9fi9 



Chemistry. — ''On a m'lr inc/Iiod of prcpurhu/ rai'ho.n/I/'c anJuj' 

 (lri<l('s\ Hy A. J. van Pkski. (Coimmiiiicjited by Prof. S. 



HoO(iKWKlU'K). 



(Clomnumicalod in llio inootino; of February i2S, r.lll), 



Mki.skns (Aim. 52, p. 270) wiis tlic first to ohlMJii sul|vhoa('elic 

 acid by the aotioii of snlpliiirio aniiydridc or fmiiiiig sidplinric acid 

 on acGlic acid at a somewhat elevated temperature. 



The same eomi)Oimd was prepared afterwards bv Fkanohimont 

 from sidplinric acid and acetic anhydride in wiiich case the reaction 

 takes place also at a higher temperature (Comp. ilend. 92, p. 1054 

 also this journal 1881 16). In an analogous manner Franchimont 

 and others prepared some higher sulphoacids such as sulphoj)ro- 

 pionic and siilpho-isobntyric acid '). With regard to the formation 

 of sulplioacetic acid according to the last method, it has already 

 been suggested by Fkancimmont that it was preceded by the for- 

 mation of acetylsulphuric acid. The correctness of this presumption 

 was proved by Stillich by his isolation of the acetylsulphate of an 

 organic base obtained in the acetylation of nitroamidobenzyl-|>nitra- 

 niline with acetic anhydride and sulphuric acid. (Ber. 38, p. 1241). 



I have now succeeded in denioiistrating that when, during the 

 action of S O^ on acetic acid, the tem[)erature is kept below 0° 

 primary acetylsulphuric acid is formed, which only at a higher 

 temperature is transformed into sul|)hoacetic acid. The acetylsulphuric 

 acid thus prepared is quite identical with that obtained hy mixing 

 acetic anhydride and sulphuric acid at a temperature below 0°. 



Acetylsnlphuric • acid is capable of forming salts, the sodium 

 compound being jircpared by adding anhydrous sodium acetate to 

 acetylsulphuric acid, when acetic acid is liberated. During this 

 reaction the temperature must be kept below 0°. This sodium salt 

 is insoluble in acetic acid and may theivfore be obtained in a pure 

 condition by collecting it on a liltei' and washing with, say, dry 

 ether. If this sodium salt is heated either by itself or suspended in 

 a liquid such as acetic acid or toluene it decomposes, as shown by 

 a quantitatixe analysis, into acetic anhydride and sodium jiyrosul- 

 l)hate according to the e(|uati(ui ; 



2 (MI,C()S(),Na = ,(:iL,C()),( ) + Na,S,( I. 



If, however, the sodium salt is healed with sodium acetate in jire- 



sence of acetic acid, double the amoiinl of acetic anhydride is formed : 



CH3C0.S(),Na+ ClI.COONa = ;(;iL,,C()).,() + Na,S(),. 



1) Moll v. Charantk Hec. XXIV. 



