AMMONOLYSIS OF URONIC ESTER GROUPS IN BIRCH XYLAN

1964 ◽  
Vol 42 (11) ◽  
pp. 2434-2439 ◽  
Author(s):  
Paul Y. Wang ◽  
H. I. Bolker ◽  
C. B. Purves
Keyword(s):  
Alkaline Hydrolysis ◽  
Uronic Acid ◽  
Liquid Ammonia ◽  
Treated Wood ◽  
Hot Water ◽  
Amide Nitrogen ◽  
White Birch

Solvent-extracted white birch, kept near 20° in liquid ammonia under pressure for 72 h and then extracted with methanol to remove acetamide, retained 0.25% of amide nitrogen. Extraction of the very finely ground residual wood with hot water yielded 21% as a 4-O-methylglucuronoxylan containing 0.53% of amide nitrogen. Alkaline hydrolysis removed the amide absorption in the infrared and restored the normal xylan spectrum. These results, supported by various control experiments, showed that amide groups in the ammonia-treated wood were derived from lactone or ester groups in the original 4-O-methylglucuronoxylan. Some of the uronic acid groups in the native wood presumably existed as ester crosslinks.

Fourier Transform Infrared Spectroscopy (FTIR) Study of ACQ-D Treated Chinese Fir with Different Post-Treatments

2013 ◽  
Vol 312 ◽  
pp. 425-428
Author(s):  
Li Li Yu ◽  
Xiao Jun Ma ◽  
Li Zhi Zhu
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Treated Wood ◽  
Fourier Transform Infrared ◽  
Chinese Fir ◽  
Hot Water ◽  
Cunninghamia Lanceolata ◽  
Ether Linkage ◽  
Treatment Conditions

Iinteractions of copper and wood components in the ACQ-D treated Chinese fir (Cunninghamia lanceolata Hook.) after hot water and hot air post-treatments were studied by using Fourier transform infrared spectroscopy (FTIR). Compared to Chinese fir (Cunninghamia lanceolata Hook.) without any treatments, significant reduction was noted at 1735±5 cm-1 assigned to carboxylic groups in the hemicellulose in all the samples with different post-treatments. The intensity of bands at 1655±5cm-1, 1510±5 cm-1 and 1265±5cm-1 are assigned to ketone carbonyl stretching groups, aromatic skeletal vibration and acetyl ether linkage in lignin were also decreased after different post-treatments compared to untreated Chinese fir. These results imply the fixation reactions of copper in the treated wood have been promoted by the post-treatment conditions, and the major bonding sites of copper in the treated wood are located in the wood lignin and hemicellulose.

Formation and deposition of pseudo-lignin on liquid-hot-water-treated wood during cooling process

2016 ◽  
Vol 51 (1) ◽  
pp. 165-174 ◽  
Author(s):  
Jingshun Zhuang ◽  
Xiaojun Wang ◽  
Jiayun Xu ◽  
Zhaojiang Wang ◽  
Menghua Qin
Keyword(s):  
Treated Wood ◽  
Hot Water ◽  
Cooling Process ◽  
Liquid Hot Water

USE OF LIQUID AMMONIA IN THE FRACTIONATION OF WHEAT STRAW HOLOCELLULOSE

1950 ◽  
Vol 28b (12) ◽  
pp. 753-761 ◽  
Author(s):  
C. T. Bishop ◽  
G. A. Adams
Keyword(s):  
Wheat Straw ◽  
Potassium Hydroxide ◽  
Galacturonic Acid ◽  
Uronic Acid ◽  
Room Temperature ◽  
Liquid Ammonia ◽  
Cold Water ◽  
Acid Anhydride ◽  
Acid Complex ◽  
Molar Ratios

Wheat straw holocellulose, after soaking in liquid ammonia for 36 hr. at room temperature, was fractionated by successive extractions with cold water, 0.5% sodium carbonate, 0.5% potassium hydroxide, and 2.2% potassium hydroxide. Pretreatment with liquid ammonia increased the material soluble in cold water from 3% to 20.2%. Hemicellulose fractions were precipitated from the extracts by ethanol. A complete analytical balance was obtained by estimating ash, pentosan, uronic acid anhydride, acetyl, and methoxyl contents of the original holocellulose, of each of the fractions and of the residue. Analyses of the isolated fractions showed some systematic differences, with pentosan contents increasing and uronic acid anhydride decreasing progressively in the alkali soluble fractions. D-xylose, L-arabinose, D-glucose, D-galactose, and hexuronic acid in approximate molar ratios of 40:7:2:1:4 were found in the hemicellulose fractions. The presence of the sugars was confirmed by isolation of crystalline derivatives. A uronic acid complex, resistant to hydrolysis, was isolated and the components shown to be D-xylose and a monomethoxyl galacturonic acid.

Silica Extraction from Rice Husk by Warm Water Pretreatment

2015 ◽  
Vol 1087 ◽  
pp. 309-315
Author(s):  
Nur Syakilla Hassan ◽  
Khairiah Haji Badri ◽  
Li Shen Lim
Keyword(s):  
Rice Husk ◽  
Alkaline Hydrolysis ◽  
Silica Content ◽  
Hot Water ◽  
Warm Water ◽  
High Yield ◽  
Chemical Compositions ◽  
X Ray ◽  
Water Pretreatment ◽  
Pre Treatment

Rice husk (RH) has high content of silica. In this study, the extraction of silica from rice husk while maintaining the organics was carried out by warm water pre-treatment followed by alkaline hydrolysis.  RH powder was treated with water at 50oC and 100oC prior to treatment with 1 M of sodium hydroxide (NaOH) aqueous solution at 50oC.  The filtrate from the alkaline hydrolysis was then further reacted with 1 M of hydrochloric acid (HCl) for silica extraction. The samples obtained after each stage of the treatments were carefully characterized and their chemical compositions were determined. The morphology of the untreated and treated RH powder was analyzed by Scanning Electron Microscopy (SEM). Estimation on the silica content was made by Energy Dispersive X-ray (EDX). The functional group present in untreated and treated RH were determined by Fourier Transform Infrared Spectroscopy (FTIR). The percentage of silica extracted from ΔH2O/NaOH-RH filtrate was higher (18.9%) than from H2O/NaOH-RH filtrate (12.6%). FTIR spectroscopy data indicated the disappearance of siloxane group when RH was treated with hot water and warm water followed by alkaline hydrolysis. The selected extraction method has successfully recovered silica at high yield but at the same time maintaining the organic compounds in the rice husk.

scholarly journals Effect of Dry Heat and Hot Water Processings on Cellulose III Crystallite of Cotton and Lyocell Fibers Treated with Liquid Ammonia.

2002 ◽  
Vol 58 (8) ◽  
pp. 299-303 ◽  
Author(s):  
Sun-Ji Park ◽  
Muncheul Lee ◽  
Tomiji Wakida ◽  
Aya Hayashi ◽  
Susumu Okada ◽  
...  
Keyword(s):  
Liquid Ammonia ◽  
Hot Water ◽  
Dry Heat ◽  
Lyocell Fibers

Effect of Hot Water Processing on Dyeing and Mechanical Properties of Cottons Treated with Liquid Ammonia and Sodium Hydroxide

2000 ◽  
Vol 70 (9) ◽  
pp. 769-774 ◽  
Author(s):  
Tomiji Wakida ◽  
Yoshiho Kitamura ◽  
Muncheul Lee ◽  
Soyeung Bae ◽  
Meilan Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Sodium Hydroxide ◽  
Liquid Ammonia ◽  
Hot Water

STRUCTURE OF A HEMICELLULOSE FROM MAPLE WOOD PREVIOUSLY EXTRACTED BY LIQUID AMMONIA

1957 ◽  
Vol 35 (4) ◽  
pp. 388-396 ◽  
Author(s):  
L. G. Neubauer ◽  
C. B. Purves
Keyword(s):  
Liquid Ammonia ◽  
Chain Structure ◽  
Hot Water ◽  
Wood Meal ◽  
Branched Chain ◽  
Conventional Study ◽  
Pectic Material

The extraction of maple wood meal with anhydrous liquid ammonia under pressure near 20° altered the wood in such a way that an additional small amount of lignin could be extracted with ethanol, and 1.9% of crude hemicelluloses with hot water. An additional 0.25% of nitrogen was retained, apparently as insoluble amides, by the residual wood. After elimination of pectic material by acetylation, the three subtractions of the hemicellulose acetate had identical specific rotations of −61 ± 1° in chloroform; all three corresponded in composition to a combination of one methylglucuronic anhydride to six anhydroxylose units. A conventional study by the methylation method suggested that the hemicellulose was a branched-chain structure averaging four anhydroxylose units linked 1—4, with one also substituted in the second position, and another linked 1—3.

scholarly journals Interrelationship between lignin-rich dichloromethane extracts of hot water-treated wood fibers and high-density polyethylene (HDPE) in wood plastic composite (WPC) production

Holzforschung ◽  
2016 ◽  
Vol 70 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Manuel R. Pelaez-Samaniego ◽  
Vikram Yadama ◽  
Manuel Garcia-Perez ◽  
Eini Lowell ◽  
Rui Zhu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Density Polyethylene ◽  
Treated Wood ◽  
Soxhlet Extraction ◽  
High Density ◽  
Hot Water ◽  
Gas Chromatography Mass Spectrometry ◽  
Wood Fibers ◽  
Pyrolysis Gas ◽  
Plastic Composite

AbstractHot water extraction (HWE) partially removes hemicelluloses from wood while leaving the majority of the lignin and cellulose; however, the lignin partially migrates to the inner surfaces of the cell wall where it can be deposited as a layer that is sometimes visible as droplets. This lignin-rich material was isolated via Soxhlet extraction with dichloromethane to investigate its rheological behavior in blends with high-density polyethylene (HDPE), a common material in wood plastic composites (WPCs). Pyrolysis gas-chromatography/mass spectrometry (Py-GC/MS) and electrospray ion mass spectrometry (ESI/MS) confirmed that the isolated material is constituted mainly of low-molecular-weight lignin oligomers. The blends of HDPE/isolated lignin, in varying ratios, were tested by means of dynamic rheology. A “shoulder” was found in plots “shear storage moduli (G′) vs. frequency sweep” and a shift of the terminal zone to lower frequencies was observed. Apparently, this shoulder is caused by the elastic contribution of the interfacial tension between the blend components. The rheology of WPCs produced from HWE wood and HDPE shows a similar shoulder in G′ plots, suggesting that the HDPE/lignin blends are in part responsible for the shape of the G′ curves.

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