Trimethyl phosphite
- Phosphorigsäuretrimethylester
- TMPI
Colorless, like pyridine -smelling ( in lower concentrations pungent ) liquid
Liquid
1.05 g · cm -3 at 20 ° C.
-78 ° C
111 ° C (1013 hPa)
28 hPa at 20 ° C.
Decomposition in water
1.4095 (20 ° C)
Risk
Template: Infobox chemical / molecular formula search available
Trimethyl phosphite ( TMPI ) or Phosphorigsäuretrimethylester is a colorless, foul-smelling, poisonous liquid, which belongs to the group of substances phosphites. It can be used for example in the Arbuzov reaction to form phosphonates, and the reaction for the synthesis of Perkow Vinylphosphonaten.
Representation and extraction
Trimethyl can be easily obtained by the reaction of phosphorus trichloride with methanol.
Properties
Physical Properties
Trimethylphosphite is a colorless liquid, boiling at atmospheric pressure at 111 ° C. The vapor pressure function is given by Antoine according to ln ( P) = A- ( B / ( T C)) (P in Pa, T in K) with A = 20.15306, B = 2519.7227 and C = -89, 44893 in the temperature range 302-343 K
Trimethyl phosphite forms flammable vapor - air mixtures. The compound has a flash point of 21 ° C. The explosive range is between 5.2 vol% as the lower explosive limit ( LEL) and 61.2 vol% as the upper explosive limit ( UEL). The ignition temperature is 250 ° C. The fabric falls within the temperature class T3. On contact with water is carried out violent decomposition.
Chemical Properties
By reaction with an alkyl halide, the corresponding phosphonic acid esters may be obtained in an Arbuzov reaction.
In a Perkow reaction with α - halo ketones resulting organic vinyl phosphates.
Of 1,2- diols, the corresponding alkenes can be obtained according to the Corey- Winter in a two-step synthesis by reaction with thiophosgene, to thiocarbonate and subsequent reduction with trimethyl phosphite. Here, the degradation step of Thiocarbonatzwischenstufe proceeds stereoselectively. Thus resulting in a good yield from the cis-1 ,2 -diols, the cis -alkenes or of trans -1 ,2- diols, trans - alkenes.
Use
The compound is referred to as methylation - phosphorylating and especially in the synthesis of insecticides and herbicides. be used.