behaviour towards the reagent. 
u _d-limonene?) and commercial — tutpenlinee ons give ae " abeided! 
| phenylene diamine solution, but not cae An orange oil which { 
beriiity resulting from the formation of baste tin <SHBGEANE was nt ‘cor ‘ 
to its rejection. Sulphurous acid and m-phenylene diamine sulphite re 
with them citral produced no yellow colour. The most convenient way 
proper amount of oxalic acid to “the original Hiltner reagent, and be ' 
results, the only colour aberration. so far observed being a "slightly bro ae ng 
developed in some cases. (ASR 2p se eee Nee 
The improved Hiltner method is carried out as follows: - bea 
The citral standard solution contains in 1 cc. pe g. citral; the ale 
The m-phenylene diate: oxalic acid Solon is pepe: ya 
m-phenylene diamine hydrochloride and 1 g. crystallized oxalic acid each 
of 80 per cent. alcohol. Both are mixed in a stoppered en cc. eas 
cylinder and made up to the mark with 80 per cent. ateonghy) 
upon a double filter. : = 
For carrying out the assay, weigh into a 50 cc. Graduated flask Uibae ee of 
normal lemon oil, or about 4 g. of orange oil, or 10 g. of lemon extract oO 50 g f 
orange extract, and make up to the mark with 94 per. cent. alcohol. x 
Epaaed amount (say 5 cc. of this “first dilution”) into a 50 Ce: c graduated 
bd i 
Om) eaahe ind. eng. Chemistry 10 918), 608. “ 4 Evidently, the ae 1c 
“limonene, pure, Schimmel & ce,’ ” as being quite ‘yellow cee rah — 3) Gild 
Volatile 0i9, Zt ed., voll, p. 598) Us Berl. Berighte AT OO 
’ 
