STRUCTURE OF AN ARABOGALACTAN FROM TAMARACK (LARIX LARICINA)

1960 ◽  
Vol 38 (2) ◽  
pp. 280-293 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Aqueous Solution ◽  
Water Soluble ◽  
Molar Ratio ◽  
Larix Laricina ◽  
Soluble Polysaccharide ◽  
Main Component ◽  
Hydrolysis Of

A water-soluble polysaccharide containing L-arabinose and D-galactose in a molar ratio 1:3.8 was isolated from tamarack. Fractionation with ethanol from aqueous solution yielded one main component which was judged to be homogeneous on the basis of electrophoresis and sedimentation data. Hydrolysis of the fully methylated polysaccharide yielded, 2,3,5-tri-O-methyl-L-arabinose (2 moles); 2,3,4,6-tetra-O-methyl-D-galactose (16 moles); 2,5-di-O-methyl-L-arabinose (5 moles); 2,3,4-tri-O-methyl-L-arabinose (5.5 moles); 2,3,4-tri-O-methyl-D-galactose (11 moles); 2,4,6-tri-O-methyl-D-galactose (3 moles); 2,6-di-O-methyl-D-galactose (1 mole); 2,4-di-O-methyl-D-galactose (20 moles); 2-O-methyl-D-galactose (3 moles).Possible structures for the arabogalactan are proposed and discussed on the basis of these results.

STRUCTURE OF AN ARABOGALACTAN FROM WHITE SPRUCE (PICEA GLAUCA (MOENCH) VOSS)

1958 ◽  
Vol 36 (5) ◽  
pp. 755-762 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Picea Glauca ◽  
Periodate Oxidation ◽  
White Spruce ◽  
Water Soluble ◽  
Molar Ratio ◽  
Glycosidic Bonds ◽  
Spruce Wood ◽  
Soluble Polysaccharide ◽  
Branched Structure ◽  
Hydrolysis Of

A water-soluble polysaccharide isolated from white spruce wood contained D-galactose, L-arabinose, and D-xylose in a molar ratio of 21:3:1. Hydrolysis of the fully methylated polysaccharide yielded 2,3,5-tri-O-methyl-L-arabinose (12 moles); 2,3,4,6-tetra-O-methyl-D-galactose (29 moles); 2,3,4-tri-O-methyl-D-galactose (34 moles); 2,6-di-O-methyl-D-galactose (0.5 moles); 2,4-di-O-methyl-D-galactose (45 moles); 2,3-di-O-methyl-D-xylose (5 moles); and monomethyl xylose (1 mole). When oxidized by periodate the polysaccharide consumed 1.18 moles of oxidant, and yielded 0.56 moles of formic acid per mole of anhydro-D-galactose. The D-xylose was attributed to the presence of a xylan mixed with the arabogalactan in the original polysaccharide preparation. The methylation and periodate oxidation data showed that the arabogalactan possessed a highly branched structure with the anhydro-D-galactose units being joined by 1 → 3 and 1 → 6 glycosidic bonds. All of the L-arabinose was present in the furanoside form as non-reducing terminal units.

CONSTITUTION OF THE GALACTOMANNAN FROM THE KERNEL OF GREEN PALMYRA PALM NUT (BORASSUS FLABELLIFER LINN.)

1961 ◽  
Vol 39 (7) ◽  
pp. 1408-1418 ◽  
Author(s):  
A. K. Mukherjee ◽  
D. Choudhury ◽  
P. Bagchi
Keyword(s):  
Periodate Oxidation ◽  
Structural Formula ◽  
Water Soluble ◽  
Molar Ratio ◽  
Partial Hydrolysis ◽  
Soluble Polysaccharide ◽  
Hydrolysis Of

The water-soluble polysaccharide extracted from the kernel of green palmyra palm nut (Borassusflabellifer Linn.) was shown to be composed of D-galactose and D-mannose in the proportion of 1:2.4. Hydrolysis of the fully methylated galactomannan yielded 2,3,4,6-tetra-O-methyl-D-galactose, 2,3,6-tri-O-methyl-D-mannose, and 2,3-di-O-methyl-D-mannose in the molar ratio of 1:1.4:0.95. Partial hydrolysis of the galactomannan afforded 4-O-β-D-mannopyranosyl-D-mannose, 6-O-α-D-galactopyranosyl-D-mannose, and two trisaccharides. Based on these results a structural formula for the galactomannan has been proposed, additional evidence for which was adduced from periodate-oxidation studies.

Acid hydrolysis of O-acetyl-galactoglucomannan in a continuous tube reactor: a new approach to sugar monomer production

Holzforschung ◽  
2016 ◽  
Vol 70 (3) ◽  
pp. 187-194 ◽  
Author(s):  
Andrea Pérez Nebreda ◽  
Henrik Grénman ◽  
Päivi Mäki-Arvela ◽  
Kari Eränen ◽  
Jarl Hemming ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Continuous Production ◽  
Product Distribution ◽  
Water Soluble ◽  
Continuous Reactor ◽  
New Approach ◽  
Tube Reactor ◽  
Soluble Polysaccharide ◽  
Hydrolysis Of ◽  
Laminar Flow Model

Abstract Hemicellulose O-acetyl-galactoglucomannan (GGM) is the main noncellulosic water-soluble polysaccharide in the coniferous softwood Norway spruce, consisting of anhydro-galactose, -glucose, and -mannose. Acid hydrolysis of GGM has been studied in a continuous tube reactor to obtain these sugars under industrially relevant conditions. The reaction was performed under atmospheric pressure at 90°C and 95°C, and hydrochloric acid (HCl) served as catalyst. The influence of the reaction parameters, such as acid concentration (pH), temperature, concentration of the substrate, as well as catalyst and reactant flow rates, has been studied on the conversion efficiency and product distribution. Continuous production of monomeric sugars was achieved without formation of low-molecular by-products. The GGM conversion was high with HCl as catalyst, at 95°C, and a pH of 0.3. The main hydrolysis products were mannose, glucose, and galactose monomers. Minor amounts of sugar dimers were detected among the products. The experimental results are described with a laminar flow model for the continuous reactor.

THE WATER-SOLUBLE POLYSACCHARIDES OF DERMATOPHYTES: II. A GLUCAN FROM MICROSPORUM QUINCKEANUM

1963 ◽  
Vol 41 (10) ◽  
pp. 2621-2627 ◽  
Author(s):  
H. Alfes ◽  
C. T. Bishop ◽  
F. Blank
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Minimum Degree ◽  
Relative Number ◽  
Degree Of Polymerization ◽  
Water Soluble ◽  
Molar Ratio ◽  
Branch Points ◽  
Degree Of Branching ◽  
Hydrolysis Of

A levorotatory glucan with a minimum degree of polymerization of 36 has been isolated from the water-soluble polysaccharides of the dermatophyte Microsporum quinckeanum. Hydrolysis of the methylated glucan yielded the following O-methyl-D-glucoses: 2,3,4,6-tetra-(10.2 mole%); 2,3,4-tri- (57.7 mole%); 2,4,6-tri- (22.2 mole%); 2,4-di- (8.2 mole%); and 2-mono- (1.6 mole%). The glucan consumed 1.53 moles of periodate with production of 0.70 mole of formic acid per mole anhydroglucose. Reduction and hydrolysis of the periodate-oxidized glucan yielded glycerol, erythritol, and D-glucose in a molar ratio of 72.3:0.6:27.1. The results showed that the glucan consisted of β-D-glucopyranose units joined in straight chains by 1 → 6 (57%) and 1 → 3 (24%) linkages. Approximately 3 in every 37 glucose residues constitute branch points in the glucan with branches occurring at the C6 and C3 positions of the same glucose unit. The glucan bears some resemblance to the yeast glucans of Saccharomyces cerevisiae and Candida albicans but differs from them in the relative number of 1 → 6 and 1 → 3 linkages and in the degree of branching.

CONSTITUTION OF A WATER SOLUBLE HEMICELLULOSE FROM AMERICAN BEECHWOOD (FAGUS GRANDIFOLIA)

1957 ◽  
Vol 35 (6) ◽  
pp. 556-564 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Average Molecular Weight ◽  
Periodate Oxidation ◽  
Reducing Power ◽  
Fagus Grandifolia ◽  
Water Soluble ◽  
Hot Water ◽  
Molar Ratio ◽  
Weight Average Molecular Weight ◽  
Homogeneous Fraction ◽  
Hydrolysis Of

Extraction of beechwood chlorite holocellulose with hot water yielded a hemicellulose in 13.4% yield (based on original extractive-free wood) containing D-xylose 72%, D-galactose 11.0%, and uronic acid 13.2%. Purification of the crude hemicellulose by complexing with Fehling's solution yielded a chemically homogeneous fraction containing D-xylose 83% and 4-O-methyl-D-glucuronic acid 15.5%. Hydrolysis of the fully methylated hemicellulose yielded 2,3,4-tri-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 3-O-methyl-D-xylose, and 3-O-methyl-2-O-(2,3,4-tri-O-methyl-D-glucopyranosyluronic acid)-D-xylose in a molar ratio of 2:35:3:5. On the basis of the methylation data, periodate oxidation, reducing power determinations, and weight average molecular weight values a possible structure for the hemicellulose is proposed.

CONSTITUTION OF AN ARABOGALACTAN FROM JACK PINE (PINUS BANKSIANA LAMB)

1957 ◽  
Vol 35 (9) ◽  
pp. 1010-1019 ◽  
Author(s):  
C. T. Bishop
Keyword(s):  
Methyl Ether ◽  
Pinus Banksiana ◽  
Jack Pine ◽  
Degree Of Polymerization ◽  
Average Degree ◽  
Water Soluble ◽  
Molar Ratio ◽  
Hydrolysis Of ◽  
Homogeneous Hydrolysis

A water soluble arabogalactan isolated from jack pine was shown to have a molar ratio of arabinose to galactose of 1:13, and a number average degree of polymerization of 53 ± 3. Fractionation data and electrophoresis indicated that the arabogalactan was homogeneous. Hydrolysis of the methyl ether of the polysaccharide yielded 2,3,5-tri-O-methyl-L-arabinose (4 moles); 2,3,4,6-tetra-O-methyl-D-galactose (12–13 moles); 2,3,4-tri-O-methyl-D-galactose (19 moles); 2,6-di-O-methyl-D-galactose (1 mole); and 2,4-di-O-methyl-D-galactose (14 moles). Some features of the structure of the arabogalactan are discussed on the basis of these results.

THE WATER-SOLUBLE POLYSACCHARIDES OF DERMATOPHYTES: III. A GALACTOMANNAN FROM TRICHOPHYTON INTERDIGITALE

1964 ◽  
Vol 42 (12) ◽  
pp. 2862-2871 ◽  
Author(s):  
F. Blank ◽  
M. B. Perry
Keyword(s):  
Formic Acid ◽  
Acid Hydrolysis ◽  
Copper Complex ◽  
Periodate Oxidation ◽  
Water Soluble ◽  
Mild Acid Hydrolysis ◽  
Trichophyton Interdigitale ◽  
Soluble Polysaccharide ◽  
Hydrolysis Of ◽  
Mild Acid

The water-soluble polysaccharide preparation from Trichophytoninterdigitale was fractionated to give two distinct galactomannans and a glucan. A galactomannan isolated via its insoluble copper complex had [α]D +75° (water) and was composed of D-galactose (12%) and D-mannose (88%). On periodate oxidation, the galactomannan consumed 1.73 mole periodate and released 0.67 mole formic acid and 0.12 mole formaldehyde per anhydrohexose unit. Hydrolysis of the methylated galactomannan gave 2,3,5,6-tetra-O-methyl-D-galactose (1 part), 2,3,4,6-tetra-O-methyl-D-mannose (1 part), 2,3,4-tri-O-methyl-D-mannose (4 parts), and3,4-di-O-methyl-D-mannose (2 parts). Mild acid hydrolysis of the galactomannan removed all the galactose residues, leaving a mannan having [α]D +84° (water) whose structure was analyzed by periodate oxidation and methylation techniques.

Rod-Like Rutile Nanoparticles: Synthesis, Structure and Morphology

2017 ◽  
Vol 50 ◽  
pp. 32-40 ◽  
Author(s):  
Volodymyr Kotsyubynsky ◽  
Ivan Myronyuk ◽  
Volodymyr Chelyadyn ◽  
Andrii Hrubiak ◽  
Volodymyr Moklyak ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrochloric Acid ◽  
Specific Surface ◽  
Reaction Medium ◽  
Nucleation And Growth ◽  
Molar Ratio ◽  
Structure And Morphology ◽  
Nanoparticles Synthesis ◽  
Preferred Oriented ◽  
Hydrolysis Of

Nanodispersed rutile with rod-like particles is synthesized by hydrolysis of TiCl4 in hydrochloric acid - ethanol alcohol aqueous solution. It is found that the specific surface area, crystallite size and degree of agglomeration are determined by molar ratio of ethanol in reaction medium. According to HR-TEM images and XRD data rutile crystallites are preferred oriented along the [001] axis. The analysis of the Raman spectra for samples with different morphology is performed. The model of rutile nanorods nucleation and growth is proposed.

Formation process of BaTiO3 particles by reaction between barium hydroxide aqueous solution and titania obtained by hydrolysis of titanium alkoxide

2007 ◽  
Vol 22 (9) ◽  
pp. 2631-2638 ◽  
Author(s):  
Min Zeng ◽  
Naofumi Uekawa ◽  
Takashi Kojima ◽  
Kazuyuki Kakegawa
Keyword(s):  
Aqueous Solution ◽  
Reaction Temperature ◽  
Fine Particles ◽  
Titanium Isopropoxide ◽  
Barium Hydroxide ◽  
Molar Ratio ◽  
Heating Process ◽  
Cubic Phase ◽  
Titanium Alkoxide ◽  
Hydrolysis Of

BaTiO3 particles were prepared by heating a suspension of titania derived from the hydrolysis of titanium isopropoxide in a barium hydroxide [Ba(OH)2] aqueous solution. Well-crystallized cubic phase BaTiO3 fine particles were obtained by heating at a temperature >328 K for 24 h. The morphology and size of the obtained particles were affected by the reaction temperature and the Ba(OH)2/titanium alkoxide molar ratio. The secondary particles with a larger size were obtained at a lower reaction temperature. The nucleation process of BaTiO3 depended on the reaction temperature. The formation mechanism of BaTiO3 and the formation kinetics were investigated by measuring the concentrations of Ba2+ ions in the solution during the heating process. The BaTiO3 particle formation occurred on the surface of the titania particles after strong adsorption of the Ba2+ ions from the solution. The experimental results showed that the heterogeneous nucleation of BaTiO3 occurred on the titania surface.

Extracellular polysaccharide of Aspergillus flavus

1981 ◽  
Vol 46 (10) ◽  
pp. 2435-2440 ◽  
Author(s):  
Alžbeta Kardošová ◽  
Jozef Rosík
Keyword(s):  
Carbon Source ◽  
Aspergillus Flavus ◽  
Sole Carbon Source ◽  
Culture Medium ◽  
Main Chain ◽  
Extracellular Polysaccharide ◽  
Water Soluble ◽  
Molar Weight ◽  
Soluble Polysaccharide ◽  
Hydrolysis Of

A crude extracellular polysaccharide was isolated by precipitation with ethanol from the culture medium of Aspergillus flavus, where the sole carbon source was D-galactose; purification afforded a homogeneous water-soluble polysaccharide in 0.05% yield on the weight of the employed carbon source. This polysaccharide had the relative molar weight 55 000 and [α]D22 -4.2° (c 0.5, H2O); upon total hydrolysis it afforded D-mannose and D-galactose in a 1 : 0.44 ratio. The products of hydrolysis of the methylated polysaccharide and also the course of partial acid and enzymic hydrolyses of the polysaccharide showed that the main chain was formed by (1 → 2) β-linked D-mannose units, of which each second, on average, was substituted by monomeric D-galactose units at C(6).

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