Amines and Related Nitrogen Compounds - Cengage Learning - page 230

d.

CH 3 CH 3 CH 3

H 2 SO 4 HN O NO 2

3

S O H 2 SO 4

3

SO 3 H SO 3 H

H 2 , Ni

CH 3 CH 3 CH 3

N + CN KCN NaNO 2 NH 2

H + Cu 2 (CN) 2

SO 3 H SO 3 H SO 3 H

11.45 Benzidine can be diazotized at each amino group. It can then couple with two
equivalents of the aminosulfonic acid. Coupling occurs ortho to the amino group
since the para position is blocked by the sulfonic acid group.

HONO

H 2 N NH 2

H +

benzidine

NH 2

N 2 + N 2 + +

SO 3 H

NH 2 NH 2

N N N N

Congo Red

SO 3 H SO 3 H