TRANSACTIONS. OF SECTION B. 687 
influence. Thus phenyl ethyl thio-ether may be para-sulphonated without diffi- 
culty, but para-bromopheny! ethyl! thio-ether is not sulphonated either by sulphuric 
or by chlorosulphonic acid, although the corresponding oxygen compound is very 
readily acted on. 
15. The behaviour of halogen derivatives may be correlated with that of 
phenols, or rather with that of their ethers, especially in view of the existence of 
compounds such as phenyl iodosochloride PhICl,, On the assumption that the 
residual affinity of iodine was satisfied in this compound, it appeared not improbable 
that it might furnish a meta-sulphonic acid. It is sulphonated without difficulty, 
but the product is highly chlorinated, and its nature has yet to be ascertained. 
The hydrocarbons homologous with benzene are the most difficult group to 
discuss. The paraflinyl radicle certainly exercises a directive effect ; whether it 
is in any way attractive is open to question. Bearing in mind the inactivity of the 
paraftins, it is difficult to believe that the radicles derived from them are possessed 
of sufficient activity to account for the striking readiness with which the homologues 
of benzene are acted upon in comparison with benzene. The introduction of 
hydrogen radicles seems, in fact, to produce a fundamental modification in the 
centric complex, the behaviour of hydrocarbons such as mesitylene being ethenoid 
rather than benzenoid; and from this point of view it seems probable that the 
derivatives of benzenoid hydrocarbons are formed more in accordance with the 
process formulated in paragraph 12. 
16. The fact that when the paraffiny! radicle undergoes chlorination or oxidation, 
for example, the attack, as a rule, takes place at the point of attachment, is proof 
that, if not itself attractive, it immediately adjoins the centre of attraction ; and it 
is possible that initially some change takes place in which both radicles are 
involved. 
4, The Relative Orienting Effect of Chlorine and Bromine. 
By Henry E. Armstrone, L.2.S. 
The object of this note was to correct a statement made by Armstrong and 
Briggs! that when parachlorobromobenzene is sulphonated only a single acid, viz. 
1:4 chlorobromobenzene- 2 sulphonic acid, is produced, not, as was to be expected, 
a mixture of this with the isomeric, 1 : 4 chlorobromobenzene-, 3 sulphonicacid. 
Further investigation has shown that the product is actually a mixture of the 
two acids. The mistake arose from the fact that corresponding derivatives of the 
two acids are isomorphous. 
Experiments made by Dr. E. C. Jee show that metachlorobromobenzene is, in 
like manner, converted into a mixture of isomeric acids on sulphonation. 
5. Isomorphism in Benzenesulphonic Derivatives. 
By Henry E. Arustrone, /.L2.S. 
In the course of the work referred to in the previous note, it became necessary 
to study the crystallography of the isomeric parachlorobromobenzene su!phonic 
acids, and ultimately it was determined to compare with these the anajogous acids 
derived from dichloro- and dibromo-benzene. 
The sulphonic chlorides and bromides were chosen for examination. Four acids 
are obtainable, viz. : 
Cl Cl Cl Br 
S80,H SO0,H «i é a 
S0,H. S0,H 
Cl Br Br Br 
I, IL. Til. IY. 
' Chem. Soc. Proceedings, 1892, p. 40. 
