PROTON SPIN RELAXATION OF THE METHYL-GROUP IN 2-METHYL-QUINOLINE AT DIFFERENT TEMPERATURES

Proton spin lattice relaxation time measurements of the methyl group in 2-Methylquinoline or quinaldine have been carried out from 30 degrees C to 126 degrees C (303 K to 399 K). The longitudinal relaxation time T-1 varies from 1.949 s (at 30 degrees C) to 6.261 s (at 126 degrees C). The logarithm of the relaxation time T-1 versus temperature T (K) obeys the classical BPP equation in the high temperature region. The minimum of In(T-1) versus temperature T curve is not achieved. A plot of InT1 versus 1000/T (K-1) is linear and an activation energy E(a) obtained from the slope is 3.04 +/- 0.17 kcal/mol with a regression coefficient r = 0.9909.

M H PHULPOTO ,S ANJUM JAFFRI ,A W K KHANZADA ,