124 Report of Schimmel $ Co. April 1913. 



Bibliography. 



We may here refer to an illustrated article by F. Rochussen 1 ) in which the author, 

 in an unconventional form, gives a brief sketch of the genesis of the chemistry of 

 odoriferous substances and of the working-methods at present applied in that branch. 



Two articles by A. Reclaire, which have appeared in the Chemiker Zeitung [36 (1912), 

 1125, 1150, 1161] and elsewhere 2 ), deal with progress in the domain of the chemistry 

 of the terpenes, essential oils and aromatic substances. 



Analytical Notes. 



On p. 45 of the present Report we present the results of our experiments in the 

 determination of certain aldehydes and ketones by the phenylhydrazine method. 



Jeancard and Satie 3 ), together with Umney and Parry 4 ), declare themselves in 

 favour of the unification of processes for commercial analysis and valuation of essential 

 oils and odoriferous compounds. Their object is to remove misunderstandings and 

 contradictions in the evaluation of the products in question. Umney and Parry have 

 communicated details on the subject before the International Congress of Applied 

 Chemistry which was held in New York last September. In addition to physical tests, 

 they attach importance above all to chemical methods of determination, and of the 

 latter they adduce a number of examples, such as the determination of aldehydes, 

 phenols, esters, and alcohols. For aldehyde estimation they suggest the bisulphite 

 method, which is objected to by Hill and Cocking 5 ), who prefer estimation with neutral 

 sulphite. 



It remains to be seen what measure of success will attend the efforts of Jeancard, 

 Satie, Umney, and Parry. We do not intend to express ourselves with regard to the 

 separate proposals until the matter has assumed a more definite shape. 



B. G. Feinberg 6 ) has subjected the various methods of estimating aldehydes to 

 control-tests, taking for this purpose six typical aldehydes, viz: formaldehyde, benzal- 

 dehyde, salicylic aldehyde, p-hydroxybenzaldehyde, anisic aldehyde, and vanillin. Fein- 

 berg gives the following method for estimating benzaldehyde by the bisulphite method: 

 About 25 cc. of a 1 p. c. benzaldehyde solution is diluted in a stoppered flask with 

 25 cc. of about 3 p. c. bisulphite solution. After 25 minutes the excess of bisulphite 

 is titrated back with iodine and starch -solution as an indicator. A blank test is 

 carried out simultaneously. The difference between the quantities of iodine consumed 

 in both cases corresponds to the quantity of aldehyde employed. 1 gram iodine == 

 0,41178 grams benzaldehyde, 0,11858 grams formaldehyde, 0,48081 grams salicylic 

 aldehyde, 0,5360 grams anisic aldehyde, and 0,5990 grams vanillin. 



The sulphite method only gave good results in the case of benzaldehyde. About 

 1 gram benzaldehyde is dissolved in 10 cc. alcohol in a well-closing flask, the sides 

 of the flask being rinsed out if necessary with about 10 cc. water, in order to remove 

 any drops adhering to them. The solution is thereupon neutralised with decinormal 

 alkali liquor, with the addition of 6 drops 1 p. c. phenolphthaleine solution; 50 cc. 



!) Prometheus 21 (1913), 305, 325, 345, 356, 373. — 2 ) Zeitschr. f. angew. Chem. 25 (1912), 2580. 

 3 ) Rev. gin. de Chim. 15 (1912), 313. — ±) Chemist and Druggist 81 (1912), 445. — B ) Ibidem 523. 

 8 ) 8th. International Congress of Applied Chemistry, Washington and New York, 1912. Vol. I, 187. 



