Reaction pathways for gas-phase hydrolysis of formyl compounds HXCO (X = H, F, and Cl)

1993 ◽  
Vol 115 (9) ◽  
pp. 3746-3751 ◽  
Author(s):  
Joseph S. Francisco ◽  
Ian H. Williams
Keyword(s):  
Gas Phase ◽  
Reaction Pathways ◽  
Hydrolysis Of

Effect of Reactor Shape and Gas Mixing on Gas Phase Production of Fine SiO2 Particles by Hydrolysis of Tetramethoxysilane

2008 ◽  
Vol 34 (2) ◽  
pp. 261-265 ◽  
Author(s):  
Toshinori Kojima ◽  
Kengo Tachi ◽  
Jun-ichi Sakai ◽  
Shigeru Kato ◽  
Shigeo Satokawa
Keyword(s):  
Gas Phase ◽  
Gas Mixing ◽  
Sio2 Particles ◽  
Hydrolysis Of ◽  
Phase Production

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

Synthesis and hydrolysis of gas-phase lanthanide and actinide oxide nitrate complexes: a correspondence to trivalent metal ion redox potentials and ionization energies

2015 ◽  
Vol 17 (15) ◽  
pp. 9942-9950 ◽  
Author(s):  
Ana F. Lucena ◽  
Célia Lourenço ◽  
Maria C. Michelini ◽  
Philip X. Rutkowski ◽  
José M. Carretas ◽  
...  
Keyword(s):  
Gas Phase ◽  
Metal Ion ◽  
Oxidation States ◽  
Redox Potentials ◽  
Trivalent Metal ◽  
Ionization Energies ◽  
Reduction Potentials ◽  
Hydrolysis Of ◽  
Nitrate Complexes

Gas-phase hydrolysis of lanthanide/actinide MO3(NO3)3−ions relates to the stabilities of the MIVoxidation states, which correlate with IV/III solution reduction potentials and 4th ionization energies.

Production of Amino and Organic Acids from Protein Using Sub-Critical Water Technology

2013 ◽  
Vol 11 (1) ◽  
pp. 369-384 ◽  
Author(s):  
Wael Abdelmoez ◽  
Hiroyuki Yoshida
Keyword(s):  
Organic Acids ◽  
Gas Phase ◽  
Solid Phase ◽  
Water Soluble ◽  
Water Soluble Protein ◽  
Study Results ◽  
Temperature Ranges ◽  
Aggregation Step ◽  
Hydrolysis Of ◽  
Protein Bovine Serum Albumin

Abstract This work presents the hydrolysis of a water-soluble protein, bovine serum albumin (BSA), for the production of both amino and organic acids under the sub-critical water condition in the temperature range of 200–300°C. The products of the reaction were a water-insoluble solid phase, an aqueous phase, and an insignificant gas phase which was neglected in this study. Results have shown that BSA passes through an aggregation step, followed by a gel formation process which results in the formation of insoluble solid aggregates. Then, such formed solids unfolded with releasing polypeptides as an intermediate product then finally hydrolyzed to produce low molecular mass products such as amino and organic acids. It was found that there were insignificant amino acids produced in the temperature ranges of 200–225°C within 2 min and 275–300°C within 0.5 min. However, by extending the reaction time, the protein transferred to both amino and organic acids.

Gas Phase Hydrolysis of Formaldehyde To Form Methanediol: Impact of Formic Acid Catalysis

2013 ◽  
Vol 117 (46) ◽  
pp. 11704-11710 ◽  
Author(s):  
Montu K. Hazra ◽  
Joseph S. Francisco ◽  
Amitabha Sinha
Keyword(s):  
Formic Acid ◽  
Gas Phase ◽  
Acid Catalysis ◽  
Hydrolysis Of

Theoretical Studies on Mechanism and Rate Constant of Gas Phase Hydrolysis of Glyoxal Catalyzed by Sulfuric Acid

2016 ◽  
Vol 29 (3) ◽  
pp. 335-343 ◽  
Author(s):  
Ming-qiang Huang ◽  
Shun-you Cai ◽  
Ying-min Liao ◽  
Wei-xiong Zhao ◽  
Chang-jin Hu ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Gas Phase ◽  
Rate Constant ◽  
Theoretical Studies ◽  
Hydrolysis Of

Generation and Reactivity of Chromium Fluoride Cations (CrF+n, n = 0-4) in the Gas Phase

1998 ◽  
Vol 63 (9) ◽  
pp. 1498-1512 ◽  
Author(s):  
Ulf Mazurek ◽  
Detlef Schröder ◽  
Helmut Schwarz
Keyword(s):  
Gas Phase ◽  
Bond Activation ◽  
Branching Ratio ◽  
Radical Cations ◽  
Reaction Pathways ◽  
Ion Cyclotron Resonance ◽  
Ion Transfer ◽  
Consistent Picture ◽  
Anion Transfer ◽  
Chain Lengths

Gaseous chromium fluoride monocations CrFn+ (n = 1-4) can be prepared by sequential fluorine-atom transfer from nitrogen trifluoride, NF3, to chromium cation. In addition, formal F- anion transfer to CrFn+ (n = 2-4) to yield the corresponding neutral chromium fluorides CrFn+1 is observed. In conjunction with a re-evaluation of previous data, the present results provide a consistent picture of the thermochemistry of neutral and cationic chromium fluorides. The reactivity of the CrFn+ ions towards alkanes is investigated in a Fourier-transform ion cyclotron resonance mass spectrometer. While "bare" Cr+ does not react with alkanes, the chromium fluoride cations CrFn+ do; CrF3+ and CrF4+ are even capable of activating methane. With both increasing oxidation state of chromium and increasing chain lengths of the alkane, the branching ratio of the possible reaction pathways shifts from homolytic C-H and C-C bond activation to hydride- and methanide-ion transfer to yield carbocations, and finally electron transfer generating hydrocarbon radical cations.

Gas phase hydrolysis of sulfur tetrafluoride: A comparison of the gaseous and liquid phase rate constants

1985 ◽  
Vol 83 (5) ◽  
pp. 2618-2619 ◽  
Author(s):  
I. Sauers ◽  
J. L. Adcock ◽  
L. G. Christophorou ◽  
H. W. Ellis
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Rate Constants ◽  
Sulfur Tetrafluoride ◽  
Hydrolysis Of
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