Factors influencing the concentration of gas phase hydrogen peroxide during the summer at Niwot Ridge, Colorado

1995 ◽  
Vol 100 (D11) ◽  
pp. 22831 ◽  
Author(s):  
B. A. Watkins ◽  
D. D. Parrish ◽  
M. Trainer ◽  
R. B. Norton ◽  
J. E. Yee ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Gas Phase ◽  
Niwot Ridge ◽  
Factors Influencing

Factors influencing the concentration of gas phase hydrogen peroxide during the summer at Kinterbish, Alabama

1995 ◽  
Vol 100 (D11) ◽  
pp. 22841 ◽  
Author(s):  
B. A. Watkins ◽  
D. D. Parrish ◽  
S. Buhr ◽  
R. B. Norton ◽  
M. Trainer ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Gas Phase ◽  
Factors Influencing

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

scholarly journals COHERENT SYNCHRONIZATION OF PYRIDINE DIMERIZATION REACTIONS AND DECOMPOSITION OF “GREEN OXIDANTS” – H2O2 AND N2O

2021 ◽  
Vol 0 (4) ◽  
pp. 6-11
Author(s):  
I.T. Nagieva ◽  
◽  
N.I. Ali-zadeh ◽  
T.М. Nagiev ◽  
◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Nitrous Oxide ◽  
Gas Phase ◽  
Atmospheric Pressure ◽  
Raw Materials ◽  
Oxidizing Agent ◽  
Optimal Conditions ◽  
Pyridine Bases ◽  
Pharmaceutical Industries ◽  
Oxidation By Hydrogen Peroxide

In recent years, hydrogen peroxide and nitrous oxide (1) "green oxidants" – have attracted much attention of researchers as a selective oxidizing agent for the catalytic oxidation of pyridine bases. In this regard, the reaction of pyridine oxidation by hydrogen peroxide and nitrous oxide under homogeneous conditions, in the gas phase, without the use of catalysts, at atmospheric pressure, has been experimentally investigated. Areas of selective oxidation of pyridine with hydrogen peroxide and nitrous oxide have been established, and optimal conditions have been found for obtaining valuable raw materials required in the petrochemical, chemical, and pharmaceutical industries

Effect of Sodium Ions on Catalytic Performance of TS-1 in Gas-Phase Epoxidation of Propylene with Hydrogen Peroxide Vapor

2019 ◽  
Vol 150 (1) ◽  
pp. 281-290
Author(s):  
Cuilan Miao ◽  
Ning He ◽  
Quanren Zhu ◽  
Yanhui Yi ◽  
Zhaochi Feng ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Gas Phase ◽  
Catalytic Performance ◽  
Sodium Ions ◽  
Epoxidation Of Propylene ◽  
Hydrogen Peroxide Vapor

Hybrid Gas/Liquid Electrical Discharge Reactors with Zeolites for Colored Wastewater Degradation

2005 ◽  
Vol 8 (2) ◽  
Author(s):  
Hrvoje Kušić ◽  
Natalija Koprivanac ◽  
Igor Peternel ◽  
Bruce R. Locke
Keyword(s):  
Hydrogen Peroxide ◽  
Liquid Phase ◽  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Electrical Discharge ◽  
Organic Dye ◽  
Electrical Discharges ◽  
Colored Wastewater ◽  
Ozone Levels ◽  
Parallel Reactor

AbstractHybrid gas/liquid electrical discharge reactors have been used to degrade an organic dye in the presence and absence of zeolites. Simultaneous gas and liquid phase electrical discharges in the hybrid parallel and hybrid series reactors have been shown in previous work to lead to the formation of hydrogen peroxide and hydroxyl radicals in the liquid phase and ozone in the gas phase. These reactors differ in their electrode configuration, and in previous work it was shown that the ozone levels in the parallel reactor are seven times higher than in the series reactor (3000 ppm and 450 ppm, respectively), while both reactors produce the same levels of hydrogen peroxide (4.9 × 10

Sign in / Sign up

Export Citation Format

Share Document