Aromatic sulphonation. Part 70. The sulphuric acid sulphonation of α,ω-diphenylalkanes, biphenylene, fluorene, 9,10-dihydrophenanthrene, 10,11-dihydro-5H-benzo[a,d]cycloheptene, and triptycene

Abstract

The sulphonic acid isomer distribution for the sulphonation of α,ω-diphenylalkanes, biphenylene (2a), fluorene (2b), 9,10-dihydrophenanthrene (2c), 10,11-dihydro-5H-benzo[a,d]cycloheptene (2e), and triptycene (3) with concentrated aqueous and with fuming sulphuric acid at 25 °C has been determined by multicomponent ¹H-n.m.r. analysis. With Ph[CH₂]_nPh in 95.4% H₂SO₄ the degree of ortho-substitution increases with increasing length of the alkylidene chain to reach for n 4 the same limiting value as observed for the 1-phenylalkanes (Ph[CH₂]_nMe) with n 3. Further sulphonation of the α,ω-bis(sulphophenyl)alkanes yields the o,o′,p,p′-tetrasulphonic acids.

Sulphonation of (2a) and biphenylene-1-sulphonic acid in 98.4% H₂SO₄ yields the 2,6- and 1,6-(or 1,7-)di-sulphonic acid respectively.

The sulphonation of (2b), (2c), and (2e) in 95.3–98.3% H₂SO₄ leads to a mixture of disulphonic acids, that of (3) to a mixture of trisulphonic acids, all containing one sulpho-group per phenylene. The isomer distribution for the monosulphonation of (2b) has been estimated from the disulphonic acid isomer composition. For (2c), (2e), and (3) the substitution ratio per phenylene has been estimated.

The isomer distributions of the tri- and of the tetrasulphonic acid mixtures obtained from (2b), and of the tetrasulphonic acid mixture formed from (2e) have also been determined.