Difference between revisions of "Hexamethylphosphoramide"

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Latest revision as of 17:20, 30 June 2020

Hexamethylphosphoramide
Hexamethylphosphoramide HMPA 2D skeletal.png
HMPA chemical structure
Names
IUPAC name
Hexamethylphosphoramide
Preferred IUPAC name
Hexamethylphosphoric triamide
Other names
Hexametapol
HMPA
N,N,N',N',N' ',N' '-hexamethylphosphoric triamide
Properties
C6H18N3OP
[(CH3)2N]3PO
Molar mass 179.20 g/mol
Appearance Colorless liquid
Odor Aromatic, "spicy" odor
Density 1.03 g/cm3 (20 °C)
Melting point 7.2 °C (45.0 °F; 280.3 K)
Boiling point 232.5 °C (450.5 °F; 505.6 K)
Miscible
Solubility Reacts with haloacids
Misicble with acetone, benzene, chloroform, diethyl ether, ethanol, methanol, THF, toluene
Vapor pressure 0.03 mmHg at 20 °C
Thermochemistry
Hazards
Safety data sheet Sigma-Aldrich
Flash point 104.4 °C (219.9 °F; 377.5 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Hexamethylphosphoramide, often abbreviated HMPA, is a phosphoramide (an amide of phosphoric acid) with the chemical formula [(CH3)2N]3PO. This colorless liquid is a useful polar aprotic solvent and additive in organic synthesis, albeit it's somewhat exotic for the hobby chemist, since it's not often encountered.

Properties

Chemical

When heated to decomposition, HMPA emits very toxic fume of phosphine, phosphorus oxides and nitrogen oxides.

Compounds containing a nitrogen–phosphorus bond typically are degraded by the action of hydrochloric acid to form a protonated amine and phosphate. As such, this is a convenient neutralization method.

HMPA dissolves alkali metals forming blue solutions of solvated electrons which are stable for a few hours.

Dimethyl sulfoxide can often be used in place of HMPA as a cosolvent. Both are strong hydrogen bond acceptors, and their oxygen atoms bind metal cations.

Physical

HMPA is a colorless liquid, miscible with water. Old samples appear more yellow or amber.

Availability

HMPA is sold by chemical suppliers though it's not very cheap

Preparation

HMPA can be prepared by reacting phosphoryl chloride and dimethylamine in a liquid diluent.[2]

Projects

  • Solvent and high temperature solvent
  • Make molybdenum peroxide complexes

Handling

Safety

HMPA is only mildly toxic but has been shown to cause nasal cancers in rats. HMPA can be degraded to less toxic compounds by the action of hydrochloric acid.

Storage

In closed bottles, in a cabinet.

Disposal

Can be degraded by the action of hydrochloric acid.

References

  1. Vorob'ev, A. F.; Yakovlev, P. N.; Russian Journal of Physical Chemistry; vol. 56; nb. 8; (1982); p. 1181 - 1183; Zhurnal Fizicheskoi Khimii; vol. 56; nb. 8; (1982); p. 1933 - 1936
  2. https://patents.google.com/patent/US3991110A/en

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