Bromoform

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Bromoform
Skeletal formula of bromoform Stereo, skeletal formula of bromoform with the explicit hydrogen added
Spacefill model of bromoform
Identifiers
Abbreviations
CAS number 75-25-2 YesY
PubChem 5558
ChemSpider 13838404 YesY
UNII TUT9J99IMU YesY
EC number 200-854-6
UN number 2515
DrugBank DB03054
KEGG C14707 YesY
MeSH bromoform
ChEBI CHEBI:38682 YesY
ChEMBL CHEMBL345248 YesY
RTECS number PB5600000
Beilstein Reference 1731048
Gmelin Reference 49500
Jmol-3D images Image 1
Properties
Molecular formula CHBr3
Molar mass 252.73 g mol−1
Appearance Colorless liquid
Density 2.89 g mL−1
Melting point −4 to 16 °C; 25 to 61 °F; 269 to 289 K
Boiling point 147 to 151 °C; 296 to 304 °F; 420 to 424 K
Solubility in water 3.2 g L−1 (at 30 °C)
log P 2.435
Vapor pressure 670 Pa (at 20.0 °C)
kH 17 μmol Pa−1 kg−1
Acidity (pKa) 13.7
Refractive index (nD) 1.595
Thermochemistry
Specific
heat capacity
C
130.5 J K−1 mol−1
Std enthalpy of
formation
ΔfHo298
6.1–12.7 kJ mol−1
Std enthalpy of
combustion
ΔcHo298
−549.1–−542.5 kJ mol−1
Hazards
MSDS External MSDS
GHS pictograms The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The environment pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
GHS hazard statements H302, H315, H319, H331, H411
GHS precautionary statements P261, P273, P305+351+338, P311
EU Index 602-007-00-X
EU classification Toxic T Dangerous for the Environment (Nature) N
R-phrases R22, R23, R36/38, R51/53
S-phrases (S1/2), S45, S63
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
LD50 933.0 mg kg−1 (oral, rat)
Related compounds
Related alkanes
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Bromoform (CHBr3) is a brominated organic solvent, pale yellow liquid at room temperature, with a high refractive index, very high density, and sweet odor is similar to that of chloroform. It is a trihalomethane, and is one of the four haloforms, the others being fluoroform, chloroform, and iodoform. Bromoform can be prepared by the haloform reaction using acetone and sodium hypobromite, by the electrolysis of potassium bromide in ethanol, or by treating chloroform with aluminum bromide. Currently its main use is as a laboratory reagent.

A bottle of bromoform with some in the adjacent beaker

Uses[edit]

Only small quantities of bromoform are currently produced industrially in the United States. In the past, it was used as a solvent, sedative and flame retardant, but now it is mainly used as a laboratory reagent, for example as an extraction solvent.

Bromoform's high density makes it useful for separation of minerals by density. When two samples are mixed with bromoform and then allowed to settle, the top layer will contain minerals lighter than bromoform, and the bottom layer will contains heavier minerals. Slightly less dense minerals can be separated in the same way by mixing the bromoform with a small amount of a less dense and fully miscible solvent.

Environment and Toxicology[edit]

Natural production of bromoform by phytoplankton and seaweeds in the ocean is thought to be its predominant source in the environment.[2] However, locally significant amounts of bromoform enter the environment formed as disinfection byproducts known as trihalomethanes when chlorine is added to drinking water to kill bacteria. It is somewhat soluble in water and readily evaporates into the air. Bromoform is the main trihalomethane produced in salt swimming pools with some public swimming pools found to contain up to 1.3 ppm (parts per million) bromoform.[3] Occupational skin exposure limits are set at 0.5 ppm.[4]

The substance may be hazardous to the environment, and special attention should be given to aquatic organisms. Its volatility and environmental persistence makes bromoform's release, either as liquid or vapor, strongly inadvisable.

Bromoform can be absorbed into the body by inhalation and through the skin. The substance is irritating to the respiratory tract, the eyes, and the skin, and may cause effects on the central nervous system and liver, resulting in impaired functions. It is soluble in about 800 parts water and is miscible with alcohol, benzene, chloroform, ether, petroleum ether, acetone, and oils. Its LD50 is 7.2 mmol/kg in mice, or 1.8g/kg. Bromoform is a confirmed animal carcinogen; (ACGIH 2004). Carcinogen category: 3B; (DFG 2004).

References[edit]

  1. ^ "bromoform - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification. Retrieved 18 June 2012. 
  2. ^ Palmer C J and Reason C J (2009), Relationships of surface bromoform concentrations with mixed layer depth and salinity in the tropical oceans (2009), Global Biogeochemical Cycles, 23, GB2014.
  3. ^ Beech AJ et al (1980) Nitrates, Chlorates and Trihalomethanes in Swimming Pool Water. Am J Public Health, 70(1), 79-82
  4. ^ CDC - NIOSH Pocket Guide to Chemical Hazards

External links[edit]