34 PROCEEDINGS OF THE AMERICAN ACADEMY. 



the mother liquor yields on distillation with steam a small quantity of 

 the same body. The yield amounts to 78 per cent of the weight 

 which could theoretically be obtained from the mucochlorylbromide, 

 or, taking both reactions into account, 70 per cent of the amount 

 which the mucochloric acid employed should give. The substance 

 recrystallized from ligroin gave on analysis the following results : — 



I. 0.4362 grm. substance gave 0.4955 grm. C0 2 and 0.0574 grm. H 2 0. 

 II. 0.3097 grm. substance gave 0.5789 grm. AgCl. 



II. 



46.21 



This dichlorcrotonolactone we have also made by the decomposition 

 of trichlorpyromucic acid, and by the action of bromine water upon 

 /3y-dichlorpyromucic acid. Trichlorpyromucic acid appears to be more 

 stable than tribrompyromucic acid. Still it is slowly decomposed with 

 the evolution of carbonic dioxide, when heated to boiling with 50 per 

 cent sulphuric acid, and the dichlorlactone is formed. We have made 

 by this method only a sufficient quantity of material to enable us to 

 identify it with precision. In studying the action of bromine upon 

 /3y-dichlorpyromucic acid we followed the same method that we had 

 employed with the /3y-dibrompyroraucic acid, and found that the re- 

 action followed precisely the same course. In this case, however, we 

 proved the presence of mucochlorylbromide amoDg the insoluble pro- 

 ducts of the reaction only through the characteristic color which was 

 developed upon the addition of sodic carbonate to the alcoholic solution. 

 The dichlorlactone was isolated from the aqueous solution by distilla- 

 tion with steam, as well as by extraction with ether. Its identity was 

 proved by its melting point, and by its conversion into a-phenylamido- 

 /3-chlorcrotonolactone melting at 183°.* 



a/3-Dichlorcrotonolactone is very readily soluble in benzol or chloro- 

 form, readily in alcohol or ether, somewhat more sparingly soluble in 

 carbonic disulphide, and sparingly soluble in cold ligroin, although 

 more freely soluble in hot. It dissolves quite readily in boiling water, 

 and volatilizes freely with steam. The substance crystallizes ordinarily 

 in long silky needles, but on slow evaporation of the ethereal solution 

 it is deposited in clear six-sided plates. It melts at 50-51°, and boils 



* See page 36. 



