scholarly journals High-Efficient and Recyclable Magnetic Separable Catalyst for Catalytic Hydrogenolysis of β-O-4 Linkage in Lignin

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1077 ◽  
Author(s):  
Jingtao Huang ◽  
Chengke Zhao ◽  
Fachuang Lu
Keyword(s):  
Catalytic Performance ◽  
High Yield ◽  
Chemical Bonds ◽  
Aryl Ether ◽  
Structural Units ◽  
Great Abundance ◽  
High Efficient ◽  
Catalytic Hydrogenolysis ◽  
Potential Applications ◽  
Lignin Depolymerization

Lignin is recognized as a good sustainable material because of its great abundance and potential applications. At present, lignin hydrogenolysis is considered as a potential but challenging way to produce low-molecular-mass aromatic chemicals. The most common linkage between the structural units of lignin polymer is the β-O-4 aryl ether, which are primary or even only target chemical bonds for many degradation processes. Herein, a Pd-Fe3O4 composite was synthesized for catalytic hydrogenolysis of β-O-4 bond in lignin. The synthesized catalyst was characterized by XRD, XPS, and SEM and the lignin depolymerization products were analyzed by GC-MS. The catalyst showed good catalytic performance during the hydrogenolysis process, lignin dimer was degraded into monomers completely and a high yield of monomers was obtained by the hydrogenolysis of bagasse lignin. More importantly, the magnetic catalyst was separated conveniently by magnet after reaction and remained highly catalytically efficient after being reused for five times. This work has demonstrated an efficient & recyclable catalyst for the cleavage of the β-O-4 bond in lignin providing an alternative way to make better use of lignins.

scholarly journals Cleavage of aryl–ether bonds in lignin model compounds using a Co–Zn-beta catalyst

RSC Advances ◽  
2020 ◽  
Vol 10 (71) ◽  
pp. 43599-43606
Author(s):  
Xiaomeng Dou ◽  
Wenzhi Li ◽  
Chaofeng Zhu ◽  
Xiao Jiang ◽  
Hou-min Chang ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Metal Catalysts ◽  
Aryl Ether ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Catalytic Hydrogenolysis ◽  
Lignin Model ◽  
Lignin Depolymerization

The catalytic hydrogenolysis of lignin model compounds containing aryl–ether linkages by Co–Zn-beta catalyst is investigated to understand the role of “Lewis acid-metal” catalysts in lignin depolymerization.

scholarly journals Application of HPCCC Combined with Polymeric Resins and HPLC for the Separation of Cyclic Lipopeptides Muscotoxins A–C and Their Antimicrobial Activity

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2653 ◽  
Author(s):  
José Cheel ◽  
Jan Hájek ◽  
Marek Kuzma ◽  
Kumar Saurav ◽  
Iva Smýkalová ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Inhibitory Concentration ◽  
Pathogenic Fungus ◽  
High Yield ◽  
Preparative Hplc ◽  
Efficient Tool ◽  
Cyclic Lipopeptides ◽  
Potential Applications ◽  
Polymeric Resins ◽  
Weak Antibacterial Activity

Muscotoxins are cyanobacterial cyclic lipopeptides with potential applications in biomedicine and biotechnology. In this study, Desmonostoc muscorum CCALA125 strain extracts were enriched by polymeric resin treatment, and subjected to HPCCC affording three cyclic lipopeptides (1–3), which were further repurified by semi-preparative HPLC, affording 1, 2, and 3, with a purity of 86%, 92%, and 90%, respectively. The chemical identities of 2–3 were determined as muscotoxins A and B, respectively, by comparison with previously reported ESI-HRMS/MS data, whereas 1 was determined as a novel muscotoxin variant (muscotoxin C) using NMR and ESI-HRMS/MS data. Owing to the high yield (50 mg), compound 2 was broadly screened for its antimicrobial potential exhibiting a strong antifungal activity against Alternaria alternata, Monographella cucumerina, and Aspergillus fumigatus, with minimum inhibitory concentration (MIC) values of 0.58, 2.34, and 2.34 µg/mL; respectively, and weak antibacterial activity against Bacillus subtilis with a MIC value of 37.5 µg/mL. Compounds 1 and 3 were tested only against the plant pathogenic fungus Sclerotinia sclerotiorum due to their low yield, displaying a moderate antifungal activity. The developed chromatographic method proved to be an efficient tool for obtaining muscotoxins with potent antifungal properties.

scholarly journals Correction: Catalytic hydrogenolysis of kraft lignin to monomers at high yield in alkaline water

2017 ◽  
Vol 19 (17) ◽  
pp. 4186-4186 ◽  
Author(s):  
Shi-Chao Qi ◽  
Jun-ichiro Hayashi ◽  
Shinji Kudo ◽  
Lu Zhang
Keyword(s):  
Kraft Lignin ◽  
High Yield ◽  
Alkaline Water ◽  
Catalytic Hydrogenolysis

Correction for ‘Catalytic hydrogenolysis of kraft lignin to monomers at high yield in alkaline water’ by Shi-Chao Qi et al., Green Chem., 2017, 19, 2636–2645.

scholarly journals Effect of Fe Additives on the Catalytic Performance of Ion-Exchanged CsX Zeolites for Side-Chain Alkylation of Toluene with Methanol

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 829 ◽  
Author(s):  
Zhang ◽  
Yuan ◽  
Miao ◽  
Li ◽  
Shan ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Performance ◽  
High Yield ◽  
Side Chain ◽  
Impregnation Method ◽  
Basic Sites ◽  
Lewis Acidic Sites ◽  
X Zeolite ◽  
Acidic Sites ◽  
Negative Effect

The side-chain alkylation of toluene with methanol was investigated over some Fe-modified Cs ion-exchanged X zeolite (CsX) catalysts prepared via the impregnation method using different iron sources. The absorption/activation behaviors of the reactants on the surface of the catalysts were studied by in situ Fourier-transform infrared (FT-IR) spectroscopy and temperature programmed desorption (TPD) mass measurements. Modification of CsX with a small amount of FeCl3 could result in a considerable decrease in catalytic activity, due mainly to the remarkable decrease in the density of acidic and basic sites of the catalysts. Interestingly, the Fe(NO3)3-modified CsX with an optimum Fe loading of 0.15 wt.% shows improved catalytic activity and high yield compared to the side-chain alkylation products. Modification of CsX with Fe(NO3)3 could also result in a decrease in basic sites of the catalyst. However, such a change does not bring an obvious negative effect on the adsorption/activation of toluene, while it could effectively inhibit the generation of the undesired bidentate formate. Furthermore, the introduced FeOx species (derived from the decomposition of Fe(NO3)3) may also act as new Lewis acidic sites to participate in the activation of methanol and to stabilize the formed active intermediates (i.e., unidentate formate). Therefore, modification of CsX with a suitable amount of Fe(NO3)3 may adjust its adsorption/activation ability for reagents by changing the acid–base properties of the catalyst, which can finally enhance the catalytic performance for the side-chain alkylation of toluene with methanol.

scholarly journals Catalytic condensation of phenol with formaldehyde into BPF on recyclable anchoring sulfuric acid

2020 ◽  
Vol 213 ◽  
pp. 01003
Author(s):  
Hui Li ◽  
Xi Cao ◽  
Huiting He ◽  
Jian Liu ◽  
Weijian Xiang ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Catalytic Performance ◽  
Significant Loss ◽  
High Yield ◽  
Element Analysis ◽  
Simple Filtration ◽  
Ft Ir ◽  
The Mind

A novel solid-acid catalyst (PVC-EDA-SO4H) based on polyvinyl chloride (PVC) were prepared after amination of Ethylenediamine (EDA) and anchorage of sulfuric acid. The as-prepared catalyst was characterized by FT-IR, Element analysis, Chemical titration and Thermal analysis, the results indicated that the sulfuric acid was successfully anchored on PVC. The PVC-EDA-SO4H showed excellent catalytic performance for the synthesis of bisphenol F, and achieved almost high yield and selectivity (94%) of BPF under the mind reaction conditions. Meanwhile, exhibited excellent reusability without the significant loss after six cycles via simple filtration.

On the synthesis of 3,4-dihydroxyprolines. II. Synthesis, stereochemistry and reactivity of some 3,4-Epoxy-DL-proline derivatives

1975 ◽  
Vol 28 (11) ◽  
pp. 2479 ◽  
Author(s):  
CB Hudson ◽  
AV Robertson ◽  
WRJ Simpson
Keyword(s):  
Acid Hydrolysis ◽  
Methyl Esters ◽  
High Yield ◽  
Butyl Esters ◽  
Epoxy Acids ◽  
Trifluoroperacetic Acid ◽  
Catalytic Hydrogenolysis ◽  
Direct Separation ◽  
Proline Derivatives ◽  
Hydrolysis Of

N-Protected esters of 3,4-dehydro-DL-proline react with trifluoroperacetic acid to give, in high yield, approximately equal amounts of the corresponding stereoisomeric 3,4-epoxy-DL-proline derivatives, direct separation of which proved difficult. However individual members of the two families were obtained by discovery of selective transformations and fractionations. Relative configurations of the two 3,4-epoxy-N-tosylproline methyl esters were established by borohydride reduction to authentic 4-hydroxy-N-tosylprolinols. Epoxide reduction is regioselective. Extensive p.m.r. analyses then permitted stereochemical assignment of other derivatives. These epoxides are remarkably resistant to catalytic hydrogenolysis, and to hydration in acid or alkali. N-Substituted 3,4-epoxyproline methyl esters undergo ready β-elimination in alkali to yield the corresponding 4-hydroxy-2,3- dehydroproline esters and ultimately the N-substituted pyrrole-2- carboxylic acid or ester. Prolonged aqueous acid hydrolysis of 3,4- epoxy-N-tosylprolines, or of their methyl esters, gives mixtures of 3,4-dihydroxy-N-tosyl-DL-prolines in the 2,3-cis-3,4-trans and 2,3- trans-3,4-trans families. Their stereochemistry was allotted from p.m.r. of the diacetate methyl esters. During acid hydrolysis of 3,4- epoxy-N-tosylproline methyl esters, the ester of the trans stereoisomer hydrolyses selectively, and some epimerization of the cis stereoisomer occurs. Ester hydrolysis is much faster than epoxide hydration. Anhydrous acid cleavage of 3,4-epoxy-N-tosyl-DL-proline t-butyl esters to the epoxy acids is unusually slow.

Cancer theranosis using mono-disperse, mesoporous gold nanoparticles obtained via a robust, high-yield synthetic methodology

RSC Advances ◽  
2016 ◽  
Vol 6 (16) ◽  
pp. 13554-13561 ◽  
Author(s):  
Taeksu Lee ◽  
Doyeon Bang ◽  
Yong Wook Chang ◽  
Yuna Choi ◽  
Kwang Yeol Park ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
High Yield ◽  
Synthetic Methodology ◽  
Facile Synthesis ◽  
Potential Applications

Here, we introduce the facile synthesis of scalable, mono-disperse, mesoporous gold nanoparticles (MPGNs) with an acidic emulsification method, which exhibit many attractive nanoplasmonic features for potential applications in many fields.

scholarly journals Pd/Au Based Catalyst Immobilization in Polymeric Nanofibrous Membranes via Electrospinning for the Selective Oxidation of 5-Hydroxymethylfurfural

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 45 ◽  
Author(s):  
Danilo Bonincontro ◽  
Francesco Fraschetti ◽  
Claire Squarzoni ◽  
Laura Mazzocchetti ◽  
Emanuele Maccaferri ◽  
...  
Keyword(s):  
Selective Oxidation ◽  
Large Scale ◽  
Catalytic Performance ◽  
High Yield ◽  
Key Factors ◽  
Hydroxymethyl Furfural ◽  
Catalyst Immobilization ◽  
Polymeric Component ◽  
Furandicarboxylic Acid ◽  
Nanofibrous Membranes

Innovative nanofibrous membranes based on Pd/Au catalysts immobilized via electrospinning onto different polymers were engineered and tested in the selective oxidation of 5-(hydroxymethyl)furfural in an aqueous phase. The type of polymer and the method used to insert the active phases in the membrane were demonstrated to have a significant effect on catalytic performance. The hydrophilicity and the glass transition temperature of the polymeric component are key factors for producing active and selective materials. Nylon-based membranes loaded with unsupported metal nanoparticles were demonstrated to be more efficient than polyacrylonitrile-based membranes, displaying good stability and leading to high yield in 2,5-furandicarboxylic acid. These results underline the promising potential of large-scale applications of electrospinning for the preparation of catalytic nanofibrous membranes to be used in processes for the conversion of renewable molecules.

In situ characterization of Cu–Co oxides for catalytic application

2015 ◽  
Vol 177 ◽  
pp. 249-262 ◽  
Author(s):  
Z. Y. Tian ◽  
H. Vieker ◽  
P. Mountapmbeme Kouotou ◽  
A. Beyer
Keyword(s):  
Thermal Properties ◽  
Chemical Vapor ◽  
Functional Materials ◽  
Catalytic Performance ◽  
Structure Property ◽  
Temperature Oxidation ◽  
Spatially Resolved ◽  
Structure Property Relationships ◽  
Potential Applications

In situ emission and absorption FTIR methods were employed to characterize the spatially resolved structure of binary Co–Cu oxides for low-temperature oxidation of CO and propene. Co–Cu oxide catalysts were controllably synthesized by pulsed-spray evaporation chemical vapor deposition. XRD, FTIR, XPS, UV-vis and helium ion microscopy (HIM) were employed to characterize the as-prepared thin films in terms of structure, composition, optical and thermal properties as well as morphology. In situ emission FTIR spectroscopy indicates that Co3O4, CuCo2O4 and CuO are thermally stable at 650, 655 and 450 °C, respectively. The catalytic tests with absorption FTIR display that the involvement of Co–Cu oxides can initiate CO and C3H6 oxidation at lower temperatures. The results indicate that in situ emission and absorption FTIR are useful techniques to explore the thermal properties and catalytic performance of functional materials, allowing many potential applications in tailoring their temporally and spatially resolved structure-property relationships.

scholarly journals A Mechanistic Investigation of Acid-Catalyzed Cleavage of Aryl-Ether Linkages: Implications for Lignin Depolymerization in Acidic Environments

2013 ◽  
Vol 2 (3) ◽  
pp. 472-485 ◽  
Author(s):  
Matthew R. Sturgeon ◽  
Seonah Kim ◽  
Kelsey Lawrence ◽  
Robert S. Paton ◽  
Stephen C. Chmely ◽  
...  
Keyword(s):  
Aryl Ether ◽  
Mechanistic Investigation ◽  
Acid Catalyzed ◽  
Acidic Environments ◽  
Lignin Depolymerization
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