( Tlo ) 



Chemistry. — ''Action o/' hjiihuxjen pcro.rj/de en (l/l'i'/cin's 1 ,2 (/nd 

 01} n-l-('(oitir acids. \\\ Pi'of. A. F. Ilofj-KMAN. 



Some aromatic acids mav be (tbtained hv first iiitrodiiciiig' the 

 acetyl group by means of the reaction of Friki)ki> and Crafts and 

 oxidising this to tlie carboxyl gi'onp. In many cases, liowever, this 

 oxidation does not take phice readily; the group CO. CH., yields with 

 comparative ease the group C-() . CO.^H but the further transformation 

 of the latter into the carboxyl group is often attended with great 

 loss. Even the method of Hoogewerff and van Dorp, consisting in 

 heating the «-ketoiiic acid with concentrated sulphuric acid does not 

 yield the theoretical quantity. I have tried whether this transforma- 

 tion might perhai)S be attained ipiantilatively by means of hydi'ogen 

 peroxide, according to the equation: 



R.CO. CO.H _ R.COOH. 



+ IIOOH — -f HOC(\H {= H/) + CO.,) 



This was indeed the case. Aqueous solutions of pyruvic acid, 

 benzoylformic acid, thienylglyoxylic acid when heated with the 

 calculated amount of 30 "/„ hydrogen peroxyde (iMerck) at once 

 eliminated CO and yielded almost quantitative amounts of acetic 

 acid, benz.oic acid and tliio[)henic acid. From Prof. Eykman, I received 

 small specimens of four «-ketonic acids which he is investigating 

 and these, when heated in aqueous or acetic acid solution with a 

 slight excess of H.^ O, also eliminated CO. On titrating the acids 

 obtained from them it \\as found that their group CO . CO.^H had 

 passed into CO^H. 



This result led us to siqtpose that «-diketones might also be readily 

 resolved by the actioji of H^ (3.^, 



+% OH ^' = ^- ^^-^ ^ + ^'- ^^-^ ^' 



Some of the diketones, such as benzil, camphoripiinone and 

 ])henanthrenequinojie were dissolved in glacial acetic acid and wai-med 

 for some days with a small excess of 30 "/„ H., 0._,. The expected 

 reaction took jdace almost (piantitatively : it was remarkable that 

 camphorcpiinone did iu»t at once yield camphoric acid but first the 

 anhydride, which was converted by boiling with dilute alkali into 

 camphoric acid. 



Messrs. J. Huisinoa and ,1. W. Beekman ha\e carried out the 

 experiments. 



GroniiKjen, March 1904. Lab. Univers. 



