JACKSON AND GRINDLEY. — ACETALS FROM QUINONES. 435 



Dichlordiethoxyquinone Tetraethylacetal^ C6Cl^(OC2H5)2(OC2H5)4. 



It has been stated already that ethyl or methyliodide did not act 

 either on the free hemiacetal or its sodium salt ; if, however, the 

 silver salt of dichlordiethoxyquinone diethylhemiacetal vpas treated 

 with ethyliodide, the corresponding tetraethylacetal was formed. As 

 this compound could be obtained only in very small quantities and 

 with great difficulty, it was necessary to prepare the sodium and silver 

 salts of the hemiacetal on a large scale, which was done as follows. 

 40 grams of dichlordiphenoxyquinone were mixed with the sodic 

 ethylate made by treating 10 grams of metallic sodium with 150 c.c. 

 of absolute alcohol, and in order to complete the reaction the mixture 

 was warmed on the steam bath for a few minutes, and then allowed to 

 stand at ordinary temperatures for four or five hours. The sodium 

 salt of the dichlordiethoxyquinone diethylhemiacetal, which separated 

 in large amount, was filtered off, and washed thoroughly, first with a 

 mixture consisting of equal parts of alcohol and ether, and finally with 

 ether alone. In this way 40 to 42 grams of the essentially pure sodium 

 salt were obtained instead of the 44 grams required by the theory ; 

 the yield, therefore, was between 90 and 95 per cent of the theoretical. 



In order to prepare the silver salt of the diethylhemiacetal, a 

 concentrated aqueous solution of the sodium salt was treated with 

 25 grams of argentic nitrate dissolved in a small amount of water. 

 The insoluble silver salt was filtered, washed thoroughly with water, 

 alcohol, and ether, and then dried as quickly as possible by sucking a 

 stream of air through it on the filter pump. 



The silver salt of the diclilordiethoxyquinone diethylhemiacetal 

 was then suspended in ether, and treated in the cold with ethyl iodide, 

 when, in addition to a very small quantity of the tetraethylacetal, a 

 large amount of dichlordiethoxyquinone was obtained. The acetal 

 was separated from the quinone by treating the products of the 

 reaction with a dilute solution of sodic hydrate in 50 per cent alcohol, 

 which converted the dichlordiethoxyquinone into the sodium salt of 

 chlorani}ic acid, while the dichlordiethoxyquinone tetraethylacetal 

 was not affected by it. By washing with water it was then easy to 

 separate the freely soluble sodic chloranilate from the insoluble 

 acetal, which was purified by recrystallization from ligroine until it 

 showed the constant melting point 101°-102°, when it was dried in 

 a desiccator, and on analysis gave the following results : — 



I. 0.2039 gram of the substance gave on combustion 0.3928 gram of 

 carbonic dioxide and 0.1335 gram of water. 



