Marshall. ] 476 [April 5, 
CONTRIBUTIONS FROM THE LABORATORY OF THE UNIVER- 
SITY OF PENNSYLVANIA. 
No. XIII. 
A Study of some of the Derivatives of Mono- and Dichlor-Salicylie Acids. 
By Dr. Jon MARsHALL. 
(Read before the American Philosophical Society, April 5th, 1878.) 
This work was undertaken at the suggestion of Dr. Edgar F. Smith, to 
whom, for his many kindnesses shown during the progress of the investi- 
gation, [ would express my best thanks. 
Of late years the monohydroxy] substitution products of benzoic acid— 
salicylicacid and its isomers—have been completely investigated, and many 
interesting facts regarding the nature of theseacids revealed. Of the unin- 
vestigated derivatives of salicylic, metaoxybenzoic and paraoxybenzoic 
acids remain yet the mono and dichlorinated compounds. In the follow - 
ing pages will be described my results obtained from the study of simply 
the mono and dichlor acids derived from salicylic acid. 
These new compounds that I have obtained show in several instances 
the stability imparted to compounds into which one or more chlorine atoms 
have been introduced. 
MoNOCHLORSALICYLIC ACID. 
Ca HClO see CrOcOpET- 
Fusing point 172°. 
This acid was first obtained by Hiibner and Brenken (Berichte der deut- 
schen Chem. Gesellschaft, 1875, p. 174). Their manner of producing it 
consisted in mixing ordinary salicylic acid with an excess of carbon bi- 
sulphide and conducting chlorine into the mixture, which was continually 
shaken. When the calculated amount of chlorine had been introduced, the 
contents of the flask were emptied into a large basin and evaporated to 
dryness on a water bath. The dry residue was taken up in water and 
crystallized from this in needles which fused at 172° C. The lead, silver, 
opper and barium salts were simply described, further investigation being 
neglected. 
Hiibner and Weiss produced metachlorbenzoic acid, and by nitration, 
amiding and forming the Diazo-compound, and subsequently treating the 
latter with water they obtained metachlororthoxybenzoic acid, fusing at 
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