Trimethyl phosphate

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Trimethyl phosphate
Ball-and-stick model of trimethyl phosphate
Preferred IUPAC name
Trimethyl phosphate
Other names
Phosphoric acid trimethyl ester
Methyl phosphate,
Trimethoxyphosphine oxide
Trimethyl orthophosphate
512-56-1 YesY
Abbreviations TMP
ChEBI CHEBI:46324 YesY
ChemSpider 10101 YesY
ECHA InfoCard 100.007.405
Jmol 3D model Interactive image
PubChem 10541
Molar mass 140.08
Appearance Colorless liquid
Melting point −46 °C (−51 °F; 227 K)
Boiling point 197 °C (387 °F; 470 K)
Harmful substances or preparations (Xn)
R-phrases R22,R36/37/38
S-phrases S36/37,S45
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

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 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.


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[edit]

It is used as a color inhibitor for fibers (e.g. polyester) and other polymers.

Safety considerations[edit]

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


  1. ^ D. E. C. Corbridge "Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology" 5th Edition Elsevier: Amsterdam 1995. ISBN 0-444-89307-5.
  2. ^ William A. Sheppard (1973). "m-Trifluoromethyl-N,N-dimethylaniline". Org. Synth. ; Coll. Vol., 5, p. 1085 
  3. ^ J. Svara, N. Weferling, T. Hofmann "Phosphorus Compounds, Organic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2006. doi:10.1002/14356007.a19_545.pub2

External links[edit]