[ COOC₂H₃ ]
[ / ]
Cal. for [C₆H₃——SO₂O ] Ba + 4H₂O.
[ \ ]
[ NO₂ ]2
Found.
I II
H₂O = 9.51 9.77 9.86
Ba = 20.00 19.84 20.02
Kastle also found that by dissolving the mixed chlorides in alcohol
in the cold, and allowing the solution to evaporate, there separated
after a time, crystals of the chloride of the acid etherial salt of
paranitroorthosulphobenzoic acid whose formation and composition are
represented in equation I.
This same product was sought for when pure symmetrical chloride was
employed, but without success. In every case, crystals of unchanged
chloride separated, or else it was found that it had been completely
converted into the acid etherial salt. In another trial cold water
was carefully added in small portions, since Kastle found that such
treatment facilitated the separation of the substance; the chloride
alone appeared. Still other attempts were made to obtain the substance
by adding a large amount of water to the solution of the chloride
in alcohol, after it had stood for some time. In this way, quite a
precipitate was thrown down, and this was filtered off and crystallized
from ether. It always proved to be the symmetrical chloride, and none
of the other substance was obtained.
Karslake[16] in working with the symmetrical chloride of
orthosulphobenzoic acid, was unable to isolate the analogous compound,
although from the mixed chlorides, by the action of alcohols, Remsen
and Dohme[17] had obtained chloro-etherial salts.
[16] Inaug. Diss. J. H. Univ. 1895.
[17] Am. Ch. Journ. XI, 341.
In as much as the pure symmetrical chloride is relatively stable in
cold alcohol (it can be crystallized from warm alcohol with very
little loss), it is possible that it is more stable than the chloro
etherial salt, and that in consequence the latter, when formed, yields
more readily to the further action of alcohol than does the unacted
on chloride. Hence when the action begins, it at once proceeds to the
limit. The fact that the symmetrical chloride is rather sparingly
soluble in cold alcohol, making the use of concentrated solutions
impossible, may also be a factor in the case. Whatever may be the
cause, this substance could not be obtained under any conditions that
were devised.
Having in my possession a very small specimen of crystallized
unsymmetrical chloride, it was submitted to the action of ethyl
alcohol, under as nearly as possible the conditions employed by Kastle.
Crystals of a colorless substance were obtained, which in every respect
agreed with Kastle’s description of the chloride of the acid ethyl
etherial salt of paranitroorthosulphobenzoic acid. Crystallized from
ether they melted at 68°.
The conditions employed by Kastle in preparing the chloride would
undoubtedly lead to a relatively large proportion of unsymmetrical
chloride, and it is to this chloride that the formation of the chloro
etherial salt is apparently due.
VII. The Action of Phenols upon the Symmetrical Chloride of
Paranitroorthosulphobenzoic Acid.
Remsen and Saunders[18] in their investigation of the chlorides of
orthosulphobenzoic acid, studied the action of phenol upon these
substances, and from both the symmetrical chloride and the mixed
chlorides, they obtained a normal diphenyl ether together with a
red substance which was not further studied. It was formed in small
quantity and was probably the corresponding sulphonphthalein. Later
McKee[19] obtained these same substances from both the symmetrical
and the unsymmetrical chlorides. R. Meyer[20] obtained analogous
substances by the action of various phenols upon phthalyl
chloride. It seemed probable, therefore, that the chlorides of
paranitroorthosulphobenzoic acid would yield similar derivatives,
and a study was accordingly made of the reaction of the symmetrical
chloride with a series of phenols. The products in some instances were
exceedingly difficult to deal with, possessing properties that made it
impossible to prepare them for analysis, but even in such cases there
could be little doubt as to the general nature of the reactions which
had occurred.
[18] Am. Chem. Journ. XVII, 347.
[19] Ibid. XVIII, 798.
[20] Ber. XXVI, 204.
1. The Action of Phenol upon the Symmetrical Chloride of
Paranitroorthosulphobenzoic Acid.
A portion of the symmetrical chloride was brought together with
somewhat more than double the molecular amount of phenol. The mixture
was placed in a good-sized test-tube and the temperature gradually
raised by means of a sulphuric acid bath.
As soon as the phenol melts, some slight action occurs, as is indicated
by the fact that the mixture assumes a bright red color. No appreciable
amount of hydrochloric acid gas is evolved however, until the liquid
mixture has reached a temperature of about 115°. At this point the
gas is freely evolved, and the action is complete at a temperature
of 125°. The temperature observations were made by means of a
thermometer used as a stirring rod in the mixture. During the heating,
the color of the liquid becomes a much more intense red, growing darker
in shade, and the liquid itself becomes somewhat viscous but does not
solidify while hot.
When cool, the melt was repeatedly extracted with boiling water,
the aqueous solution being very deep purple in color. The colored
matter was removed very slowly in this manner, and so the process
was continued with dilute alkali. A solid insoluble residue was thus
obtained, of a light-brownish color. This was dissolved in alcohol,
boiled with boneblack and filtered. On cooling, needles of a straw
yellow color were deposited from the alcoholic solution.
This proved to be the normal diphenyl etherial salt of
paranitroorthosulphobenzoic acid, the formation of this substance being
expressed by the equation:
COCl COOC₆H₅
/ /
C₆H₃——SO₂Cl + 2C₆H₅OH = C₆H₃——SO₂OC₆H₅ + 2HCl.
\ \
NO₂ NO₂
Analysis of the substance gave the following results: