Trimethyl phosphate

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 ;
3D model (JSmol)	Interactive image;
Abbreviations	TMP
Beilstein Reference	1071731
ChEBI	CHEBI:46324 ;
ChemSpider	10101 ;
ECHA InfoCard	100.007.405
Gmelin Reference	49926
PubChem CID	10541;
RTECS number	TC8225000;
UNII	Z1E45TMW1Z ;
CompTox Dashboard (EPA)	DTXSID1021403 ;
	InChI InChI=1S/C3H9O4P/c1-5-8(4,6-2)7-3/h1-3H3 Key: WVLBCYQITXONBZ-UHFFFAOYSA-N ; 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	140.075 g·mol−1
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
Related compounds
Related compounds	Triethyl phosphate
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Trimethyl phosphate is the trimethyl ester of phosphoric acid. It is a colourless, nonvolatile liquid. It has the chemical formula (CH₃)₃PO₄ or (CH₃O)₃P=O. It has some specialized uses in the production of other compounds.^[1]

Production

Trimethyl phosphate is prepared by treating phosphorus oxychloride with methanol in the presence of an amine base:

POCl₃ + 3 CH₃OH + 3 R₃N → OP(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.

Safety considerations

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

References

^ D. E. C. Corbridge "Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology" 5th Edition Elsevier: Amsterdam 1995. ISBN 0-444-89307-5.
^ William A. Sheppard (1973). "m-Trifluoromethyl-N,N-dimethylaniline". Organic Syntheses; Collected Volumes, vol. 5, p. 1085.
^ 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

WebBook page for C3H9PO4

[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". Organic Syntheses; Collected Volumes, 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

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