scholarly journals Chemical Changes of Wood Treated with Caffeine

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 497
Author(s):  
Patrycja Kwaśniewska-Sip ◽  
Magdalena Woźniak ◽  
Wojciech Jankowski ◽  
Izabela Ratajczak ◽  
Grzegorz Cofta
Keyword(s):  
Nitrogen Concentration ◽  
Treated Wood ◽  
Wood Structure ◽  
Aromatic Rings ◽  
Decay Fungi ◽  
Lignin Model Compound ◽  
Wood Impregnation ◽  
Lignin Model ◽  
The Stability ◽  
Methylene Group

Earlier studies have revealed that wood treated with caffeine was effectively protected against decay fungi and molds. However, there is a need to establish how the caffeine molecule behaves after wood impregnation and how it can protect wood. The objective of the research was to characterize the interaction between caffeine and Scots pine (Pinus sylvestris L.) wood as well as to assess the stability of the alkaloid molecule in lignocellulosic material. For this purpose, an elementary analyzer was used to assess the nitrogen concentration in the treated wood. The results showed that caffeine is easily removed from the wood structure through large amounts of water. The changes occurring in the wood structure after impregnation were evaluated with regard to the results obtained by Fourier transform infrared (FTIR) spectroscopy of two model mixtures with caffeine and cellulose or lignin for the purpose of conducting a comparison with the spectrum of impregnated and non-impregnated samples. The observed changes in FTIR spectra involve the intensity of the C=O(6) caffeine carbonyl group and signals from guaiacyl units. It might indicate favorable interactions between caffeine and lignin. Additionally, molecular simulation of the caffeine’s interaction with the guaiacyl β-O-4 lignin model compound characteristic for the lignin structure using computational studies was performed. Consequently, all analyses confirmed that caffeine may interact with the methylene group derived from the aromatic rings of the guaiacyl group of lignin. In summary, scanning electron microscope (SEM) observations suggest that caffeine was accumulated in the lignin-rich areas of the primary walls.

scholarly journals Revisiting the mechanism of β-O-4 bond cleavage during acidolysis of lignin VII: acidolyses of non-phenolic C6-C2-type model compounds using HBr, HCl and H2SO4, and a proposal on the characteristic action of Br− and Cl−

2020 ◽  
Vol 66 (1) ◽  
Author(s):  
Qiaoqiao Ye ◽  
Tomoya Yokoyama
Keyword(s):  
Model Compound ◽  
Bond Cleavage ◽  
Type Model ◽  
Enol Ether ◽  
Lignin Model Compound ◽  
Benzyl Cation ◽  
Acid Type ◽  
Unstable Compound ◽  
Lignin Model ◽  
Acidolysis Reaction

AbstractA non-phenolic C6-C2-type lignin model compound with the β-O-4 bond, 2-(2-methoxyphenoxy)-1-(3,4-dimethoxyphenyl)ethanol (I), was acidolyzed in aqueous 82% 1,4-dioxane containing HBr, HCl, or H2SO4 with a concentration of 0.2 mol/L at 85 ℃ to examine the differences between these acidolyses. Compound I primarily converted to an enol ether compound, 1-(2-methoxyphenoxy)-2-(3,4-dimethoxyphenyl)ethene (II), via the benzyl cation followed by acidolytic β-O-4 bond cleavage regardless of the acid-type, although the disappearance rates of compound I were remarkably different (HBr > HCl >> H2SO4). Acidolyses of compound II using these acids under the same conditions showed a similar tendency, but the rate differences were much smaller than in the acidolyses of compound I. Acidolyses of the α-methyl-etherified derivative of compound I (I-α-OMe) using these acids under the same conditions suggested that the formation rates of the benzyl cation from compound I-α-OMe (also from compound I) are not largely different between the acidolyses using these acids, but those of compound II from the benzyl cation are remarkably different. Acidolysis of the α-bromo-substituting derivative of compound I (I-α-Br) using HBr under the same conditions showed a characteristic action of Br¯ in the acidolysis. Br¯ adds to the benzyl cation generated from compound I or I-α-OMe to afford unstable compound I-α-Br, resulting in acceleration of the formation of compound II and of the whole acidolysis reaction.

Growth behavior of wood-destroying fungi in chemically modified wood: wood degradation and translocation of nitrogen compounds

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lukas Emmerich ◽  
Maja Bleckmann ◽  
Sarah Strohbusch ◽  
Christian Brischke ◽  
Susanne Bollmus ◽  
...  
Keyword(s):  
Protective Action ◽  
Treated Wood ◽  
Untreated Wood ◽  
Brown Rot ◽  
Decay Resistance ◽  
White Rot ◽  
Decay Fungi ◽  
Chemically Modified ◽  
Decay Tests ◽  
Modified Wood

Abstract Chemical wood modification has been used to modify wood and improve its decay resistance. However, the mode of protective action is still not fully understood. Occasionally, outdoor products made from chemically modified timber (CMT) show internal decay while their outer shell remains intact. Hence, it was hypothesized that wood decay fungi may grow through CMT without losing their capability to degrade non-modified wood. This study aimed at developing a laboratory test set-up to investigate (1) whether decay fungi grow through CMT and (2) retain their ability to degrade non-modified wood. Acetylated and 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) treated wood were used in decay tests with modified ‘mantle specimens’ and untreated ‘core dowels’. It became evident that white rot (Trametes versicolor), brown rot (Coniophora puteana) and soft rot fungi can grow through CMT without losing their ability to degrade untreated wood. Consequently, full volume impregnation of wood with the modifying agent is required to achieve complete protection of wooden products. In decay tests with DMDHEU treated specimens, significant amounts of apparently non-fixated DMDHEU were translocated from modified mantle specimens to untreated wood cores. A diffusion-driven transport of nitrogen and DMDHEU seemed to be responsible for mass translocation during decay testing.

scholarly journals Model compounds-based study on adsorption and dispersion properties of lignin-based superplasticizer

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098062
Author(s):  
Shuangping Ma ◽  
Qingjun Ding ◽  
Fen Zhou ◽  
Huaxiong Zhu
Keyword(s):  
Molecular Structure ◽  
Zeta Potential ◽  
Model Compound ◽  
Research Work ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Lignin Model Compound ◽  
Structure Activity ◽  
Lignin Model ◽  
Relationship Of

The chemical modifications of lignin-based superplasticizers have attracted extensive attentions during recent years. The comprehending of the structure-activity relationship of lignin-based superplasticizer is important to promote the modification and application research of lignin resources. However, lignin features complex and variable molecular structure, which is not conducive to study on structure-activity relationship of lignin-based superplasticizer as well as development and application of new lignin-based superplasticizer. However, the related research work can be simplified by selecting small molecular compound with appropriate molecular structure as the lignin model compound. This article intends to study the structure-activity relationship of lignin-based superplasticizer by using dihydroeugenol as the lignin model compound. Through the substitution of lignin by dihydroeugenol during the synthesis process, a model compound lignin-based superplasticizer (DAFS) was synthesized. The adsorption and dispersion properties of this superplasticizer and reference sample (LAFS) were investigated by fluidity test, Zeta-potential measurement, Total organic carbon analysis and others. The results suggest that the adsorption behavior of both DAFS and LAFS conformed to the Langmuir isotherms and Pseudo-second order kinetic. In cement paste, added with 1 g/L of LAFS and DAFS, Zeta potential were reduced from +3.5 to −15.2 mV and −18.7 mV, respectively. The substitution of lignin by dihydroeugenol has no significantly influence on the dispersive property, but differences on rheological properties which need to be optimized in the future. All the tests confirmed that dihydroeugenol is suitable to replace lignin on exploring the structure-activity relationship of lignin-based superplasticizer. This research work provides new insight on model study of lignin-based superplasticizer.

scholarly journals Effect of side-chain length in lignin model compound on MnO2 oxidation: comparison of oxidations between C6-C2- and C6-C1-type compounds

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Shirong Sun ◽  
Tomoya Yokoyama
Keyword(s):  
Isotope Effects ◽  
Aromatic Nucleus ◽  
Side Chain ◽  
Direct Oxidation ◽  
Initial Oxidation ◽  
Methyl Group ◽  
Lignin Model Compound ◽  
Oxidation Rates ◽  
Kinetic Isotope ◽  
Lignin Model

AbstractMonomeric C6-C2-type lignin model compounds with a p-hydroxyphenyl (H), guaiacyl (G), syringyl (S), or p-ethylphenyl (E) nucleus (1-phenylethanol derivatives) were individually oxidized by MnO2 at a pH of 1.5 and room temperature. The results were compared with those of the corresponding C6-C1-type benzyl alcohol derivatives obtained in our recent report to examine the effect of the presence of the β-methyl group on the oxidation. The presence decelerated the oxidation regardless of the type of aromatic nucleus, although it did not change the order of the oxidation rates: G > S >> H > E. This deceleration results from the steric factor of the β-methyl group in the C6-C2-type compounds. The MnO2 oxidations of the corresponding C6-C2-type compounds deuterated at their α-(benzyl)positions showed that the magnitudes of the kinetic isotope effects are smaller than those observed in the oxidations of the corresponding C6-C1-type compounds, regardless of the type of aromatic nucleus. These smaller magnitudes suggest that the presence of the β-methyl group shifts the initial oxidation mode of MnO2 from direct oxidation of the benzyl position to one-electron oxidation of the aromatic nucleus. Only the S-type compounds afforded products via degradation of the aromatic nuclei.

Synthesis and application of Co(salen) complexes containing proximal imidazolium ionic liquid cores

2012 ◽  
Vol 90 (1) ◽  
pp. 60-70 ◽  
Author(s):  
Swapnil Sonar ◽  
Kenson Ambrose ◽  
Arthur D. Hendsbee ◽  
Jason D. Masuda ◽  
Robert D. Singer
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Model Compound ◽  
Veratryl Alcohol ◽  
Oxidation Catalysts ◽  
Imidazolium Ionic Liquid ◽  
Lignin Model Compound ◽  
Salen Complexes ◽  
Lignin Model ◽  
Salen Ligand

Ionic ligands derived from a salen ligand containing two proximal 1,3-disubstituted imidazolium ionic liquid cores form cobalt(III) complexes capable of selectively oxidizing veratryl alcohol, a lignin model compound, to veratraldehyde using air as the source of oxygen. These complexes are easy to prepare, inexpensive, water stable, and soluble in ionic liquids, making them viable candidates for use as oxidation catalysts.

scholarly journals Exhaustive laccase-catalysed oxidation of a lignin model compound (vanillyl glycol) produces methanol and polymeric quinoid products

1985 ◽  
Vol 229 (1) ◽  
pp. 277-279 ◽  
Author(s):  
K Lundquist ◽  
P Kristersson
Keyword(s):  
Model Compound ◽  
Polymerization Process ◽  
Lignin Biodegradation ◽  
Simultaneous Formation ◽  
Initial Formation ◽  
Lignin Model Compound ◽  
Catalysed Oxidation ◽  
Visible Spectra ◽  
Lignin Model

Laccase-catalysed oxidation of the lignin-related phenol vanillyl glycol results in the initial formation of dimers and subsequent polymerization. The polymerization is accompanied by a liberation of methanol corresponding to 15-20% demethylation. Visible spectra together with reduction experiments suggest the simultaneous formation of o-quinones. The participation of quinone formation in the polymerization process and the possible role of such intermediates in lignin biodegradation is discussed.

In Situ Study of Barrier Layers Using Spectroscopic Ellipsometry and Mass Spectroscopy of Recoiled Ions

2000 ◽  
Vol 619 ◽  
Author(s):  
Y. Gao ◽  
A.H. Mueller ◽  
E.A. Irene ◽  
O. Auciello ◽  
A.R. Krauss ◽  
...  
Keyword(s):  
Real Time ◽  
Mass Spectroscopy ◽  
Spectroscopic Ellipsometry ◽  
Nitrogen Concentration ◽  
Random Access ◽  
Copper Interconnects ◽  
Access Memory ◽  
Barrier Layers ◽  
The Stability

ABSTRACTAn in situ study of barrier layers using spectroscopic ellipsometry (SE) and Time-of-Flight (ToF) mass spectroscopy of recoiled ions (MSRI) is presented. First the formation of copper silicides has been observed by real-time SE and in situ MSRI in annealed Cu/Si samples. Second TaSiN films as barrier layers for copper interconnects were investigated. Failure of the TaSiN layers in Cu/TaSiN/Si samples was detected by real-time SE during annealing and confirmed by in situ MSRI. The effect of nitrogen concentration on TaSiN film performance as a barrier was also examined. The stability of both TiN and TaSiN films as barriers for electrodes for dynamic random access memory (DRAM) devices has been studied. It is shown that a combination of in situ SE and MSRI can be used to monitor the evolution of barrier layers and detect the failure of barriers in real-time.

Sign in / Sign up

Export Citation Format

Share Document