scholarly journals Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis

2021 ◽  
pp. 173-183
Author(s):  
Alexander I. Sizov ◽  
◽  
Sergey D. Pimenov ◽  
Anastasia D. Stroiteleva ◽  
Katherine D. Stroiteleva ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Pharmaceutical Industry ◽  
Gas Phase ◽  
Sodium Hypochlorite ◽  
Microcrystalline Cellulose ◽  
High Rate ◽  
Subsequent Formation ◽  
Hydrolysis Of Cellulose ◽  
Yellow Tint ◽  
Hydrolysis Of

One of the main consumers of microcrystalline cellulose (MCC) is the pharmaceutical industry, where MCC is used as a binder and filler in direct compression of tablets. MCC is produced by acidic hydrolysis of cellulose, which usually results in a decrease in whiteness. This is due to the destruction of sugars formed during hydrolysis and the subsequent formation of colored products. The composition and properties of these products depend on the method of hydrolysis, acid concentration, temperature, and process duration. One of the most promising methods for producing MCC is gas-phase hydrolysis of cellulose with hydrogen chloride gas-air mixtures. The method has a high rate of hydrolysis, low reagent and energy consumption. The requirements of the pharmaceutical industry determine the need to produce MCC with high whiteness. The research purpose is to select bleaching modes for MCC using sodium hypochlorite and hydrogen peroxide as bleaching agents. MCC produced by gas-phase hydrolysis of bleached wood pulp was used during the study. The whiteness and intensity of the yellow tint of MCC in the bleaching process were determined by digital colorimetry on a flatbed scanner. The paper shows that sodium hypochlorite and hydrogen peroxide allow achieving the whiteness not less than 90 % and the intensity of the yellow tint not more than 3 standard units. High-quality bleaching can be carried out even for MCC samples with an initial whiteness of about 40 %. The most effective bleaching agent is sodium hypochlorite when the pH of the bleaching solution is 2–3. Hydrogen peroxide also provides high whiteness of MCC at pH of 10–11. However, the consumption of active oxygen (AO) for bleaching is more than three times higher in comparison with the consumption of active chlorine (ACh). It was found that the dyes of MCC produced by gas-phase hydrolysis consist of two chromophore groups that decolorize at different rates. The easily oxidized group of components makes up about 90 % of the total amount of dyes, and the resistant to oxidation components make up about 10 % and determine the intensity of the yellow tint of MCC. The modes of bleaching MCC with sodium hypochlorite and hydrogen peroxide to product samples with whiteness comparable to that of imported samples were determined. For citation: Sizov A.I., Pimenov S.D., Stroiteleva A.D., Stroiteleva K.D. Bleaching of Microcrystalline Cellulose Produced by Gas-Phase Hydrolysis. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 173–183. DOI: 10.37482/0536-1036-2021-6-173-183

Efficient Hydrolytic Breakage of β-1,4-Glycosidic Bond Catalyzed by a Difunctional Magnetic Nanocatalyst

2018 ◽  
Vol 71 (8) ◽  
pp. 559 ◽  
Author(s):  
Ren-Qiang Yang ◽  
Ni Zhang ◽  
Xiang-Guang Meng ◽  
Xiao-Hong Liao ◽  
Lu Li ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Time ◽  
Microcrystalline Cellulose ◽  
Significant Loss ◽  
Reducing Sugar ◽  
Magnetic Nanocatalyst ◽  
Efficient Catalyst ◽  
Glycosidic Bonds ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

A novel difunctional magnetic nanocatalyst (DMNC) was prepared and used to catalyse the hydrolytic breakage of β-1,4-glycosidic bonds. The functional nanoparticle displayed excellent catalytic activity for hydrolysis of cellobiose to glucose under moderate conditions. The conversion of cellobiose and yield of glucose could reach 95.3 and 91.1 %, respectively, for a reaction time of 6 h at pH 4.0 and 130°C. DMNC was also an efficient catalyst for the hydrolysis of cellulose: 53.9 % microcrystalline cellulose was hydrolyzed, and 45.7 % reducing sugar was obtained at pH 4.0 and 130°C after 10 h. The magnetic catalyst could be recycled and reused five times without significant loss of catalytic activity.

Pretreatment of microcrystalline cellulose by ultrasounds: effect of particle size in the heterogeneously-catalyzed hydrolysis of cellulose to glucose

2013 ◽  
Vol 15 (4) ◽  
pp. 963 ◽  
Author(s):  
Qinghua Zhang ◽  
Maud Benoit ◽  
Karine De Oliveira Vigier ◽  
Joël Barrault ◽  
Gwenaëlle Jégou ◽  
...  
Keyword(s):  
Particle Size ◽  
Microcrystalline Cellulose ◽  
Hydrolysis Of Cellulose ◽  
Effect Of Particle Size ◽  
Hydrolysis Of

EFFECT OF HYDROGEN PEROXIDE PRETREATMENT ON THE ENZYMATIC HYDROLYSIS OF CELLULOSE

2009 ◽  
Vol 34 (3) ◽  
pp. 905-921 ◽  
Author(s):  
GUANGLIN SHEN ◽  
HONG TAO ◽  
MOUMING ZHAO ◽  
BAO YANG ◽  
DONGQI WEN ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Enzymatic Hydrolysis ◽  
Enzymatic Hydrolysis Of Cellulose ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

scholarly journals Catalytic Oxidation of Olefins

2011 ◽  
Vol 4 (1) ◽  
pp. 9-11
Author(s):  
Zhang Yongmei ◽  
You Hongjun
Keyword(s):  
Hydrogen Peroxide ◽  
Visible Light ◽  
Catalytic Oxidation ◽  
Gas Phase ◽  
Sodium Hypochlorite ◽  
Synthesis Method ◽  
The Public ◽  
Phase Oxidation ◽  
Oxidation Of Olefins ◽  
Gas Phase Oxidation

This paper introduces the development circumstance of catalytic oxidation of olefins. And the synthesis method of catalytic oxidation of olefins are discussed in detail, such as, catalytic gas-phase oxidation of olefins; catalytic liquidphase oxidation of olefins; catalytic oxidation of enzyme; catalytic oxidation of olefins by using sodium hypochlorite and hydrogen peroxide as the catalyst; directly catalytic oxidation of olefins by using visible light. When hydrogen peroxide is used as the catalyst, it has no pollution and is good beneficial to the public.

scholarly journals Optimization of Selective Acid Hydrolysis of Cellulose for Microcrystalline Cellulose using FeCl3

BioResources ◽  
2014 ◽  
Vol 9 (1) ◽  
Author(s):  
Jinbao Li ◽  
Xiangrong Zhang ◽  
Meiyun Zhang ◽  
Huijuan Xiu ◽  
Hang He
Keyword(s):  
Acid Hydrolysis ◽  
Microcrystalline Cellulose ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Selective hydrolysis of cellulose for the preparation of microcrystalline cellulose by phosphotungstic acid

Cellulose ◽  
2016 ◽  
Vol 23 (2) ◽  
pp. 1199-1207 ◽  
Author(s):  
Dandan Qiang ◽  
Meiyun Zhang ◽  
Jinbao Li ◽  
Huijuan Xiu ◽  
Qiang Liu
Keyword(s):  
Microcrystalline Cellulose ◽  
Phosphotungstic Acid ◽  
Selective Hydrolysis ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Reactions in Activated Peroxide Systems and their Influences on Bleaching Performance

2020 ◽  
Vol 17 ◽  
Author(s):  
Xiaoyan Wang ◽  
Jinmei Du ◽  
Changhai Xu
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Energy Efficiency ◽  
Textile Industry ◽  
High Energy ◽  
Side Reactions ◽  
Competitive Reactions ◽  
High Energy Efficiency ◽  
Hydrolysis Of ◽  
Bleach Activators

Abstract:: Activated peroxide systems are formed by adding so-called bleach activators to aqueous solution of hydrogen peroxide, developed in the seventies of the last century for use in domestic laundry for their high energy efficiency and introduced at the beginning of the 21st century to the textile industry as an approach toward overcoming the extensive energy consumption in bleaching. In activated peroxide systems, bleach activators undergo perhydrolysis to generate more kinetically active peracids that enable bleaching under milder conditions while hydrolysis of bleach activators and decomposition of peracids may occur as side reactions to weaken the bleaching efficiency. This mini-review aims to summarize these competitive reactions in activated peroxide systems and their influence on bleaching performance.

Immobilized Nanoparticles-Mediated Enzymatic Hydrolysis of Cellulose for Clean Sugar Production: A Novel Approach

2019 ◽  
Vol 15 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Swapnil Gaikwad ◽  
Avinash P. Ingle ◽  
Silvio Silverio da Silva ◽  
Mahendra Rai
Keyword(s):  
Catalytic Activity ◽  
Enzymatic Hydrolysis ◽  
Immobilized Enzyme ◽  
Free Enzyme ◽  
Magnetic Nanomaterials ◽  
Sugar Production ◽  
Cellulase Enzyme ◽  
Enzymatic Hydrolysis Of Cellulose ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Background: Enzymatic hydrolysis of cellulose is an expensive approach due to the high cost of an enzyme involved in the process. The goal of the current study was to apply magnetic nanomaterials as a support for immobilization of enzyme, which helps in the repeated use of immobilized enzyme for hydrolysis to make the process cost-effective. In addition, it will also provide stability to enzyme and increase its catalytic activity. Objective: The main aim of the present study is to immobilize cellulase enzyme on Magnetic Nanoparticles (MNPs) in order to enable the enzyme to be re-used for clean sugar production from cellulose. Methods: MNPs were synthesized using chemical precipitation methods and characterized by different techniques. Further, cellulase enzyme was immobilized on MNPs and efficacy of free and immobilized cellulase for hydrolysis of cellulose was evaluated. Results: Enzymatic hydrolysis of cellulose by immobilized enzyme showed enhanced catalytic activity after 48 hours compared to free enzyme. In first cycle of hydrolysis, immobilized enzyme hydrolyzed the cellulose and produced 19.5 ± 0.15 gm/L of glucose after 48 hours. On the contrary, free enzyme produced only 13.7 ± 0.25 gm/L of glucose in 48 hours. Immobilized enzyme maintained its stability and produced 6.15 ± 0.15 and 3.03 ± 0.25 gm/L of glucose in second and third cycle, respectively after 48 hours. Conclusion: This study will be very useful for sugar production because of enzyme binding efficiency and admirable reusability of immobilized enzyme, which leads to the significant increase in production of sugar from cellulosic materials.

Enzymatic colorimetry of lecithin and sphingomyelin in aqueous solution.

1983 ◽  
Vol 29 (8) ◽  
pp. 1513-1517 ◽  
Author(s):  
M W McGowan ◽  
J D Artiss ◽  
B Zak
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Amniotic Fluid ◽  
Enzymatic Reaction ◽  
Detergent Solution ◽  
Enzymatic Determination ◽  
Red Color ◽  
Hydrolysis Of ◽  
Zwitterionic Detergent

Abstract A procedure for the enzymatic determination of lecithin and sphingomyelin in aqueous solution is described. The phospholipids are first dissolved in chloroform:methanol (2:1 by vol), the solvent is evaporated, and the residue is redissolved in an aqueous zwitterionic detergent solution. The enzymatic reaction sequences of both assays involve hydrolysis of the phospholipids to produce choline, which is then oxidized to betaine, thus generating hydrogen peroxide. The hydrogen peroxide is subsequently utilized in the enzymatic coupling of 4-aminoantipyrine and sodium 2-hydroxy-3,5-dichlorobenzenesulfonate, an intensely red color being formed. The presence of a non-reacting phospholipid enhances the hydrolysis of the reacting phospholipid. Thus we added lecithin to the sphingomyelin standards and sphingomyelin to the lecithin standards. This precise procedure may be applicable to determination of lecithin and sphingomyelin in amniotic fluid.

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