Lignin and related compounds. I. A comparative study of catalysts for lignin hydrogenolysis

1969 ◽  
Vol 47 (5) ◽  
pp. 723-727 ◽  
Author(s):  
J. M. Pepper ◽  
Y. W. Lee
Keyword(s):  
Comparative Study ◽  
Raney Nickel ◽  
Lignin Degradation ◽  
Soluble Fraction ◽  
Degradation Products ◽  
Quantitative Estimation ◽  
Liquid Chromatographic Separation ◽  
Lignin Degradation Products ◽  
Liquid Chromatographic ◽  
Related Compounds

A detailed comparative study has been made of the effectiveness of various catalysts for the hydrogenolysis of spruce wood lignin. The catalysts studied were Raney nickel, 10% palladium–charcoal, 5% rhodium–charcoal, 5% rhodium–alumina, 5% ruthenium–charcoal, and 5% ruthenium–alumina. Lignin degradation products were obtained initially as a chloroform-soluble fraction which was then divided and studied as diethyl ether-soluble and -insoluble fractions. Gas–liquid chromatographic separation of the ether-soluble fraction made possible the characterization and quantitative estimation of many of the lower molecular weight lignin degradation products.The data indicate that rhodium, palladium, and a limited amount of Raney nickel produce similar results as do ruthenium and an excess of Raney nickel; however, with the latter catalysts the degradation is more severe. In particular, rhodium–charcoal and palladium–charcoal appear to offer interesting advantages as catalysts for lignin hydrogenolysis.

Lignin and related compounds. V. The hydrogenolysis of aspen wood lignin using rhodium-on-charcoal as catalyst

1978 ◽  
Vol 56 (7) ◽  
pp. 896-898 ◽  
Author(s):  
James M. Pepper ◽  
Reginald W. Fleming
Keyword(s):  
Lignin Degradation ◽  
Soluble Fraction ◽  
Degradation Products ◽  
Total Yield ◽  
Maximum Yield ◽  
Aspen Wood ◽  
Lignin Degradation Products ◽  
Phenolic Derivatives ◽  
Related Compounds ◽  
Soluble Lignin

The hydrogenolysis of aspen lignin using rhodium-on-charcoalas catalyst has been studied. The maximum yield of chloroform-soluble lignin degradation products was obtained at a reaction temperature of 195 °C. Analysis of this chloroform-soluble fraction revealed that the monomeric fraction was composed essentially of the four compounds, 1–4, only, and in a total yield representing at least 40% of the original lignin.Solvent extraction was shown to be preferred over thermal distillation as a preparative procedure for the separation of these phenolic derivatives. The significance of the isolation of these lignin degradation products is discussed.

Lignin and related compounds. VIII. Lignin monomers and dimers from hydrogenolysis of aspen poplar wood using rhodium-on-charcoal catalyst

1981 ◽  
Vol 59 (7) ◽  
pp. 1028-1031 ◽  
Author(s):  
Kenichi Sudo ◽  
Donald J. Mullord ◽  
James M. Pepper
Keyword(s):  
Silica Gel ◽  
Lignin Degradation ◽  
Degradation Products ◽  
Initial Pressure ◽  
Hydroxybenzoic Acid ◽  
Poplar Wood ◽  
Catalytic Hydrogenolysis ◽  
Lignin Degradation Products ◽  
Related Compounds ◽  
Soluble Lignin

Aspen poplar wood meal has been subjected to catalytic hydrogenolysis in dioxane–water (9:1) at 500 psig initial pressure of hydrogen over a 5% rhodium-on-charcoal catalyst for five hours at 195 + 5 °C. The resulting chloroform-soluble lignin degradation products were separated by cellulose and silica gel column chromatography. The following compounds were isolated and identified: 4-hydroxybenzoic acid (5), 1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone (propiosyringone) (6), 2,2′-dihydroxy-3,3′-dimethoxy-5,5′-dipropylbiphenyl (7), 2,3-bis(4-hydroxy-3,5-dimethoxyphenyl)-1-propanol (11), and a mixture of 3-(4-hydroxy-3,5-dimethoxyphenyl)-2-(4-hydroxy-3-methoxyphenyl)-1-propanol (9) and 3-(4-hydroxy-3-methoxyphenyl)-2-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanol (10).

Chemical characterization and in vitro fermentation ofBrassicastraw treated with the aerobic fungus,Trametes versicolor

2011 ◽  
Vol 91 (4) ◽  
pp. 695-702 ◽  
Author(s):  
J. E. Ramirez-Bribiesca ◽  
Y. Wang ◽  
L. Jin ◽  
T. Canam ◽  
J. R. Town ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Trametes Versicolor ◽  
Lignin Degradation ◽  
Volatile Fatty Acids ◽  
Degradation Products ◽  
Chemical Characterization ◽  
Gas Production ◽  
In Vitro Fermentation ◽  
Lignin Degradation Products

Ramirez-Bribiesca, J. E., Wang, Y., Jin, L., Canam, T., Town, J. R., Tsang, A., Dumonceaux, T. J. and McAllister, T. A. 2011. Chemical characterization and in vitro fermentation of Brassica straw treated with the aerobic fungus, Trametes versicolor . Can. J. Anim. Sci. 91: 695–702. Brassica napus straw (BNS) was either not treated or was treated with two strains of Trametes versicolor; 52J (wild type) or m4D (a cellobiose dehydrogenase-deficient mutant) with four treatments: (i) untreated control (C-BNS), (ii) 52J (B-52J), (iii) m4D (B-m4D) or (iv) m4D+glucose (B-m4Dg). Glucose was provided to encourage growth of the mutant strain. All treatments with T. versicolor decreased (P<0.05) neutral-detergent fibre and increased (P<0.05) protein and the concentration of lignin degradation products in straw. Ergosterol was highest (P<0.05) in straw treated with B-52J, suggesting it generated the most fungal biomass. Insoluble lignin was reduced (P<0.05) in straw treated with B-52J and B-m4D, but not with B-m4Dg. Mannose and xylose concentration were generally higher (P<0.05) in straw treated with fungi, whereas glucose and galactose were lower as compared with C-BNS. The four treatments above were subsequently assessed in rumen in vitro fermentations, along with BNS treated with 2 mL g−1of 5 N NaOH. Concentrations of total volatile fatty acids after 24 and 48h were lower (P<0.05) in incubations that contained BNS treated with T. versicolor as compared with C-BNSor NaOH-treated BNS. Compared with C-BNS, in vitrodry matter disappearance and gas production were increased (P<0.05) by NaOH, but not by treatment with either strain of T. versicolor. Although treatment with T. versicolor did release more lignin degradation products, it did not appear to provide more degradable carbohydrate to in vitro rumen microbial populations, even when a mutant strain with compromised carbohydrate metabolism was utilized. Production of secondary compounds by the aerobic fungi may inhibit rumen microbial fermentation.

Lignin degradation products as palaeoenvironmental proxies in the sediments of small lakes

2007 ◽  
Vol 38 (4) ◽  
pp. 555-567 ◽  
Author(s):  
Karol Kuliński ◽  
Joanna Święta-Musznicka ◽  
Andrzej Staniszewski ◽  
Janusz Pempkowiak ◽  
Małgorzata Latałowa
Keyword(s):  
Lignin Degradation ◽  
Degradation Products ◽  
Small Lakes ◽  
Lignin Degradation Products

scholarly journals Stability Indicating HPLC Determination of Risperidone in Bulk Drug and Pharmaceutical Formulations

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Zarna R. Dedania ◽  
Ronak R. Dedania ◽  
Navin R. Sheth ◽  
Jigar B. Patel ◽  
Bhavna Patel
Keyword(s):  
Limit Of Detection ◽  
Degradation Products ◽  
Pharmaceutical Formulations ◽  
Assay Method ◽  
Pharmaceutical Dosage Forms ◽  
Stability Indicating ◽  
Stress Studies ◽  
Liquid Chromatographic Separation ◽  
Bulk Drug ◽  
Liquid Chromatographic

The objective of the current study was to develop a validated stability-indicating assay method (SIAM) for risperidone after subjecting it to forced decomposition under hydrolysis, oxidation, photolysis, and thermal stress conditions. The liquid chromatographic separation was achieved isocratically on a symmetry C18 column (5 μm size, 250 mm × 4.6 mm i.d.) using a mobile phase containing methanol: acetonitrile (80 : 20, v/v) at a flow rate of 1 mL/min and UV detection at 280 nm. Retention time of risperidone was found to be . The method was linear over the concentration range of 10–60 μg/mL with a limit of detection and quantitation of 1.79 and 5.44 μg/mL, respectively. The method has the requisite accuracy, specificity, sensitivity, and precision to assay risperidone in bulk form and pharmaceutical dosage forms. Degradation products resulting from the stress studies did not interfere with the detection of Risperidone, and the assay is thus stability indicating.

scholarly journals Functional acidic ionic liquids as effective solvents for the fractionation of lignocelluloses

BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 4721-4732
Author(s):  
Shi Jia Dong ◽  
Bi Xian Zhang ◽  
Peng Zhang ◽  
Kun Yang Wu ◽  
Xin Miao He ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Lignin Degradation ◽  
Degradation Products ◽  
Reducing Sugar ◽  
Alkaline Extraction ◽  
Enzymatic Conversion ◽  
Acidic Ionic Liquids ◽  
Lignin Degradation Products ◽  
High Yields ◽  
Hydrolysis Of

There is increasing interest in the application of ionic liquids for the pretreatment and fractionation of lignocelluloses. In this study, a series of functional acidic ionic liquids (ILs) with various heterocyclic organic cations were synthesized. Corn stalks were successfully fractionated into lignin, hemicelluloses, and cellulose when ultrasonically pretreated with ILs at 70 °C for 3 h, and subsequently treated with alkaline extraction. High yields of IL-isolated lignin (18.3% to 19.6%) and (8.3% to 14.6%) were obtained using ILs in the absence and presence of water, respectively. The yield of cellulose ranged from 40.0 to 77.0% from IL treatments, whereas the yield of hemicelluloses ranged from 1.1% to 17.3%. Enzymatic hydrolysis of the isolated cellulose residual produced 89.2% to 94.9% reducing sugar with 77.8% to 86.1% glucose, which corresponded to 80.5% to 91.4% enzymatic conversion of cellulose. Syringol and vanillin were found as the main lignin degradation products.

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