Notes on scientific research. 131 



hydrazones of terpene ketones with mercuric oxide, or the double salts of mercuric 

 chloride and the hydrazones, after addition of the equivalent amount of alkali, in an 

 indifferent solvent. By the interaction of the mercuric oxide and the hydrazones, 

 difficultly-soluble basic mercury compounds are formed whose constitution possibly 

 resembles that of the mercuri-ammonium compounds and which decompose, on heating 

 in indifferent liquids, according to the following equation: — 



CioH 16 :N-NH'.Hg-OH — > C 10 H 16 + N 2 + Hg + H 2 0. 



The patent specification contains details for the preparation of tricyclene from 

 camphor hydrazone (crude yield, 78.3 per cent.), of d-q/cfofenchene from d-fenchone 

 hydrazone, and of aj)ocyc\ene from camphenilone hydrazone. 



The principal products resulting from the pyrogenetic decomposition of benzene 

 are, according to E. Peytral 1 ), hydrogen and diphenyl; 2C 6 H 6 — >• C 6 H 5 -C 6 H5 + H 2 . 

 One-third of the hydrogen formed results either from a radical decomposition of part 

 of the benzene into methane, carbon (graphite), and hydrogen, or (as is more probable) 

 from a part of the diphenyl formed and then decomposed further. 



Benzaldehyde, when submitted to the treatment indicated, decomposed principally 

 into benzene and carbon monoxide, besides into diphenyl, carbon monoxide, and 

 hydrogen. In addition, a small amount of anthracene is formed due to condensation 

 in the hydrogen atmosphere. As secondary products of the decomposition of diphenyl, 

 carbon and methane were traced. 



A process for obtaining p-cymene from the waste terpenes (b. p. about 175°) 

 resulting from the camphor synthesis, or the fractions boiling at 175° and at 160° of 

 Swedish or Polish "turpentine" (pine) oils has been published by the Rheinische 

 Campherfabrik 2 ), of Dusseldorf. The respective fractions are chlorinated slowly at 

 temperatures ranging from 10 to 80°, the reaction-product distilled with steam, the 

 volatile oil heated with some zinc chloride and subjected to distillation. Yield about 

 60 per cent, of the primary material; it may be raised to 75 per cent, by heating the 

 crude material with an inorganic or organic acid, or an acid salt, and by using the 

 fraction boiling at 175° for the chlorination. 



Ralph H. McKee and Leland J. Lewis 3 ) recommend fat-splitting reagents obtained 

 from cytnene, i. e.. cymene stearosulphonic acid. The compound is obtained analogous 

 to Twitchell's 4 ) method for preparing aromatic stearosulphonic acids. 280 gr. of oleic 

 acid and 140 gr. of cymene were stirred, and 300 gr. of sulphuric acid (66 deg. Be.) 

 was gradually added, keeping the temperature below 35°. Further details on the 

 preparation and purification of the product may be gathered from the original paper. 



On comparison with Twitchell's reagent, benzene and naphthalene stearosulphonic 

 acids, and the "Kontakt" reagent, the cymene derivative offers, in the opinion of the 

 authors, the following advantages: — It is more easily and cheaply made and can be 

 produced as a uniform product. The fatty acids as well as the glycerin obtained by 

 its use are both of a lighter colour. 



Terpinene. — Contrary to the other nitrosites of unsaturated bodies, whose structure 

 is 1 mostly bimolecular, the nitrosite of terpinene possesses the simple molecularity of 

 Ci Hi 6 O 3 N 2 , and it does not show the colour reactions characteristic of the dissociation 



*) Bull. soc. ehim. IV, 29 (1921), 44. — 2 ) Germ. Pat. 819162 and 319163, July 14* h , 1921. Engl. Pat. 156329, 

 Febr. 3"», 1921. — *) Americ. Perfumer 16 (1921), 175. — *) Journ. Americ. chem. Soc. 22 (1900), 22. 



9* 



