N-Benzylated Poly(vinylamine): Synthesis, Characterization, and Catalytic Activity in Ester Cleavage

Abstract

Poly(vinylamine) (2) and copolymers (3) resulting from various degrees of substitution (DS) with benzyl groups were synthesized. The viscosity of the polymers measured in Tris buffer (µ = 0.05 M) at different pH values decreases with the increase of the hydrophobic character, and 3 takes a very tight conformation for DS > 50 %. A fluorescence study was carried out using potassium 2-p-toluidinylnaphthalene-6-sulfonate (TNS) as the hydrophobic probe. We showed the existence of an apolar microdomain which is at the origin of the solubilizing power of 3. The hydrolysis of p-nitrophenyl acetate (PNPA) carried out at 25 ± 0.1 °C in Tris buffer solution (pH = 8.74; µ = 0.05 M) was accelerated up to 20-fold compared to the 2 catalyzed reaction. Fluorometry, in agreement with kinetic measurements, showed that the solubilizing power and catalytic properties increase with DS. From these remarks, it was concluded that the substrate is entrapped in the power microdomain and undergoes the nucleophilic attack of the vicinal NH2 groups. A kinetic study in the presence of cyclodextrin (CD) was carried out and resulted in an inhibition effect.

Hydrophobically-modified poly(vinyl pyrrolidone) as a physically-associative, shear-responsive ophthalmic hydrogel

“…The primary amine groups on the hydrolyzed P(VP-co-VF) polymers were grafted with hydrophobes via a condensation reaction with alkyl halides of chain length C 10 , C 12 , and C 18 adapted from published methods (Chen et al, 2005;Martel et al, 1994). Briefly, 0.1 wt% of hydrolyzed P(VP-co-VF) was dissolved in a water/ methanol (1/10 weight ratio) mixture containing 0.02 wt% NaOH.…”

“…1) but also two hydrophobes (via a tertiary amine) or even three hydrophobes (via a quaternary amine) grafted to a single graft site; indeed, from a purely chemical perspective, multiple grafts to a single amine are favored since higher order amines are stronger nucleophiles. However, the fact that the reactive amine is tethered to the PVP backbone polymer also introduces steric hindrance in that once one alkyl group is reacted, the grafted amine becomes sterically crowded and thus significantly less likely than in small molecule models to continue to react (Everaerts et al, 1984;Martel et al, 1994). Polymers with higher molecular weights (PVP255kDa) facilitated slightly lower percent alkylation, with between 1.1 and 1.2 mol% hydrophobe functionalization (on a total monomer basis) achieved.…”

Solvatochromism and acidochromism of azobenzene-functionalized poly(vinyl amines)

“…in catalysis, 2 chelation, 3 treatment of waste water, 4 paper making, 5 recovery of oil, 6 and as superabsorber. 7 Modified PVAm is excepted to be useful in the preparation of polymeric water-soluble dyes, 8 mimicking natural enzymes, 9 and as polymer surfactants. 10 Depending on the surrounding pH value, the primary amino groups of the PVAm can be protonated (ÀNH 3 + ) or can be present as charge-neutral amines (ÀNH 2 ).…”

Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine)

“…The water-soluble PVAm copolymer has been widely applied for a number of purposes, e.g., in catalysis [7], chelation [8], treatment of waste water [9], paper making [10], recovery of oil [11] and as superabsorber [12]. Modified PVAm is expected to be useful in the preparation of polymeric water-soluble dyes [13], in mimicking natural enzymes [14] and as a polymeric surfactant [15]. Depending on the pH of the aqueous solution, the primary amino groups of PVAm can be partly protonated (−NH 3 + ) or they can be present as charge-neutral amines (−NH 2 ).…”