Methyl iodide
- Methyl iodide
- Monoiodomethane
- Halon 10001
Colorless, pungent ethereal smelling liquid
Liquid
2.27 g · cm -3
-66 ° C
42 ° C
441 hPa ( 20 ° C)
Poorly in water ( 14 g · l-1 at 20 ° C)
1.62 D ( 5.4 x 10-30 C · m)
1.5304
Risk
Repealed as evidence of a carcinogenic effect
76 mg · kg -1 ( LD50, rat, oral)
-13.6 ± 0.5 kJ · mol -1
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Iodomethane outdated, methyl iodide, is a colorless, ethereal smelling liquid. It has proven in animal studies to cause cancer. Iodomethane reacts with alkali and alkaline earth metals and is used for methylation ( introduction of a methyl group ) is used by organic substances. Ammonia and amines react with iodomethane to form ammonium iodides. By repeating this reaction, quaternary ammonium ions may be generated, wherein, after each step, the amine is liberated with a base:
Quaternary ammonium ions can not be deprotonated by bases. Its salts are completely dissociated.
Representation
Methyl iodide is produced in an exothermic reaction, when iodine is added to a mixture of methanol and red phosphorus. The reagent is phosphorus triiodide iodinating, which is formed in situ:
Alternatively, methyl iodide can be prepared by the reaction of dimethyl sulfate with potassium iodide in the presence of calcium carbonate:
Methyliodid/CH3I can be purified by distillation and subsequently washing with Na2S2O3 iodine.
Physiological effects
Methyl iodide as other methylation reagents (for example, dimethyl sulfate ) carcinogenic and very toxic. The carcinogenic effect is causally connected to the methylating effect. Methyl iodide is a very good electrophile and thus tends to undergo nucleophilic substitution reactions with endogenous nucleophiles. This leads to methylation of the DNA, which is then in cell division can not be correctly read by the DNA polymerase.