ON A NEW CLASS OF ALCOHOLS. 
559 
utmost facility. Iodide of allyl obtained by this process, possesses all the properties of 
the iodide of propylene which is produced by the action of iodide of phosphorus on 
glycerin; and in a similar manner the chloride and bromide of allyl, and the chloride 
and bromide of propylene, are identical in every respect. 
AUyhc alcohol dissolves without colour in concentrated sulphuric acid, and gives rise 
to a conjugate acid, which forms soluble and crystalline salts with baryta, strontia, and 
oxide of lead. 
Anhydrous phosphoric acid powerfully attacks allylic alcohol at a moderate tempera- 
ture, a colourless gas being disengaged which burns with a very luminous flame. Its 
analysis has not been made, but most probably it is a hydrocarbon represented by the 
formula C 6 H 4 . 
Allyhc alcohol is readily acted upon by oxidizing agents. A mixture of bichromate 
of potassium and sulphuric acid attacks this body mth extreme violence. The products 
of the reaction are acrolein and allylic acid. The same transformation is effected by 
platinum-black, though more slowly. Lastly, this alcohol, when treated with potassa 
and bisulphide of carbon, gives rise to a compound which crystallizes in beautiful yellow 
needles, resembling xanthate of potassium, and to which analysis will probably assign 
an analogous formula. 
Sulphide of Allyl {Essence of Garlic). 
When iodide of allyl is allowed to fall drop by drop into a concentrated alcoholic 
solution of protosulphide of potassium, a very energetic action ensues, the liquid becomes 
very hot, and an abundant crystalline deposit takes place of iodide of potassium. It is 
important that the iodide of allyl should only be added gradually, to avoid spirting, by 
which a part of the product would be lost. As soon as the action ceases, the liquid is 
mixed with a slight excess of sulphide of potassium ; on the addition of water a light 
yellowish limpid oil separates, possessing a strong smell of garlic. When rectified, this 
liquid becomes colourless ; it boils at 140° C., and gives with nitrate of silver a crystalline 
precipitate soluble in a boiling mixture of alcohol and water, and separating from this 
solvent in the form of beautiful white needles, absolutely identical with those which the 
natural essence of garlic produces. Sulphide of allyl also comports itself with corrosive 
sublimate and bichloride of platinum, exactly like the natural garlic oil. 
On analysis sulphide of allyl gave the following results : — 
0*420 grm. of substance yielded 0*975 grm. of carbonic acid and 0*338 grm. of water. 
The formula C ,2 Hjo 82 = 205 H 5 S, requires the following values : — 
Theory. Experiment. 

12 equivs. of Carbon 
. 72 
63*16 
63*3 
10 equivs. of Hydrogen . 
10 
8*78 
8*9 
2 equivs. of Sulphur 
. 32 
28*06 
1 eqmv. of Sulphide of allyl . 
. 114 
100*00 
4 D 2 
