444 PROCEEDINGS OF THE AMERICAN ACADEMY. 



DlcJilordimethoxyquinone Dibenzoyldimethylacetal, 

 C6Cl2(OCH3)o(OCig2(OCOCeH5)2. 



This substance was made in the hope that its saponification might 

 throw some additional light on the curious products obtained from the 

 corresponding ethyl compound, and described in the preceding sections. 

 For this jDurpose 17 grams of the sodium salt of dichlordimethoxy- 

 quinone dimethylhemiacetal were suspended in methyl alcohol, and 

 20 grams of benzoyl chloride added (this is a little more than the 

 calculated amount), after warming for a short time to finish the 

 reaction, the liquid was allowed to cool, the solid, which had separated, 

 filtered out, and washed first with alcohol and afterward with water. 

 The residue was purified by crystallization from a mixture of alcohol 

 and chloroform until it showed the constant melting point 193°, when 

 it was dried at 100°, and analyzed with the following result: — 



0.2052 gram of the substance gave by the method of Carius 0.1163 

 gram of argentic chloride. 



Calculated for 

 C6Cl2(0CH3)j(0CU3)2(0C0CgH5)2. Found. 



Chlorine 13.95 14.02 



The substance crystallizes from a mixture of alcohol and chloroform 

 in several different forms, which however may be produced by the 

 twinning of a single form in different ways. The simplest form ob- 

 served consisted of rather long plates terminated by two planes at an 

 obtuse angle to each other ; these frequently appeared as broad blades 

 in radiating groups, when less well developed. A second very common 

 form was white thick plates, square or nearly so, which showed evi- 

 dence of twinning, and finally mixed with these were sharp thick 

 rhombic crystals looking like very acute scalenohedra, and showing a 

 line of twinning along the diagonal between the two acute angles. 

 Whether these were different habits of the same form, or indicated 

 that the substance was not homogeneous, mattered little to us, as 

 the saponification with sulphuric acid of specific gravity 1.44 gave a 

 product which was evidently homogeneous, and this was the substance 

 in which we were especially interested. The dichlordimethoxyquinone 

 dibenzoyldimethylacetal is white, and melts at 193°. It is easily 

 soluble in chloroform ; soluble in benzol ; sparingly soluble in alcohol, 

 ether, glacial acetic acid, or carbonic disulphide ; insoluble in water 

 or ligroine. The best solvent for it is a mixture of alcohol and 

 chloroform. 



