On the Importance of the Amide-Bonded Hydrogen Atom in the Cationically Induced Oligomerization of N-Vinylamides

Abstract

A critical review of former investigations on the cationically induced oligomerization of N-vinylformamide points out that some of the results are not in agreement with the model of an cationic propagation mechanism. Special attention in the discussion of the results is given on the chain structure of the oligo(N-vinylformamide)s. In comparison with N-vinylformamide, the ability of different N-vinylamides to undergo a cationically induced polymerization to oligomeric products was investigated. Only the secondary N-vinylamides, N-vinylformamide (VFA) or N-vinylacetamide (VAcA), readily form higher oligomers with various cationic initiators. N-Methyl-N-vinylformamide and the cyclic N-vinylpyrrolidone (VP) dimerize with acidic catalysts, whereas N-methyl-N-vinylacetamide gives a mixture of low molecular products. The N-alkyl-substituted N-vinylamides are not able to undergo a oligomerization to higher oligomers (M n > 200) under the conditions investigated. The cationic polymerization of N-deutero-N-vinylformamide (VFAD) and the 2H NMR analysis of the obtained oligomers show that the nitrogen-bonded hydrogen (deuterium) is strongly involved in the proton transfer as well as the propagation reaction. From these results, we propose an alternative oligomerization mechanism for the oligomerization of secondary N-vinylamides. A nonionic pericyclic transition state is potentially suggested involving a N-formylimine end group and the monomer rather than a cationically active chain.

Radical Grafting Polymerization of Vinylformamide with Functionalized Silica Particles

“…The small shoulder at δ = 46 ppm (2) may be assigned to CH units of adsorbed PVFA segments. According to the literature, CH 2  and CH groups are expected to give a broad signal at δ ∼ 49–50 ppm 40. The signal appearing at δ = 100 ppm is a spinning side band.…”

“…Among other polyelectrolytes, PVAm possesses the highest charge density known along the polymer backbone. Furthermore, the primary amino groups of PVAm can be utilized for many chemical post‐derivatization reactions, which allows the construction of multifunctional materials 39–43. Therefore, the use of PVAm for surface functionalization of silica has been studied during the recent years 42–44.…”

Selective Ion Pair Adsorption of Cobalt and Copper Salts on Cationically Produced Poly(1,3-divinylimidazolid-2-one)/Silica Hybrid Particles

“…Usually, N -vinylcarbonic acid amides do not cationically polymerize to high-molecularweight products. However, they dimerize well cationically and it is expected that each dimerization step produces a double bond and a methyl group (32). Because the BVU monomer possesses two vinyl groups, a polymerization to high molecular products occurs.…”

N-vinylformamide - a new environmentally friendly water-soluble monomer

“…Warunkiem formowania ³añcucha polimeru w polimeryzacji jonowej jest atak elektrofilowy tylko w kierunku "a". Zatem mo¿liwooeae ataku w pozosta³ych dwóch kierunkach ("b" i "c") prowadzi do utworzenia wy³¹cznie krótkich ³añcuchów i licznych niepo¿¹danych produktów ubocznych [12,[18][19][20]. W polimeryzacji rodnikowej NVF uzyskiwane ciê¿ary cz¹steczkowe tak¿e nie s¹ zbyt du¿e i nie dorównuj¹ wartooeciom jakie mo¿na otrzymaae polimeryzuj¹c akryloamid.…”