56 BACON. 



of di-y hydrogen in a strong flask fitted with a mechanical stirrer. After tlie 

 change was complete, 30 grams of benzaldehyde, dissolved in an equal volume of 

 absolute ether, were added, drop by drop. Tlxe reaction was violent, taking place 

 with a considerable evolution of heat, while at the same time a nearly solid, 

 yellowish-colored substance separated. The product was now vigorously stirred 

 for one hour, it was then treated in the usual manner, the ethereal layer being 

 well shaken out with acids and alkalies. The alkaline solution on acidifying 

 gave 2.3 grams of benzoic acid. As the neutral solution, after distilling tlie ether, 

 did not readily solidifj', it was fractioned in vacuo with the following result: 



No. 1 : B. P. 85° to 90° at 30 millimeters, 38 grams; 



No. 2: B. P. 90° to 130° at 20 millimeters, 3 grams; 



No. 3: B. P. 130° to 180° at 20 millimeters, 7 grams; 



Tar-like residue, 4 grams. 



Decomposition appeared to take place above 130° and excepting the first frac- 

 tion, there was no indication of a constant boiling substance. No solid bodies 

 could be obtained from numbers 2, 3 and 4, in ice and salt. 



Fraction number 1 was dissolved in low boiling petroleum ether and treated 

 with an excess of phenylhydrazine." Thirty-five grams of benzaldehyde phenyl- 

 hydrazone of a melting point of 154° were thus separated, this quantity cor- 

 responds to 18.9 grams of benzaldehyde. The remainder of fraction number 1 

 consisted for the greater part of doHis. 



The higher boiling fractions proved themselves to be an inseparable mi.xture 

 containing much tar. 



As the princif)al products of the reaction were benzaldeh3'de and 

 CjjHjg, it was thought possible that the benzaldehj'de had not acted 

 upon tlie Grignard addition product at all, but on the contrary that the 

 yellowisli, nearly solid substance was produced by the action of benzalde- 

 hyde on magnesium powder in a manner similar to the substances formed 

 by the interaction of sodium and benzaldehyde, as noted by Beclmiann 

 and FmiU" 



To disprove this assumption the action of benzaldehyde on magnesium 

 was studied. 



Experiment 5- — Five grains of magnesium powder in absolute ether were ren- 

 dered active by means of iodine, and a solution of 10 grams benzaldehyde in 

 absolute ether was then added. No action took place even after the whole was 

 heated on a reflux condenser for one hour. 



The following experiment demonstrates that when Ijenzaldehyde acts 

 on the jjroduct formed by the action of niagnesium on limonene hydro- 

 chloride it does so in such a manner as at once to liberate CioHj,, or in 

 other words, just as if benzaldehyde were an alcohol in this instance. 



Experiment 6. — Forty grams of limonene hydrochloride, 10 grams of magnesium 

 and 150 cubjic centimeters of absolute ether were taken. The apparatus was in 

 principle like that employed by Freer in his work on sodium acetone. A strong, 



" It has been shown in this laboratory that benzaldeliyde can promptly and 

 satisfactorily be separated from its solution in petroleum ether by plienylhydrazine. 

 "A»». Chem. {Liebig}, (1891), 266, 6. 



