A Kinetic Study of the Metathetical and Addition Reactions Characteristic of Allyl Polymerization

SynopsisThe polymerization of a series of a-(substituted methyl) acrylates was investigated. Polymerization rate measurements showed that each of the monomers, though containing allylic hydrogen atoms, polymerizes readily. Polymer viscosity data were obtained which indicate that appreciable nondegradative chain tratlsfer occurs with several of the monomers. An explanation for the rapid polymerization of the monomers was proposed.

Polymerization studies on allylic compounds. I

Baldwin

Reed

1963

Homopolymerization of N‐allylacetamide and N‐allylstearamide

Jordan

Wrigley

1964

When benzoyl peroxide was decomposed at 90°C. in N‐allylacetamide and in N‐allylstearamide, d[M]/d[P] was about 2 and DP was between 9 and 10, because of a wastage of benzoyloxy radicals. These radicals formed benzoic acid and benzene as a consequence of hydrogen abstraction from the amide, and the resulting amide radicals became substituted with ester and phenyl groups from the initiator. N‐butylstearamide, a saturated model for N‐allylstearamide, gave corresponding products. Rates of peroxide decomposition indicated strong induced effects, decreasing in the order: N‐allylacetamide, N‐allylstearamide, N‐butylstearamide. Slopes of the linear plots of the four products (in moles per kilogram) against initiator (in equivalents per kilogram) in the three amides in the above order were: benzoic 0.521, 0.570, 0.575; benzene 0.027, 0.086, 0.168; amide substituted by benzoate 0.459, 0.320, 0.106; amide substituted by phenyl 0.087, 0.087, 0.142. Transfer, compared to substitution, increased with chain length and decrease in unsaturation, and induced peroxide decomposition was correspondingly lowered. Thus, kinetic chain decreased with acyl chain length and decrease in unsaturation. A mechanism that postulates polar species in the transition state when amides were solvents accounted for both transfer and aromatic substitution and helped explain the difference in behavior of N‐allylamides and allyl esters. Plots of amide entering polymer (in moles per kilogram) against initiator concentration (in equivalents per kilogram) were curves; plots of log (a – x) for amide disappearance against the same coordinate were linear. Slopes were: N‐allylacetamide −0.0742; N‐allylstearamide −0.1771.

Radical displacement in allyl ester polymerization. I. Allyl acetate; evidence from gas‐phase kinetics

James¹,

Troughton²

1965

Photolysis of diethyl ketone in the presence of allyl acetate in the range 35–175°C. leads to the addition and dismutation reactions: The proposed reaction scheme is supported by the values: R(CO2)/[R(C5H10) + R(C4H8)] = 1.02 ± 0.03, and R(C5H10)/[R(CH4) + R(C3H8)] = 1.01 ± 0.03, and allows the evaluation of k7 and k8: where k2 refers to: 2CH3CH·2 → C4H10 and k7a to: CH3CH·2 + ·C5H10OCOCH3 → C7H15OCOCH3. These results are discussed in relation to the radical displacement mechanism of effective chain transfer in the polymerization of allylic monomers.