1886.] on Recent Progress in the Coal-tar Industry. 465 



Carbonic acid is set free, and a mixture of ortliotoluene sulphonic 

 amide and ammonium chloride remains. 



^^^^SO/CI + (NHJ,C03 = CeH, [2'^; ^^^ + NH.Cl + H,0 + CO^. 



Toluene sulphonic chloride Toluene sulphonic amide 



As the mixture is very liable to solidify on cooling, cold water is at 

 once added to prevent this, and to dissolve out the ammonium chloride, 

 the amide remaining in the solid state. The liquid is separated by 

 centrifugating. 



Step VII. — The orthotoluene sulphonic amide is now oxidised, 

 preferably by means of potassium permanganate. The result of this 

 will be, precipitated manganese dioxide, free alkali and alkaline 

 carbonate, and an alkaline orthosulphamido-benzoate. The alkaline 

 liquid requires careful neutralisation during the oxidising jDrocess, 

 and especially before evaporating, with a mineral acid, or else the 

 sulphamido-benzoate formed would be again split up into ortho- 

 sulphonic benzoate and free ammonia, thus : — 



^.H^ga-Tn, + NaOH = C.H,{C0.0Na^ ^ ^^^ 

 The oxidation process itself is thus represented : — 



C«H.{gg=.NH, + 30 + NaOH = C,H.{CO-p^ + 2H,0. 



Sodium orthotoluene 

 sulphamido-benzoate 



By precipitation with dilute mineral acids, such as hydrochloric or 

 sulphurous acids, the pure benzoyl sulphonic imide is at once pre- 

 cipitated : — 



C.H.{^§;.^^"^ + HOI = KaCl + H,0 + C.H.{CO Jnh. 



" Saccharine," or benzoyl 

 sulphonic imide 



Saccharine possesses a far sweeter taste than cane sugar, and has a 

 faint and delicate flavour of bitter almonds. It is said to be 220 

 times sweeter than cane sugar, and to possess considerable antiseptic 

 properties. On this account, and because of its great sweetness, it is 

 possible that it may be useful in producing fruit preserves or jams, 

 consisting of almost the pure fruit alone ; the small percentage of 

 saccharine necessary for sweetening these preserves being probably 

 sufficient to prevent mouldiness. Saccharine has been proved by 

 Stutzer, of Bonn, to be quite uninjurious when administered in con- 

 siderable doses to dogs, the equivalent as regards sweetness in sugar 

 administered, being comparable to over a pound of sugar each day. 

 Stutzer found, moreover, that saccharine does not nourish as sugar 

 does, but that it passes off in the urine unchanged. It is proposed 

 thus to use it for many medical purposes, where cane sugar is excluded 

 from the diet of certain patients, as in cases of " diabetes mellitus," 



2 H 2 



