1031 
isomerides 1,2,4 and 1,2,6. In the first compound, at the interaction 
of NaOCH,, both chlorine atoms appeared to be already mobile at 
85°, but contrary to what takes place with monochloronitrobenzenes, 
the chlorine atom on 2 is being replaced first. The consequence was 
that at this temperature the constant became greater as time proceeded. 
At 25° and 50°, however, the reaction with the p-Cl-atom in regard 
to that of the o-Cl-atom was so retarded that very concordant values 
were now found for K. With diethylamine, only the o-Cl-atom was 
mobile. 
In the isomeride 1,2,6 the two Cl-atoms were situated in o-positions 
in regard to the nitro-group. Nevertheless only one Cl-atom could 
be made to react with NaOCH, at 85°; and the same likewise with 
diethylamine at 150°. 
The subjoined table IT gives a survey of the measured velocity 
TABLE: It 
Isomeride 25° 50? 85° 110° 
1,28 == — | 74 | 143 
1,2,4 | 0.030 | 0.628 | 19.41 — 
| 
See BOOR OEL +}, IOS : 5450 
1, 2,6 = = 0.135 | 1.34 
153, 4} 0,033 0.601 17.42 — 
1,2 va = 0.369 | 3.09 
1, 4 me == 1.39 | 11.45 
| 
constants with Na-methoxide. The figures in heavy type indicate the 
Cl-atom that is being replaced. NO, on 1. Time in hours. On 1 mol. 
of nitrodichlorobenzene one mol. of methoxide was employed. Both 
were in about gas-concentration. From this we notice that the 
position of the groups in regard to each other exerts a very great 
influence on the velocity of the reaction. If we put the reaction 
velocity of 1,2,4 at 85° = 100, that of 1,2,6 will then be only 0.7. 
also in the case of the other vicinal isomeride the reaction constant 
is very small, namely only 8.9 for 1, 2, 4 — 100. 
If we compare the reaction constant of o-chloronitrobenzene with 
that of the nitrodichlorobenzenes in which also one of the Cl-atoms 
is situated in the o-position in regard to NO,, the introduction of a 
second chlorine atom then appears to considerably increase that 
constant, except in the case where the second Cl-atom occupied the 
