d we aparently there: is not. Buck worry over the chief E ditficulty, viz., the accurate 
F feimation ‘of. such small. quantities of chlorine; at least, various, benzaldehydes with — 
d ‘guaranteed chlorine content, which arrived at our laboratory for examination, mostly 
_ contained very much more Ginn. than was stated, as is seen from ae following 
a Repti. a ¥ 
3 
" Benzaldehyde 1. Guaranteed chlorine content 0.02 per cent.; found 0.42 per cent. 
Ta ie 2. 920% Sig Egy : ” 0.02 ” fA9s ” 0.54 ” ” 
— 9 Nabe | ‘ \ Vite ho ieee Des 0.002 EN $9 : oo» 4) pn O:eo ” ” 
’ alana 4, ee . oy 4 Ly 9 0.02 n e ” 0.062 ” ” 
The causes of these differences are not clear to us... Perhaps it is a case of the ~ 
benzaldehyde containing the impurity chlorinated partly in the nucleus, and partly in the 
side-chain, and probably it was only this latter that had been estimated. By our method 
however, the total chlorine » was eovendted, and the total chlorine content, is the © 
important thing. | Lee 
In a product sent to us as “technically ‘chlorine- free” we found a chlorine-content 
of 0.08 per cent., an amount which gave such strong reactions even in the qualitative — 
tests that we felt strongly inehmed to. describe the es as not coming up to the © 
quality of even “technical”. , 
~ It seems to us that one is on the wrong track here, and that this custom will lead 
_ to universal confusion, in which the honest trader will have all his trouble for nothing. 
_ If this nuisance — giving a misleading description — continues, it will end in all benz- 
_.). 
ys 
chlorinated compound. In the long run this condition becomes impossible. It is to be | 
_ hoped that a return will soon be made to the good old principle of only distinguishing 
between truly chlorine-free and chlorine-containing benzaldehyde, and getting rid of all 
* intermediate grades, for what was possible before the war, should be equally possible after. 
_ This would mean making it easier for trade, as every disinterested thoughtful, person 
f will readily admit; for a qualitative test is performed much more rapidly than a 
quantitative one, which is of very great importance; for quick decisions are generally 
eT, WT Te ee ee 
to absolutely false results in the quantitative estimation of the chlorine in benz- 
aldehyde (whether this is due to the way the experiment is carried out, or whether 
to the method of estimation, is of secondary importance), and as the quality of a benz- 
_ aldehyde can with a little practice be very well determined by a qualitative test, so 
- is this one more reason for us taking up the standpoint just expressed. 
This view, of course, does not prevent us from making the way easier for the 
quantitative estimation of benzaldehyde. Already in our last Report we brought. forward 
_a method (boiling with alcoholic potash) with which good results are obtainable, but 
the chief drawback of which is that only the side-chain chlorine can be estimated. 
_ What is of importance, however, in such an estimation, is that it is not a case of the 
position of the chlorine in the molecule; and meanwhile we have persued our investiga- . 
tions in this direction. Earlier quantitative estimations’), brought forward by us on 
_ the occasion of a dispute, will not be taken up again this time, for then we estimated 
the chlorine in the nucleus and in the side chain separately and this method does 
_ not serve our present purpose. A method een. out by R. Benedikt and H. Zikes®) 
1) Probably due to a slip of the pen of the sender who probably Se 0.002 instead of 0.02 the true 
value. — 7) Report ape 1831, 8.0 ==.5) Chem. he 18 VO ER 
5 
6H ieee 
_ aldehyde being finally designated ‘as chlorine-free, even when containing ever so much 
necessary in buying at sales. As experience moreover points out, how many. €ome 
