Methyllithium
MELI · LITHIUM METHANIDE · Methyllithium lithium bromide complex solution · Methyllithium solution · Lowhalide · 1-2MinEther · methyl-lithiu · METHYLLITHIUM
Identifiers & Physical Properties
| CAS No. | 917-54-4 |
|---|---|
| Molecular formula | CH3Li |
| Average molar mass | 22 g/mol |
| SMILES | [CH3-].[Li+] |
| InChIKey | DVSDBMFJEQPWNO-UHFFFAOYSA-N |
| PubChem CID | 2724049 |
| ChEBI | CHEBI:51486 |
| DTXSID | DTXSID7061273 |
Chemical & Physical Properties
| Topological polar surface area | 0 |
|---|---|
| Hydrogen bond donors | 0 |
| Hydrogen bond acceptors | 1 |
| Rotatable bonds | 0 |
| Heavy atoms | 2 |
| Formal charge | 0 |
| Complexity | 2 |
| Melting point | 70-71℃ |
| Boiling point | 88℃ |
| Density | 0.85 g/mL at 20 °C |
| Vapor density | 3 (vs air) |
| Flash point | 5 °F |
| Storage conditions | 2-8°C |
| Physical state | Solution |
| Specific gravity | 0.83 |
| Color | Colorless to yellow |
| Explosive limits | 1.7-36% (v/v) Information refers to the main component.) |
| Solubility | Reacts with water. |
| Sensitivity | Air & Moisture Sensitive |
| Hydrolytic Sensitivity | 9: reacts extremely rapidly with atmospheric moisture - may be pyrophoric - glove box or sealed system required |
| BRN | 3587162 |
| InChI | 1S/CH3.Li/h1H3 |
| InChIKey | DVSDBMFJEQPWNO-UHFFFAOYSA-N |
| SMILES | [Li]C |
| CAS DataBase Reference | 917-54-4(CAS DataBase Reference) |
| EPA Substance Registry System | Lithium, methyl- (917-54-4) |
| UNSPSC Code | 12352103 |
| NACRES | NA.22 |
| GHS pictogram | GHS02,GHS05 |
| Signal word | Danger |
| GHS hazard statements | H250-H260-H314 |
| GHS precautionary statements | P210-P222-P231+P232-P233-P280-P223-P260-P264-P302+P334-P370+P378-P301+P330+P331-P303+P361+P353-P363-P304+P340-P310-P305+P351+P338-P402+P404-P405-P501 |
| Personal protective equipment (PPE) | Faceshields, Gloves, Goggles, type ABEK (EN14387) respirator filter |
| Hazard symbols | F+,C,N,F,Xn,Xi |
| Risk statements (R) | 12-15-17-22-34-66-67-65-51/53-11-36/37/38-36/38-19-40-36/37-37-14/15 |
| Safety statements (S) | 16-26-36/37/39-45-43-30-60-62-61-36/37 |
| UN transport number | UN 3399 4.3/PG 1 |
| Water hazard class (WGK) | 2 |
| F | 10 |
| Autoignition temperature | 180°C (Information refers to the main component.) |
| TSCA inventory status | TSCA listed |
| Hazard class | 4.3Eye Dam. 1Flam. Liq. 2Pyr. Liq. 1Skin Corr. 1BWater-react 1 |
| Packing group | I |
| Customs code | 29319090 |
| Storage class | 4.2 - Pyrophoric and self-heating hazardous materials |
| REACH registrations | Active |
Safety & Regulations
| F | 10 |
|---|---|
| Personal protective equipment (PPE) | Faceshields, Gloves, Goggles, type ABEK (EN14387) respirator filter |
| Water hazard class (WGK) | 2 |
| TSCA inventory status | TSCA listed |
| UN transport number | UN 3399 4.3/PG 1 |
| Customs code | 29319090 |
| Risk statements (R) | 12-15-17-22-34-66-67-65-51/53-11-36/37/38-36/38-19-40-36/37-37-14/15 |
| Signal word | Danger |
| GHS pictogram | GHS02,GHS05 |
| Hazard symbols | F+,C,N,F,Xn,Xi |
| Safety statements (S) | 16-26-36/37/39-45-43-30-60-62-61-36/37 |
| Hazard class | 4.3Eye Dam. 1Flam. Liq. 2Pyr. Liq. 1Skin Corr. 1BWater-react 1 |
| Storage class | 4.2 - Pyrophoric and self-heating hazardous materials |
| Packing group | I |
| GHS hazard statements | H250-H260-H314 |
| REACH registrations | Active |
| Autoignition temperature | 180°C (Information refers to the main component.) |
| GHS precautionary statements | P210-P222-P231+P232-P233-P280-P223-P260-P264-P302+P334-P370+P378-P301+P330+P331-P303+P361+P353-P363-P304+P340-P310-P305+P351+P338-P402+P404-P405-P501 |
Applications & Uses
Uses
There are no significant industrial uses of methyllithium, but it is widely used in the laboratory in Grignard type reactions. Methyllithium is an organolithium reagent mainly used for deprotonation and as a source of methyl anion. It is a strong base and a strong nucleophile.
Uses
Methyllithium lithium bromide complex solution (MeLi.LiBr) can be used as a methylating agent for the α-methylation of alkoxyaryl ketones.
Preparation & Synthesis
Preparation
Methyllithium is produced industrially by the reaction of methyl chloride or methyl bromide with lithium metal dispersion in diethyl ether. The reaction with methyl chloride yields a solution of methyllithium and a precipitate of lithium chloride which may be readily separated. When methyl bromide is used, the lithium bromide byproduct remains in solution and complexes with the methyllithium. This reduces the reactivity of the methyllithium and, in certain cases, affects its usefulness. On the other hand, the less reactive complex is more stable in diethyl ether. Methyllithium produced from methyl chloride contains only about 0.3 % lithium chloride in a 5 % solution in diethyl ether. It is more reactive than the lithium bromide complex, but decomposes at the rate of 1 % of the contained methyllithium per year (that is 5.00 % solution goes to 4.95 %) at room temperature. The decomposition by ether cleavage results in methane and ethylene formation which increases the pressure in the container on long storage. Methyllithium can be prepared easily in tetrahydrofuran but it has a half-life of only about 2 days at room temperature due to solvent cleavage.