2330
Vol. 57
COMMUNICATIONS TO THE EDITOR
the exception of illinium and thulium and con- comparable with that of samarium. Hence, a cluded that samarium was the only oneof the group study of the radioactivity of thulium preparawhose radioactivity persisted after purification.* tions is well worth investigating. As thulium is classified in the first group, it also FROM THE may possess radioactive properties of a magnitude DEPARTMENT OF CHEMISTRY (8) G . von Hevesy and M. Pabl. Nature, iS1, 434 (1933); ibid.,
Z. physik. Chrm., A169, 147 (1934).
COLUMBIA UNIVERSITY,
NEWYORKCITY
RECEIVED JULY 16, 1935
COMMUNICATIONS T O T H E EDITOR ATTEMPTED PREPARATION OF VANILLOYLFORMIC ACID
Sir:
successful; their concordant conclusion is expressed by the latter’s statement: “The synthesis of vanillin cannot be carried out following the disclosures of the paper published in THISJOURNAL, 1934, page 2107.”
In an attempt to repeat the oxidation of apocyanin to vanilloylformic acid with nitrobenzene in alkaline solution as described by H. 0. Mot- OCTOBER‘10,1935 ARTHURB. LAMB, Editor tern [THISJOURNAL, 56, 2107 (1934)l no action whatever was observable under the conditions described by the author. Nitrobenzene was reTHERMAL DECOMPOSITION OF CrOg3NR3 covered quantitatively from the reaction mixSir: ture and neither aniline nor azobenzene was Some unusual observations recently made in detectable by qualitative means. this Laboratory, and which we hope to study in Difficulty was also experienced in repeating the greater detail, should prove of considerable genauthor’s description of the preparation of apoeral interest. While attempting the preparacyanin by means of the Fries reaction. The alution of the tetroxide of chromium, Cr04, by minum chloride double compound with guaiacol (I) [made according deammonating Cr04.3NHa acetate is quite solid a t the temperatures deto Riesenfeld, Ber., 38,4070 (1905) 1, the following scribed (0-So). Before a third of the required was noted. (1) Compound (I) loses practically amount of aluminum chloride has been added, the no ammonia upon standing for four months over mass is so hard as to be impenetrable to a stirconcentrated sulfuric acid in vacuo and a t room ring rod, making it impossible to incorporate the balance. The apocyanin used was prepared by temperature. (2) If the pressure in a tube conthe method for low temperature Fries isomeriza- taining some (I) is reduced to less than 1mm. and tions described by Baltzly and Bass [ibid., 5 5 , the tube, still attached to the vacuum line, is 4293 (1933) ] which differs from the authors in the immersed in a bath whose temperature may be controlled, a vigorous reaction ensues a t 120 * use of nitrobenzene as a solvent. Particles of (I) become incandescent and W E. BARCH 10’. FARMINGDALE, L. I. dart about in spectacular fashion. The action is RECEIVED MARCH 12, 1935 reminiscent of the thermal decomposition of amNOTE BY THE EDITOR monium dichromate and also of certain models After the receipt of this Communication a repe- that have been constructed to portray molecular tition of the oxidation of apocyanin to vanilloyl- motion in gases. (3) The solid residue of the formic acid with nitrobenzene in alkaline solution above mentioned decomposition of (I) is composed as described by H. 0. Mottern was attempted by of microscopic, elongated square prisms of black a member of the Editorial Board and independ- Cr03.NH3(11). Analysis of (11) for ammonia was ently by the Director of Research of a firm manu- made by distilling into standard acid and for facturing vanillin on a large scale. Both were m- chromium by forming lead chromate. The re-
