On the Synthesis of Succinic and Pyrotartaric Acids. 327 



mula C 4 H 4 Cy 2 +4(AgO, NO.). The crystals are soluble in water 

 and alcohol, insoluble in ether. When heated, they melt and explode 

 like gunpowder. They do not detonate on percussion. This com- 

 pound may possibly throw some light on the constitution of the 

 fulminates. 



I have also slightly modified the process I gave in my last note 

 for succinic acid. The modified process is very productive, and 

 yields the acid at once in a state of purity. From 1500 grains of 

 bromide of ethylene I obtained 480 grains of succinic acid, or nearly 

 33 per cent. It gave on analysis 40*54 instead of 40* G7 per cent, of 

 carbon. 



We are now enabled, thanks to the researches of Messrs. Perkin 

 and Duppa and of M. Kekule*, to build up three highly complex 

 organic acids (succinic, paratartaric, and malic) from a simple hydro- 

 carbon ; and, what is more important, we are enabled to do this by 

 processes every stage of which is perfectly intelligible. 



With the view of ascertaining whether or not the homologues of 

 succinic acid could be obtained in a similar manner, I have endea- 

 voured to prepare pyrotartaric acid from the cyanide of propylene, 

 propylene being the radical of propylglycol. 



Preparation of Cyanide of Propylene. — A mixture of one equi- 

 valent of bromide of propylene and two of cyanide of potassium, to- 

 gether with a considerable quantity of alcohol, was exposed to the 

 temperature of a water-bath for about sixteen hours. The alcohol 

 was then filtered and distilled. A liquid residue was thus obtained, 

 which was dissolved in ether. The body left on evaporating the 

 etherial solution was then submitted to distillation. Almost the 

 entire liquid passed over between 265° and 290° Cent. The fraction 

 distilling between 277° and 290° Cent, was collected apart and ana- 

 lysed. It gave 62*0 instead of 63*8 per cent, of carbon. This body 

 cannot be obtained purer by distillation under atmospheric pressure, 

 as it suffers partial decomposition during the process. 



The properties of this cyanide very much resemble those of the 

 preceding. It differs, however, in its physical state, which is that 

 of Sf liquid at the ordinary temperature of the air. It is soluble in 

 water, alcohol, and ether. It has an acrid taste. It is neutral to 

 test-paper. It is decomposed by potassium, cyanide of potassium 

 being formed. Its solution in water does not precipitate nitrate of 

 silver. Heated with potash, it is resolved into an acid and ammonia. 



Formation of Pyrotartaric Acid. — A mixture of one volume of 

 cyanide of propylene and about 1| volume of strong muriatic acid 

 was exposed in a sealed tube to the temperature of a water-bath 

 for a few hours. On cooling, the contents of the tube became a 

 mass of crystals. These were dried and dissolved in absolute 

 alcohol. The residue obtained on evaporating the alcoholic solu- 

 tion was then twice crystallized from water, and finally digested 

 with ether. The body left on distilling off the ether is the acid in 



* Quarterly Journal of the Chemical Society, July I860; and Bulletin de la 

 Societe Chimique de Paris du Aout, 1860, p." 208. 



