Kinetics fo Free-Radical Polymerization of 8-Quinolinyl Acrylate

The synthesis of water insoluble poly 8-quinolinylacrylate was investigated for free radical polymerization. The kinetics of polymerizatio of 8-quinolinylacrylate initiated by AIBN in DMF at 60-100°C were studied. The rate of polymerization was determined at various concentration of monomer and initiator. The overall activation energy was found to be 15.0 K.J. mol" 1 .


INTRODUCTION
It is known that 8-hydroxyquinoline and its derivative possess antibacterial, antimycotic and ameobicidal properties, several authors have suggested that their antimicrobial properties are due to their complex forming ability. The chelating ion-exchange properties of 8-HQ and its derivatives have been widely exploited for many application such as in metallurgical operations, separation and estimation of metals, effluent treatment, purification of water and as a catalyst in many organic synthesis. The polymeric 8-HQ derivatives have been synthesized by its condensation with aldehydes and by modification of poly (ethylene glycol) and poly (caprolactone)s. There are few examples of synthesis and polymerization of vinyl monomers containing quinolinyl groups. Data are also lacking for kinetics of polymerization of 8-QA. A number of kinetic studies of the aqueous polymerization of acryl amide have been reported [1][2][3][4][5] but there are few reports on polyacylamides with N-substituted carboxyphenyl residues and little information is available [6][7][8][9] .
The present article deals with the study of kinetic of solution polymerization of 8-QA in different experimental conditions. The synthesis of 8-quinolinyl acrytlate and some studies on the polymerization and characterization of their polymers have been published 10 ' 1 .

Materials
All the chemical used during the study were of analytical grade. The solvents and monomers were purified by the conventional method 12 . 2,2'azobisisobutyronitrite was recrystalized from methanol and dried in a dessicator.

Monomer synthesis
The monomer 8-quinolinyl acrylate was synthesized from 8-hydroxy quinoline-and acryloyl chloride as described in previous article 10 .
Polymerization procedure A typical polymerization method is described below. Thus the order of reaction with respect to initiator is found to be 0.21 ( Figure.2)

Effect of temperature
The polymerization of 8-QA initiated by AIBN was investigated in the temperature range 60-100°C in DMF as reaction medium, keeping the concentration of all other reagents constant. The rate of polymerization was found to increase progressively with rise in temperature. From the Arrhenius plot Rp versus 1/T (Figure-3), the overall activation energy Ea was computed to be 15.0 K.J./mol.

Relation between concversion and reaction time.
8-quinolinyl acrylate was polymerized in DMF in the temperature range 60,80 and 100°C using AIBN as initiator.Time conversion curves at three different concentration of monomer and initiator respectively are shown in Figure 4 to 6, from which it is concluded that the percentage conversion increases as the monomer and initiators concentration increases. The order of the reaction with respect to initiator concentration for the polymerization of 8-QH has been determined graphically from the double logarithemic plot of rate of polymerization (Rp) versus initiator concentration 13 . The plot is linear and from the slope of-the plot, the order of reaction was found to be around 0.19 (Figure-7).

CONCLUSION
On the basis of the standard free radical polymerization scheme and the derivation of the kinetic equation suggested in the literature 15 , the rate expression is derived.This rate experession satisfactorily explains all the kinetic results obtained, these results of the present study are in agreement with those reported by Suthar et.al 15 ' 16 .