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Iodoform

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Title: Iodoform  
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Subject: Diiodomethane, Carbon tetraiodide, Fluoroform, ATC code D09, Iodoalkanes
Collection: Antiseptics, Halomethanes, Iodoalkanes, Organoiodides
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Iodoform

for use of the term "iodoform" in cryptography, see Group key
Iodoform
Stereo, skeletal formula of iodoform with the explicit hydrogen added
Ball and stick model of iodoform
Spacefill model of iodoform
Sample of crystalline iodoform in a watchglass
Names
Other names
Triiodomethane
Identifiers
 Y
ATC code D09
1697010
ChEBI  Y
ChEMBL  N
ChemSpider  Y
EC number 200-874-5
Jmol-3D images Image
KEGG  Y
MeSH
PubChem
RTECS number PB7000000
UNII  Y
Properties
CHI3
Molar mass 393.73 g·mol−1
Appearance Pale, light yellow, opaque crystals
Odor Saffron-like[1]
Density 4.008 g mL−1[1]
Melting point 119 °C (246 °F; 392 K) [1]
Boiling point 218 °C (424 °F; 491 K) [1]
100 mg L−1[1]
Solubility in diethyl ether 136 g L−1
Solubility in acetone 120 g L−1
Solubility in ethanol 78 g L−1
log P 3.118
3.4 μmol Pa−1 kg−1
Structure
Hexagonal
Tetragonal
Tetrahedron
Thermochemistry
157.5 J K−1 mol−1
180.1–182.1 kJ mol−1
−716.9–−718.1 kJ mol−1
Hazards
GHS pictograms The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word WARNING
H315, H319, H335
P261, P280, P305+351+338
Harmful Xn
R-phrases R20/21/22, R36/37/38
S-phrases S26, S36/37
NFPA 704
0
2
1
Flash point 204 °C (399 °F; 477 K)
Lethal dose or concentration (LD, LC):
LD50 (Median dose)
  • 355 mg kg−1 (oral, rat)[1]
  • 1180 mg kg−1 (dermal, rat)[1]
  • 1.6 mmol kg−1(s.c., mouse)[2]
US health exposure limits (NIOSH):
PEL (Permissible)
none[3]
REL (Recommended)
0.6 ppm (10 mg/m3)[3]
N.D.[3]
Related compounds
Related haloalkanes
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 N  (: Y/N?)

Iodoform is the formula CHI3. A pale yellow, crystalline, volatile substance, it has a penetrating odor (in older chemistry texts, the smell is sometimes referred to as the smell of hospitals) and, analogous to chloroform, sweetish taste. It is occasionally used as a disinfectant. It is also known as tri-iodomethane, carbon triiodide, and methyl triiodide.

Contents

  • Synthesis and reactions 1
    • Natural occurrence 1.1
  • Applications 2
  • See also 3
  • References 4
  • External links 5

Synthesis and reactions

The synthesis of Iodoform was first described by Georges Serrulas in 1822, by reactions of iodine vapour with steam over red hot coals, and also by reaction of potassium with ethanolic iodine in the presence of water;[4] and at much the same time independently by ketone: CH3COR, acetaldehyde (CH3CHO), ethanol (CH3CH2OH), and certain secondary alcohols (CH3CHROH, where R is an alkyl or aryl group).

The reaction of iodine and base with methyl ketones is so reliable that the "iodoform test" (the appearance of a yellow precipitate) is used to probe the presence of a methyl ketone. This is also the case when testing for secondary alcohols (methyl alcohols).

Some reagents (e.g. hydrogen iodide) convert iodoform to diiodomethane. Also conversion to carbon dioxide is possible: Iodoform reacts with aqueous silver nitrate to produce carbon monoxide. When treated with powdered elemental silver the iodoform is reduced, producing acetylene. Upon heating iodoform decomposes to produce diatomic iodine, hydrogen iodide gas, and carbon.

Natural occurrence

Angel's bonnets contain iodoform and show its characteristic odor.

Applications

The compound finds small scale use as a disinfectant.[2][6] Around the beginning of the 20th century it was used in medicine as a healing and antiseptic dressing for wounds and sores, although this use is now superseded by superior antiseptics. Adolf Hitler's mother, Klara Hitler, died of iodoform poisoning brought on by her treatment for breast cancer. It is the active ingredient in many ear powders for dogs and cats, along with zinc oxide and propanoic acid, which are used to prevent infection and facilitate removal of ear hair.

See also

References

  1. ^ a b c d e f g Record in the GESTIS Substance Database of the IFA
  2. ^ a b Merck Index, 12 Edition, 5054
  3. ^ a b c "NIOSH Pocket Guide to Chemical Hazards #0343".  
  4. ^ Surellas, Georges-Simon (1822), ]Notes on the hydroiodide of potassium and on hydroiodic acid -- hydroiodide of carbon; means of obtaining instantly this compound of three elements [Notes sur l'Hydriodate de potasse et l'Acide hydriodique. -- Hydriodure de carbone; moyen d'obtenir, à l'instant, ce composé triple (in franch), Metz, France: Antoine, pp. 17–20, 28–29 
  5. ^ James, Frank A. J. L. "Cooper, John Thomas (1790–1854), chemist". Oxford Dictionary of National Biography. Oxford University Press. Retrieved 26 January 2012. 
  6. ^ Lyday, Phyllis A. (2005), "Iodine and Iodine Compounds", Ullmann's Encyclopedia of Industrial Chemistry (Wiley-VCH, Weinheim) 

External links

  • "NIOSH Pocket Guide to Chemical Hazards #0343".  
  • MSDS at JT Baker
  • A Method for the Specific Conversion of Iodoform to Carbon Dioxide
  • Article at 1911 Encyclopaedia Britannica
  • Preparation
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