310 MESSRS. E. FEANKLAND AND B. F. DUPPA'S 



readily effected by acting upon the ethereal salts of oxalic acid by the zinc compounds 

 of the alcohol radicals. 



I. Action of Zincethyl upon Ethylic Oxalate. 



In this reaction ethylic oxalate * was mixed with rather more than its own volume 



of pure zincethyl ; the temperature of the mixture gradually rose, and large volumes of 



gas were evolved. This gas, which, as the following analyses prove, consists of about 



equal volumes of ethylic hydride and ethylene, was passed through a U-tube immersed 



in ice, and subsequently through sulphuric acid, and was then collected over merciu-y. 



It was found to be soluble in an equal volume of strong alcohol, and gave the following 



numbers on analysis : — 



T. 



Millimetres of mercury. Temperature. 



o 



Pressure of gas used . • . . . . 237'2 14'0 C. 



Pressure after absorption of C^HaJ -lo-i.] ii.n p 



by sulphuric anhydride . . -J 



II. 



Pressure of gas used 29*1 13-0 C. 



« Pressure after addition of oxygen . 278'6 13-0 C. 



Pressure after explosion .... 207'0 13*0 C. 



Pressure after absorption of C O., . 149-6 13-0 C. 



III. 



Pressure of gas used 27*8 14-0 C. 



Pressure after addition of oxygen . 304*5 14-0 C. 



Pressure after explosion .... 242'3 14-0 C. 



Pressure after absorption of C O2 . 186-8 14-0 C. 



* As large quantities of ethylic oxalate were required for this and the following reactions, it became a 

 matter of importance to prepare this compound in the most economical manner. After tr3'ing the numerous 

 methods which have been recommended, we found the following process to give the largest product : — 



1500 grammes of oxalic acid, thoroughly dried at 100° C, are placed, together with 1000 grammes of abso- 

 lute methylated spirit, in a capacious retort, which is then very slowly heated by an oU-bath to 100° C, at which 

 temperature water begins to distil over ; when the thermometer has risen to 105°, a steady stream of absolute 

 methylated spirit is conducted to the bottom of the retort at the rate of about 80 grammes per hour, the tem- 

 perature being allowed to rise very slowly to 125°-130°C., care being taken on the one hand that alcohol shall 

 not distil over, in which case the temperature should be raised, and on the other that the heat is not so great 

 as to cause the generation of gas. At this rate it requires about twelve hours to make the addition of 1000 

 grammes of alcohol ; after which the retort must be gradually heated to the boiling-point of ethylic oxalate, 

 and the remainder of the distillate, which is the pure oxalic ether, collected apart. By fractional distillation 

 the first portions afford a considerable additional quantity of the pure product besides ethylic formate. During 

 the final operation, in consequence of the presence of some unconverted oxalic acid, a quantity of gas is alwaj^s 

 evolved ; nevertheless, in frequently repeated operations, we have obtained an amount of pure ethyUc oxalate 

 equal in weight to the dried oxalic acid employed. 



