Arsonic acids RAsO

Arsonic acids RAsO(OH)2 are amongst the most important organoarsonium compounds. Alkyl arsonic acids are generally prepared by the Meyer reaction in which an alkaline solution of AS2O3 is heated with an alkyl halide ... 

Several methods are available for the synthesis of cycloarsoxanes (a) hydrolysis of organoarsenic(III) dihalides RASX2 (X = Cl, Br, I), (b) reduction of arsonic acids RAsO(OH)2 and (c) oxidation of primary arsines RASH2 or cyclopolyarsines (RAs) . The tetramer cyclo-(MeAsO)4 exhibits the boat-chair conformation, whereas the mesityl derivative cyclo-(MesAsO)4 adopts the crown conformation (Figure 11.24). The As-O bond distances are in the range 1.77-1.82 A, typical for single bonds. 

If R is aromatic with electron-withdrawing substituents, the acid is the major prodnct. Becanse the anhydride is thought to be in eqnilibrium with the acid in solution, the separation conditions can determine whether the acid or anhydride is obtained. Becanse many dihaloarsines dissolve in water withont appreciable hydrolysis, the addition of base is required to form the acid salt. Reduction of an arsonic acid, RAsO(OH)2, in hydrochloric acid with SO2 and as a catalyst gives the anhydride (eqnation 127). The anhydride is also produced during the oxidation of cyclopolyarsines and primary arsines in the absence of water (equation 128). 

These As-O bonded species are related by the fact that they contain arsenic in the -1-5 oxidation state. The arsonic acids, RAsO(OH)2, have one organo substituent bonded to the arsenic, while the arsinic acids, R2As(0)0H, have two. The most common preparative methods involve isolating the sodium or potassium salt. 

D. Reduction of Arsonic Acids, RAsO(OH)2, R = Alkyl, Aryl.. 466... 

Studies of the electrochemical reduction of RMO(OH)2 are scarce for M = Sb and Bi, while the reduction of arsonic acids, RAsO(OH)2, especially the arylarsonic acids, ArAsO(OH)2, has received considerable attention since 1930 . The electrochemical reductions of arsonic acids have been carried out almost exclusively by polarographic methods in buffered aqueous solution, and the work has focused on three main aspects (1) the effects of substituents on correlation of with pR, (2) mechanistic... 

Arsonic and Arsinic Acids. The arsonic acids, compounds of the type RAsO(OH)2, are among the most important organic arsenicals. The ahphatic arsonic acids are generally prepared by the Meyer reaction ie, heating an alkyl haUde with As O in alkaline solution ... 

Arsinsaure, /. arsonic acid, arsinic acid (better translated arsonic acid when referring to compounds of the formula RAsO(OH)a). Art,/, kind, sort, type, species, variety nature manner, way race, breed pi, manners (Biol.) species. (Used as a suffix to give a generic meaning as, Pecharten, pitches, kinds of pitch.)... 

Arsonic acid general formula RAsO(OH)2, where R is an alkyl or aryl group... 

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