TERPENES AND ESSENTIAL OILS, I. 55 



usual manner of the Grignard reaction, is really produced in this in- 

 stance, as reactions undertaken to produce the classes of sj'nthetic prod- 

 ucts usuallj^ formed by working with similar magnesiiun derivatives 

 of other halides have not been successful, but the following quantitative 

 experiments remove all doubt of the existence of such a body. 



Experiment 3. — Ten grams of limonene hydrochloride were subjected to the 

 action of magnesium after the usual, method of Grignard. The etlier, containing 

 tlie soluble magnesium addition product was then filtered in an atmosphere of 

 dry hydrogen in a similar apparatus to that employed by Freer ' in his work on 

 sodium acetone. The filtrate was decomposed by means of cracked ice and dilute 

 acid in the usual manner and the magnesivim contained in an aliquot portion of 

 the aqueous solution then determined. 



Found Calculated for CioHis MgCl 



(percent). (percent). 



Mg 12.4 12.2 



It will be noted that a slight excess of magnesium was found and it 

 seems probable that this is due to the few drops of methyl iodide which 

 must be added to start the reaction. The ethereal solution after adding 

 the ice and acidifying gave 5.7 grams of CioHis, with the usual properties. 

 Another fact to be remembered in considering the formation of the mag- 

 nesimn addition product is that there is always a considerable evolution 

 of heat when the latter is decomposed by water, a fact which is difficult 

 to exj)lain if it is assumed that the magnesium has simply acted on 

 limonene hydrochloride as a reducing agent. 



It is not advisable at the present time to discuss at greater length 

 which of the possible bodies of the empiric formula Ci(,His is formed 

 during this reaction. The second reduction product of the formitla 

 CidHoo always, so far, has possessed a slight optical rotation and this 

 fact renders it probable that the latter has not been obtained entirely 

 pure. However, the above experiments prove bej'ond any doubt that 

 limonene hydrochloride reacts with magnesium after the normal manner 

 of the Grignard reaction. 



It has been shown that alcohol or other compounds containing hydroxyl 

 react with the products of the Grignard reaction according to the fol- 

 lowing scheme : 



EOH -f E'MgX = EOMgX + E'H. 



The reactions with water which have been outlined gave this result. 

 The next step was to stud}^ the action of aldehydes upon the product of 

 the interaction of magnesium and limonene lydrochloride in the presence 

 of absolute ether, and lienzaldehyde was the first representative of the 

 class selected. 



Experiment If. — Forty grams of limonene liydrochloride, 10 grams of magnesium 

 and 150 cubic centimeters of absolute ether were allowed to react in an atmosphere 



^ Aim. Ghem. (LieUg), (1894), 278, 123; 283, 38. 



