THE SYNTHESIS OF AROYL METHYL KETONES AS LIGNIN MODEL SUBSTANCES

1964 ◽  
Vol 42 (1) ◽  
pp. 113-120 ◽  
Author(s):  
J. M. Pepper ◽  
Maitreyi Saha
Keyword(s):  
Selenium Dioxide ◽  
Methyl Ketones ◽  
Lignin Model ◽  
Model Substances

A series of aroyl methyl ketones (ArCOCOCH3 in which Ar was phenyl, p-hydroxyphenyl, p-methoxy phenyl, 4-hydroxy-3-methoxyphenyl, 3,4-dimethoxyphenyl, 4-hydroxy-3,5-dimethoxyphenyl, and 3,4,5-trimethoxyphenyl) has been prepared by the oxidation, using selenium dioxide, of the correspondingly substituted benzyl methyl ketones.

Microwave-assisted selenium dioxide oxidation of aryl methyl ketones to aryl glyoxals

2011 ◽  
Vol 52 (31) ◽  
pp. 4036-4038 ◽  
Author(s):  
Ryan M. Young ◽  
Michael T. Davies-Coleman
Keyword(s):  
Selenium Dioxide ◽  
Methyl Ketones ◽  
Microwave Assisted ◽  
Aryl Methyl

THE ALKALINE NITROBENZENE OXIDATION OF ASPEN WOOD AND LIGNIN MODEL SUBSTANCES

1955 ◽  
Vol 33 (1) ◽  
pp. 24-30 ◽  
Author(s):  
K. R. Kavanagh ◽  
J. M. Pepper
Keyword(s):  
Reaction Time ◽  
Sodium Hydroxide ◽  
Maximum Yield ◽  
Aspen Wood ◽  
Wood Meal ◽  
Nitrobenzene Oxidation ◽  
Subsequent Heating ◽  
Lignin Model ◽  
Model Substances

The yields of vanillin and syringaldehyde obtained by the alkaline nitrobenzene oxidation of aspen wood meal have been determined at various temperatures for various times. The maximum yield of each of these aldehydes, ca. 15 and 36% respectively, was obtained under the same conditions. Similar maximum yields result at 130 ± 5 °C. as at 170 ± 5 °C. if the reaction time is markedly increased. Treatment of the wood meal with sodium hydroxide at 160 °C. for two and one half hours prior to the addition of nitrobenzene and subsequent heating under the same conditions decreases, by over 30%, the yields of aldehydes. Samples of 3,4,5-trimethoxybenzaldehyde, β-D-glucovanillin, and β-D-glucosyringaldehyde were oxidized by alkaline nitrobenzene at 160 °C. for two and one half hours and yields of the corresponding phenolic aldehydes of 10.7, 69.6, and 71.9% respectively were obtained. These results are discussed with respect to the chemistry of aspen lignin.

Analysis of 1H-NMR spectra of cinnamaldehyde type model substances of lignin

1980 ◽  
Vol 45 (2) ◽  
pp. 330-334 ◽  
Author(s):  
Tibor Liptaj ◽  
Milan Remko ◽  
Ján Polčin
Keyword(s):  
Double Bond ◽  
Nmr Spectra ◽  
Side Chain ◽  
Type Model ◽  
Stable Conformer ◽  
Spectra Analysis ◽  
H Nmr ◽  
Nmr Data ◽  
Lignin Model ◽  
Model Substances

1H-NMR spectra of the following lignin model substances have been analyzed: cinnamaldehyde, 2-methoxycinnamaldehyde, 3-methoxycinnamaldehyde, 4-methoxycinnamaldehyde, 3,4-dimethoxycinnamaldehyde, 3-methoxy-4-hydroxycinnamaldehyde and 3,4,5-trimethoxycinnamaldehyde. From the NMR spectra analysis it follows that the studied compounds exist in solutions as trans isomers. Theoretical (PCILO) calculations in agreement with the NMR data have shown that the more stable conformer has trans orientation of C=O group with respect to the double bond of the conjugated side chain.

Selenocyanation of Aryl and Styryl Methyl Ketones in the Presence of Selenium Dioxide and Malononitrile: An Approach for the Synthesis of α-Carbonyl Selenocyanates

2020 ◽  
Author(s):  
Ibakyntiew D. Marpna ◽  
Kmendashisha Wanniang ◽  
Tyrchain Mitre Lipon ◽  
O. Risuklang Shangpliang ◽  
Bekington Myrboh
Keyword(s):  
Selenium Dioxide ◽  
Methyl Ketones

Selenium Dioxide As an Alternative Reagent for the Direct α-Selenoamidation of Aryl Methyl Ketones

2018 ◽  
Vol 83 (10) ◽  
pp. 5829-5835 ◽  
Author(s):  
O. Risuklang Shangpliang ◽  
Baskhemlang Kshiar ◽  
Kmendashisha Wanniang ◽  
Ibakyntiew D. Marpna ◽  
Tyrchain Mitre Lipon ◽  
...  
Keyword(s):  
Selenium Dioxide ◽  
Methyl Ketones ◽  
Aryl Methyl

scholarly journals Enhancement of colloidal particle and lignin removal from pre-hydrolysis liquor by pectinase pre-treatment – Study on model substances

BioResources ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 409-420
Author(s):  
Zongquan Li ◽  
Qin Liu ◽  
Jiansong Chen ◽  
Yingjuan Fu
Keyword(s):  
Colloidal Particle ◽  
Cationic Polymer ◽  
Polygalacturonic Acid ◽  
Cationic Polymers ◽  
Negative Effects ◽  
Lignin Removal ◽  
Lignin Model ◽  
Negative Charge Density ◽  
Model Substances ◽  
Pre Treatment

Removal of colloidal particle and lignin from pre-hydrolysis liquor (PHL) is important for the subsequent processing and utilization of the saccharides in the PHL. Cationic polymers treatment is a common method for the purpose, and pectinase pre-treatment of PHL can improve the efficiency of the treatment with cationic polymers. To investigate the mechanism of pectinase pre-treatment for improvement of the cationic polymer efficiency, polygalacturonic acid (PGA) was added in the colloidal lignin and dissolved lignin model substances systems, respectively, and the effects of polygalacturonic acid (PGA) and its pectinase pre-treatment on the removal of colloidal and dissolved lignin in the following cationic polymer treatment process were studied. The results showed that the presence of PGA caused the increase of negative charge density of the colloidal lignin and dissolved lignin systems, which lowered the efficiency of the cationic polymers and negatively affected the removal of both the colloidal lignin and the dissolved lignin. After pectinase treatment, the PGA present in the colloidal and dissolved lignin system was degraded and the negative effects on the cationic polymers were eliminated, and the efficiency of the cationic polymers was improved. Compared to the colloidal lignin and dissolved lignin systems with PGA, less cationic polymers were needed for the same systems with pectinase treatment to obtain the similar lignin removal level.

THE SYNTHESIS OF LIGNIN MODEL SUBSTANCES: 5-HYDROXYVANILLIN AND 5-HYDROXYACETOGUAIACONE

1962 ◽  
Vol 40 (11) ◽  
pp. 2175-2177 ◽  
Author(s):  
S. K. Banerjee ◽  
M. Manolopoulo ◽  
J. M. Pepper
Keyword(s):  
Lignin Model ◽  
Model Substances

not available

scholarly journals PTSA-Catalyzed Reaction of Alkyl/Aryl Methyl Ketones with Aliphatic Alcohols in the Presence of Selenium Dioxide: A Protocol for the Generation of an α-Ketoacetals Library

ACS Omega ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 6035-6043 ◽  
Author(s):  
O. Risuklang Shangpliang ◽  
Kmendashisha Wanniang ◽  
Baskhemlang Kshiar ◽  
Ibakyntiew D. Marpna ◽  
Tyrchain Mitre Lipon ◽  
...  
Keyword(s):  
Selenium Dioxide ◽  
Aliphatic Alcohols ◽  
Methyl Ketones ◽  
Alkyl Aryl ◽  
Aryl Methyl
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