4-NITRO-5-METHYL-2-SULPHOBENZOIC ACID 
201 
DERIVATIVES OBTAINED BY THE ACTION OP ALCOHOL ON THE 
ACID CHLORIDES. 
When either of the two acid chlorides of 4-nitro-5-methyl-2- 
sulphobenzoic acid is treated with alcohol, a reaction may occur 
which, at boiling temperature, results in the formation of the 
benzoic ester of the free sulphonic acid, 
NOg . CH 3 . CeHg • cdoR . SO^OH 
The symmetrical acid chloride on treatment with absolute 
alcohol at boiling temperature, dissolves and on cooling repre- 
cipitates, in part at least, unchanged. If, however, the solution 
is boiled for sofne time, nothing crystallizes out on cooling. On 
evaporation an oil is left, which crystallizes after long standing 
as the alkyl ester of the free sulphonic acid mentioned above. 
There is no trace of chlorine in this product after recrystalliza- 
tion, hence the alkyl ester of the sulphone chloride appears not 
to be formed. 
The unsymmetrical acid chloride goes into solution in alco- 
hol rather easily even at ordinary temperatures. It was found 
best for purposes of obtaining the product, however, to dissolve 
the acid chloride at boiling temperature as in the other case. 
On cooling at once, there were deposited crystals which con- 
tained much chlorine, but which were not the original acid 
chloride. They were identified as the alkyl ester of the sul- 
phone chloride, 
NO, . CH 3 . CeH, . COOR . SO'CI 
The filtrate, on evaporation gave the same product as was ob- 
tained from the symmetrical chloride. 
In work which has been done upon the acid chlorides of re- 
lated bodies, such as the o-sulpho benzoic acid, by Sohon,^® 
Henderson,^® and Kastle,^^ or the p-nitro-o-sulpho benzoic acid by 
Chambers,^® the results finally have been shown to be exactly 
like those obtained for our acid. Sohon and Kastle worked with 
impure substances, but the work of Henderson and Chambers is 
in complete agreement. Kastle ’s explanation of the process has 
254m. Chem. J., 20, 260, 1898. 
2'>Am, Chem. J., 25, 8, 1901. 
27Am. Chem. J., 11, 181, 1889. 
2SAm. Chem. J., 30, 387, 1903. 
