Effect of water on wood liquefaction and the properties of phenolated wood

Holzforschung ◽  
2005 ◽  
Vol 59 (6) ◽  
pp. 628-634 ◽  
Author(s):  
Seung-Hwan Lee ◽  
Siqun Wang
Keyword(s):  
Activation Energy ◽  
Reaction Temperature ◽  
Weight Ratio ◽  
Flexural Properties ◽  
Phenol Content ◽  
Reaction Conditions ◽  
Wood Residue ◽  
Wood Liquefaction ◽  
Temperature Time ◽  
Phenolated Wood

Abstract The effects of water on wood liquefaction were investigated under various reaction conditions: reaction temperature, time, and wood/phenol weight ratio. Although the addition of water decreased the reaction temperature and reduced the liquefaction rate and combined phenol content of the resulting phenolated wood, residue of <20% and a combined phenol content of >95% were obtained by controlling the reaction conditions. The addition of water suppressed an increase in the combined phenol content and molecular weight by a recondensation reaction observed in liquefaction in the absence of water under the same reaction conditions. Phenolated wood obtained in the presence of water showed comparable thermoflow properties and slightly higher activation energy for cure when compared with phenolated wood obtained in the absence of water. Moldings from both phenolated woods showed comparable flexural properties to those of moldings from commercial Novolak resin.

Preparation and Properties of MgAl2O4-CaAl12O19 High Temperature Composite

2012 ◽  
Vol 512-515 ◽  
pp. 617-620
Author(s):  
Yong Hong Wang ◽  
Yan Gai Liu ◽  
Tao Yang ◽  
Zhao Hui Huang ◽  
Ming Hao Fang
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Reaction Temperature ◽  
Bending Strength ◽  
Raw Materials ◽  
Weight Ratio ◽  
Raw Material ◽  
Reaction Conditions ◽  
Optimum Reaction ◽  
Industrial Alumina

The utilization of lightweight refractories plays an important role in reducing the energy consumption of industrial furnaces. In this paper, MgAl2O4-CaA112O19 high temperature composite was synthesized via solid state reaction using magnesite, dolomite and industrial alumina as raw materials. The influences of raw materials and reaction temperature on phase compositions and microstructure of the composite were investigated by XRD and SEM，respectively. The parameters to prepare MgAl2O4-CaA112O19 high temperature composite were optimized. The results show that the optimum reaction conditions for synthesizing MgAl2O4-CaA112O19 composite is the CA6/MA weight ratio of 2:3, and the reaction temperature of 1500°C for 4h. The CaA112O19 crystals showed laminated or plate-like structure, and the MgAl2O4 showed spherical morphology. The reaction temperature had little effect on the phase compositions of MA-CA6 composite in this experiment. The content of Al2O3 in the raw material affected the phase composition of MA-CA6 composite.With the increase of the CaA112O19 amount, the bending strength of the composite decreased.

scholarly journals Effects of reaction conditions on the degree of substitution in acetylated nanocellulose

2020 ◽  
Vol 9 (4) ◽  
Author(s):  
Thien Doan Van Hong ◽  
Nhu Tran Thao ◽  
Trang Do Thi Kieu ◽  
Chanh-Nghiem Nguyen ◽  
Toan Pham Van ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Reaction Temperature ◽  
1H Nmr Spectroscopy ◽  
Interaction Effects ◽  
Degree Of Substitution ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Acid Ratio ◽  
Temperature Time ◽  
Three Factor

In this study, cellulose nanocrystals (CNC) were chemically extracted from the waste newspapers and acetylated by reacting CNC with acetic anhydride, using sulfuric acid as a catalyst. Response Surface Methodology based on a three-factor factorial design was applied to analyze the interaction effects of reaction temperature, time, and the ratio of nanocellulose and acetic acid (wt/v) on the degree of substitution (DS) which was calculated and compared. Various experimental conditions as reaction temperature (50-70 °C), reaction time (90-150 min), and the ratio of nanocellulose and acetic acid (wt/v) (1:15-1:25) were under investigation. It was found that reaction temperature and its interaction effects have the most significant effects on DS. The acetylated CNC was characterized by FTIR and 1H-NMR spectroscopy. The highest DS (2.997) was obtained in 90 min and the CNC/acetic acid ratio of 1:15 at 70 °C.

scholarly journals Kinetic Study of the Leaching of Iraqi Akashat Phosphate Ore Using Lactic Acid

2018 ◽  
Vol 14 (1) ◽  
pp. 128-135
Author(s):  
Mohammed Y. Eisa ◽  
Basma A. Abdulmajeed ◽  
C. K. Hawee
Keyword(s):  
Activation Energy ◽  
Lactic Acid ◽  
Kinetic Study ◽  
Weight Ratio ◽  
Acid Leaching ◽  
Reaction Rate Constant ◽  
Selective Leaching ◽  
Reaction Conditions ◽  
Phosphate Ore ◽  
Shrinking Core

     In the present work, a kinetic study was performed to the extraction of phosphate from Iraqi Akashat phosphate ore using organic acid. Leaching was studied using lactic acid for the separation of calcareous materials (mainly calcite). Reaction conditions were 2% by weight acid concentration and 5ml/gm of acid volume to ore weight ratio. Reaction time was taken in the range 2 to 30 minutes (step 2 minutes) to determine the reaction rate constant k based on the change in calcite concentration. To determine value of activation energy when reaction temperature is varied from 25 to 65 , another investigation was accomplished. Through the kinetic data, it was found that selective leaching was controlled by surface chemical reaction. The study showed that the reaction kinetics was specifically described by the shrinking core model (SCM). Regression analyses gave values of activation energy (Ea) and Arrhenius constant (ko) as 40.108 KJ/mole and (2.256 103 sec-1) respectively.

scholarly journals Effects of reaction conditions on the degree of substitution in acetylated nanocellulose

2020 ◽  
Vol 9 (4) ◽  
Author(s):  
Thien Doan Van Hong ◽  
Nhu Tran Thao ◽  
Trang Do Thi Kieu ◽  
Chanh-Nghiem Nguyen ◽  
Toan Pham Van ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Reaction Temperature ◽  
1H Nmr Spectroscopy ◽  
Interaction Effects ◽  
Degree Of Substitution ◽  
Reaction Conditions ◽  
Experimental Conditions ◽  
Acid Ratio ◽  
Temperature Time ◽  
Three Factor

In this study, cellulose nanocrystals (CNC) were chemically extracted from the waste newspapers and acetylated by reacting CNC with acetic anhydride, using sulfuric acid as a catalyst. Response Surface Methodology based on a three-factor factorial design was applied to analyze the interaction effects of reaction temperature, time, and the ratio of nanocellulose and acetic acid (wt/v) on the degree of substitution (DS) which was calculated and compared. Various experimental conditions as reaction temperature (50-70 °C), reaction time (90-150 min), and the ratio of nanocellulose and acetic acid (wt/v) (1:15-1:25) were under investigation. It was found that reaction temperature and its interaction effects have the most significant effects on DS. The acetylated CNC was characterized by FTIR and 1H-NMR spectroscopy. The highest DS (2.997) was obtained in 90 min and the CNC/acetic acid ratio of 1:15 at 70 °C.

scholarly journals Synthesis of propylene carbonate from urea and 1,2-propylene glycol over metal carbonates

2011 ◽  
Vol 17 (3) ◽  
pp. 323-331 ◽  
Author(s):  
Jiancheng Zhou ◽  
Wu Dongfang ◽  
Birong Zhang ◽  
Yali Guo
Keyword(s):  
Reaction Time ◽  
Propylene Glycol ◽  
Propylene Carbonate ◽  
Reaction Temperature ◽  
Reaction Conditions ◽  
Lead Carbonate ◽  
Synthetic Process ◽  
Metal Carbonates ◽  
Optimal Reaction ◽  
Mixed Carbonate

A series of single-metal carbonates and Pb-Zn mixed-metal carbonates were prepared as catalysts for alcoholysis of urea with 1,2-propylene glycol (PG) for the synthesis of propylene carbonate (PC). The mixed carbonates all show much better catalytic activities than the single carbonates, arising from a strong synergistic effect between the two crystalline phases, hydrozincite and lead carbonate. The mixed carbonate with Pb/Zn=1:2 gives the highest yield of PC, followed by the mixed carbonate with Pb/Zn=1:3. Furthermore, Taguchi method was used to optimize the synthetic process for improving the yield of PC. It is shown that the reaction temperature is the most significant factor affecting the yield of PC, followed by the reaction time, and that the optimal reaction conditions are the reaction time at 5 hours, the reaction temperature at 180 oC and the catalyst amount at 1.8 wt%, resulting in the highest PC yield of 96.3%.

Kinetic Model of the 1,2-Propanediol Oxidation Reaction in the Presence of 3wt%Pd/α-Al2O3 Catalyst

2021 ◽  
Vol 903 ◽  
pp. 143-148
Author(s):  
Svetlana Cornaja ◽  
Svetlana Zhizhkuna ◽  
Jevgenija Vladiko
Keyword(s):  
Activation Energy ◽  
Lactic Acid ◽  
Kinetic Model ◽  
Catalytic Oxidation ◽  
Molecular Oxygen ◽  
Oxidation Reaction ◽  
Main Product ◽  
Oxidation Process ◽  
Water Solution ◽  
Reaction Conditions

Supported 3wt%Pd/α-Al₂O₃ catalyst was tested in selective oxidation of 1,2-propanediol by molecular oxygen. It was found that the catalyst is active in an alkaline water solution. Lactic acid was obtained as the main product of the reaction. Influence of different reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. Partial kinetic orders of the reaction with respect to 1,2-propanediol, c0(NaOH), p(O2), n(1,2-PDO)/n(Pd)) were determined and an experimental kinetic model of the catalytic oxidation reaction was obtained. Activation energy of the process was calculated and was found to be about 53 ± 5 kJ/mol.

Synthesis of a Ruthenium Complex Based on 2,6-Bis[1-(Pyridin-2-yl)-1H-Benzo[d]Imidazol-2-yl]Pyridine and Catalytic Oxidation of (1H-Benzo[d]-Imidazol-2-yl)Methanol to 1H-Benzo[d]Imidazole-2-Carbaldehyde with H2O2

2017 ◽  
Vol 41 (2) ◽  
pp. 88-92
Author(s):  
Shenggui Liu ◽  
Rongkai Pan ◽  
Wenyi Su ◽  
Guobi Li ◽  
Chunlin Ni
Keyword(s):  
Reaction Time ◽  
Catalytic Oxidation ◽  
Reaction Temperature ◽  
Ruthenium Complex ◽  
Reaction Conditions ◽  
Molar Ratios ◽  
Optimal Reaction

2,6-Bis[1-(pyridin-2-yl)-1H-benzo[d]-imidazol-2-yl]pyridine (bpbp), which has been synthesised by intramolecular thermocyclisation of N2,N6-bis[2-(pyridin-2-ylamino)phenyl]pyridine-2,6-dicarboxamide, reacts with sodium pyridine-2,6-dicarboxylate (pydic) and RuCl3 to give [Ru(bpbp)(pydic)] which can catalyse the oxidation of (1H-benzo[d]imidazol-2-yl)methanol to 1H-benzo[d]imidazole-2-carbaldehyde by H2O2. The optimal reaction conditions were: molar ratios of catalyst to substrate to H2O2 set at 1: 1000: 3000; reaction temperature 50 °C; reaction time 5 h. The yield of (1H-benzo[d]imidazol-2-yl) methanol was 70%.

scholarly journals Nickel-catalyzed annulations of ortho-haloarylimines

2021 ◽  
Author(s):  
Srinivas Kolluru ◽  
Manvendra Singh ◽  
Bryce Gaskins ◽  
Zarko Boskovic
Keyword(s):  
Activation Energy ◽  
Secondary Amine ◽  
Oxidative Addition ◽  
Reaction Conditions ◽  
Quantitative Manner

Abstract We report the discovery, development, and mechanism of a nickel-catalyzed annulation reaction between o-haloarylimines and electron-poor olefins. The reaction produces two adjacent anti stereocenters and a free secondary amine. Spirocycles are formed from cyclic imines. We characterized the key oxidative addition intermediate and identified a major path leading to competing homo-coupling products. The activation energy of oxidative addition, and the rate of oxidative addition complex isomerization were determined. Sensitivity of the reaction to reaction conditions was established in a quantitative manner and both the scope and limitations of the method are presented.

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