Structural Analysis of Lignin-Based Furan Resin

The global “carbon emission peak” and “carbon neutrality” strategic goals promote us to replace current petroleum-based resin products with biomass-based resins. The use of technical lignins and hemicellulose-derived furfuryl alcohol in the production of biomass-based resins are among the most promising ways. Deep understanding of the resulting resin structure is a prerequisite for the optimization of biomass-based resins. Herein, a semiquantitative 2D HSQC NMR technique supplemented by the quantitative 31P NMR and methoxyl group wet chemistry analysis were employed for the structural elucidation of softwood kraft lignin-based furfuryl alcohol resin (LFA). The LFA was fractionated into water-insoluble (LFA-I) and soluble (LFA-S) parts. The analysis of methoxyl groups showed that the amount of lignin was 85 wt% and 44 wt% in LFA-I and LFA-S fractions, respectively. The HSQC spectra revealed the high diversity of linkages formed between lignin and poly FA (pFA). The HSQC and 31P results indicated the formation of new condensed structures, particularly at the 5-position of the aromatic ring. Esterification reactions between carboxyl groups of lignin and hydroxyl groups of pFA could also occur. Furthermore, it was suggested that lignin phenolic hydroxyl oxygen could attack an opened furan ring to form several aryl ethers structures. Therefore, the LFA resin was produced through crosslinking between lignin fragments and pFA chains.

Download Full-text

Effect of periodate on lignin for wood adhesive application

Holzforschung ◽

10.1515/hf.2011.025 ◽

2011 ◽

Vol 65 (2) ◽

Cited By ~ 17

Author(s):

Richard J.A. Gosselink ◽

Jan E.G. van Dam ◽

Ed de Jong ◽

Göran Gellerstedt ◽

Elinor L. Scott ◽

...

Keyword(s):

Furfuryl Alcohol ◽

Molar Mass ◽

Phenol Formaldehyde ◽

Periodate Oxidation ◽

Wood Adhesive ◽

Wood Failure ◽

Harmful Emission ◽

Complete Life Cycle ◽

Adhesive Application ◽

Softwood Kraft Lignin

Abstract Development of eco-friendly binders with no harmful emission during its complete life cycle is of high interest for the wood-based industry. In this paper, a fully renewable binder based on activated lignin and poly-furfuryl alcohol and a partly renewable lignin based phenol-formaldehyde (PF) binder were evaluated. Activation of kraft and soda lignins, isolated respectively from softwood and non-woods, by periodate oxidation was performed to improve lignin reactivity and application in wood adhesives. Periodate oxidation of lignin leads to higher lignin acidity, formation of quinonoid groups under more severe conditions, higher molar mass and higher reactivity towards the curing of furfuryl alcohol within a temperature range currently used in industry. Comparison of a 100% furan-based glue with a furan-based glue substituted by 10% lignin yields comparable product properties. However, periodate-activated lignin leads to lower wood failure, which might be caused by incompletely solubilised lignin particles in the acidic formulation disturbing crosslinking of the furan resin. Unmodified softwood kraft lignin performs well in a PF resin formulation at substitution levels up to 30% (w/w). Periodate oxidation of soda lignins enhances the glue performance because higher wood failure is attained. The higher molar mass after periodate treatment could be an important parameter for development of a stronger wood binder.

Download Full-text

The Transition of the World‘s Largest Economies to Carbon Neutrality: Areas of Potential Cooperation with Russia

International Organisations Research Journal ◽

10.17323/1996-7845-2021-04-05 ◽

2021 ◽

Vol 16 (4) ◽

pp. 98-124

Author(s):

Tatiana Lanshina ◽

◽

Dmitry Stoyanov ◽

Arina Loginova ◽

◽

...

Keyword(s):

Large Scale ◽

Fossil Fuels ◽

Energy Transition ◽

The European Union ◽

Carbon Neutrality ◽

Russian Economy ◽

Current State ◽

International Economic Cooperation ◽

Strategic Goals ◽

Global Transition

In 2020, despite the global economic crisis caused by the COVID-19 pandemic, it became clear that decarbonization and energy transition had become strategic goals rather than market trends. Moreover, they have become part of the broader and more ambitious plans of the world’s largest economies to move toward carbon neutrality by the middle of the 21st century. These economies include the European Union, the U.S., China, Japan and Korea. In Russia, these trends are typically viewed through the prism of risk: carbon neutrality implies a dramatic decrease in demand for fossil fuels, the production and export of which still play a key role in the Russian economy. However, apart from the risk to traditional sources of income, the global transition to carbon neutrality creates new opportunities for the development and diversification of the Russian economy, as well as for international cooperation in new areas. This article is devoted to the general identification of such opportunities. The authors perform a content analysis of the official plans of the largest economies related to achieving carbon neutrality by 2050–60. The main areas in which actions will be taken are identified. The current state of the corresponding industries in Russia and the possibilities for improvement are investigated. On the basis of this analysis, promising directions for the development of the Russian economy are proposed in which the implementation of large-scale international economic cooperation is possible in the coming decades.

Download Full-text

Wood Surface Modification—Classic and Modern Approaches in Wood Chemical Treatment by Esterification Reactions

Coatings ◽

10.3390/coatings10070629 ◽

2020 ◽

Vol 10 (7) ◽

pp. 629 ◽

Cited By ~ 1

Author(s):

Carmen-Alice Teacă ◽

Fulga Tanasă

Keyword(s):

Surface Modification ◽

Carboxylic Acids ◽

Wood Surface ◽

Dicarboxylic Acids ◽

Hydroxyl Groups ◽

Acyl Chlorides ◽

Complex Processes ◽

Mechanical Durability ◽

Long Time ◽

Esterification Reactions

Wood surface modification is a comprehensive concept which, in time, turned out to be as successful as challenging when it comes to improve the resistance of wood during its life cycle in both indoor and outdoor applications. The initial approaches have aimed at simple methods with immediate results. Nowadays, the paradigm has slightly changed due to the scientific and technical advances, and some methods has become intermediate stages in more complex processes, after being used, for long time, as stand-alone procedures. The esterification was employed as a convenient method for wood surface modification due to the high amount of free hydroxyl groups available at the surface of wood and other lignocellulosic materials. Therefore, different esterification approaches were tested: activated condensation with carboxylic acids (monocarboxylic, as well as dicarboxylic acids, fatty acids, etc.) in the presence of condensation activating agents (such as trifluoroacetic anhydride); reaction with β-halogen-substituted carboxylic acids; esterification using carboxylic acids derivatives (acyl chlorides, anhydrides) or even multifunctional carboxylic acids (i.e., tricine). Thus, wood with improved dimensional stability and weathering resilience, higher fire resistance, enhanced hydrophobic character, and mechanical durability was obtained. This paper offers an overview of some of the most recent advances reported in the field, presented in a systematic manner, using the type of reaction as classification criterion. The main improvements will be outlined in a critical assessment in order to provide an useful tool for a wise choice in future applications.

Download Full-text

Characterisation of extracellular polymeric substances from different cyanobacterial species and their influence on biocalcification processes

Environmental Chemistry ◽

10.1071/en17068 ◽

2017 ◽

Vol 14 (4) ◽

pp. 254 ◽

Cited By ~ 2

Author(s):

Xiaomin Li ◽

Kemeng Luo ◽

Jinqian Ren ◽

Xiangrui Wang ◽

Qian Mu ◽

...

Keyword(s):

Calcium Carbonate ◽

Protein Content ◽

Functional Groups ◽

Extracellular Polymeric Substances ◽

Nucleation Site ◽

Hydroxyl Groups ◽

Solution Ph ◽

Cyanobacterial Species ◽

Sediment Formation ◽

Global Carbon

Environmental contextExtracellular polymeric substances provide a nucleation site for calcium carbonate and hence are important for bio-calcification processes, with implications for sediment formation and the global carbon cycle. We investigate the calcification potential of polymeric substances produced by five species of cyanobacteria. The results indicate that the protein content and alkaline functional groups of the extracellular polymeric substances may have a significant effect on cyanobacterial calcification. AbstractCyanobacterial calcification plays a crucial role in the formation of freshwater calcium carbonate precipitates, with cyanobacterial extracellular polymeric substances (EPSs) contributing significantly, partly by providing a nucleation site for calcium carbonate. Despite this, cyanobacterial EPS and their effect on calcification processes have not been completely characterised. In the present study, five cyanobacterial species were selected. First, EPS characteristics of these cyanobacterial species were examined, showing that proteins dominated both EPSs released in to solution (REPSs) and cell-surface bound (LEPSs). The major EPS functional groups included acidic groups, such as carboxyl groups, and highly alkaline groups, such as hydroxyl and amino groups. The calcification ability of different cyanobacterial species was found to vary dramatically. Solution pH increased during the calcification process, which was beneficial to the supersaturation of CaCO3, and could affect the calcification potential. Precipitation, however, was positively correlated with EPS protein content and the concentration of basic functional groups, such as amino or hydroxyl groups. These results suggest EPS protein content and alkaline functional groups may have a significant effect on cyanobacterial calcification. The results also provide a potential application in that EPS proteins of cyanobacteria may have beneficial positive applications in the removal of multivalent cations from wastewater.

Download Full-text

Nonformaldehyde Polymerization-Crosslinking Treatment of Cotton Fabrics for Improved Strength Retention

Textile Research Journal ◽

10.1177/004051759206201010 ◽

1992 ◽

Vol 62 (10) ◽

pp. 614-618 ◽

Cited By ~ 38

Author(s):

Hyung-Min Choi

Keyword(s):

Dicarboxylic Acids ◽

Cotton Fabrics ◽

Hydroxyl Groups ◽

Chemical Analyses ◽

Free Radical Initiator ◽

Carboxylic Groups ◽

Ft Ir ◽

Esterification Reactions ◽

Strength Retention ◽

Crosslinking Agents

A new concept in polycarboxylic crosslinking agents for cellulose is introduced using olefinically unsaturated dicarboxylic acids, maleic acid (MA), and itaconic acid (IA). In contrast to previous studies involving acids containing at least three carboxylic groups per molecule, we found that the dicarboxylic monomers can be effective cross-linking agents for cellulose when they are applied in the presence of a free radical initiator and an esterification catalyst. The results demonstrate that the system of a 1:1 mole ratio of MA and IA substantially increases a smooth drying appearance while maintaining much improved strength retention of the treated fabric and without involving any formaldehyde. Striking effects appear in the increased Stoll flex abrasion resistance of the treated fabric. The evidence of cellulose crosslinks through esterification reactions of carboxyl groups in MA and IA and cellulose hydroxyl groups is confirmed by chemical analyses and FT-IR spectra.

Download Full-text

Weak arene/nickel interaction lights on monoarylation of alcohols

10.21203/rs.3.rs-771338/v1 ◽

2021 ◽

Author(s):

Zhiyan Huang ◽

Kun Xie ◽

Ge Meng ◽

Jun He ◽

Mingsong Shi ◽

...

Keyword(s):

Bioactive Molecules ◽

Hydroxyl Groups ◽

Nickel Catalysis ◽

Metal Catalysis ◽

Pharmaceutical Ingredients ◽

Aryl Bromides ◽

Earth Abundant ◽

Arene Ligand ◽

Catalytic Reactivity ◽

Aryl Ethers

Abstract Despite a growing body of work in nickel catalysis, the potential of organo-photocatalyst serving both as an arene ligand and a sensitizer remains underexplored. Here, we describe such an organo-photocatalyst to promote arylation of alcohols. Mechanistic studies suggest that the formation of sandwich complex via weak arene/nickel interaction and the resulting dexter energy transfer be responsible for this activity. This interaction provides a mechanistically alternative strategy for challenging carbon-oxygen bond assembly, where the elementary steps in transition metal catalysis previously facilitated by intermolecular photoevents replaced by more efficient intramolecular ones. With only 0.05 mol% photocatalyst loading and 8 mol% nickel bromide, a series of alcohols, diols and triols were (mono)arylated with (hetero)aryl bromides and chlorides. Importantly, many bioactive molecules and active pharmaceutical ingredients containing multiple hydroxyl groups could be efficiently monoarylated, too. This work provides a new approach to access bioactive aryl ethers, but also lights on a highly desirable direction to manipulate the catalytic reactivity of earth abundant nickel.

Download Full-text

The Missing Limb: Including Impacts of Biomass Extraction on Forest Carbon Stocks in GHG Balances of Wood Use

10.20944/preprints202112.0499.v1 ◽

2021 ◽

Author(s):

Horst Fehrenbach ◽

Mascha Bischoff ◽

Hannes Böttcher ◽

Judith Reise ◽

Klaus Josef Hennenberg

Keyword(s):

Carbon Storage ◽

Energy Use ◽

Carbon Sink ◽

Ghg Emissions ◽

Forest Carbon ◽

Wood Products ◽

Ghg Mitigation ◽

Carbon Neutrality ◽

Energy Wood ◽

Global Carbon

The global carbon neutrality challenge places a spotlight on forests as carbon sinks. However, greenhouse gas (GHG) balances of wood for material and energy use often reveal GHG emission savings in comparison with a non-wood reference. Is it thus better to increase wood production and use, or to conserve and expand the carbon stock in forests? GHG balances of wood products mostly ignore the dynamics of carbon storage in forests, which can be expressed as the carbon storage balance in forests (CSBF). For Germany, a CSBF of 0.25 to 1.15 t CO2/m³ wood can be assumed. When the CSBF is integrated into the GHG balance, GHG mitigation substantially deteriorates and wood products may even turn into a GHG source, e.g. in the case of energy wood. Here, building up the forest carbon sink would be the better option. We conclude that it is vital to include the CSBF in GHG balances of wood products if the wood is extracted from forests. Only then can GHG balances provide political decision-makers and stakeholders in the wood sector with a complete picture of GHG emissions.

Download Full-text

Net carbon sink of China was overestimated by more than 35%

10.21203/rs.3.rs-1063386/v1 ◽

2021 ◽

Author(s):

Chaochao Du ◽

Xiaoyong Bai ◽

yangbing Li ◽

Qiu Tan ◽

Cuiwei Zhao Zhao ◽

...

Keyword(s):

Forest Fires ◽

Atmospheric Carbon Dioxide ◽

Carbon Sink ◽

Terrestrial Ecosystems ◽

Carbon Neutrality ◽

Relative Contribution ◽

Reactive Carbon ◽

Source Sink ◽

Global Carbon ◽

Net Carbon Sink

Abstract As a carbon source/sink of atmospheric carbon dioxide, the net regional carbon budget (NRCB) of terrestrial ecosystems is very important to effect global warming, especially China with the largest emissions at present. However, the carbon consumption is difficult to measure accurately, which is caused by the emissions of CH4 and CO, the utilization of agriculture, forestry and grass, and the emissions from rivers and other physical processes, such as forest fires. Therefore, the spatial patterns and driving factors of NRCB are not clear. Here, we used multi-source data to estimate the NRCB of 31 provincial administrative divisions of China and to develop NRCB datasets from 2000 to 2018. We found that the average of NRCB was 669 TgC yr−1, and it significantly decreased at a rate of 2.56 TgC yr−1. The relative contribution rates of fluxes of emissions from anthropogenic (FEAD), reactive carbon and creature ingestion (FERCCI), autotrophic respiration (Ra), heterotrophic respiration (Rh) and natural disturbances (FEND) were 35.17%, 26.09%, 19.68%, 17.38% and 1.68% respectively. In addition, NRCB datasets of the different administrative regions of China were mapped. These datasets will provide support for China's carbon neutrality and the study of the global carbon cycle.

Download Full-text

A Review on Citric Acid as Green Modifying Agent and Binder for Wood

Polymers ◽

10.3390/polym12081692 ◽

2020 ◽

Vol 12 (8) ◽

pp. 1692 ◽

Cited By ~ 2

Author(s):

Seng Hua Lee ◽

Paridah Md Tahir ◽

Wei Chen Lum ◽

Li Peng Tan ◽

Paiman Bawon ◽

...

Keyword(s):

Citric Acid ◽

Fruits And Vegetables ◽

Citrus Fruit ◽

Treated Wood ◽

Hydroxyl Groups ◽

Modifying Agent ◽

Wood Modification ◽

Wood Bonding ◽

Bonded Composite ◽

Esterification Reactions

Citric acid (CA) can be found naturally in fruits and vegetables, particularly citrus fruit. CA is widely used in many fields but its usage as a green modifying agent and binder for wood is barely addressed. Esterification is one of the most common chemical reactions applied in wood modification. CA contains three carboxyl groups, making it possible to attain at least two esterification reactions that are required for crosslinking when reacting with the hydroxyl groups of the cell wall polymers. In addition, the reaction could form ester linkages to bring adhesivity and good bonding characteristics, and therefore CA could be used as wood binder too. This paper presents a review concerning the usage of CA as a wood modifying agent and binder. For wood modification, the reaction mechanism between wood and CA and the pros and cons of using CA are discussed. CA and its combination with various reactants and their respective optimum parameters are also compiled in this paper. As for the major wood bonding component, the bonding mechanism and types of wood composites bonded with CA are presented. The best working conditions for the CA in the fabrication of wood-based panels are discussed. In addition, the environmental impacts and future outlook of CA-treated wood and bonded composite are also considered.

Download Full-text

Chemical improvement of surfaces. Part 5: surfactants as structural lead for wood hydrophobization – covalent modification with p-alkylated benzoates

Holzforschung ◽

10.1515/hf-2019-0196 ◽

2020 ◽

Vol 74 (7) ◽

pp. 703-713 ◽

Cited By ~ 2

Author(s):

Christian Kaldun ◽

Martin Söftje ◽

Jan C. Namyslo ◽

Dieter E. Kaufmann

Keyword(s):

Reaction Times ◽

Weight Percent ◽

Contact Angles ◽

Covalent Modification ◽

Total Reflection ◽

Attenuated Total Reflection ◽

Covalent Attachment ◽

Hydroxyl Groups ◽

Covalently Bonded ◽

Esterification Reactions

AbstractFor a durable improvement of the hydrophobization properties of wood Scots pine (Pinus sylvestris L.) sapwood veneer chips were covalently modified with surfactant-like p-alkylated benzoates and a corresponding 4-cyanophenyl derivative. These esterification reactions of wood hydroxyl groups at varied temperatures and different reaction times afforded weight percent gains (WPG) ranging from 8 to 44% and quantities of covalently bonded organomaterials (QCO) of 0.3–2.6 mmol per gram, respectively. The successful covalent attachment of the functional precursors was proven by attenuated total reflection-infrared spectroscopy (ATR-IR), while the improvement of hydrophobicity was demonstrated by resulting contact angles (CAs) in a range from 113 to 150°.

Download Full-text