Trimethyl phosphite

|

Names
Preferred IUPAC name

Trimethyl phosphite[1]

Other names

Trimethoxyphosphine
Trimethoxyphosphane

Identifiers

CAS Number

* 121-45-9 Y

3D model (JSmol)

* Interactive image

ChEBI |

* CHEBI:183313

ChemSpider |

* 8159 Y

PubChem CID

* 8472

UNII |

* 26Q0321ZDG Y

InChI

* InChI=1S/C3H9O3P/c1-4-7(5-2)6-3/h1-3H3 Y

Key: CYTQBVOFDCPGCX-UHFFFAOYSA-N Y

* InChI=1/C3H9O3P/c1-4-7(5-2)6-3/h1-3H3

Key: CYTQBVOFDCPGCX-UHFFFAOYAO

SMILES

* COP(OC)OC

Properties

Chemical formula

| C3H9O3P
Molar mass | 124.08
Appearance  | colorless liquid
Odor | distinctive, pungent[2]
Density | 1.052
Melting point |  −78 °C (−108 °F; 195 K)
Boiling point |  111 °C (232 °F; 384 K)

Solubility in water

| reacts[2]
Vapor pressure | 24 mmHg (25°C)[2]
Hazards
Flash point |  28 °C; 82 °F; 301 K[2]
NIOSH (US health exposure limits):

PEL (Permissible)

| none[2]

REL (Recommended)

| TWA 2 ppm (10 mg/m3)[2]

IDLH (Immediate danger)

| N.D.[2]
Related compounds

Related compounds

| Dimethyl methylphosphonate

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

Tracking categories (test):

* SizeSet
* PairSizeSet

Trimethyl phosphite is an organophosphorus compound with the formula P(OCH3)3, often abbreviated P(OMe)3. It is a colorless liquid with a highly pungent odor. It is the simplest phosphite ester and finds used as a ligand in organometallic chemistry and as a reagent in organic synthesis. The molecule features a pyramidal phosphorus(III) center bound to three methoxy groups.

## Contents

* 1 Synthesis
* 2 Reactions
* 3 Toxicity
* 4 References
* 5 External links

## Synthesis

Trimethyl phosphite is in principle obtainable by methanolysis of phosphorus trichloride, say in the presence of a proton accepting base. This method suffers from numerous side reactions however. The use of sodium methoxide is superior:[3]

PCl
3 \+ 3 NaOCH
3 → P(OCH

3 \+ 3 NaCl

## Reactions

Trimethyl phosphite is susceptible to oxidation to trimethyl phosphate:

P(OCH

3 \+ 0.5 O
2 → OP(OCH

It reacts with a catalytic amount of methyl iodide in the Arbuzov reaction to give dimethyl methylphosphonate:

P(OCH3)3 → CH3P(O)(OCH3)2

As a ligand, trimethyl phosphite has a smaller cone angle and better acceptor properties relative to trimethylphosphine. A representative derivative is the colorless tetrahedral complex Ni(P(OMe)3)4 (m.p. 108 °C).[4] The tridentate ligand called the Kläui ligand is derived from trimethyl phosphite. The formation of this ligand illustrates the susceptibility of trimethyl phosphite (and metal complexes thereof) to the Arbuzov reaction.

Trimethyl phosphite is also used as a mild desulfurization reagent in organic synthesis, for example in the preparation of derivatives of tetrathiafulvalene.[5]

## Toxicity

The LD50 is 1600–2890 mg/kg (oral, rat).[6]

## References

1. ↑ Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 931. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 NIOSH Pocket Guide to Chemical Hazards. "#0640". National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/npg/npgd0640.html.
3. ↑ Crofts, Peter C.; Kosolapoff, Gennady M. (1953). "Preparation and Determination of Apparent Dissociation Constants of Some Alkylphosphonic and Dialkylphosphinic Acids1". Journal of the American Chemical Society 75 (14): 3379–3383. doi:10.1021/ja01110a024.
4. ↑ Steven D. Ittel; Cushing, M. A. (1990). Complexes of Nickel(0). Inorganic Syntheses. 28. pp. 98–104. doi:10.1002/9780470132593.ch25. ISBN 978-0-471-52619-3.
5. ↑ Larsen, Jan; Lenoir, Christine (1995). "2,2'-Bi-5,6-Dihydro-1,3-Dithiolo[4,5-b][1,4]dithiinylidene (BEDT-TTF)". Org. Synth. 72: 265. doi:10.15227/orgsyn.072.0265.
6. ↑ Svara, J.; Weferling, N.; Hofmann, T.. "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_545.pub2.

## External links

* WebBook page for C3H9PO3
* CDC - NIOSH Pocket Guide to Chemical Hazards

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Trimethyl phosphite. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Trimethyl_phosphite&oldid=2601178"
*[CID]: Compound ID