402 The Philippine Journal of Science ma 



color with alkali. The absorption spectrum of pure phthalide 

 in alcohol shows a well-marked band heading at =■ = 3680. The 





3000 32 3 



Oscillation frequency. 



4 36 33 4000 42 4-4- 



3.8 



2.1 /] 

















3.6 





















. 34 



















r solution 

 Co 





















"3 



a 



1 30 





















«H 



i 2.8 





















s 



1 2.6 







1 * 



i 













a 



tn 

 tn 

 V 



a 



•S 2.4 





















A 



*-> 



> 



« 22. 



2 



O 



m 



1 2.0 



























•\ 













at 

 be 

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/.£ 





















/.4 









































Fig. 2. Curve 1. Phthalic anhydride in glacial acetic acid. Curve t. Phthalic 

 anhydride in sulphuric acid. 



spectrum is not altered by the addition of one equivalent of 

 sodium ethoxide. The solution in sulphuric acid shows faint 



