166 



The Philippine Journal of Science* 



1913 



strongly to the unsymmetrical structure. The fact that phthal- 

 oxime may be made from phthalyl chloride and hydroxylamine 

 does not distinguish between the two structures, as the reaction 

 is not a mere elimination of hydrogen chloride with the formation 

 of the oxime, but takes place in two steps, giving phthalhydrox- 

 amic acid as an intermediate product. Ott 5 has recently shown 

 that the ordinary phthalyl chloride may be symmetrical, a fact 

 indicated by its absorption spectrum according to Scheiber. 6 

 It is evident that an unsymmetrical oxime may result from a 

 symmetrical chloride in the following manner: 



—CO CI 

 -CO CI 

 Phthalyl chloride. 



NH2OH 



/CI 



— CfOH 



x NHOH+2H 2 -* 

 —CO CI 



/V 



\/ 



/\ 



/CI 

 -Cf-OH 



x NHOH 

 -CO CI 



\y 



/NHOH 



/\-</o 



/ 



-c=o 



NHOH 



+2HC1 



-C— OH 



Phthalhydroxamic acid. 



\/ 



y 



OH 

 



— > 



/\ 



\y 



-C=NOH 

 >0 +H2O 



Phthaloxime. 



The reactions are entirely analogous to these between phthalyl 

 chloride and ammonia. 7 Phthalhydroxamic acid cannot be iso- 

 lated from solution as it loses water to form the oxime, but its 

 presence may be shown by the characteristic color given with 

 ferric chloride, and its alkali salts may be obtained as colorless 

 crystals. The reaction between phthalic anhydride and hydroxyl- 

 amine follows a similar course. The anhydride combines 

 with the free hydroxylamine giving a clear solution of hydrox- 

 amic acid. Since both the anhydride and the oxime are very 

 slightly soluble in water, it is evident that the first phase of the 

 reaction may be completed before dehydration with the result- 



6 Ann. d. Chem. (Liebig) (1912), 392, 245. 

 "Ibid. (1912), 389, 121. 



7 Scheiber, Ber. d. deutschen chem. Ges. (1912), 45, 2252. 



