8 ODOROGRAPHIA. 
carbons may be produced in the ordinary way, but we produce 
them by the following operation :—Toluene or xylol is heated in a 
digestor with iso-propyl, or iso-butyl, or iso-amyl alcohol in mo- 
lecular quantities with the addition of from four to five times the 
quantity of chloride of zinc to the boiling-point of the hydrocarbon, 
or to about 40° or 50° above the boiling-point of alcohol, until the 
pressure, which at the commencement was equal to about 26 atmo- 
spheres, sinks to a little above 2 or 3 atmospheres. The product 
of the reaction is subjected to fractional distillation. 
“ By theabove process the following hydrocarbonsare obtained :— 
1. From Toluene—Methylisopropyl-benzene. 
Methylisobutyl- __,, 
Methylisoamyl- __,, 
2. From Xylol — Dimethylisopropyl-benzene. 
Dimethylisobutyl- 
Dimethylisoamyl- __,, 
“To produce the ‘ Musk-substitute ’ we add to the above-men- 
tioned hydrocarbons, which during the operation should be kept 
thoroughly cool, a little more than the molecular quantity of fuming 
nitric acid or nitro-sulphuric acid. The acid should be gradually 
run in and the whole then allowed to stand undisturbed for from 
one to two hours, the resulting mass being then poured into water 
in order to get rid of the excess of acid. The well-washed sub- 
stances thus obtained are then subjected to distillation by means of 
steam, whereupon simultaneously-formed bodies which smell like 
nitro-benzol and overpower the musk-odour readily distil over, 
whilst the pure substances remain behind.” 
The musk-substitute obtamed by Baur’s process (the trinitro 
derivative of isobutyl-toluene above-mentioned) is insoluble in 
water. A process has been devised by Valentiner for obtaining a 
product which he thinks may be more useful in perfumery inas- 
much as it is soluble in water. This is effected by nitrating a 
sulpho-acid of butyl-xylene. A mixture of isobutyl alcohol and 
aceto-xylene in equivalent proportions is gradually mixed with five 
parts concentrated sulphuric acid without being allowed to become 
hot. After some time the mixture is diluted with a four-fold 
quantity of water, and the oily layer of unaltered material thus 
separated is removed. The clear, rose-coloured, watery solution 
is mixed with saturated sodium-chloride solution until the para- 
isobutyl-xylene-sulphonic acid is deposited in white crystals, which 
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