Trimethyl phosphate

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.^[1]

Trimethyl phosphate

Ball-and-stick model of trimethyl phosphate
Names
Preferred IUPAC name Trimethyl phosphate
Other names Phosphoric acid trimethyl ester Methyl phosphate, tribasic Trimethoxyphosphine oxide Trimethyl orthophosphate fraction
Identifiers
CAS Number	512-56-1 Y
3D model (JSmol)	Interactive image
Abbreviations	TMP
Beilstein Reference	1071731
ChEBI	CHEBI:46324 Y
ChemSpider	10101 Y
ECHA InfoCard	100.007.405
Gmelin Reference	49926
PubChem CID	10541
RTECS number	TC8225000
UNII	Z1E45TMW1Z Y
CompTox Dashboard (EPA)	DTXSID1021403
InChI InChI=1S/C3H9O4P/c1-5-8(4,6-2)7-3/h1-3H3 Y Key: WVLBCYQITXONBZ-UHFFFAOYSA-N Y InChI=1/C3H9O4P/c1-5-8(4,6-2)7-3/h1-3H3 Key: WVLBCYQITXONBZ-UHFFFAOYAV
SMILES O=P(OC)(OC)OC
Properties
Chemical formula	(CH3O)3PO
Molar mass	140.08
Appearance	Colorless liquid
Melting point	−46 °C (−51 °F; 227 K)
Boiling point	197 °C (387 °F; 470 K)
Solubility in water	good
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H315, H318, H319, H340, H350, H351, H361, H373
Precautionary statements	P201, P202, P260, P264, P270, P280, P281, P301+P312, P302+P352, P305+P351+P338, P308+P313, P310, P314, P321, P330, P332+P313, P337+P313, P362, P405, P501
NFPA 704 (fire diamond)	2 1 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Production

Trimethyl phosphate is prepared by treating phosphorus oxychloride with methanol in the presence of an amine 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 agent, useful for dimethylation of anilines and related heterocyclic compounds.^[2] 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.

Other applications

It is used as a color inhibitor for fibers (e.g. polyester) and other polymers. Trimethyl phosphate is used as a simulant for chemical weapon nerve agents.^{[citation needed]}

Safety considerations

With an LD50 of 2g/kg for rats, trimethylphosphate is expected to have low acute toxicity.^[3]