or thermal shock.
  • Notes on the Selection and Use of Fluorocarbon Polymers
Considerable experience has been gained with the use of fluorocarbon polymers, especially polyvinylidene fluoride (PVDF). PVDF lined mild steel pipework and solid PVDF (ie pipework made entirely of PVDF, that is, not a lining) are both commonly available commercially. Both have excellent resistance to wet and dry bromine.All fluorocarbon polymers are permeable, the degree of permeability progressively increasing from PVDF to PCTFE and to PTFE. Experience has shown that PVDF linings are chemically resistant to wet and dry bromine up to temperatures of 120°C. Considerable stress and distortion occur at higher temperatures and the maximum temperature recommended is 95°C.Where solid PVDF pipework is used it should be of fusion weld construction and jointed with steel backed stub or full face flanges. Socket weld joints are used in sizes up to about 3″ ns and butt welds in sizes of 3″ ns and above. Severe embrittlement has been reported in both butt and socket welds on certain PVDF polymers. Before using solid PVDF pipework with fusion weld joints the conditions of use should be fully considered and advice sought. In all cases particular attention should be given to specifying and controlling the fabrication methods to be used.Except over very short distances all pipework should be continuously supported and free from imposed stresses (eg heavy values). Initially most solid PVDF pipework has the advantage of being translucent, but this will be limited in time by permeation of bromine into it. Where BS or Industry Standards have not yet been established the design and construction of plastic pipelines should be strictly in accord with the manufacturer’s recommendations and installed by competent personnel using suitable equipment approved by the manufacturer. Pipework should be suitably examined and tested before use with bromine.
Services
Handbook

The purpose of this document is to provide information and guidance to both bromine users and trained response personnel. The manual contains technical facts, engineering detail, health information and media response data.