Upon distillation of fresh mignonette root with water-vapor 0,014 to 0,035 p.c. of oil were obtained.
The oil of mignonette root is light brown in color and has an odor very much like that of Spanish radish: d15o1,010 to 1,084; aD + l°30'. At 255° it begins to boil with a decided evolution of gas. Even in vacuum it does not distil without decomposition.
A small amount of this oil was first distilled from fresh roots by A. Vollrath3) in 1871, who recognized its character as that of a mustard oil. However, his supposition that it is identical with allyl mustard oil proved erroneous. As shown by ). Bertram and H. Walbaum4), the mustard oil of mignonette root oil is phenylethyl mustard oil C6H6Ch2ch.,Ncs.
1) Yield 1,3 to 1,5 p.c. Comp. vol. I, p. 251.
2) H. von Soden, Journ. f. prakt. Chem. II. 69 (1904), 264.
3) Arch, der Pharm. 198 (1871), 156.
4) Journ. f. prakt. Chem. II. 50 (1894), 555.
Phenylethyl mustard oil smells quite like mignonette root oil. When heated with ammonia beautiful crystals of the thio-urea that melt at 137° are obtained, Nh2-CS-Nhc2h4c6h5 When the thio-urea is treated with silver nitrate and baryta water, silver sulphide and phenylethyl urea, crystallizing in long slender needles that melt at 111 to 112°, are formed. If the phenylethyl mustard oil be heated with concentrated Hydrochloric acid in sealed tubes, laminar crystals of phenylethylamine chlorhydrate melting at 217° are formed. With ethyl oxalate the phenyl-ethylamine combines to form diphenylethyloxamide which melts at 186°.
All of these derivatives of phenylethyl mustard oil were prepared by Bertram and Walbaum from the natural oil obtained from mignonette root and from the phenylethyl mustard oil prepared artificially from phenylethylamine and carbon disul-phide1). The corresponding products from both sources were identical throughout.