3oi PROCEEDINGS OP THE AMERICAN ACADEMY 



pare this tetrachloride in a pure condition, and indeed we first obtained 

 the trichlorpyromucic acid from one of the earlier preparations of the 

 ethyl pyromucic tetrachloride in which an unusually great spontaneous 

 elevation of temperature had taken place through the rapid absorption 

 of chlorine. For its preparation we heated the ethyl pyromucate to 

 145°, and passed in chlorine at this temperature until the gain in 

 weio-ht showed that one atom of hydrogen had been replaced by 

 chlorine. We then allowed the temperature to fall to about 120°, 

 and continued the chlorination to saturation. The total gain in 

 weight then corresponded approximately to that required by the 

 formation of the tetrachloride of the ethyl chlorpyromucate. On 

 decomposing this product as usual with a cold concentrated alcoholic 

 solution of sodic hydrate, the alcoholic solution filtered from the 

 insoluble sodium salts contained, as in the previous cases, small quan- 

 tities of liquid furfuran derivatives, but the amount was so minute that 

 no separate study of them was made. The sodium salts dissolved in 

 hot water gave with hydrochloric acid an impure trichlorpyromucic 

 acid as a more or less colored oil, which solidified as the solution 

 cooled. For the purification of the acid we have found it convenient 

 to take advantage of the slight solubility of the ammonium salt in cold 

 water. The crude acid was suspended in about thirty times its weight 

 of water, amraonic hydrate added in excess, and the hot solution treated 

 with bone-black. The filtered solution deposits on cooling the greater 

 part of the trichlorpyromucic acid as the ammonium salt from which 

 the pure acid can readily be obtained. The small amount of trichlorpy- 

 romucic acid remaining in the ammoniacal solution may be recovered, 

 although at the expense of considerable trouble, by precipitation with 

 calcic chloride and repeated recrystallization from water and dilute 

 alcohol of the acid obtained from the insoluble calcium salt. 



The yield of pure trichlorpyromucic acid was far from satisfactory, 

 as we could obtain only 30 per cent of the weight of the ethyl pyromu- 

 cate taken, but 15 per cent of the theoretical amount. 



For analysis the acid was dried over sulphuric acid. 



I. 0.3214 grm. substance gave 0.3248 grm.COj and 0.0211 grm. HgO. 

 II. 0.2107 grm, substance gave 0.4192 grm. AgCl. 

 III. 0.2135 grm. substance gave 0.4255 grm. AgCl. 



III. 



49.27 



