1 



358 t)r. Hofmann on Methylic Aldehyde. [Nov. 21> ^ 



On heating the methyl-alcoholic solution of the aldehyde with a few ' 



drops of a fixed alkali, the liquid becomes turbid on ebullition, acquires a j 



yellowish coloration, and soon deposits droplets of a brownish oil, possess- | 



ing in the highest degree the peculiar odour of ethyl-aldehyde-resin. i 



After the observation which I have mentioned, it was scarcely doubtful 3 

 that the product of the slow combustion of methylic alcohol contained the 



aldehyde of this alcohol in considerable proportion. Nevertheless it ap- , 



peared necessary to fix the nature of this compound by some numbers. ^ 

 The commxcncement of the vacations being at hand, there was but little 



hope of preparing the liquid in sufficient quantity for the purpose of ■■ 



obtaining the aldehyde, which will probably be found to be either gaseous i 



at the common temperature or extremely volatile, in a state of purity for \ 



analysis. Under these circumstances I have been compelled to limit myself \ 



to the preparation of an easily accessible derivative of methyl-aldehyde i 



possessing a characteristic composition, and the analysis of which would | 



not be less conclusive than that of the aldehyde itself. The slight solubility I 



and the powerfully crystalline tendencies of the sulphaldehyde of the ethyl 1 



series could not fail to indicate the direction in which I had a right to hope I 



that the object which I was aiming at might be accomplished. • 



If a current of sulphuretted hydrogen be passed through the methyl-alco- i 

 holic solution of methyl-aldehyde, the liquid becomes turbid after a few 



minutes, and on allowing the saturated solution to stand for some hours, : 



a body of an alliaceous odour begins to be separated at the bottom of the * 



flask. If the liquid be now mixed with half its volume of concentrated j 



hydrochloric acid, and heated to ebullition, it becomes limpid, and solidi- ! 



fies on cooling into a mass of felted needles of dazzling whiteness. These j 

 needles fuse at 218°; they are volatile without decomposition. Slightly 



soluble in water, they are more readily dissolved by alcohol, and still more i 



so by ether. For the purpose of analysis they were recrystalhzed from j 



boiling water, in order to exclude free sulphur, with which they might have i 



possibly been contaminated. The numbers obtained in the analysis of ' 



the crystals unmistakeably establish their nature. The white crystals, as ; 

 might have been expected, have the composition of the sulphaldehyde of 

 the methyl- series, CH^ S. 



The analysis of the sulphur-compound fixes, of course, the presence of 

 the corresponding oxygen compound among the products of the slow com- 

 bustion of methylic alcohol. 



A more minute examination of methylic aldehyde and its derivatives 

 remains still to be made. It will be absolutely necessary to isolate the 

 oxygen-term and to determine its vapour- density, in order to ascertain its 

 molecular weight. If we remember the facility with which the aldehydes 



are polimerized, the question presents itself, whether the aldehyde formed > 



bj the slow combustion of methylic alcohol is represented by the formula 1 



CH^O, 



or a multiple thereof. A similar remark applies to the sulphur-derivative. 



