Aliphatic oximes aqueous solutions

Oxime carbamates have high polarity and solubility in water and are relatively chemically and thermally unstable. They are relatively stable in weakly acidic to neutral media (pH 4-6) but unstable in strongly acidic and basic media. Rapid hydrolysis occurs in strongly basic aqueous solutions (pH > 9) to form the parent oxime/alcohol and methylamine, which is enhanced at elevated temperature. Additionally, oxime carbamates are, generally, stable in most organic solvents and readily soluble in acetone, methanol, acetonitrile, and ethyl acetate, with the exception of aliphatic hydrocarbons. Furthermore, most oxime carbamates contain an active -alkyl (methyl) moiety that can be easily oxidized to form the corresponding sulfoxide or sulfone metabolites. 

G. A Brief Discussion of Aliphatic Oximes in Aqueous Solution... 

The pX a (6.5-8.2) and nucleophilicity of MINA, 44, and of a series of aliphatic oximes derived from it, were found to be consistent with their ability to reactivate AChE inhibited by the nerve agents, sarin and VX. Yet, despite their ability to significantly reactivate AChE in the brains of sarin-intoxicated rats, these aliphatic oximes are not used as antidotes for treatment of OP poisoning in humans this is presumably due to their poor stability in aqueous solution and to their rapid clearance from the circulation. 

Most reactions in two-phase systems occur in a liquid phase following the transfer of a reactant across an interface these are commonly known as extractive reactions. If the transfer is facilitated by a catalyst, it is known as phase-transfer catalysis [2]. Unusually, reactions may actually occur at an interface (interfacial reactions) examples include solvolysis and nucleophilic substitution reactions of aliphatic acid chlorides [3 ] and the extraction of cupric ion from aqueous solution using oxime ligands insoluble in water [4], see Section 5.2.1.3(ii). 

Bis(salicylaldoximato)nickel(II) is diamagnetic in the solid state, but becomes partially paramagnetic in solution in chloroform157 and aqueous dioxane.151 This is likely to be due to molecular association or solvation,158 rather than to the adoption of a distorted tetrahedral structure in solution.151 The nickel(II) complex readily forms pseudo-octahedral bis-adducts in the presence of large amounts of amines,159 160 although analogous complexes of commercial orffto-hydroxy-oximes have been reported to retain the square-planar structure in hydrocarbon solution in the presence of moderate amounts of ammonia or aliphatic amines.161... 

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