Microscopic progression in the free radical addition reaction: modeling, geometry, energy, and kinetics

Abstract

The free radical addition reaction is very important in UV curing. The benzoyl radical is the most commonly observed radical. In the addition process, the benzoyl radical adds to an acrylate monomer, forming a primary radical that has great value for subsequent research. In this article, a quantum chemical method was used to study the microscopic progression from the reactive complex to the saddle point. The reactions of three monomers (amylene, allyl methyl ether and methyl acrylate) with a benzoyl radical were evaluated in terms of geometry and energy. The results were also interpreted with an expanded version of the Polanyi rules and the interaction/deformation theory. The deformation energy of methyl acrylate was found to be the smallest, and the bond formation index showed that the transition state in the methyl acrylate system forms early, and can easily reach the saddle point. The activity of the monomer was ascertained by charge analysis and was further confirmed by the reaction rate. Mayer bond order curves depicted the constantly changing chemical bonds during formation and dissociation. Reduced density gradient analysis showed a weak interaction between the monomer and the benzoyl radical.

Minimally Invasive Hemostatic Materials: Tackling a Dilemma of Fluidity and Adhesion by Photopolymerization in situ

“…We believe that polymerization will still proceed quickly to yield a hemostatic effect, as confirmed in the following animal experiment. The mechanism of the free radical addition has been thoroughly investigated by our group elsewhere 14 .…”

Density Functional Theory Guide for an Allyl Monomer Polymerization Mechanism: Photoinduced Radical-Mediated [3 + 2] Cyclization

“…For example, to initiate, vinyl ether requires iodonium or sulfonium salts, and the reaction proceeds via cationic polymerization. Our quantum chemistry calculation showed (Figure S1) that when a benzoyl radical from photocleavage of HMPP is added onto the double bond of AME, the addition rate constant ( k ) in the gas state is 4.6 × 10 –21 , one thousand times slower than k for addition to acrylate (2.2 × 10 –18 ) . However, in a previous study, we observed that SAE polymerization proceeded at a fairly rapid rate and formed a stable polymer, a phenomenon that is difficult to explain using the traditional FRA polymerization mechanism.…”

Controllable preparation and performance of bio-based poly(lactic acid-iminodiacetic acid) as sustained-release Pb2+ chelating agent

“…The geometric structures of LA and IDA molecules are optimized through the B3LYP function by Materials Studio, then the charge distribution is computed, and the possible reaction sites are analyzed. For different reaction modes that may occur at different sites, their transition states and energy barriers are calculated and searched, respectively, which provides a theoretical basis for the synthesis process, as well as the structure and performance analysis ( Lu and Manzetti, 2014 ; Gorantla and Mallik, 2020 ; Zhang et al., 2017 ).…”