Arsinic acid

Cool the reaction-solution, and pour it into a 250 ml. beaker, washing out the flask with ca. 50 ml. of water into the beaker. Chill the solution in ice-water and add dilute hydrochloric acid with stirring until the solution is just acid when spotted externally on to Congo Red paper. The arsinic acid rapidly separates. Filter at the pump, wash well with water and drain. (Yield of crude dry product, 7-5-8 o g. m.p. 200-203°.)... 

The arsinic acid thus obtained is of high quality after draining, however, it can be directly recrystallised from ethanol or from a large volume of hot water m.p. of recrystallised acid, 205-206°. 

AMA cacodyhc acid [75-60-5] ammonium methylarsonic acid dimethyl arsinic acid C2H2ASO2... 

Secondary aisines, which can be synthesized by methods analogous to those used for piimaiy arsines, are obtained in good yields by the reduction of arsinic acids (44) or haloarsines (45) with amalgamated zinc and hydrochloric acid. They can also be prepared by the alkylation of primary arsenides (46) ... 

Diarsines and Diarsenes. Under certain conditions, the reduction of compounds with two organic groups attached to arsenic may give rise to tetraalkyl-or tetraaryldiarsines. Thus a number of diarsines have been obtained by the reduction of arsinic acids with phosphorous or hypophosphorous acid (100). Diarsines can also be prepared by the treatment of a metal dialkyl- or diarylarsenide with iodine (101) or a 1,2-dihaloethane (102). 

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 ... 

Where X is Br or Q, the free acids may be obtained by acidification of the alkaline solution, but where X is I, the acids must be isolated as salts to avoid reduction of the arsonic acids by HI. Rather than using alkyl haUdes, alkyl or dialkyl sulfates or alkyl arenesulfonates can be used. Primary alkyl haUdes react rapidly and smoothly, secondary haUdes react only slowly, whereas tertiary haUdes do not give arsonic acids. AHyl haUdes undergo the Meyer reaction, but vinyl hahdes do not. Substituted alkyl haUdes can be used eg, ethylene chlorohydrin gives 2-hydroxyethylarsonic acid [65423-87-2], C2H2ASO4. Arsinic acids, R2AsO(OH), are also readily prepared by substituting an alkaU metal arsonite, RAs(OM)2, for sodium arsenite ... 

A number of substituted phenylarsonic acids have been prepared by means of the Bart reaction (121). For the preparation of arsinic acids a sodium arylarsonite is used, and mixed diaryl or alkylarylarsinic acids can be prepared ... 

The Bart reaction is successful with a wide variety of aromatic and heterocycHc amines. A variation in which an aromatic amine, in the presence of arsenic trichloride, is dia2oti2ed in an organic solvent (the ScheUer reaction) has also found wide appHcation. Both arsonic and arsinic acids can be prepared by the ScheUer reaction which often gives better yields than the Bart reaction with electron-attracting substituents on the aromatic ring. For the commercial preparation of 4-aminophenylarsonic acid [98-50-0] (arsaniUc acid), C HgAsNO, and 4-hydroxyphenylarsonic acid [98-14-6] C H AsO, the Bnchamp reaction is used ... 

Arsonic and arsinic acids have found a number of industrial uses. They have been used as corrosion inhibitors for iron and steel, additives to motor fuel, agricultural bactericides, herbicides, and fungicides. 3-Nitro-4-hydroxyphenylarsonic acid (roxarsone) [121 -19-7] C H AsNOg, has found widespread use as an additive to poultry feed for the control of coccidiosis and other poultry diseases (122,123). Arsanilic acid [98-50-0] C HgAsNO, has also been used for this purpose (124) and for growth promotion in swine. It is manufactured and suppHed by Duphar Nutrition Co., Inc., Fleming Laboratories, Inc., Dr. Mayfield Laboratories, Inc., and Whitmoyer Laboratories, Inc. 4-Nitrophenylarsonic acid [98-72-6] C H AsNO and... 

Both arsonic and arsinic acids give precipitates with many metal ions, a property which has found considerable use in analytical chemistry. Of particular importance are certain a2o dyes (qv) containing both arsonic and sulfonic acid groups which give specific color reactions with a wide variety of transition, lanthanide, and actinide metal ions. One of the best known of these dyes is... 

A number of esters of arsonic and arsinic acids have been prepared. One method involves the oxidation of dialkyl alkylarsonites with selenium dioxide ... 

Similar reactions on alkyl or aryl arsonites yield the arsinic acids R2AsO(OH) and Ar2AsO(OH). Arsine oxides are made by alkaline hydrolysis of R3ASX2 (or Ar3AsX2> or by oxidation of a tertiary arsine with KMn04, H2O2 or I2. 

Arsinigsaure, /. arsinous acid, arsinic acid (better translated arsinic acid when referring to compounds of the formula RR AsO OH), Arsinoverbindung, /, arsino compound, ( Ar-sino preferably denotes the group —AsHj but has also been used to denote > AsO OH and —AsO(OH)j.)... 

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.)... 

Concerning anthropogenic sources, methyl arsenic compounds such as methyl arsonic acid and dimethylarsinic acid have been used as herbicides, and were once a significant source of environmental residues. Dimethyl-arsinic acid (Agent Blue) was used as a defoliant during the Vietnam War. 

The introduction of the arsinic acid group into the aromatic nucleus is of great interest in connexion with the therapeutic application of arsenic compounds in combating certain infectious diseases (atoxyl = sodium arsanilate salvorsan). 

Compare this process with sulphonation and nitration, and note especially the difference between nitrogen and arsenic, which are introduced respectively as the neutral nitro-group and the corresponding hydrate, viz. the dibasic arsinic acid group. 

The reduction of the arsinic acids to arsenobenzenes corresponds to that of the nitro-compounds to azo-compounds ... 

Aromatic substitution by the SrnI reaction, 54, 1 Arsinic acids, 2, 10 Arsonic acids, 2, 10... 

Arsin Acid Bis-[4-fluoro-phenyl]-XII1/8. 333 (Ar-NJ + AsF8 / H,0) ElOa. 725 (At jAsFj 4... 

Because arsenic(V) (as arsonic or arsinic acids) is readily reduced to arsenic(III) by sulfur dioxide in concentrated HX,102,103 this makes chloroarsines much more readily accessible than the corresponding phosphine compounds. This is shown in equation (31),104... 

The synthesis of the first arsabenzene, 9-arsaanthracene, 6, was simultaneously communicated by Bickelhaupt16) and Jutzi17> in 1969. The elimination of hydrogen chloride from 9,10-dihydroaarsanthracene 7 afforded 6. These precursors are available from either reduction of the corresponding arsinic acids 816,18) or by the exchange reaction of dihydrostannaanthracenes 9 with arsenic trihalides 17). 

Finally, particular chemical species can be determined in some cases, as when arsenic content is separated into As(III), As(V), monomethyl arsonic acid, and dimethyl arsinic acid using ion-exchange chromatography. Chemical speciation is sometimes possible but is often very difficult. If the metals... 

The mixture was then diluted with water to a volume of 1400 ml and allowed to cool to 23°C. At this point, 52.0 g of by-product material, which was predominantly tri-(p-aminophenyl)-arsineoxide, were filtered out. The pH of the filtrate was then brought from 8.7 to 5.1 by the addition of 1.8 mol of hydrochloric acid while the volume of the mixture was increased to 2,200 ml by the addition of water. The mixture was stirred for 5 h at room temperature and again filtered. 108.0 g of by-product material comprising predominantly di-(p-aminophenyl)-arsinic acid was filtered off at this point. 

Arsonic acids may be regarded as derived from orthoarsenic acid, (HO)3As—>0, by replacement of one of the hydroxyl groups with an organic residue the arsinic acids are similarly derived by replacement of... 

Arsinic acids and arsine oxides may be prepared by extensions of the t Bart synthesis. Thus, diphenylardnic acid is obtained from benzene- diazonium chloride and disodium phenylarsenite. 

In the Bechamp reaction, para orientation predominates, although small amounts of ortho isomers are formed, together with some arsinic acids (e.g., 4,4,-diaminodiphenylarsinic acid from aniline) none of the meta isomer results. If the para position is blocked, the reaction usually yields the ortho isomer in a low yield however, in the case of p-hydroxy-benzenesulfonic acid no reaction occurs.76 As might be expected, ortho 4 substitution prevails when a-naphthylamine is employed as the starting material.58... 

In addition to ortho isomers, as by-products in the Bechamp reactions, small amounts of arsinic acids are produced. As the reaction temperature rises the proportion of arsinic acids increases until at 220-230° they are the principal products. At higher temperatures oxidation brings about a decrease in yield. 4,4 -Diaminodiphenylarsinic acid has been prepared in a 20-30% yield by the interaction of aniline with arsenic acid at 230°.76... 

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