EA-1763,John B. Samuel, Elwin C. Penski, John J. Callahan. PHYSICAL PROPERTIES OF STANDARD AGENTS, CANDIDATE AGENTS, AND RELATED COMPOUNDS AT SEVERAL TEMPERATURES (U). p 24 and 279. O-PPVX, V1 or propyl S-2-diisopropylaminoethylmethylphosphonothiolate is a military-grade neurotoxic organophosphonate nerve agent related to VX as it is the propyl analogue of VX. It is part of the V-series.
Chemical characteristics Little information about EA-1763's physicochemical properties has been reported. V1 is a more viscous and less dense liquid than VX.Coulter, P. B.; Callahan, J. J.; Link, R.S. Physical Constants of Thirteen V Agents. U. S. Army Chemical Warfare Laboratories Technical Report (Report). CWLR-2346. It is colorless, odorless and tasteless in its pure form. When impure or in the crude form, it has a characteristic viscous amber color, giving it an appearance similar to motor oil. The appearance of the impure form varies between several shades of amber, from a viscous liquid of a transparent pale yellow color to a pasty liquid of a semi-transparent and cloudy dirty amber color. The smell varies from engine oil to an offensive brew of organosulfur compounds and organoamines.Ledgard, J. A Laboratory History of Chemical Warfare Agents. p 223-225.
Its larger alkane chain pushes its melting point above that of VX. The estimated solubility of V1 in water is 4 times lower compared to VX (6.8 g/L of water at 25 °C). V1 has high solubility in organic solvents and other non-polar compounds. The stability of V1 is roughly the same as that of VX in either environment. Higher insolubility and lower volatility can slow down the process. A vapor pressure at least 3 times lower than VX is speculated.
The longer alkane chain tends to stabilize the induction of electrons from P to O, making P less electrophilic. It is expected that the persistence of V1 is slightly higher than that of VX since the hydrolysis rate of ethyl paraoxon is 1.6 times higher than the one of n-propyl paraoxon in a neutral medium.CHEMICAL REVIEWS VOLUME6 4, NUMBER 4. JULY 24, 1964. page 318.
The lower volatility and minimal persistence difference makes VX preferable to V1.cit-OPDC. The preparatory manual to chemical warfare. Vol 1: V1
Preparation It is prepared by the same route as VX using propanol instead of ethanol.
References