TBRPENES AND ESSENTIAL OILS, I. 59 



product was covered with fresh ether, decomposed with ice and dilute acid in the 

 usual maimer and the solvent distilled, 55 grams of an oil, vchich was fractioned 

 in vacuo, being obtained. 



No. 1: B. P. 70° to 100° at 15 millimeters, 28 grams. 



No. 2: B. P. 100° to 150° at 15 millimeters, 12 grams. 



No. 3: B. P. 180° to 210° at 15 millimeters (metal bath to 280°), 8 grams. 



No. 4: Tarry residue, 4.5 grams. 



Number 1 gave 14 grams of benzaldehyde phenylhydrazone and 19 grams of 



30° 30° 



CioHis, specific gravity, —5- =0.8304; N^=p =1.4640. Five grams of benzoin melt- 

 ing at 137° after reorystallization from ligroin and 1.2 grams of benzoic acid 

 melting at 121° were obtained from Numbers 2 and 3. The residual 14 grama 

 was a tar-like oil, which regenerated considerable quantities of benzaldehyde on 

 being boiled with dilute acids. It is probably in greater part a mixture of 

 polymers of benzaldehyde. 



It is seen from the above that benzoin, which should be expected in 

 quantity in the residues of all of these reactions, as it should be formed 

 from a benzaldehyde magnesium comijound, is really produced if this 

 compound is heated. 



Experiment 9. — There were used 50 grams of limonene hydrochloride and 10 

 grams magnesium, the reaction (which in this instance unfortunately did not 

 reach completion) being conducted in the apparatus with a filter tube described 

 in Experiment 6. A small amount of the ethereal solution was filtered, decom- 

 posed with ice and acid and analyzed, giving 2.6 grams of organic liquid, princi- 

 pally CioHis, and 0.307 gram magnesium (calculated Mg=: 12.2, . found= 10.3 per 

 cent). The remainder was now also filtered from the unchanged magnesium and 

 from the insoluble portion of the ethereal compound of hydro-limonene magnesium 

 chloride, and the filtrate, which now only contained the soluble portion of the 

 addition product, was then treated with 35 grams of benzaldehyde. The usual 

 evolution of heat took place and the yellow solid already described separated, 

 so that the magnesium addition product produced according to the method of 

 Grignard and separated from all other substances by filtration, is in reality the 

 compound taking part in the reaction, any excess of benzaldehyde, or of magne- 

 sium powder, which is generally present, not taking part therein. The yellow 

 solid produced from this soluble portion was now again filtered in an atmosphere 

 of dry hydrogen and well washed with absolute ether; it was finally transferred 

 to another flask and placed under absolute ether, it is designated below as the 

 insoluile portion. The united etherial solution filtered from this insoluble sub- 

 stance, and the ether used to wash it are termed the sohihle portion. 



The soluble portion: This part was free from magnesium and after removing 

 the ether it consisted of an oil which weighed 45 grams in the crude state and 

 which gave the following fractions when distilled in vacuo: 



No. I: B. P. 80° to 90° at 20 millimeters, 33 grams. 



No. 2: B. P. 90° to 110° at 20 millimeters, 5 grams. 



No. 3 : A residue of tar, 6 grams. 



The above fractions, when treated with the usual reagent gave 35 grams of 

 benzaldehyde phenylhydrazone melting at 155°, representing the excess of benzal- 

 dehyde added to the above solution and 14.8 grams of Chilis of a specific gravity 



30° 30 



at — TT of 0.8262 and a refractive index, N tt— of 1.4584, the remainder consisted 

 4° D 



of unclianged limonene hydrochloride and of diterpenes. 



