Trimethyl phosphate
Encyclopedia
Trimethyl phosphate is the trimethyl ester
of phosphoric acid
. It is a colourless, nonvolatile liquid. It has some specialized uses in the production of other compounds.
in the presence of an amine
base:
It is a tetrahedral molecule that is a weakly polar solvent.
, useful for preparing dimethylation of aniline
s and related heterocyclic compounds. The method is complementary to the traditional Eschweiler-Clarke reaction
in cases where formaldehyde engages in side reactions.
Trimethyl phosphate is used as a solvent
for aromatic halogenations and nitrations as required for the preparation of pesticides and pharmaceuticals.
It is used as a color inhibitor for fibers (e.g. polyester
) and other polymers.
of 2g/kg for rats, trimethylphosphate is expected to have low acute toxicity.
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...
of phosphoric acid
Phosphoric acid
Phosphoric acid, also known as orthophosphoric acid or phosphoric acid, is a mineral acid having the chemical formula H3PO4. Orthophosphoric acid molecules can combine with themselves to form a variety of compounds which are also referred to as phosphoric acids, but in a more general way...
. It is a colourless, nonvolatile liquid. It has some specialized uses in the production of other compounds.
Production
Trimethyl phosphate is prepared by treating phosphorus oxychloride with methanolMethanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
in the presence of an amine
Amine
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...
base:
- POCl3 + 3 CH3OH + 3 R3N → PO(OCH3)3 + 3 R3NH+Cl-
It is a tetrahedral molecule that is a weakly polar solvent.
Applications
Trimethyl phosphate is a mild methylating agentMethylation
In the chemical sciences, methylation denotes the addition of a methyl group to a substrate or the substitution of an atom or group by a methyl group. Methylation is a form of alkylation with, to be specific, a methyl group, rather than a larger carbon chain, replacing a hydrogen atom...
, useful for preparing dimethylation of aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
s and related heterocyclic compounds. The method is complementary to the traditional Eschweiler-Clarke reaction
Eschweiler-Clarke reaction
The Eschweiler–Clarke reaction is a chemical reaction whereby a primary amine is methylated using excess formic acid and formaldehyde. Reductive amination reactions such as this one will not produce quaternary ammonium salts, but instead will stop at the tertiary amine stage...
in cases where formaldehyde engages in side reactions.
Trimethyl phosphate is used as a solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
for aromatic halogenations and nitrations as required for the preparation of pesticides and pharmaceuticals.
Other applications
It is used as a color inhibitor for fibers (e.g. polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
) and other polymers.
Safety considerations
With an LD50LD50
In toxicology, the median lethal dose, LD50 , LC50 or LCt50 of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration...
of 2g/kg for rats, trimethylphosphate is expected to have low acute toxicity.