Commercial and scientific notes on essential oils. 7 



Oil of Andropogon Iwarancusa. — J. L. Simonsen 1 ) investigated the oil of Andro- 



pogon Iwarancusa, Jones, a graminea occurring in the Himalayas and the outer hill zone 

 from Kashmir to Assam and ascending to 8000 ft. and above, also in the plains from 

 North West Himalaya to Bombay Presidency. The pale yellow oil, which had been 

 obtained in a 1 per cent, yield from the grass, possessed a marked smell of peppermint 

 and had the following constants : — d~ 0.9203, [«] Da0 o + 51.68 o , n D30 o 1.481, acid v. 0.7, 

 sap. v. 12.0, sap. v. after acet. 47.4, percentage of ketone, by absorption with neutral 

 sodium sulphite solution, 77 per cent. On distilling and refractionating the oil under 

 diminished pressure (200 mm.), the following fractions were obtained: — 1)1 15 to 130° 

 (14.6 per cent), 2) 130 to 174 (1.6 per cent), 3) 174 to 185° (70 per cent), 4) 185 to 205° 

 (12 per cent). The first fraction consisted essentially of a hydrocarbon, b. p. 1 01 ° (1 00 mm.), 

 163 to 164° (698 mm.), dgg 0.8565, [«] D80 o + 54.82 °, n D30O 1.474, smelling pleasantly remi- 

 niscent of cymene. When dissolved in acetic anhydride and treated with a drop of 

 sulphuric acid, a transient purple coloration appeared, which rapidly passed into a deep 

 brown. When the hydrocarbon was treated with hydrogen chloride in ethereal solution, 

 an oil resulted which was probably a monohydrochloride; with hydrogen bromide in 

 acetic acid solution a viscous oil was obtained, which was evidently a dihydrobromide 

 Ci Hi 8 Br 2 . The hydrogen iodide derivative was very unstable, and decomposed even 

 when kept at 0°. Fraction 2) consisted apparently mainly of a mixture of d-A^p-men- 

 thenone-3 and the hydrocarbon. Fraction 3) (d|| 0.9321, [«J D30 o + 36.76°, n D30o 1.481) 

 consisted, by 98 per cent, of d-A^p-menthenone and was purified by solution in sodium 

 sulphite solution and reprecipitation (and racemisation, comp. Read and Smith, p. 34 of 

 this Report) by alkali, when it showed the following constants: — b. p. 180 to 181° (200 mm.), 

 230 to 231° (697 mm.), dg| 0.9307, [«] D30 o + 7.92°, n D30 o 1.481. Fraction 4) still contained a 

 considerable quantity of the ketone. The identity of the racemic ketone with dl-A x -p- 

 menthenone-3 = piperitone (comp. p. 149 of this Report) is proved, according to Simonsen, 

 by the formation of the benzylidene derivative (m. p. 61°) and the hydroxylamino-oxime 

 (m. p. 170 to 171°), furthermore by oxidation of the ketone, by ferric chloride, to thymol 

 and by the reduction to menthol. Besides, the author prepared: — the a-semicarbazone 

 (m. p. 225 to 227°), the ^-semicarbazone (m. p. 174 to 176°), an optically active /?-semi- 

 carbazone (m. p. 193 to 194°), the oxime (m. p. 117 to 118°), and proved thus the identity 

 of his ketone with the z^-menthenone-S obtained byWallach and others 2 ). The discrep- 

 ancies observed in the constants as compared with the values found by former authors 

 («-semicarbazone, m. p. 224 to 226°, /?-semicarbazone, m. p. 171 to 172°, oxime, m. p. 

 107 to 109°) are explained by Simonsen by assuming that the compounds obtained 

 formerly had not been quite pure and free from isomerides. 



On oxidising the ketone with potassium permanganate solution, at 0°, I, /-acetyl- 

 «-isopropylbutyric acid was obtained; b. p. 195 to 200° (48 mm.). 



Thus the oil of Andropogon Iicarancusa consists up to 80 per cent, of d-zF-menthen- 

 one-3 and of a hydrocarbon of unknown constitution. 



Angelica Oil. — Last autumn, it is true, the Thuringian plantations supplied 

 abundant quantites of raw material, but the prices remained high, as there was a 

 vivid demand, owing to the completely exhausted stocks of oil. Although we had 

 secured considerable lots, our production was scarcely large enough to come up to 

 the requirements from all quarters, so that we were almost sold out at the beginning 

 of the present year. The prospects are not very favourable, as there are only few 



l ) Jfjurn. chem. Soc. 119 (1921), 1644. — 2 ) Comp. Reports October 1910, 99; 1916, 18. 



