Mesquite gum. I. The 4-O-methylglucuronogalactan core

1970 ◽  
Vol 48 (24) ◽  
pp. 3840-3849 ◽  
Author(s):  
G. O. Aspinall ◽  
C. C. Whitehead
Keyword(s):  
Partial Hydrolysis ◽  
Hydrolysis Of ◽  
Mesquite Gum

A re-examination of mesquite gum has shown that partial hydrolysis of the gum furnishes a mixture of acidic oligosaccharides including 6-O-(4-O-methyl-β-D-glucopyranosyluronic acid)-D-galactose (1), 4-O-(4-O-methyl-α-D-glucopyranosyluronic acid)-D-galactose (2), 6-O-(β-D-glucopyranosyluronic acid)-D-galactose (3), O-(4-O-ethyl-β-D-glucopyranosyluronic acid)-(1→6)-O-β-D-galactopyranosyl-(1→6)-D-galactose (4), and O-(4-O-methyl-α-D-glucopyranosyluronic acid)-(1→4)-O-β-D-galactopyranosyl-(1→3)-D-galactose (5). A series of degradations of the gum affords successively, arabinose-free degraded gum A, carboxy-reduced degraded gum A, and degraded gums B and C. Degraded gum C contains a high proportion of 1→3′ linked β-D-galactopyranose residues. The structure of the 4-O-methylglucuronogalactan core of the gum is re-assessed in the light of these and other results.

Organic material dissolved during oxygen-alkali pulping of hot water extracted birch sawdust

TAPPI Journal ◽  
2015 ◽  
Vol 14 (4) ◽  
pp. 237-244 ◽  
Author(s):  
JONI LEHTO ◽  
RAIMO ALÉN
Keyword(s):  
Acetic Acid ◽  
Betula Pendula ◽  
Cooking Time ◽  
Hot Water ◽  
Partial Hydrolysis ◽  
Chemical Pulping ◽  
Black Liquors ◽  
Aliphatic Carboxylic Acids ◽  
Hydrolysis Of ◽  
Cooking Conditions

Untreated and hot water-treated birch (Betula pendula) sawdust were cooked by the oxygen-alkali method under the same cooking conditions (temperature = 170°C, liquor-to-wood ratio = 5 L/kg, and 19% sodium hydroxide charge on the ovendry sawdust). The pretreatment of feedstock clearly facilitated delignification. After a cooking time of 90 min, the kappa numbers were 47.6 for the untreated birch and 10.3 for the hot water-treated birch. Additionally, the amounts of hydroxy acids in black liquors based on the pretreated sawdust were higher (19.5-22.5g/L) than those in the untreated sawdust black liquors (14.8-15.5 g/L). In contrast, in the former case, the amounts of acetic acid were lower in the pretreated sawdust (13.3-14.8 g/L vs. 16.9-19.1 g/L) because the partial hydrolysis of the acetyl groups in xylan already took place during the hot water extraction of feedstock. The sulfur-free fractions in the pretreatment hydrolysates (mainly carbohydrates and acetic acid) and in black liquors (mainly lignin and aliphatic carboxylic acids) were considered as attractive novel byproducts of chemical pulping.

THE ALDOBIOURONIC ACIDS OF HEMICELLULOSE B OF OAT HULLS

1956 ◽  
Vol 34 (3) ◽  
pp. 338-344 ◽  
Author(s):  
E. L. Falconer ◽  
G. A. Adams
Keyword(s):  
Glucuronic Acid ◽  
The Other ◽  
Partial Hydrolysis ◽  
Oat Hulls ◽  
Hydrolysis Of

Partial hydrolysis of hemicellulose B from oat hulls yielded two aldobiouronic acids, which were identified as 2-O-(4-O-methyl-α-D-glucopyruronosyl)-D-xylose and 2-O-(α-D-glucopyruronosyl)-D-xylose respectively. In addition, two aldotriouronic acids were isolated, one yielding on hydrolysis xylose and 4-O-methyl-glucuronic acid, and the other, xylose, galactose, and glucurone.

Halides and oxide halides of molybdenum and tungsten. III. Oxo-bridged species of tungsten(IV) and molybdenum(V)

1968 ◽  
Vol 21 (4) ◽  
pp. 883 ◽  
Author(s):  
R Colton ◽  
GG Rose
Keyword(s):  
Partial Hydrolysis ◽  
First Time ◽  
Hydrolysis Of ◽  
And Tungsten

The compound formulated in the literature as K2W(OH)Cl5 has been shown to be the oxo-bridged dimer K4[WT2Ocl10], and the diamagnetic dimer formed by the partial hydrolysis of the MOOCl2- ion has been isolated for the first time and shown to be the oxo-bridged [Mo2O3Cl8]4- ion.

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