Solvent-free chemical modification of wood by acetic and butyric anhydride with iodine as catalyst

Holzforschung ◽  
2012 ◽  
Vol 66 (8) ◽  
pp. 967-971 ◽  
Author(s):  
Prasad Bhadravati Eranna ◽  
Krishna Kumar Pandey
Keyword(s):  
Chemical Modification ◽  
Reaction Times ◽  
Weight Percent Gain ◽  
Weight Percent ◽  
Solvent Free ◽  
Effect Of Temperature ◽  
Attenuated Total Reflectance ◽  
Free Process ◽  
Butyric Anhydride ◽  
Modified Wood

Abstract A solvent-free process has been developed concerning the chemical modification of rubberwood and the isolates from it (holocellulose and Klason lignin) by means of acetic anhydride (Ac2O) and butyric anhydride (But2O), with iodine as the catalyst. The effect of temperature and reaction time was in focus, and the conversion products were characterized by Fourier transform infrared (FTIR) spectroscopy. The acetylation of holocellulose and lignin with Ac2O was performed at 120°C, whereas the modification of wood with Ac2O and But2O was carried out in the temperature range of 90–120°C for different reaction times between 15 and 240 min. The extent of the chemical modification was measured by the weight percent gain, and the modified wood was characterized by FTIR-attenuated total reflectance (ATR) method. The presence of small amounts of iodine (0.02 or 0.035 M) elevated the conversion rate of modification. The dimensional stability of the modified woods was essentially improved.

Chemical reaction of maritime pine sapwood (Pinus pinaster Soland) with alkoxysilane molecules: A study of chemical pathways

Holzforschung ◽  
2004 ◽  
Vol 58 (5) ◽  
pp. 511-518 ◽  
Author(s):  
Gilles Sèbe ◽  
Philippe Tingaut ◽  
Rodrigue Safou-Tchiama ◽  
Michel Pétraud ◽  
Stéphane Grelier ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Chemical Modification ◽  
Chemical Reaction ◽  
Cell Walls ◽  
Pinus Pinaster ◽  
Weight Percent Gain ◽  
Weight Percent ◽  
Maritime Pine ◽  
Water Leaching

Abstract The chemical modification of maritime pine sapwood (Pinus pinaster) with alkoxysilanes was studied according to three different pathways: carbamoylation with 3-isocyanatopropyltriethoxysilane, etherification with 3-glycidoxypropyltrimethoxysilane and alcoholysis of n-propyltrimethoxysilane. Grafting was confirmed by weight percent gain calculations (WPG), infrared spectroscopy (FTIR) as well as 13C and 29Si NMR CP MAS analysis. Signals of the grafted groups in the different spectra were assigned and the reactivity of the trialkoxysilane moieties towards wood was discussed. Experiments with model wood blocks showed that the reactions investigated occurred within the wood cell walls. Grafted chemicals were found to be relatively stable with regard to water leaching but only slight dimensional stabilisation was noted after treatment.

scholarly journals Improving Hydrophobicity of Tropical Hardwood along Axial Positions

2021 ◽  
Vol 25 (8) ◽  
pp. 1339-1343
Author(s):  
O.A. Adegoke ◽  
F.G. Adebawo ◽  
O.O. Ajala ◽  
E.A. Adelusi ◽  
A.J. Oloketuyi
Keyword(s):  
Water Absorption ◽  
Dimensional Stability ◽  
Weight Percent Gain ◽  
Weight Percent ◽  
Axial Position ◽  
Water Repellent ◽  
Tropical Hardwood ◽  
Acetyl Group ◽  
Percentage Of Water Absorption ◽  
Modified Wood

Wood is hygroscopic and is considered dimensionally unstable materials when exposed to wet conditions. To increase the hydrophobicity of wood, this study focused on the modification of tropical hardwood (Triplochiton scleroxylon) along different positions of the stem using acetic anhydride The weight percent gain (WPG) was determined and acetylation reaction was confirmed with FTIR. The dimensional stability of the wood was characterized by water absorption (WA), volumetric swelling (VS), anti-swelling efficiency (ASE), and water repellent efficiency (WRE). Data obtained were subjected to analysis of variance at α0.05. It was observed that the weight gain (WG) by acetylation increases along the axial position (base to top) of T. scleroxylon wood. IR-spectra confirmed properly the substitution of the acetyl group. The treatment resulted in a marked improvement in the WA and VS, ASE, and WRE of acetylated T. scleroxylon wood were also found to improve considerably from base to top of the wood. It could be said that the WPG and hydrophobicity increased, but the percentage of water absorption and volumetric swelling diminished. Hence, the modified wood showed good hydrophobicity and improved dimensional stability.

The Resistance of Wood Chemically Modified with Isocyanates. Part 1. Brown Rot, White Rot and Acid Chlorite Delignification

Holzforschung ◽  
1999 ◽  
Vol 53 (3) ◽  
pp. 230-236 ◽  
Author(s):  
F. Cardias Williams ◽  
M.D. Hale
Keyword(s):  
Chemical Modification ◽  
Weight Percent Gain ◽  
Brown Rot ◽  
Weight Percent ◽  
Pinus Nigra ◽  
Fungal Species ◽  
White Rot ◽  
Sodium Chlorite ◽  
Pycnoporus Sanguineus ◽  
Wood Protection

Summary This study was to assess the bioprotectant performance of chemical modification with three different isocyanates (n-butyl, hexyl and 1,6-diisocyanatohexane, BuNCO, HeNCO and HDI respectively) in Corsican pine (Pinus nigra Schneid) sapwood. Wood-isocyanate bond formation was verified by the increase in sample weight, volume and by infra-red spectroscopy. Basidiomycete (Coniophora puteana, Gloeophyllum trabeum, Coriolus versicolor, Pycnoporus sanguineus) decay tests demonstrated protection by chemical modification. The relationships of fungal species, weight percent gain (WPG), and decay induced weight loss were examined. One of the brown rot fungi, C. puteana, showed higher threshold protection values than the other fungi tested and the diisocyanate showed better performance. Chemical characteristics of the sound and brown rotted wood (C. puteana) have been examined using sulphuric acid and sodium chlorite procedures to clarify the principles which govern isocyanate modifications and restrict fungal decay. These demonstrated that appreciable wood protection against C. puteana only occurred when the holocellulose fraction showed substantial changes due to chemical modification.

scholarly journals The Importance of Moisture for Brown Rot Degradation of Modified Wood: A Critical Discussion

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 522 ◽  
Author(s):  
Rebecka Ringman ◽  
Greeley Beck ◽  
Annica Pilgård
Keyword(s):  
Cell Wall ◽  
Capillary Condensation ◽  
Critical Factor ◽  
Weight Percent Gain ◽  
Brown Rot ◽  
Weight Percent ◽  
Critical Discussion ◽  
Wood Modification ◽  
Thermally Modified Wood ◽  
Modified Wood

The effect of wood modification on wood-water interactions in modified wood is poorly understood, even though water is a critical factor in fungal wood degradation. A previous review suggested that decay resistance in modified wood is caused by a reduced wood moisture content (MC) that inhibits the diffusion of oxidative fungal metabolites. It has been reported that a MC below 23%–25% will protect wood from decay, which correlates with the weight percent gain (WPG) level seen to inhibit decay in modified wood for several different kinds of wood modifications. In this review, the focus is on the role of water in brown rot decay of chemically and thermally modified wood. The study synthesizes recent advances in the inhibition of decay and the effects of wood modification on the MC and moisture relationships in modified wood. We discuss three potential mechanisms for diffusion inhibition in modified wood: (i) nanopore blocking; (ii) capillary condensation in nanopores; and (iii) plasticization of hemicelluloses. The nanopore blocking theory works well with cell wall bulking and crosslinking modifications, but it seems less applicable to thermal modification, which may increase nanoporosity. Preventing the formation of capillary water in nanopores also explains cell wall bulking modification well. However, the possibility of increased nanoporosity in thermally modified wood and increased wood-water surface tension for 1.3-dimethylol-4.5-dihydroxyethyleneurea (DMDHEU) modification complicate the interpretation of this theory for these modifications. Inhibition of hemicellulose plasticization fits well with diffusion prevention in acetylated, DMDHEU and thermally modified wood, but plasticity in furfurylated wood may be increased. We also point out that the different mechanisms are not mutually exclusive, and it may be the case that they all play some role to varying degrees for each modification. Furthermore, we highlight recent work which shows that brown rot fungi will eventually degrade modified wood materials, even at high treatment levels. The herein reviewed literature suggests that the modification itself may initially be degraded, followed by an increase in wood cell wall MC to a level where chemical transport is possible.

Wettability and swelling of acetylated and furfurylated wood analyzed by multicycle Wilhelmy plate method

Holzforschung ◽  
2016 ◽  
Vol 70 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Maziar Sedighi Moghaddam ◽  
Magnus E.P. Wålinder ◽  
Per M. Claesson ◽  
Agne Swerin
Keyword(s):  
Weight Percent Gain ◽  
Wood Properties ◽  
Weight Percent ◽  
Sorption Properties ◽  
Plate Method ◽  
Modification Process ◽  
Wilhelmy Plate ◽  
Property Changes ◽  
Wilhelmy Plate Method ◽  
Modified Wood

Abstract The wetting, dimensional stability and sorption properties of a range of modified wood samples obtained either by acetylation or furfurylation were compared with those of unmodified samples of the same wood species via a multicycle Wilhelmy plate method. Wettability measurements were performed with water and octane as the swelling and non-swelling liquids, respectively. It was found that acetylation reduces water uptake mainly by reducing the swelling. In comparison, furfurylation reduces both swelling and the void volume in the sample. To quantify the effect of the modification process of the wood properties, the parameters “liquid up-take reduction” and the “perimeter change reduction” were introduced, which were determined from multicycle Wilhelmy plate measurements. Compared with the acetylated wood, the furfurylated wood with a higher level of weight percent gain exhibited larger property changes on the surface and in terms of swelling and sorption properties.

scholarly journals Cocoa olein glycerolysis with lipase Candida antarctica in a solvent free system

2020 ◽  
Vol 71 (4) ◽  
pp. 383
Author(s):  
L. S. Zamorano ◽  
P. Calero Magaña ◽  
E. García Cisneros ◽  
A. V. Martínez ◽  
L. F. Martín
Keyword(s):  
Reaction Times ◽  
Candida Antarctica ◽  
Solvent Free ◽  
Raw Material ◽  
Molar Ratio ◽  
Free Acidity ◽  
Glycerol Content ◽  
Free System ◽  
Free Process ◽  
Solvent Free System

In this paper we present the valorization of cocoa olein obtained from the acid fat-splitting of soapstocks. The aim is to develop a solvent free process (enzymatically catalyzed) to maximize the production of a final product with high content of monoglycerides (MAG) and diglycerides (DAG). The effect of the enzyme dose, glycerol content, reaction times as well as the modification of the raw material and pressure were studied. The yield of the reaction increased up to 90-95% when using a vacuum of 2-3 mbar at 65 °C, enough to evaporate the water which is generated as a by-product, an enzyme dose of 1% and molar ratio oil:glycerol of 1:2. The highest yield in terms of MAG and DAG production was obtained by starting from a raw material which was rich in free acidity (FFA), rendering oil with 33.4 and 44.2% MAG and DAG, respectively. Short reaction times (6-8 h) were observed compared to previously reported results (24 h).

Chlorosulfonic Acid Supported Piperidine-4-carboxylic Acid (PPCA) Functionalized Fe3O4 Nanoparticles (Fe3O4-PPCA): The Efficient, Green and Reusable Nanocatalyst for the Synthesis of Pyrazolyl Coumarin Derivatives under Solvent-Free Conditions

2019 ◽  
Vol 22 (2) ◽  
pp. 123-128
Author(s):  
Setareh Habibzadeh ◽  
Hassan Ghasemnejad-Bosra ◽  
Mina Haghdadi ◽  
Soheila Heydari-Parastar
Keyword(s):  
Carboxylic Acid ◽  
Fe3o4 Nanoparticles ◽  
High Efficiency ◽  
Reaction Times ◽  
Chlorosulfonic Acid ◽  
Aromatic Aldehydes ◽  
Solvent Free ◽  
Magnetic Nanocatalyst ◽  
One Pot ◽  
Solvent Free Conditions

Background: In this study, we developed a convenient methodology for the synthesis of coumarin linked to pyrazolines and pyrano [2,3-h] coumarins linked to 3-(1,5-diphenyl-4,5- dihydro-1H-pyrazol-3-yl)-chromen-2-one derivatives using Chlorosulfonic acid supported Piperidine-4-carboxylic acid (PPCA) functionalized Fe3O4 nanoparticles (Fe3O4-PPCA) catalyst. Materials and Methods:: Fe3O4-PPCA was investigated as an efficient and magnetically recoverable Nanocatalyst for the one-pot synthesis of substituted coumarins from the reaction of coumarin with a variety of aromatic aldehydes in high to excellent yield at room temperature under solvent-free conditions. The magnetic nanocatalyst can be easily recovered by applying an external magnet device and reused for at least 10 reaction runs without considerable loss of reactivity. Results and Conclusion: The advantages of this protocol are the use of commercially available materials, simple and an inexpensive procedure, easy separation, and an eco-friendly procedure, and it shows good reaction times, good to high yields, inexpensive and practicability procedure, and high efficiency.

Preparation and Characterization of a Novel Room Temperature Dicationic Ionic Liquid and its Application in the Synthesis of Xanthenediones Under Solvent-Free Conditions

2018 ◽  
Vol 21 (8) ◽  
pp. 602-608 ◽  
Author(s):  
Zainab Ehsani-Nasab ◽  
Ali Ezabadi
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Reaction Times ◽  
Significant Loss ◽  
Solvent Free ◽  
Acidity Function ◽  
Efficient Catalyst ◽  
Solvent Free Conditions ◽  
Hammett Acidity Function ◽  
Dicationic Ionic Liquid

Aim and Objective: In the present work, 1, 1’-sulfinyldiethylammonium bis (hydrogen sulfate) as a novel room temperature dicationic ionic liquid was synthesized and used as a catalyst for xanthenediones synthesis. Material and Method: The dicationic ionic liquid has been synthesized using ethylamine and thionyl chloride as precursors. Then, by the reaction of [(EtNH2)2SO]Cl2 with H2SO4, [(EtNH2)2SO][HSO4]2 was prepared and after that, it was characterized by FT-IR, 1H NMR, 13C NMR as well as Hammett acidity function. This dicationic ionic liquid was used as a catalyst for the synthesis of xanthenediones via condensation of structurally diverse aldehydes and dimedone under solvent-free conditions. The progress of the reaction was monitored by thin layer chromatography (ethyl acetate/n-hexane = 3/7). Results: An efficient solvent-free method for the synthesis of xanthenediones has been developed in the presence of [(EtNH2)2SO][HSO4]2 as a powerful catalyst with high to excellent yields, and short reaction times. Additionally, recycling studies have demonstrated that the dicationic ionic liquid can be readily recovered and reused at least four times without significant loss of its catalytic activity. Conclusion: This new dicationic ionic liquid can act as a highly efficient catalyst for xanthenediones synthesis under solvent-free conditions.

scholarly journals Effect of Furfurylation on Hierarchical Porous Structure of Poplar Wood

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 32
Author(s):  
Xiaoshuang Shen ◽  
Pan Jiang ◽  
Dengkang Guo ◽  
Gaiyun Li ◽  
Fuxiang Chu ◽  
...  
Keyword(s):  
Porous Structure ◽  
Value Added ◽  
Untreated Wood ◽  
Weight Percent Gain ◽  
Wood Properties ◽  
Weight Percent ◽  
Acoustic Properties ◽  
Hierarchical Porous Structure ◽  
Wood Processing ◽  
Hierarchical Porous

Some wood properties (such as permeability and acoustic properties) are closely related to its hierarchical porous structure, which is responsible for its potential applications. In this study, the effect of wood impregnation with furfuryl alcohol on its hierarchical porous structure was investigated by microscopy, mercury intrusion porosimetry and nuclear magnetic resonance cryoporometry. Results indicated decreasing lumina diameters and increasing cell wall thickness of various cells after modification. These alterations became serious with enhancing weight percent gain (WPG). Some perforations and pits were also occluded. Compared with those of untreated wood, the porosity and pore volume of two furfurylated woods decreased at most of the pore diameters, which became more remarkable with raising WPG. The majority of pore sizes (diameters of 1000~100,000 nm and 10~80 nm) of macrospores and micro-mesopores of two furfurylated woods were the same as those of untreated wood. This work could offer thorough knowledge of the hierarchical porous structure of impregnatedly modified wood and pore-related properties, thereby providing guidance for subsequent wood processing and value-added applications.

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