Selective oxidation of monoethanolamine to glycine over supported gold catalysts: The influence of support and the promoting effect of polyvinyl alcohol

et al. 2019

Ind. Eng. Chem. Res.

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Au supported on monoclinic ZrO 2 (Au/m-ZrO 2 ) prepared by deposition−precipitation method showed excellent catalytic performance in the aerobic oxidation of amino alcohols to amino acids, i.e., glycine, alanine, serine, β-alanine, and 2-aminobutyric acid. The Au particle size and valence distribution of the gold species were adjusted by calcination temperature, as demonstrated by XRD, TEM, UV−vis DRS, XPS, and H 2 -TPR, which significantly influenced the catalytic activity but not the selectivity of amino acids. Metallic gold atoms on the surface were shown to be the active sites by the correlation between reaction rate per mole of metallic Au and Au particle size. The kinetics of oxidation of monoethanolamine (MEA) was studied in detail, and the results indicated that MEA oxidation is a first-order reaction with an activation energy of 52.8 kJ•mol −1 .

Section: Resultsmentioning

confidence: 99%

Selective Oxidation of Amino Alcohols to Amino Acids over Au Supported on Monoclinic ZrO₂: Dominant Active Sites and Kinetic Study

Meng

et al. 2019

Ind. Eng. Chem. Res.

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“…The oxidation of MEA was used as the model reaction to evaluate the catalytic activity of the prepared catalysts, and the reaction was conducted according to the described procedures reported in literature. , Briefly, the reaction mixture containing 0.236 g of catalyst, 0.96 g of NaOH, and 20 mL of aqueous MEA solution (0.3 M) was loaded into a 50 mL autoclave. After purging with O 2 for three times, the reactor was pressurized to 0.5 MPa at room temperature.…”

Section: Experimental Sectionmentioning

confidence: 99%

“…After 30 min, the temperature of the system reached 323 K and the reaction was immediately initiated by vigorous stirring with a speed of 1000 rpm, which could eliminate the mass transfer limitation of the reaction . Conversion of the MEA and selectivity of glycine were quantitatively analyzed using 1 H NMR as described before. , …”

Section: Experimental Sectionmentioning

confidence: 99%

“…30 Conversion of the MEA and selectivity of glycine were quantitatively analyzed using 1 H NMR as described before. 29,30 ■ RESULTS AND DISCUSSION Metal Composition Analysis. The monometallic and bimetallic catalysts were prepared as described in the Experimental Section.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…The oxidation of amino alcohol, i.e. , monoethanolamine (MEA), was chosen as the model reaction to test the catalytic activity of the prepared catalysts based on the previous research and its environmentally benign properties for the production of amino acids. ,, The effect of metal composition on the intrinsic properties of the catalysts and their catalytic performance was also revealed.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Bimetallic Au-Ag/CMK-3 Catalysts and Their Catalytic Activity for the Oxidation of Amino Alcohol

Meng

Yan

Zuo

et al. 2020

Ind. Eng. Chem. Res.

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CMK-3 supported highly dispersed Au-Ag bimetallic nanoparticles with different Ag/Au ratios were prepared by a sequential impregnation–reduction method without the use of any polymer stabilizer. The physicochemical properties of these catalysts were characterized with XRD, ICP-OES, EDS, TEM, XAFS, XPS, STEM, and H2-TPD. The introduction of Ag influenced the surface Ag/Au ratios, particle size, and electronic and structural properties. The relationship between the desorption amount of H2 and the ideal atomic arrangements with different Ag/Au ratios on the (111) planes revealed that the isolated atomic sites on the surface of alloy nanoparticles significantly improved the ability of hydrogen dissociation and the catalytic activity. As a result, compared with the monometallic Au/CMK-3, the conversion of monoethanolamine catalyzed by 10Ag90Au/CMK-3 could increase by 23% and the apparent activation energy was reduced by 10.9 kJ·mol–1.

Construction of thermoplastic cellulose esters matrix composites with enhanced flame retardancy and mechanical properties by embedding hydrophobic magnesium hydroxide

Zhou

J of Applied Polymer Sci

et al. 2021

Biomass‐based composites with renewability and biodegradability have attracted extensive researches, but their applications are hindered by poor mechanical properties and flame retardancy. Cellulose ester matrix composites (CEMC), a kind of biomass‐based composites, were prepared with inorganic crystals as flame retardant and reinforcement. Cellulose acetate oleate (CAO) prepared by mechanical activation‐assisted solid‐phase reaction was used as thermoplastic matrix. Hydrophobic oleate‐magnesium hydroxide (O‐MH), which was surface‐modified with oleic acid, was embedded into CAO to prepare O‐MH/CAO composites by hot pressing. The introduction of oleoyl contributed to favorable thermoplasticity of cellulose ester, resulting in enhanced thermal stability and mechanical properties of CEMC. The uniform dispersion of O‐MH in the CAO matrix via metal–organic coordination increased the mechanical properties and flame retardancy of O‐MH/CAO composites, ascribing to the toughening effect and combustion inhibition effect induced by O‐MH. This study provides a feasible technology for fabricating the CEMC with outstanding thermal stability and mechanical properties.