Utilization and neutralizing sulphitation liquors

The sulphitation liquors contain dinitrotoluenesulphonic acids in a quantity amounting to about 4% of the TNT produced. In a period of intensive manufacture of TNT this may be of considerable importance from an economic point of view. This is why the problem has arisen of how to utilize the organic compounds contained in sulphitation liquors. 

Batik [27] found that the acidification of sulphitation liquors with an inorganic acid resulted in the formation of NaHS03, which reduced the nitro- to the amino group. Simultaneously, due to the presence of NaN02, diazotization took place and a red diazonium salt 

The compound may be utilized for further reactions, for example in dyestuffs manufacture. 

British Technical Records [6] mentioned another approach to the problem of utilization of sulphitation liquors. According to these data, attempts were made in Great Britain during World War I to make use of the reactivity of the sulpho group in the ortho or para position to the nitro ones. By acting with methylamine, N-methyl-dinitrotoluidine (I and II) was obtained, which, when further nitrated, yielded methyltetryl All the methods mentioned proved uneconomical. 

Gomall and R. Robinson [28] suggested reducing sodium dinitrotoluene sulphate (e.g. the sodium salt of 2,4-dinitrotoluene-3-sulphonic acid) to yield m- toluene-diamine-3-sulphonic acid which could serve as an intermediate for obtaining azo dyes. Oxidation of sodium 2,4-dinitrotoluene-3-sulphonic acid with potassium permanganate in alkaline medium gave 2,4-dinitro-3-sulphobenzoic acid, also an intermediate for azo dyes. 

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