JACKSON AND GRINDLEY. — ACETALS FROM QUINONES. 417 



The principal argumeuts in favor of tliis theory are the following. 

 It requires the union of one molecule of quinone with one molecule of 

 a diatomic phenol such as hydroquinoue or resorcine, but with two of a 

 monatomic phenol like common phenol or mouomethylhydroquinone,and 

 is in this respect in accordance with the facts. Such substances would 

 not be formed when the hydroxyl groups of the phenols had been con- 

 verted into alkyloxyl groups, and dimethyl liydroquinone has no action 

 on quinone. The products should be unstable, as we have found that 

 the stability of our new hemiacetals depends on the number and strength 

 of the negative radicals attached to the (juinone ring, and in these cases, 

 where there are no negative radicals, we should expect a very slight 

 stability. As a matter of fact, these substances are not only decom- 

 posed by acids or alkalies, but quinhydrone even by solution in 

 neutral solvents.* The action of acetic anhydride giving diacetylhy- 

 droquinone and quinone,t which is brought up by Nietzki as a proof 

 of the absence of free hydroxyl, is really in accordance with our 

 theory, as our dimethyl hemiacetal with acetic anhydride gave methyl 

 acetate and the quinone from which the hemiacetal was derived. 

 All these observed facts, therefore, are in harmony with our theory. 

 Against it is the marked color of all this quinhydrone group, whereas 

 our hemiacetals are colorless. This may be due, however, to the 

 difference in the nature of the radicals attached to the carbonyl groups, 

 our hemiacetals containing methyl or ethyl, the quinhydrone group 

 aromatic radicals, which might well give more colored compounds. It 

 may be remarked in this connection, that, while the methyl or ethyl 

 ether of resorcine is colorless, the simple resorcine ether itself is red- 

 dish brown. An attempt will be made next year to find other parallel 

 cases. Another objection to our theory is, that no salts have been 

 obtained from phenoquinone, whereas the substance, according to our 

 formula, contains two free hydroxyls. Wichelhaus, who states that 

 he obtained no salts of it, adds that the substance turns blue when 

 treated with alkalies ; this may indicate the formation of a salt not yet 

 isolated. We have attempted to test our theory by experiment in this 

 direction, but so far with little result. By treating phenoquinone with 

 sodic ethylate, not in excess, we obtained a green salt; but, as much 

 phenol was found in the filtrate, we are inclined to consider this salt 

 at present rather a product of the action of sodic ethylate on the qui- 

 none formed by the decomposition, than a salt of the phenoquinone 



* Clark, Am. Chem. Journ., XIV. 574. 

 t Hesse, Ann. Cliem., CC. 248. 



VOL. XXX. (n. S. XXII.) 27 



