Reaction pathways to dimer in polystyrene pyrolysis: A mechanistic modeling study

Resource recovery via catalytic fast pyrolysis of polystyrene using zeolites

“…As hydrogen abstraction reactions possess higher activation energy of c.a. 11 kcal mol -1 compared to disproportionation (2.3 kcal mol -1 ), the latter step occurs predominantly at lower temperatures, while the former is significant at higher temperatures [32]. Other products like benzene and cumene were observed at very low yields (<1 wt.%) at all the temperatures during non-catalytic fast pyrolysis.…”

“…kcal mol -1 ) [32]. Therefore, the latter pathway is favored at low temperatures, while the former is favored at high pyrolysis temperatures.…”

“…Non-catalytic pyrolysis of PS is known to proceed via free radical reactions involving elementary steps including chain fission, chain termination, hydrogen abstraction, chain β-scission, radical addition and intramolecular backbiting reactions to produce monomer as the major product, and dimers and trimers as minor products [31,32]. The primary reaction involved in the formation of styrene is successive β-scission of the secondary benzylic end-chain radical.…”

In situ fast pyrolysis of biomass with zeolite catalysts for bioaromatics/gasoline production: A review

“…Aromatics (i.e., mono-, branched and polyaromatics) were the most likely dominant products. Without the influence of a catalyst, the mechanism was reported to involve the generation of radical species from the polymer followed by coupling, fission and rearrangements to form the aromatic products [141,142]. In this study, the non-catalytic reaction produced primarily styrene with decreasing yields at high temperatures.…”

Relevance of backbiting and beta‐scission reactions in the free radical polymerization of Acrylonitrile

“…In these cases, secondary reactions are responsible for the production of low molecular weight species. [13,[16][17] In the case of polyvinyl chloride (PVC), the presence of the MCRs leads to the formation of chain defects which can affect the physical properties and the main applicative features of the final polymeric material. [18] Backbiting The backbiting reactions consist in the hydrogen transposition in a terminal radical chain that takes place because of the higher reactivity of the radical in the terminal position with respect to the MCRs.…”