Reactions of lignin model compounds with pulp bleaching chemicals. Reactions of 4-methyltrichlorocatechol

1992 ◽  
Vol 70 (6) ◽  
pp. 1711-1716 ◽  
Author(s):  
A. Bruce McKague ◽  
Douglas W. Reeve ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Direct Methods ◽  
Aqueous Sodium Hydroxide ◽  
Pulp Bleaching ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Full Matrix ◽  
Aqueous Sodium ◽  
Space Group ◽  
Lignin Model ◽  
Benzilic Acid

Aqueous chlorination of 4-methyltrichlorocatechol 2 gave the tetrachlorohydroxycyclohexenone 4, which crystallized as the hydrate 5. Reaction of 4 with aqueous sodium hydroxide resulted in a benzilic acid rearrangement to the tetrachlorodihydroxycyclopentenecarboxylic acid 6. These reactions have important implications with respect to understanding how lignin is removed during pulp bleaching. Crystals of the tetrachlorotrihydroxycyclohexenone 5 are monoclinic, a = 11.4420(6), b = 7.5873(9), c = 12.6443(6) Å, β = 101.266(4)°, Z = 4, space group P21/c, and those of the methyl tetrachlorodihydroxycyclopentenecarboxylate 7 are monoclinic, a = 28.447(1), b = 6.929(1), c = 12.597(1) Å, β = 103.074(5)°, Z = 8, space group C2/c. The structures were solved by direct methods and were refined by full-matrix least-squares procedures to R = 0.028 and 0.034 for 1716 and 2164 reflections with I ≥ 3σ(I), respectively.

Reactions of lignin model compounds with pulp bleaching chemicals. Cannizzaro-type reaction of tetrachloro-o-benzoquinone with alkali

1992 ◽  
Vol 70 (6) ◽  
pp. 1706-1710 ◽  
Author(s):  
A. Bruce McKague ◽  
Douglas W. Reeve ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Direct Methods ◽  
Aqueous Sodium Hydroxide ◽  
Pulp Bleaching ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Full Matrix ◽  
Aqueous Sodium ◽  
X Ray ◽  
X Ray Crystallography ◽  
Lignin Model

Reaction of tetrachloro-o-benzoquinone 1 with aqueous sodium hydroxide resulted in a Cannizzaro-type disproportionation into tetrachloromuconic acid and tetrachlorocatechol. The tetrachloromuconic acid was isolated and identified by X-ray crystallography as the methyl ester of the cyclized lactone 3. Crystals of C7H3Cl3O4, 4, are orthorhombic, a = 9.991 (2), b = 7.981 (1), c = 24.626(2) Å, Z = 8, space group Pna21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.033 for 1609 reflections with I ≥ 3σ(I).

scholarly journals Effect of lignin structure on adsorbable organic halogens formation in chlorine dioxide bleaching

2019 ◽  
Vol 6 (2) ◽  
pp. 182024 ◽  
Author(s):  
Lisheng Shi ◽  
Jiayan Ge ◽  
Shuangxi Nie ◽  
Chengrong Qin ◽  
Shuangquan Yao
Keyword(s):  
Chlorine Dioxide ◽  
Model Compound ◽  
Pulp Bleaching ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Lignin Model Compound ◽  
Lignin Model ◽  
Organic Halogens ◽  
Adsorbable Organic Halogens ◽  
Lignin Structure

Adsorbable organic halogens (AOX) are formed in pulp bleaching as a result of the reaction of residual lignin with chlorine dioxide. The natural structure of lignin is very complex and it tends to be damaged by various extraction methods. All the factors can affect the study about the mechanism of AOX formation in the reaction of lignin with chlorine dioxide. Lignin model compounds, with certain structures, can be used to study the role of different lignin structures on AOX formation. The effect of lignin structure on AOX formation was determined by reacting phenolic and non-phenolic lignin model compound with a chlorine dioxide solution. Vanillyl alcohol (VA) and veratryl alcohol (VE) were selected for the phenolic and non-phenolic lignin model compound, respectively. The pattern consumption of lignin model compounds suggests that both VA and VE began reacting with chlorine dioxide within 10 min and then gradually steadied. The volume of AOX produced by VE was significantly higher than that produced by VA for a given initial lignin model compound concentration. In a solution containing a combination of VA and VE in chlorine dioxide, VE was the dominant producer of AOX. This result indicates that the non-phenolic lignin structure was more easily chlorinated, while the phenolic lignin structure was mainly oxidized. In addition, AOX content produced in the combined experiments exceeded the total content of the two separate experiments. It suggested that the combination of phenolic and non-phenolic lignin structure can promote AOX formation.

Reaction of lignin model compounds with pulp bleaching chemicals

1995 ◽  
Vol 10 (2) ◽  
pp. 119-121 ◽  
Author(s):  
Esa Vilen ◽  
Douglas W. Reeve ◽  
A. Bruce McKague ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Pulp Bleaching ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Lignin Model

Oxalate formation during ClO2 bleaching of bamboo kraft pulp

2020 ◽  
Vol 35 (1) ◽  
pp. 18-24
Author(s):  
Hailong Li ◽  
Chao Du ◽  
Shujuan Ge ◽  
Mengru Liu
Keyword(s):  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Reaction System ◽  
Kappa Number ◽  
Pulp Bleaching ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Bleaching Process ◽  
Prolonged Reaction Time ◽  
Lignin Model

AbstractThis study aimed to investigate the oxalate formation mechanism during chlorine dioxide ({\mathrm{ClO}_{2}}) bleaching of bamboo kraft pulp, and thus explore favourable {\mathrm{ClO}_{2}} bleaching conditions to better control oxalate formation. The amount of oxalate formed varied linearly with {\mathrm{ClO}_{2}} dosage within the whole research range, while it rose exponentially within the first 90 mins of pulp bleaching. Then the actual bleaching process was simulated by reacting {\mathrm{ClO}_{2}} with three representative lignin model compounds and comparatively studied. The rule of oxalate formation in the simulated reaction system was identical to that in pulp bleaching by {\mathrm{ClO}_{2}}, except for oxalate production by veratraldehyde with prolonged reaction time. Under identical conditions, vanillin formed the highest amount of oxalate, while veratraldehyde formed the least. Furthermore, the amount of oxalate formed increased by 19.59 mg/kg when the kappa number of the delignified pulp was reduced by one unit. Considering the satisfactory pulp brightness and decreased oxalate formation, the recommended conditions for {\mathrm{ClO}_{2}} bleaching of bamboo kraft pulp were a {\mathrm{ClO}_{2}} dosage of 4 %, 60 °C and 70 mins.

Lignin to Value-Added Chemical Synthesis

2020 ◽  
Vol 16 ◽  
Author(s):  
Mahdieh Sharifi ◽  
Ramyakrishna Pothu ◽  
Rajender Boddula ◽  
Inamuddin
Keyword(s):  
Ionic Liquids ◽  
Lignocellulosic Biomass ◽  
Academic Research ◽  
Power Saving ◽  
Value Added ◽  
Glycerol Ether ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Biomass Activity ◽  
Lignin Model

Background: There is a developing demand for innovation in petroleum systems replacements. Towards this aim, lignocellulosic biomass suggested as a possible sustainable source for the manufacturing of fuels and produced chemicals. The aims of this paper are to investigate different kinds of β-O-4 lignin model compounds for the production of value-added chemicals in presence of ionic liquids. Especially, a cheap β-O-4 lignin model Guaiacol glycerol ether (GGE) (Guaifenesin) is introduced to produce valuable chemicals and novel products. Methods: Research related to chemical depolymerization of lignocellulosic biomass activity is reviewed, the notes from different methods such as thermal and microwave collected during at least 10 years. So, this collection provides a good source for academic research and it gives an efficient strategy for the manufacturing of novel value-added chemicals at an industrial scale. Results: This research presented that ionic liquid microwave-assisted is a power saving, cost efficient, fast reaction, and clean way with high selectively and purity for production of high value chemicals rather that conversional heating. Guaiacol and catechol are some of these valuable chemicals that is produced from β-O-4 lignin model compounds with high word demands that are capable to produce in industry scale. Conclusion: The β-O-4 lignin model compounds such as Guaiacol glycerol ether (GGE) (Guaifenesin) are good platform for developing food materials, perfumery, biorefinery, and pharmaceutical industry by ionic liquids-assisted lignin depolymerization method.

Insights into the electrochemical degradation of phenolic lignin model compounds in protic ionic liquid-water system

2021 ◽  
Author(s):  
Guangyong Liu ◽  
Qian Wang ◽  
Dongxia Yan ◽  
Yaqin Zhang ◽  
Chenlu Wang ◽  
...  
Keyword(s):  
Water System ◽  
Value Added ◽  
Electrochemical Degradation ◽  
Aryl Ether ◽  
Model Compounds ◽  
Protic Ionic Liquid ◽  
Lignin Model Compounds ◽  
Mild Conditions ◽  
System P ◽  
Lignin Model

Cleavage of aryl ether (Caryl-O) bonds is crucial for conversion and value-added utilization of lignin and its derivatives, but remains extremely challenging under mild conditions due to strong Caryl-O linkages....

Eco-friendly preparation of ultrathin biomass-derived Ni3S2-doped carbon nanosheets for selective hydrogenolysis of lignin model compounds in the absence of hydrogen

2021 ◽  
Vol 23 (8) ◽  
pp. 3090-3103
Author(s):  
Changzhou Chen ◽  
Dichao Wu ◽  
Peng Liu ◽  
Jing Li ◽  
Haihong Xia ◽  
...  
Keyword(s):  
Model Compounds ◽  
Lignin Model Compounds ◽  
Carbon Nanosheets ◽  
Significant Potential ◽  
Selective Hydrogenolysis ◽  
Lignin Model

Lignin is an abundant source of aromatics, and the depolymerization of lignin provides significant potential for producing high-value chemicals.

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