Oxidative degradation of ethylenethiourea (ETU) and ETU progenitors by hydrogen peroxide and hypochlorite

1979 ◽  
Vol 27 (2) ◽  
pp. 295-299 ◽  
Author(s):  
William D. Marshall
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidative Degradation

A review of lignin hydrogen peroxide oxidation chemistry with emphasis on aromatic aldehydes and acids

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajinkya More ◽  
Thomas Elder ◽  
Zhihua Jiang
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidative Degradation ◽  
Reaction Medium ◽  
Dicarboxylic Acids ◽  
Aromatic Aldehydes ◽  
Product Distribution ◽  
Reaction Conditions ◽  
Alkaline Conditions ◽  
The Stability ◽  
Oxidation Chemistry

Abstract This review discusses the main factors that govern the oxidation processes of lignins into aromatic aldehydes and acids using hydrogen peroxide. Aromatic aldehydes and acids are produced in the oxidative degradation of lignin whereas mono and dicarboxylic acids are the main products. The stability of hydrogen peroxide under the reaction conditions is an important factor that needs to be addressed for selectively improving the yield of aromatic aldehydes. Hydrogen peroxide in the presence of heavy metal ions readily decomposes, leading to minor degradation of lignin. This degradation results in quinones which are highly reactive towards peroxide. Under these reaction conditions, the pH of the reaction medium defines the reaction mechanism and the product distribution. Under acidic conditions, hydrogen peroxide reacts electrophilically with electron rich aromatic and olefinic structures at comparatively higher temperatures. In contrast, under alkaline conditions it reacts nucleophilically with electron deficient carbonyl and conjugated carbonyl structures in lignin. The reaction pattern in the oxidation of lignin usually involves cleavage of the aromatic ring, the aliphatic side chain or other linkages which will be discussed in this review.

Combinative dyebath treatment with activated carbon and UV/H2O2: a case study on Everzol Black-GSP®

2002 ◽  
Vol 46 (4-5) ◽  
pp. 51-58 ◽  
Author(s):  
N.H. Ince ◽  
D.A. Hasan ◽  
B. Üstün ◽  
G. Tezcanli
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Carbon ◽  
Carbon Mineralization ◽  
Oxidative Degradation ◽  
Advanced Oxidation ◽  
Color Removal ◽  
Operating Parameters ◽  
Cost Reductions ◽  
H2o2 System

Treatability of textile dyebath effluents by two simultaneously operated processes comprising adsorption and advanced oxidation was investigated using a reactive dyestuff, Everzol Black-GSP® (EBG). The method was comprised of contacting aqueous solutions of the dye with hydrogen peroxide and granules of activated carbon (GAC) during irradiation of the reactor with ultraviolet light (UV). Control experiments were run separately with each individual process (advanced oxidation with UV/H2O2 and adsorption on GAC) to select the operating parameters on the basis of maximum color removal. The effectiveness of the combined scheme was tested by monitoring the rate of decolorization and the degree of carbon mineralization in effluent samples. It was found that in a combined medium of advanced oxidation and adsorption, color was principally removed by oxidative degradation, while adsorption contributed to the longer process of dye mineralization. Economic evaluation of the system based on total color removal and 50% mineralization showed that in the case of Everzol Black-GSP®, which adsorbs relatively poorly on GAC, the proposed combination provides 25% and 35% reduction in hydrogen peroxide and energy consumption relative to the UV/H2O2 system. Higher cost reductions are expected in cases with well adsorbing dyes and/or with less costly adsorbents.

A recyclable polymer-supported ruthenium catalyst for the oxidative degradation of bisphenol A in water using hydrogen peroxide

2011 ◽  
Vol 35 (1) ◽  
pp. 149-155 ◽  
Author(s):  
Zongmin Hu ◽  
Chi-Fai Leung ◽  
Yat-Kwai Tsang ◽  
Hongxia Du ◽  
Haojun Liang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Bisphenol A ◽  
Oxidative Degradation ◽  
Ruthenium Catalyst ◽  
Polymer Supported

Oxidative Degradation ofin Situand Isolated Spruce Lignins by Water-Soluble Hydrogen Peroxide Resistant Pentafluorophenylporphyrin

1996 ◽  
Vol 44 (7) ◽  
pp. 1953-1959 ◽  
Author(s):  
Bernard Kurek ◽  
Isabelle Artaud ◽  
Brigitte Pollet ◽  
Catherine Lapierre ◽  
Bernard Monties
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidative Degradation ◽  
Water Soluble

Physicochemical Characterization of Oxidatively Degraded Calcium Lignosulfonate via Alkaline Hydrogen Peroxide

2014 ◽  
Vol 887-888 ◽  
pp. 575-580 ◽  
Author(s):  
Li Hong Hu ◽  
Jing Zhou ◽  
Cai Ying Bo ◽  
Bing Chuan Liang ◽  
Yong Hong Zhou
Keyword(s):  
Hydrogen Peroxide ◽  
Phenolic Resin ◽  
Physicochemical Characterization ◽  
Oxidative Degradation ◽  
Alkaline Condition ◽  
Alkaline Hydrogen Peroxide ◽  
Phenolic Contents ◽  
H Nmr ◽  
Ft Ir

In order to increase the application prospect of calcium lignosulfonate in phenolic resin, Calcium lignosulfonate was oxidatively degraded by Hydrogen peroxide under alkaline condition. Both lignins were characterized by FT-IR, 1H NMR, UV, GC-MS and GPC. The optimal degradation conditions are: lignosulfonate:water=1:1, wt/wt, pH=10, temperature 60 °C, reaction time 2 h, and H2O2 dosage 6 wt% (based on weight of lignosulfonate). The results show that the degraded resultant is higher in phenolic contents, and lower in methoxyl content. Number molecular weight (Mn) of calcium lignosulfonate sharply decreases to 2294, versus 17774 before oxidative degradation.Guaiacly monoer content increased and kinds of phenolic compounds occurre in oxidative degradation fractions, mainly due to β-O-4 and β-5 cleavage. And reactive activity of the oxidatively degraded compounds is sharply increased.

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