Alginate polyelectrolyte ionotropic gels. VI. Novel synthesis of diketoalginates as biopolymer precursors

Abstract

SYNOPSIS

A promising methyl ester of pectic acid polysaccharide in biomedicine and pharmaceutics applications: Oxidation of methyl ester of pectic acid by alkaline hexacyanoferrate(III). A kinetic and mechanistic orientation

“…Therefore, all present experimental runs were performed under the conditions of [PEC] 0 < 10 −2 mol dm −3 . Similar behavior was observed in some redox reactions involving pectin polysaccharide as a reducing agent …”

“…[Fe(CN) 6 ] 3− = 7 × 10 −4 , [OH − ] = 3 × 10 −2 , I = 0.1 mol dm −3 at 40 • C oxidation rates. Therefore, all present experimental runs were performed under the conditions of [PEC] 0 < 10 −2 mol dm −3 .Similar behavior was observed in some redox reactions involving pectin polysaccharide as a reducing agent 22,23,37,38.…”

Oxidation of Some Sulfated Carbohydrates: Kinetics and Mechanism of Oxidation of Chondroitin-4-Sulfate by Alkaline Permanganate with Novel Synthesis of Coordination Biopolymer Precursor

“…Although, permanganate ion is a strong oxidizing agent which has been widely used for oxidation of most organic and inorganic compounds (Stewart, 1965;Lee, 1980;Fatiadi, 1987;Dash, Patel, & Mishra, 2009), a little attention has been focused to the oxidation of macromolecules by this oxidant. Eventhough, the kinetics of permanganate oxidation of some carbohydrates containing secondary alcoholic groups such as alginates (Hassan, 1993), pectates (Khairou & Hassan, 2000;Khairou, 2003;Abdel-Mohsen & Nassr, 2010), carboxymethyl cellulose (Shaker, 2001) and methyl cellulose (El-Khatib, 2002;Shaker, El-Khatib, & Mahran, 2007) in alkaline solution has been studied by us for the first time. Unfortunately, the oxidation of sulfated carbohydrates has received a little attention .…”

Spectrophotometric evidence for the formation of short-lived hypomanganate(V) and manganate(VI) transient species during the oxidation of K-carrageenan by alkaline permanganate

“…In addition, this work also aims at shedding light on the nature of these short-lived transient species and the aqueous chemistry of carrageenan macromolecule as well as extending our investigation on the oxidation of carbohydrate macromolecules. [9][10][11][12][13] Preliminary experiments indicated that the oxidation of K-carrageenan by alkaline permanganate proceeded via detectable intermediate complexes and the rates of formation and decomposition were of such magnitude that they could be monitored using a conventional spectrophotometer. The initial step was found to be fast involving the formation of complexes, followed by a slower step corresponding to the decomposition of these complexes at the final stage of the reaction to give rise to the products.…”

“…Hence, the stoichiometric reaction can be represented by the following equation:ðC 12 H 17 O 12 SÞ n À þ 2MnO 4 À þ 1=2O 2 ¼ ðC 12 H 11 O 13 SÞ n À þ 2MnO 2 þ 2OH À þ 2H 2 Oð3Þwhere ðC 12 H 17 O 12 SÞ n À and ðC 12 H 11 O 13 SÞ n À are K-carrageenan and its keto-acid oxidation product, respectively. The oxidation product of K-carrageenan was identified by IR spectroscopy and chemical analysis as described elsewhere 11. 13 Na---O-Mn VI O 3 Na---O-Mn VI O 3 Na---O-Mn VI O 3…”