EA-1763,[1] O-PPVX, V1[2] or propyl S-2-diisopropylaminoethylmethylphosphonothiolate is a military-grade neurotoxic organophosphonatenerve 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.[1] V1 is a more viscous and less dense liquid than VX.[3] 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.[4]
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.[5]
The longer alkane chain tends to stabilize the induction of electrons from P to O, making P less electrophilic.[5] 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.[6]
The lower volatility and minimal persistence difference makes VX preferable to V1.[5]
Preparation
It is prepared by the same route as VX using propanol instead of ethanol.
References
^ abJohn 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.
^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.
^Ledgard, J. A Laboratory History of Chemical Warfare Agents. p 223-225.
^ abccit-OPDC. The preparatory manual to chemical warfare. Vol 1: V1
^CHEMICAL REVIEWS VOLUME6 4, NUMBER 4. JULY 24, 1964. page 318.