57 



wide-mouthed flask was fitted with a stojiper witli five holes, the latter carrying 

 respectively : ( 1 ) The inlet for dry hydrogen ; ( 2 ) the stirrer set in a mercury 

 trap, (3) a dropping funnel, (4) the reflux condenser which was fitted witli a 

 glass stopcock sealed into it, and which was protected at its upper end by a 

 tube of soda-lime and (5) a tube running to the bottom of the reaction flask. 

 The latter had sealed onto it a fvmnel fitted with an asbestos filter and was 

 connected with a filter flask by means of a tube and glass stopcock. The filter 

 flask could be evacuated in the usual manner. After the reaction according to 

 Grignard was complete, 25 grams of benzaldehyde dissolved in absolute ether, 

 were slowly dropped into the flask. The usual, violent reaction with much 

 evolution of heat took place and the yellowish, semisolid substance separated, the 

 whole soon becoming so thick that it was impossible to run the stirrer. After 

 one-half hour, absolute ether to dilute was added in small portions, and by closing 

 the reflux and opening the filter funnel connected with a slight vacuum, the reac- 

 tion product was separated into two portions, one soluble and the other insoluble 

 in absolute ether ; of course, care was taken thoroughly to wash the insoluble part 

 witli absolute ether. Both the soluble and insoluble portions were now decomposed 

 by means of ice and acid in the usual manner, the etheral solutions resulting 

 were separated, dried and the ether distilled. 



Soluble portion: The aqueous solution obtained by decomposing the soluble 

 portion contains no magnesium. The neutral oil when treated with an excess of 

 phenylhydrazine in petroleum ether gave 4.1 grams of benzaldehyde phenylhydra- 

 zone of a melting point of 153°. The excess of phenylhydrazine was removed by 

 means of dilute sulphuric acid, the petroleum ether distilled and the product 

 fractioned in vacuo. Twenty-five grams of an oil boiling between 90° and 93° at 

 50 millimeters pressure was thus obtained. This fraction contained no chlorine, 

 and after two distillations over sodium at ordinary pressure had the following 

 properties: Boiling point, 175° to 177°, thermometer wholly in the vapor; specific 



qno ono OQO 



gravity, ^ = 0.8250; N ^ = 1.4605; A ^ = 72.7°. These properties demon- 

 strate it to be the same compound Ci„His, produced by the action of water on 

 the body formed by magnesium and limonene hydrochloride. The residual 7 grams 

 in the distilling flask contained a little chlorine and seemed to consist of the 

 diterpene always obtained as a part of the product of the action of magnesium on 

 limonene hydrochloride. 



Insoluhle portion: Thirty-four grams of benzaldehyde phenj'lli.ydrazone of a 

 melting point of 154° after one crystallization from ligroin were obtained by the 

 usual methods from this part. 



There remained 6.6 grams of a tar-like oil after removing the excess of phenyl- 

 hydrazine and from this neither a crystalline solid nor a constant boiling 

 substance could be separated. 



Experiments 1, 2, and 3 clearly demonstrate that limonene lij'dro- 

 chloride forms a comi30und with magnesium of the usual nature of the 

 Grignard addition products, the bod}' being soluble in ether and carrying 

 the theoretical amount of magnesium. Experiment 6 proves that benzal- 

 dehyde, acting on this substance, forms a solid body carrying all the 

 magnesium and that this solid when decomposed with water, |)rincipally 

 gives benzaldehyde, at the same time the product soluble in ether and free 

 from magnesium contaias the dihydroterpene CioHjg, which has been 

 split off from the Clrignard body just as if water had reacted with 



