Bechamp reaction

Bechamp batch process Bechamp reaction Beck and Guthke cell Becke line technique... 

The Faux process is a modification of the Bechamp reaction that was discovered in 1854. It has been used for the reduction of nitrobenzene to aniline using metallic iron ... 

Baeyer-Villiger reaction, 9, 3 43, 3 Bamford-Stevens reaction, 23, 3 Barbier Reaction, 58, 2 Bart reaction, 2, 10 Barton fragmentation reaction, 48, 2 Bechamp reaction, 2, 10 Beckmann rearrangement, 11, 1 35, 1 Benzils, reduction of, 4, 5 Benzoin condensation, 4, 5 Benzoquinones ... 

Tables of Compounds Prepared by the Bart and Bechamp Reactions. . 433...

In 1863, Bechamp 2 heated aniline arsenite with an excess of aniline at 190-200° and obtained a colorless solid which he thought was an acidic anilide. However, in 1907, Ehrlich and Bertheim 67 clearly demonstrated that the reaction, now known as the Bechamp reaction, involves the replacement of a nuclear hydrogen by the arsono group and that the compound produced is 4-aminophenylarsonic acid. Since its discovery the Bechamp reaction has been extended to include many phenols, substituted phenyl ethers, amines, and their various derivatives. In all, the literature contains more than sixty articles dealing with this method. 

The effect of nuclear chloro and nitro groups, alone, on the yields in the Bechamp reaction has not been studied. However, the reaction proceeds in the expected manner with o- 68 64 and p-nitroaniline 66 >66 and o-59 and p-chloroaniline,67 but fails completely with o-nitrophenol.68... 

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... 

In the following tables are listed the compounds which have been prepared by the Bart and Bechamp reactions. No table for the Rosen-mund reaction is presented because the few known examples of this reac-tion already have been briefly outlined. 

All known examples of the Bart and Bechamp reactions in which the product contains an arsonic or arsinic acid group attached directly to an aromatic carbocyclic ring structure have been included. For example, quinoline arsonic acids are included if the arsono group is linked to the 5-, 6-, 7-, or 8-position but are not included if the attachment occurs in the 2-, 3-, or 4-position. 

The Bechamp reaction has been applied to the following arylamines Aniline, o- and p-chloroanilines, o-, m- and -toluidines, m and p-xylidines, and a-naphthylamine. 

Diaminodiphenylarsinic acid.— This acid is a by-product of the Bechamp reaction between aniline and arsenic add at 180° C. The crude aminophenylarsinic acid from the reaction is dissolved in hot sodium hydroxide solution, a little charcoal added, then 2 volumes of alcohol, and the whole filtered. From the filtrate the sodium salt of the primary acid separates out, which is removed and the filtrate evaporated. Alcohol is then added, the solid removed, and the alcohol evaporated off from the filtrate, which on neutralisation with hydrochloric acid gives the secondary acid as a resinous mass. This is dissolved in sodium hydroxide, filtered, and neutralised with dilute hydrochloric acid, when the product is precipitated as a powder. It is filtered off, washed, dried, and recrystallised from 50 per cent, acetic acid. The yield is 2 to 8 per cent. ... 

COMPOUNDS PREPARED BY THE BECHAMP REACTION 449 Compounds Prepared by the Bart Reaction—Coniinued... 

Bechamp reaction. Formation ofp-aminoorp-hydroxyphenylarsonic acids by heating aromatic amines or phenols with arsenic acid. The arsonyla-tion requires an active hydrogen atom, and is practically limited to the benzene series. Apart from para... 

Also the Bechamp reaction, although not generally applicable, is useful for synthesis of certain arylarsonic acids 507 aromatic hydrocarbons activated... 

Other references related to the Bechamp reaction are cited in the literature. ... 

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