16
K. MUHAMMAD ET AL.
Scheme 2. Modification of PVP to poly(4-(4-vinylphenoxy)butan-1-ol). Reaction conditions: (i)
Triethylamine, r.t.; (ii) p-Toluenesulphonyl chloride, pyridine, 0 ꢂC; (iii) K2CO3, butanone, reflux; (iv)
NaOH/H2O, THF, reflux.
(0.108 mol) of NaOH was added dropwise into the flask with stirring. The stirring was
continued at room temperature for 6 h. The reaction mixture was washed thrice with
distilled water (3 ꢀ 50 mL), dichloromethane layer separated and dried over anhydrous
Na2SO4. The desiccant was removed by filtration and the solvent evaporated in vacuo.
The product was purified by column chromatography using n-hexane and acetone mix-
ture (90:10) as eluent.
Yield: 70%; m.p.: 32 ꢁ 33 ꢂC; Rf¼0.33 (petroleum ether: ethyl acetate; 3:2); IR (neat,
ῡ, cmꢁ1): 2949, 1717, 1595, 1435, 1275, 1180, 1105, 1018, 998, 964, 890, 832, 780, 712.
1H-NMR (CDCl3): d (ppm) 3.92 (s, 3H, –CH3), 6.62 (d, 1H, J ¼ 12.3 Hz, H-7), 6.82
(d, 1H, J ¼ 12.3 Hz, H-8), 7.09 (d, 2H, J ¼ 6.3 Hz, H-10,13), 7.28 (d, 2H, J ¼ 8.4 Hz,
H-3,5), 7.93 (d, 2H, J ¼ 8.4 Hz, H-2,6), 8.47 (d, 2H, J ¼ 6.0 Hz, H-11,12).
2.3.2. Modification of poly(4-vinylphenol) to poly(4-(4-vinylphenoxy)butan-1-ol) (4)
Poly(4-vinylphenol) was modified to poly(4-(4-vinylphenoxy)butan-1-ol) following the
reaction sequence given in Scheme 2.
For the preparation of poly(4-(4-vinylphenoxy)butyl benzoate) (3), a solution of 0.83 g
(6.9 mmol) of poly(4-vinylphenol) in 30mL dry butanone containing 0.95g (6.9 mmol)
anhydrous K2CO3 was refluxed for an hour. Then, 4-(benzoyloxy)butyl tosylate (2) (2.4 g,
6.9 mmol) was added and reflux continued for 12h. The reaction mixture was cooled to
room temperature and the solvent evaporated under vacuum. The contents were poured
into 500 mL distilled water, where upon a sticky mass settled down which was separated
and purified by column chromatography using petroleum ether and ethyl acetate in 90:10
ratio as solvent system. Yield: 96%; extent of substitution: 95% (as calculated from
1
1H-NMR spectrum). H-NMR (THF-d8): d (ppm) 1.44 (broad s, 1.87H, CH2 of poly-
mer chain), 1.93 (s, 4.56H, H-2,3 & CH of polymer chain), 3.97 (s, 1.74H, H-1), 4.37
(s, 1.82H, H-4), 6.3ꢁ 6.8 (m, 4H, phenylene), 7.43 (t, 1.89H, H ꢁ 3,5 phenyl, J¼ 6.6 Hz),
7.54 (t, 0.96H, H-4 phenyl, J¼ 6.5 Hz), 8.05 (d, 1.9H, H-2,6 phenyl, J¼ 6.3 Hz).
The hydrolysis of intermediate (3) to prepare poly(4-(4-vinylphenoxy)butan-1-ol) (4)
was carried out by dissolving 1.98 g (6.9 mmol) of poly(4-(4-vinylphenoxy)butyl benzo-
ate) (3) in THF/water mixture (30:10) followed by the addition of 0.28 g (7 mmol) of
NaOH. The mixture was heated under reflux for 8 h. After cooling to room tempera-
ture, the contents were poured into 500 mL distilled water and stirred using mechan-
ical stirrer. The solid product was separated by filtration and dried in vacuum
desiccator. Yield: 99.6%; color: light brown; IR (neat, ῡ , cmꢁ1): 3311, 2917, 2875,
1608, 1582, 1558, 1541, 1510, 1469, 1445, 1388, 1237, 1175, 1111, 1046, 1011, 962,