Notes on scientific research. 141 



process. The tetrahydrocarveol obtained from nitro-«-phellandrene («-phellandrene, 

 b. p. 75° at 15 mm.; di 5 o 0.848; « D — 81°30'; n D20O 1.4769) by reduction with sodium 

 and absolute alcohol showed the following constants: — b. p. 218° (corr.); di 5 o 0.9073; 

 [«] D — 10.83°, n D150 1.463. From this alcohol the author prepared, by the cold process, 

 the hydrogen phthalate of /-carvomenthol (m. p. 89°; [«] D — 45°4') which yielded 

 on saponification pure /-«-carvomenthol (b. p. 218° [corr.]; d 15 o 0.9074; « D — 20.38°; 

 n D150 1.463). From the mother liquor of the carvomenthol phthalate mentioned above 

 a second, syrupy hydrogen carvomenthol phthalate was produced, which on trans- 

 formation into its silver salt (m. p. 175 to 176°) yielded furtheron /-^-carvomenthol 

 (b. p. 218° [corr.]; d 15 o 0.9071; [«] D — 8.63°; n D15C 1.463). Paolini proposes to term the 

 isomeric carvomenthols obtained by him 1 ) from carvone, for sake of differentiation, 

 ^-/-carvomenthol ([a] D + 1.82°) and /-/-carvomenthol ([«] D — 1.83°). 



Furthermore, Paolini 2 ) succeeded in obtaining from ^-carvone, by following the 

 directions given by Vavon 3 ), on reduction with hydrogen and platinum, a carvomenthol, 

 the constants of which were in accord with those of Vavon's preparation, with exception 

 of the rotation ([«] D — 2.75°, instead [«] D — 24.7°). Paolini proved the products with 

 different rotatory power to consist of mixtures of optical isomerides. Either the one 

 or the other isomeride preponderated, according to the more or less complete process 

 of the reduction. From carvomenthol ([«] D —2.75°) the author, by aid of his so-called 

 cold process 1 ) (via the d\-d. /?-carvomenthyl phthalate, m. p. 85°, [«] D -j- 38.53°), was 

 able to separate two isomeric compounds:— cZ ; /?- carvomenthol (b. p. 218° [corr.]; 

 d 15O 0.9074; [«] +8.29°) and ^-carvomenthol (b. p. 218° [corr.]; d 15 o 0.9073; [<*] D — 8.54°; 

 n D i 5 o 1.463; identical with the one of the two isomerides resulting from nitrophellandrene, 

 see above). 



Terpin hydrate. — According to a patent granted to the Societe Landaise du terpineol*), 

 terpin hydrate may be obtained from turpentine oil by means of the following contri- 

 vance:— A wooden vat, lined with lead, and filled with turpentine oil and dilute 

 acid, is connected with two pumps of acid-resisting metal. The suction pipe of 

 the one pump dips into the acid, that of the other into the oil, whereas the discharge 

 pipes terminate in the oil and the acid respectively. On putting both pumps in 

 motion a very close mixture of both acid and oil results within a short time, yielding 

 terpin hydrate. 



Terpin hydrate is, according to R. Marchand 5 ), obtained in almost theoretical 

 quantity and in the crystalline state on mixing oil of turpentine (one pt.) with a 

 23 per cent, sulphuric acid (2 pts.) and shaking vigorously in an atmosphere of nitrogen 

 or carbon dioxide for about 90 hours. 



Concerning the estimation of terpin hydrate, see p. 113 of this Report. 



P. Lipp and C Padberg 6 ), with the object of studying the behaviour of apotricyclol (I), 

 a derivative of the hitherto unobtainable cyclopropane*] (II), prepared the first-mentioned 

 alcohol from tricyclenic acid amide (III), which, owing to the lability of the trimethylene 

 ring was primarily degradated according to Hofmann-Jeffreys 7 ) down to ^otricyclyl- 

 methylurethane (m. p. 114 to 116°). In this reaction, tricycloyl-opotricycyl-urea (decomp. 



*) Cf. Berickt (Germ, ed.) 1921, 113. — 2 ) Rend, delta E. Accademia dei Lincei 30 (1921), 371. As per 

 a reprint kindly forwarded to us. — *) Cf. Report October 1911, 150. — *) Fr. Pat. 522657, Aug. 14, 1920. 

 See also Chem. Zentralbl. 1921, IV. 1328. — B ) Brit. Pat. 153606, Nov. 10, 1920. As per Journ. Soc. chem. 



try 40 (1921), A. 716. — «) Berl. Berichte 54 (1921), 1316. — 7 ) Bert. Berichte 30 (1897), 898. 



