3—THE HOMOGENEOUS ACID HYDROLYSIS OF METHYL CELLULOSE Part II—THE CHANGE OF VISCOSITY AND MOLECULAR WEIGHT DURING HYDROLYSIS

1952 ◽  
Vol 43 (2) ◽  
pp. T38-T52 ◽  
Author(s):  
G. C. Gibbons
Keyword(s):  
Molecular Weight ◽  
Acid Hydrolysis ◽  
Methyl Cellulose ◽  
Homogeneous Acid ◽  
Hydrolysis Of

scholarly journals Mechanism and theory of d-glucopyranose homogeneous acid catalysis in the aqueous solution phase

2019 ◽  
Vol 21 (32) ◽  
pp. 17993-18011 ◽  
Author(s):  
Manik Kumer Ghosh ◽  
Mícheál Séamus Howard ◽  
Karla Dussan ◽  
Stephen Dooley
Keyword(s):  
Aqueous Solution ◽  
Acid Hydrolysis ◽  
Acid Catalysis ◽  
Theoretical Study ◽  
Solution Phase ◽  
Homogeneous Acid ◽  
Hydrolysis Of

Theoretical study of the mechanism of acid hydrolysis of β-d-glucopyranose in the aqueous solution.

"Colloidal" Phosphorus Errors in Gel Chromatography

1983 ◽  
Vol 40 (10) ◽  
pp. 1614-1621 ◽  
Author(s):  
B. Kent Burnison
Keyword(s):  
Molecular Weight ◽  
Acid Hydrolysis ◽  
High Molecular Weight ◽  
Gel Chromatography ◽  
Chemical Analyses ◽  
Molybdophosphoric Acid ◽  
Molybdenum Blue ◽  
Soluble Reactive Phosphate ◽  
Colloidal Phosphorus ◽  
Hydrolysis Of

Gel chromatography has been used for the separation of 32PO4 and a high molecular weight "colloidal" 32P-labeled fraction from 32PO4-labeled lakewater. When the labeled filtrate is treated with reagents required for the molybdenum blue method for orthophosphate analysis, only a small fraction of the "colloidal" peak is hydrolyzed to orthophosphate. As the reduced molybdophosphoric acid is strongly adsorbed to the dextran gel, quantitative elution of 32PO4 can be achieved with 0.05 mol∙L−1 NaOH and 0.3% NaCl. In hardwater lakes, care must be taken to eliminate the possibility of orthophosphate precipitation at higher pH. In these lakes, it is unlikely that the discrepancy between 32PO4 bioassays and chemical analyses can be solely attributed to acid hydrolysis of "colloidal" phosphorus. Microparticulate apatite also has the potential to release soluble reactive phosphate when the acidic molybdenum blue method is used.

scholarly journals Synthesis and properties of oligochitosan ascorbate from Bombyx mori

2021 ◽  
Vol 101 (1) ◽  
pp. 91-98
Author(s):  
K.K. Pirniyazov ◽  
◽  
V.E. Tikhonov ◽  
S.Sh. Rashidova ◽  
◽  
...  
Keyword(s):  
Molecular Weight ◽  
Acid Hydrolysis ◽  
Bombyx Mori ◽  
Antimicrobial Properties ◽  
A Value ◽  
Optimal Duration ◽  
Physicochemical Methods ◽  
Composition Structure ◽  
Hydrolysis Of ◽  
High Molecular Weight Chitosan

Oligochitosan samples were obtained by acid hydrolysis of high molecular weight chitosan isolated from Bombyx mori (B.M.). Carrying out acid hydrolysis for 6 hours, it was found that after 4 hours and further with increasing duration, the molecular weight of chitosan decreases to a value corresponding to the ranges of mo-lecular weights of oligochitosan 2–16 kDa. It has been seen that the optimal duration of hydrolysis, leading to the production of oligochitosan with a molecular weight of less than 16 kDa, should be considered 4–5 hours. Depolymerization of chitosan with a molecular weight of 177 kDa was carried out using sodium nitrite in so-lution to obtain oligochitosan with a molecular weight of 6 kDa. On the basis of oligochitosan samples ob-tained by two methods, their ascorbates were received. Under constant conditions with varying the ratio of the components (ChS:AA) and the pH of the solution, the reaction of chitosan ascorbate formation was car-ried out on the basis of the suspension method. The composition, structure, and molecular weight characteris-tics of oligochitosan ascorbate and oligochitosan Bombyx morisamples were confirmed by physicochemical methods. It has been seen that the obtained samples have antimicrobial properties against Fuzarium oxysporum.

scholarly journals Ultrasound-Assisted Ultra-Mild-Acid Hydrolisis of -Carrageenan

REAKTOR ◽  
2018 ◽  
Vol 17 (4) ◽  
pp. 191
Author(s):  
Ratnawati Ratnawati ◽  
Nita Indriyani
Keyword(s):  
Molecular Weight ◽  
Acid Hydrolysis ◽  
Average Molecular Weight ◽  
Weight Fraction ◽  
Number Average Molecular Weight ◽  
Hydrolysis Process ◽  
Higher Temperature ◽  
Ultrasound Assisted ◽  
Hydrolysis Of ◽  
Mild Acid

The low molecular weight fraction of κ-carrageenan is useful in biomedical applications. An ultrasound-assisted acid hydrolysis of κ-carrageenan has been studied. κ-carrageenan with an initial number-average molecular weight of 629 kDa was dispersed in distilled water to form a 5 g/l solution. The pH (3 and 6) of the solution was adjusted by adding HCl solution. The depolymerization reaction was carried out in an ultrasonic device at various temperatures (30, 40, 50, and 60°C) and times (8, 16, 24, and 32 min). The experimental results showed that ultrasound positively contributed to acid hydrolysis process. The number-average molecular weight of the treated k-carrageenan was lower or the percentage of reduction was higher at lower pH, longer reaction time, and higher temperature. The lowest number-average molecular weight (14 kDa) or the highest percent of molecular weight reduction reduction (97.7%) was achieved after ultrasonic irradiation at 60°C and pH 3 for 32 min. Keywords: depolymerization; midpoint scission; ultrasonication

A MANNAN PRODUCED BY BACILLUS POLYMYXA

1959 ◽  
Vol 37 (6) ◽  
pp. 1012-1017 ◽  
Author(s):  
D. H. Ball ◽  
G. A. Adams
Keyword(s):  
Molecular Weight ◽  
Acid Hydrolysis ◽  
Periodate Oxidation ◽  
Methylation Data ◽  
Bacillus Polymyxa ◽  
Hydrolysis Of

During the fermentation of glucose, sucrose, or lactose by Bacilluspolymyxa, a mixture of polysaccharides is formed, one of which has been isolated by mild procedures and shown to contain mannose as the only sugar together with approximately 13% protein. Acid hydrolysis of the methylated mannan gave 2,3,4,6-tetra-O-methyl-D-mannose, 2,4,6-tri-O-methyl-D-mannose, 3,4,6-tri-O-methyl-D-mannose, and 3,4-di-O-methyl-D-mannose in the approximate ratio 2:1:1:2. Periodate oxidation results are in agreement with the methylation data and indicate a molecular weight of approximately 3000.

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