Über natürliche und synthetische amylose. XII. Über die verteilung der substituenten in wasserlöslichen amyloseäthern

Abstract

An homogen hergestellten Oxyäthyläthern, Carboxymethyläthern und Sulfopropyläthern der Amylose wird durch Perjodatoxydation und Tritylierung die Verteilung der Substituenten bestimmt. In allen Fällen reagieren im Beginn der Reaktion sekundäre Gruppen – vermutlich an C2 – bevorzugt. Eine Darstellung von reinen C2‐Äthern gelingt jedoch nicht, da bei Substitutionsgraden von 1 bereits auch die anderen Hydroxylgruppen mitreagiert haben.

Amphiphilic derivatives of dextran: Adsorption at air/water and oil/water interfaces

“…significant variation of γ e is observed), the maximum surface coverage, Γ max , as well as Π CC = γ 0 − γ CC (Table 6). It appears that the DexP 49 S 23 has a significantly higher CC than the two others, DexP 80 S 26 and DexP 23 . The more hydrophobic DexP 80 S 26 exhibits a slightly lower Π CC than the others.…”

“…Although t * strongly increases when s increases from 0 to 24%, its dependence on polymer concentration remains similar from one polymer to another. For the two charged polymers, we observed a decrease of t * with C following a power law and the exponent was −1.1 for DexP 23 S 7 and −0.9 for DexP 23 S 24 (for DexP 23 it was −0.9).…”

“…Moreover, with our polymers, viscometric experiments showed that for τ = 49 or 80%, the hydrophobic effect was able to significantly reduce the intrinsic viscosity despite the expanding effect of sulfopropyl groups. The maximum surface coverage, Γ max , is lower for the charged polymers, DexP 49 S 23 and DexP 80 S 26 , than for the neutral DexP 23 .…”

“…A similar synthetic scheme has been followed for amphiphilic derivatives of poly(vinyl alcohol) [21]. The reaction of propane sulfone with polysaccharides has been applied, among other use, to cellulose [22], amylose [23], and starch [22] and more recently to dextran [24]. Sulfopropyldextran, dextran sulfate, and carboxymethyldextran have been studied with regard to their solution properties [25][26][27][28].…”

Anionic graft polymerization of ethylene oxide on starch. II. Structure of the graft polymers

“…Some work in this direction was carried out before. [2][3][4][5][6] The results were found to depend on the reaction conditions. There is no absolute selectivity, but in many reactions there is preferential participation of the secondary hydroxyl at C2.…”