Degradation of high-molar-mass hyaluronan by an oxidative system comprising ascorbate, Cu(II), and hydrogen peroxide: Inhibitory action of antiinflammatory drugs—Naproxen and acetylsalicylic acid

Protective effects of manganese(II) chloride on hyaluronan degradation by oxidative system ascorbatepluscupric chlorideThe degradation of several high-molar-mass hyaluronan samples was investigated in the presence of ascorbic acid itself and further by an oxidative system composed of ascorbic acid plus transition metal ions, i.e. Fe(II) or Cu(II) ions. The latter oxidative system imitates conditions in a joint synovial fluid during early phase of acute joint inflammation and can be used as a model for monitoring oxidative degradation of hyaluronan under pathophysiological conditions. The system Cu(II)plusascorbate (the Weissberger oxidative system) resulted in a more significant decrease of hyaluronan molar mass compared to the oxidative system Fe(II) plus ascorbate. Addition of manganese(II) chloride was found to decrease the rate of the oxidative damage of hyaluronan initiated by ascorbate itself and by the Weissberger system.

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Paper Chemistry: Interactions of thermo mechanical pulp fractions with high molar mass cationic polyacrylamides: Part 2. Flocculation

Nordic Pulp & Paper Research Journal ◽

10.3183/npprj-2010-25-03-p310-318 ◽

2010 ◽

Vol 25 (3) ◽

pp. 310-318 ◽

Cited By ~ 2

Author(s):

Tero Taipale ◽

Janne Laine ◽

Susanna Holappa ◽

Jonni Ahlgren ◽

Juan Cecchini

Keyword(s):

Molar Mass ◽

High Molar Mass ◽

Mechanical Pulp ◽

Paper Chemistry

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Highly Efficient MOF Catalyst Systems for CO2 Conversion to Bis-Cyclic Carbonates as Building Blocks for NIPHUs (Non-Isocyanate Polyhydroxyurethanes) Synthesis

Catalysts ◽

10.3390/catal11050628 ◽

2021 ◽

Vol 11 (5) ◽

pp. 628

Author(s):

Adolfo Benedito ◽

Eider Acarreta ◽

Enrique Giménez

Keyword(s):

Molar Mass ◽

Cycloaddition Reaction ◽

Building Blocks ◽

Catalyst System ◽

Cyclic Carbonate ◽

Ammonium Bromide ◽

Cyclic Carbonates ◽

High Molar Mass ◽

Highly Efficient ◽

Free Process

The present paper describes a greener sustainable route toward the synthesis of NIPHUs. We report a highly efficient solvent-free process to produce [4,4′-bi(1,3-dioxolane)]-2,2′-dione (BDC), involving CO2, as renewable feedstock, and bis-epoxide (1,3-butadiendiepoxide) using only metal–organic frameworks (MOFs) as catalysts and cetyltrimethyl-ammonium bromide (CTAB) as a co-catalyst. This synthetic procedure is evaluated in the context of reducing global emissions of waste CO2 and converting CO2 into useful chemical feedstocks. The reaction was carried out in a pressurized reactor at pressures of 30 bars and controlled temperatures of around 120–130 °C. This study examines how reaction parameters such as catalyst used, temperature, or reaction time can influence the molar mass, yield, or reactivity of BDC. High BDC reactivity is essential for producing high molar mass linear non-isocyanate polyhydroxyurethane (NIPHU) via melt-phase polyaddition with aliphatic diamines. The optimized Al-OH-fumarate catalyst system described in this paper exhibited a 78% GC-MS conversion for the desired cyclic carbonates, in the absence of a solvent and a 50 wt % chemically fixed CO2. The cycloaddition reaction could also be carried out in the absence of CTAB, although lower cyclic carbonate yields were observed.

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