THE GEIGNARD REAGENT ON O-PHTHALTC ESTERS. 9 



agreeing well with the numbers required by the formula Cn HjsO, 



viz. 



C=82.50 H = 7.50. 



yC(CH3)2 . 



The constitution, CgH4<^ /O, given to the substance 



was proved by the study of its oxidation product. 



a) One part of the oil was mixed with 1.5 parts of chromic 

 acid, 2 parts of cone, sulphuric acid, 4 parts of water, and the 

 mixture, contained in a flask provided with reflux condenser, 

 was warmed on a water bath. The original orange yellow colour 

 of the mixture changed into deep green, and large crystals began 

 to adhere to the walls of the flask. After diluting the acid 

 mixture with a large quantity of water, these crystals were re- 

 moved and recrystallised from alcohol. The substance was thus 

 obtained in the form of large tabular crystals, and its melting 

 point was found to be 69-71°. 



b) A benzene solution of the oil was shaken w^ith the mix- 

 ture of an equal volume of r)% solution of potassium perman- 

 ganate and dilute sulphuric acid (2%), the permanganate mixture 

 being added in small portions, until it was no longer decolourised. 

 The precipitated manganese dioxide was dissolved by means of 

 sulphurous acid, and the benzene layer separated and distilled. 

 Crystals were thus obtained, which were found to be identical 

 with those above obtained by oxidation with chromic acid mix- 

 ture. 



A determination of carbon and hydrogen gave the following 

 numbers : 



0.1769 g. of the substance gave 0.4846 g. of CO2 and 

 0.1000 g. of H2O, therefore 



C=74.71 H=6.32. 



