Diazomethane is a compound with the gross formula CH 2 N 2 having the following structure:
| Diazomethane | |
|---|---|
 | |
| Are common | |
| Traditional names | Diazomethane |
| Chem. formula | CH 2 N 2 |
| Physical properties | |
| condition | unpleasant yellow gas |
| Molar mass | 42.04 g / mol |
| Ionization energy | |
| Thermal properties | |
| T. melt. | -145 ° C |
| T. bale. | -23 ° C |
| Steam pressure | |
| Classification | |
| Reg. CAS number | 334-88-3 |
| PubChem | |
| Reg. EINECS number | |
| Smiles | |
| Inchi | |
| Reg. EC number | 006-068-00-8 |
| RTECS | PA7000000 |
| Chebi | |
| ChemSpider | |
| Security | |
| Toxicity | toxic |
H 2 C = N≡N ↔
In its pure form, diazomethane is a yellow gas. For laboratory practice, as a rule, it is used in the form of a solution in diethyl ether . A convenient source of carbene radicals and a mild alkylating agent.
Getting
- The most convenient laboratory method is the effect of 30% alkali on bis (N-methyl-N-nitrosoamide) phthalic acid [2] :
- Another option: the reaction of N-methyl-N-nitroso-para-toluenesulfonamide or 1-methyl-3-nitro-1-nitrosoguanidine with sodium or potassium hydroxide when heated [3] :
Chemical Properties
The chemical properties of diazomethane can be described in terms of the presence of resonance [2] :
- During the pyrolysis of diazomethane, carbene CH 2 is formed : - a highly reactive short-lived particle, which is easily attached via a double or triple bond :
1. The first stage is the formation of carbene:
CH 2 = N = N → CH 2 : + N 2 ( pyrolysis or photolysis of diazomethane)
2. The second stage is the addition of carbene with the formation of cyclo compounds:
- With the protonation of diazomethane, a methyldiazonium cation is formed:
Due to this property, diazomethane quite easily enters into alkylation reactions [4] :
R-COOH + CH 2 N 2 → R-COOCH 3 + N 2
R-OH + CH 2 N 2 → R-OCH 3 + N 2
R-CHO + CH 2 N 2 → R-CO-CH 3 + N 2
Ketones in the reaction with diazomethane give a mixture of products ( Buchner – Curtius – Schlotterbeck reaction ) [5] :
- The most important is the Arndt-Eystert reaction - the conversion of a carboxylic acid into its nearest homolog using diazomethane:
Security
Diazomethane is toxic by inhalation and in contact with eyes and skin. Symptoms of poisoning include chest discomfort, headache, weakness, and in severe cases, collapse. [6] Symptoms may not appear immediately. Cases of fatal poisoning are described. [7] Like other alkylating agents , diazomethane can be carcinogenic , but it is usually blocked by the acute toxicity of diazomethane.
CH 2 N 2 is able to detonate upon contact with sharp edges of solid objects, in particular, with cracks in the glass and with polished surfaces. For the same reason, granular KOH is recommended for draining the ether solution of CH 2 N 2 . The preparation of diazomethane solutions should be carried out using a protective screen.
Notes
- ↑ 1 2 http://www.cdc.gov/niosh/npg/npgd0182.html
- ↑ 1 2 Traven V.F. Organic Chemistry, M.: IKC Akademkniga, 2004. - ISBN 5-94628-068-6 .
- ↑ DIAZOMETHANE
- ↑ Nitro and diazo compounds. Chapter 4
- ↑ XuMuK.ru - BUCHNER - CURCIUS - SLOTTERBACK REACTION - Chemical Encyclopedia
- ↑ Muir, GD (ed.) 1971, Hazards in the Chemical Laboratory , The Royal Institute of Chemistry, London.
- ↑ LeWinn, EB "Diazomethane Poisoning: Report of a fatal case with autopsy", The American Journal of the Medical Sciences , 1949, 218, 556-562