Triethyl phosphite

Structural formula
General
Surname	Triethyl phosphite
other names	Triethyl phosphate
Molecular formula	C 6 H 15 O 3 P
Brief description	colorless, malodorous liquid
External identifiers / databases
CAS number 122-52-1 EC number 204-552-5 ECHA InfoCard 100.004.139 PubChem 31215 ChemSpider 28956 Wikidata Q414714
properties
Molar mass	166.16 g · mol -1
Physical state	liquid
density	0.96 g cm −3
Melting point	−112 ° C
boiling point	156 ° C
Vapor pressure	4.09 h Pa (20 ° C) 7.42 hPa (30 ° C) 12.9 hPa (40 ° C) 21.5 hPa (50 ° C)
solubility	miscible with organic solvents insoluble in water (hydrolysis)
Refractive index	1.4127 (20 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 226-302-317-412 P: 210-280-301 + 312 + 330-370 + 378
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Triethyl phosphite is the triethyl ester of phosphorous acid .

Presentation and extraction

Triethyl phosphite can be produced by reacting phosphorus trichloride with ethanol .

${\displaystyle \mathrm {PCl_{3}+3\,C_{2}H_{5}OH\rightarrow P(OC_{2}H_{5})_{3}+3\,HCl} }$

properties

Triethyl phosphite is a colorless liquid with a characteristic odor. The boiling point is at a pressure of 1013 hPa at 158 ​​° C, under a reduced pressure of 19 hPa at 54 ° C. According to Antoine, the vapor pressure function results from log ₁₀ (P) = A− (B / (T + C)) (P in Torr, T in ° C) with A = 7.2, B = 1683 and C = 230 in the temperature range from 20 ° C to 156 ° C. The compound forms easily flammable vapor-air mixtures above the flash point . The compound has a flash point of 44 ° C. The explosion range is between 3.75% by volume as the lower explosion limit (LEL) and 42.5% by volume as the upper explosion limit (UEL). The ignition temperature is 250 ° C. The substance therefore falls into temperature class T3.

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  Vapor pressure function of triethyl phosphite

Thermal decomposition occurs above 260 ° C with the formation of phosphorus oxides , ethanol and phosphine . The compound reacts violently and with strong heat generation with water . Highly flammable ethanol is formed during hydrolysis . Contact with magnesium perchlorate (e.g. as a desiccant) leads to a violent reaction or explosion with the formation of explosive ethyl perchlorate .

use

In the industrial production of the insecticide chlorfenvinphos , triethyl phosphite is used as the starting material. In organic chemistry it is often used for the synthesis of olefins , alkynes , dehydrodimers and nitrogen heterocycles from aromatic nitro compounds . Via the Michaelis-Arbusow reaction , phosphonates can be produced via the Perkow reaction vinyl phosphate . In the production of alkenes from 1,2-diols by the Corey-Winter reaction , triethyl phosphite is used as a desulfurizing reagent. It can be used as a ligand in organometallic compounds and metal complexes . Such compounds are used for. B. as isomerization catalysts.

Individual evidence

1. ↑ ^{a b c d e f g h i j k} Entry on triethyl phosphite in the GESTIS substance database of the IFA , accessed on May 2, 2020(JavaScript required) .
2. ↑ ^{a b c d e f g h i} Entry on triethyl phosphite. In: Römpp Online . Georg Thieme Verlag, accessed on June 19, 2014.
3. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-498.
4. ^ E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases , Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.
5. ↑ ^{a b c} Roth / Weller: Hazardous chemical reactions , ecomed SECURITY, publishing group Hüthig Jehle Rehm GmbH, edition 08/2011.