Modeling of Superacid Catalyzed Step‐Growth Polymerization of Isatin and Biphenyl or Terphenyl Monomers

Abstract

reactions and found that they can be used in the synthesis of diarylated compounds.Zolotukhin and co-workers [3][4][5][6][7][8][9] develo ped a superacid catalyzed polyhydroxyalkylation novel synthetic route (see Figure 2), which can be classified as an unusual A 2 + B 2 step-growth poly merization since ultrahigh molecular weights and molar mass dispersities (Ð) less or higher than two are possible, at nonstoichiometric conditions. The dramatic acceleration in polymerization rate observed in superacid catalyzed poly hydroxyalkylations with a small excess of the carbonyl compound is known as the "nonstoichiometric effect." [6] Superacid catalyzed polyhydroxyalkylations have the following advantages: [6] (i) the reaction proceeds at room temperature and atmospheric pressure, (ii) structural variety and commercial availability of monomers, (iii) high conversion yields, (iv) high regioselectivities, (v) acceptable reaction times, (vi) great versatility in polymer architectures, (vii) functional groups that allow polymer chemical modification reactions, (viii) easy polymer purification, (ix) good physical, chemical, and thermal properties of the produced polymers, and (x) high polymer molecular weights.

Analysis of the Competition between Cyclization and Linear Chain Growth in Kinetically Controlled A2 + B2 Step‐Growth Polymerizations Using Modeling Tools

“…[ 6 ] One issue that we faced in our previous study was the poor agreement of our model (similar to the one proposed here, but without cyclization) with available experimental data of Ð versus time (see dotted profile in Figure , which corresponds to Figure 11c at r = 1 in Romero‐Hernández et al. [ 6 ] ). As observed in Figure 22, the inclusion of cyclization makes the agreement to be significantly better (solid line).…”

“…No rigorous estimation procedures for the unknown parameters in our model were attempted, not only because of the excessively high computation times required for ultrahigh molar mass polymers, but also because the only system where time evolution profiles of molar mass averages were available included the use of modified isatin, and the modification process was not included within the polymerization scheme behind our model. 6 Further experimental and theoretical work continues being developed in our laboratories on these issues, but the analysis presented here is an important step forward in the understanding of this unique polymerization system.…”

“…There are three issues that should be considered when analyzing the poor agreement between calculated and experimental profiles of M w versus time observed in Figure 23: 1) the original calculations required the inclusion of DCEs to reduce calculated molecular weights, since the model predicted much higher molecular weights than the experimental data; 6 2) the simulations of Figures 21-23 considering cyclization with our current model considered a cut-off value of N = 60, which was adequate for calculation of N(R) and Ð, but was clearly too low for calculation of M w (the maximum possible value of M w using N = 60 would be M w ≈ 24 000 g mol −1 , much lower than the observed maximum of M w ≈ 375,000 g mol −1 ); 3) the inclusion of cyclization reduces the maximum values of M w .…”

“…We recently modeled the superacid catalyzed polymerization of isatin and biphenyl or terphenyl, [ 6 ] which are examples of superacid catalyzed polyhydroxyalkylation. This polymerization route, developed in one of our laboratories, [ 7–13 ] allows to produce ultra‐high molecular weight polymer molecules by non‐stoichiometric A 2 + B 2 step‐growth polymerizations ( r < 1, where r is stoichiometric imbalance ratio).…”

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during the early stages of polymerization, when monomers such as 6-aminehexanoic acid, which can lead to ε-caprolactam, a seven-member ring, [1] or monomers with higher member rings, such as those containing Si, P, or heavier elements from the periodic table are used. [2][3][4][5] We recently modeled the superacid catalyzed polymerization of isatin and biphenyl or terphenyl, [6] which are examples of superacid catalyzed poly hydroxyalkylation. This polymerization route, developed in one of our laboratories, [7][8][9][10][11][12][13] allows to produce ultra-high molecular weight polymer molecules by non-stoichiometric A 2 + B 2 step-growth polymerizations (r < 1, where r is stoichiometric imbalance ratio).

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