Names | |
---|---|
Preferred IUPAC name
Tetramethylurea | |
Other names
1,1,3,3-Tetramethylurea
*TMU | |
Identifiers | |
3D model (
JSmol)
|
|
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.010.159 |
EC Number |
|
PubChem
CID
|
|
UNII | |
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
C5H12N2O | |
Molar mass | 116.164 g·mol−1 |
Appearance | Colorless liquid |
Density | 0.968 g/mL |
Melting point | −1.2 °C (29.8 °F; 271.9 K) |
Boiling point | 176.5 °C (349.7 °F; 449.6 K) |
Hazards | |
GHS labelling: | |
Danger | |
H302, H360, H361 | |
P201, P202, P264, P270, P281, P301+P312, P308+P313, P330, P405, P501 | |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Tetramethylurea is the organic compound with the formula (Me2N)2CO. It is a substituted urea. This colorless liquid is used as an aprotic-polar solvent, especially for aromatic compounds and is used e. g. for Grignard reagents. [1]
The synthesis and properties of tetramethylurea were comprehensively described. [1]
The reaction of dimethylamine with phosgene in the presence of e. g. 50 % sodium hydroxide solution and subsequent extraction with 1,2-dichloroethane yields tetramethylurea in 95% yield. [2]
The reactions with dimethylcarbamoyl chloride or phosgene are highly exothermic and the removal of the resulting dimethylamine hydrochloride requires some effort. [1]
The reaction of diphenylcarbonate with dimethylamine in an autoclave is also effective.
Tetramethylurea is formed in the reaction of dimethylcarbamoyl chloride with anhydrous sodium carbonate in a yield of 96.5%. [3]
Dimethylcarbamoyl chloride also reacts with excess dimethylamine forming tetramethylurea. Even though the product is contaminated and smelly it may be purified by addition of calcium oxide and subsequent fractional distillation. [4]
Tetramethylurea is also formed during the oxidation of tetrakis(dimethylamino)ethylene (TDAE), a very electron-rich alkene [5] and a strong reducing agent, available from tris(dimethylamino)methane by pyrolysis [6] or from chlorotrifluoroethene and dimethylamine. [7]
Tetrakis(dimethylamino)ethylene (TDAE) reacts with oxygen in a (2+2) cycloaddition reaction to a 1,2-dioxetane which decomposes to electronically excited tetramethylurea. This returns to the ground state while emitting green light with an emission maximum at 515 nm. [8] [9]
Tetramethylurea is a clear, colorless liquid with mild aromatic odor that is miscible with water and many organic solvents. [10] Unusual for an urea is the liquid state of tetramethylurea in a range of > 170 °C.
Tetramethylurea is miscible with a variety of organic compounds, including acids such as acetic acid or bases such as pyridine and an excellent solvent for organic substances such as ε-caprolactam or benzoic acid and dissolves even some inorganic salts such as silver nitrate or sodium iodide. [11] [12] Due to its distinct solvent properties tetramethylurea is often used as a replacement for the carcinogenic hexamethylphosphoramide (HMPT). [13]
Tetramethylurea is suitable as a reaction medium for the polymerization of aromatic diacid chlorides (such as isophthalic acid) and aromatic diamines (such as 1,3-diaminobenzene (m-phenylenediamine)) to aramids such as poly (m-phenylene isophthalamide) (Nomex®) [14] [15]
The polymerization of 4-amino benzoic acid chloride hydrochloride in tetramethylurea provides isotropic viscous solutions of poly(p-benzamide) (PPB), which can be directly spun into fibers. [16]
In a tetramethylurea- LiCl mixture stable isotropic solutions can be obtained up to a PPB polymer concentration of 14%. [17]
Tetramethylurea also dissolves cellulose ester and swells other polymers such as polycarbonates, polyvinyl chloride or aliphatic polyamides, usually at elevated temperature. [1]
Strong and hindered non-nucleophilic guanidine bases are accessible from tetramethylurea in a simple manner, [18] [19] which are in contrast to the fused amidine bases DBN or DBU not alkylated.
A modification of the Koenigs-Knorr reaction for building glycosides from 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide ( acetobromoglucose) originates from S. Hanessian who used the silver salt silver trifluoromethanesulfonate (TfOAg) and as a proton acceptor tetramethylurea. [20] This process variant is characterized by a simplified process control, high anomeric purity and high yields of the products. If the reaction is carried out with acetobromoglucose and silver triflate/tetramethylurea at room temperature, then tetramethylurea reacts not only as a base, but also with the glycosyl to form a good isolable uroniumtriflates in 56% yield. [21]
The acute toxicity of tetramethylurea is moderate. However, it is embryotoxic and teratogenic towards several animal species. [22]
Names | |
---|---|
Preferred IUPAC name
Tetramethylurea | |
Other names
1,1,3,3-Tetramethylurea
*TMU | |
Identifiers | |
3D model (
JSmol)
|
|
ChEBI | |
ChEMBL | |
ChemSpider | |
ECHA InfoCard | 100.010.159 |
EC Number |
|
PubChem
CID
|
|
UNII | |
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
C5H12N2O | |
Molar mass | 116.164 g·mol−1 |
Appearance | Colorless liquid |
Density | 0.968 g/mL |
Melting point | −1.2 °C (29.8 °F; 271.9 K) |
Boiling point | 176.5 °C (349.7 °F; 449.6 K) |
Hazards | |
GHS labelling: | |
Danger | |
H302, H360, H361 | |
P201, P202, P264, P270, P281, P301+P312, P308+P313, P330, P405, P501 | |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Tetramethylurea is the organic compound with the formula (Me2N)2CO. It is a substituted urea. This colorless liquid is used as an aprotic-polar solvent, especially for aromatic compounds and is used e. g. for Grignard reagents. [1]
The synthesis and properties of tetramethylurea were comprehensively described. [1]
The reaction of dimethylamine with phosgene in the presence of e. g. 50 % sodium hydroxide solution and subsequent extraction with 1,2-dichloroethane yields tetramethylurea in 95% yield. [2]
The reactions with dimethylcarbamoyl chloride or phosgene are highly exothermic and the removal of the resulting dimethylamine hydrochloride requires some effort. [1]
The reaction of diphenylcarbonate with dimethylamine in an autoclave is also effective.
Tetramethylurea is formed in the reaction of dimethylcarbamoyl chloride with anhydrous sodium carbonate in a yield of 96.5%. [3]
Dimethylcarbamoyl chloride also reacts with excess dimethylamine forming tetramethylurea. Even though the product is contaminated and smelly it may be purified by addition of calcium oxide and subsequent fractional distillation. [4]
Tetramethylurea is also formed during the oxidation of tetrakis(dimethylamino)ethylene (TDAE), a very electron-rich alkene [5] and a strong reducing agent, available from tris(dimethylamino)methane by pyrolysis [6] or from chlorotrifluoroethene and dimethylamine. [7]
Tetrakis(dimethylamino)ethylene (TDAE) reacts with oxygen in a (2+2) cycloaddition reaction to a 1,2-dioxetane which decomposes to electronically excited tetramethylurea. This returns to the ground state while emitting green light with an emission maximum at 515 nm. [8] [9]
Tetramethylurea is a clear, colorless liquid with mild aromatic odor that is miscible with water and many organic solvents. [10] Unusual for an urea is the liquid state of tetramethylurea in a range of > 170 °C.
Tetramethylurea is miscible with a variety of organic compounds, including acids such as acetic acid or bases such as pyridine and an excellent solvent for organic substances such as ε-caprolactam or benzoic acid and dissolves even some inorganic salts such as silver nitrate or sodium iodide. [11] [12] Due to its distinct solvent properties tetramethylurea is often used as a replacement for the carcinogenic hexamethylphosphoramide (HMPT). [13]
Tetramethylurea is suitable as a reaction medium for the polymerization of aromatic diacid chlorides (such as isophthalic acid) and aromatic diamines (such as 1,3-diaminobenzene (m-phenylenediamine)) to aramids such as poly (m-phenylene isophthalamide) (Nomex®) [14] [15]
The polymerization of 4-amino benzoic acid chloride hydrochloride in tetramethylurea provides isotropic viscous solutions of poly(p-benzamide) (PPB), which can be directly spun into fibers. [16]
In a tetramethylurea- LiCl mixture stable isotropic solutions can be obtained up to a PPB polymer concentration of 14%. [17]
Tetramethylurea also dissolves cellulose ester and swells other polymers such as polycarbonates, polyvinyl chloride or aliphatic polyamides, usually at elevated temperature. [1]
Strong and hindered non-nucleophilic guanidine bases are accessible from tetramethylurea in a simple manner, [18] [19] which are in contrast to the fused amidine bases DBN or DBU not alkylated.
A modification of the Koenigs-Knorr reaction for building glycosides from 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide ( acetobromoglucose) originates from S. Hanessian who used the silver salt silver trifluoromethanesulfonate (TfOAg) and as a proton acceptor tetramethylurea. [20] This process variant is characterized by a simplified process control, high anomeric purity and high yields of the products. If the reaction is carried out with acetobromoglucose and silver triflate/tetramethylurea at room temperature, then tetramethylurea reacts not only as a base, but also with the glycosyl to form a good isolable uroniumtriflates in 56% yield. [21]
The acute toxicity of tetramethylurea is moderate. However, it is embryotoxic and teratogenic towards several animal species. [22]