Synthesis of Amphiphilic Starch Derivatives Using One-pot Synthesis Procedure

Amphiphilic starch derivatives with high content of functional groups were prepared from potato starch using a one-pot synthesis method with a single reaction medium for the entire procedure. Potato starch was benzylated, followed by the introduction of hydroxypropyltrimethylammonium(HPMA) moieties without the purification of intermediates. The synthesis was performed under heterogeneous conditions, leading to the formation of benzyl 2-hydroxypropyltri methylammonium starch chloride(BnHPMAS) with a total degree of substitution(DS) of up to 1.4. This process improved the efficiency of the preparation of amphiphilic starch derivatives and reduced the time and resources consumed by avoiding a separation process and purification of the intermediate compounds.The DS of BnHPMAS was in the range of 0.36 to 1.4, which could be tuned by varying the molar ratio of the reagents to repeating unit or by changing the reaction temperature, time, and medium. The structure of the amphiphilic starches was characterized using elemental analysis, size exclusion chromatography,fourier transform infrared spectroscopy(FT-IR), and nuclear magnetic resonance(NMR) spectroscopy. Moreover, the surface tension and turbidity of the solutions of the products were measured for their potential application in the removal of dissolved and colloidal substances in paper cycling water.

Structure Elucidation of Hydroxypropyl Cellulose Homogenously Prepared from NaOH/Urea Aqueous Solution

Hydroxypropyl celluloses(HPC) were homogenously synthesized by the reaction of cellulose with propylene oxide in NaOH/urea aqueous solution.Water-soluble HPC with molar degree of substitution(MSNMR) in the range of 0.52~0.78 was prepared from microcrystalline cellulose,cotton linters,and spruce sulfite pulp.The structure of the HPC samples was characterized by means of FT-IR,NMR,gas chromatography(GC),and size exclusion chromatography(SEC) analyses.Three types of cellulose samples with different molecular weights were found to dissolve well in the NaOH/urea solvent with no obvious differences in reactivity and regioselectivity.The relative reactivity of hydroxyl groups in the glycosyl unit was in the following order:O-6>O-2>O-3.In addition,the results of the study indicated that the tandem reaction during hydroxypropylation could be ignored.

A Facile Strategy to Fabricate Polysaccharide-Based Magnetic Hydrogel Based on Enamine Bond

of main observation and conclusion Magnetic hydrogels have found extensive applications in fields such as soft robotics,drug delivery and shape morphing.Here a facile method was fabricated to prepare polysaccharide-based magnetic hydrogels.The chitosan-Fe3O4 ferrofluid was obtained by dispersing carboxyl groups modified Fe3O4 nanoparticles uniformly in chitosan matrix.Subsequently,the magnetic polysaccharide hydrogel was obtained by simply mixing cellulose acetoacetate solution with chitosan-Fe3O4 ferrofluid.The structures and properties of the magnetic hydrogel were analyzed using Fourier-transform infrared spectroscopy,rheological recovery,responsiveness,and stability measurements.The results indicated that magnetic polysaccharide hydrogel showed pH responsiveness and excellent self-healing properties,and the hydrogel manifested outstanding stability under physiological conditions(37℃)for 72 h.In addition,the injectable polysaccharide-based hydrogel exhibited sensitive magnetic responsive and shape-shifting ability under an external magnetic field.Therefore,the strategy for the facile preparation of the magnetic polysaccharide-based hydrogel in this work could provide a benign and versatile method for achieving self-healing,responsive,injectable properties for the application in biomedical fields.

Porous Hafnium-Containing Acid/Base Bifunctional Catalysts for Efficient Upgrading of Bio-Derived Aldehydes

Novel organic-inorganic hybrids were synthesized by using HfCl 4 and organic ligand 1H-pyrrole-2,5-dicarboxylic acid(PDCA)via a simple hydrothermal method.The as-prepared Hf-PDCA were characterized by various techniques,such as electron microscope,N_(2) adsorption/desorption,and X-ray photoelectron spectroscopy.Among them,the porous and nitrogen-containing Hf-PDCA as heterogeneous acid/base bifunctional catalyst was then applied to the catalytic hydrogenation of furfural to produce furfuryl alcohol(FFA).It exhibited excellent catalytic performance,with high conversion(98.8%)and selectivity(98.5%)by using 2-propanol as hydrogen source under a relatively mild condition.Moreover,the Hf-PDCA has strong stability and durability,and can be recovered after the catalyst reaction.In addition,the Hf-PDCA as catalyst can be extended to fabricate corresponding alcohols by catalytic conversion of other biomass derived aldehydes.