Quantum study of the adsorption of small molecules on ice: The infrared frequency of the surface hydroxyl group and the vibrational stark effect

2001 ◽  
Vol 114 (9) ◽  
pp. 4226-4234 ◽  
Author(s):  
C. Manca ◽  
A. Allouche
Keyword(s):  
Small Molecules ◽  
Stark Effect ◽  
Hydroxyl Group ◽  
Surface Hydroxyl

scholarly journals How Small Molecules Affect the Thermo-Oxidative Aging Mechanism of Polypropylene: A Reactive Molecular Dynamics Study

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1243
Author(s):  
Fan Zhang ◽  
Yufei Cao ◽  
Xuan Liu ◽  
Huan Xu ◽  
Diannan Lu ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Acetic Acid ◽  
Small Molecules ◽  
Aging Process ◽  
Experimental Studies ◽  
Hydroxyl Group ◽  
Oxidative Aging ◽  
Reactive Molecular Dynamics ◽  
Aging Mechanism ◽  
Effects Of Temperature

Understanding the aging mechanism of polypropylene (PP) is fundamental for the fabrication and application of PP-based materials. In this paper, we present our study in which we first used reactive molecular dynamics (RMD) simulations to explore the thermo-oxidative aging of PP in the presence of acetic acid or acetone. We studied the effects of temperature and oxygen on the aging process and discussed the formation pathways of typical small molecule products (H2, CO, CO2, CH4, C2H4, and C2H6). The effect of two infection agents, acetic acid and acetone, on the aging reaction was analyzed emphatically. The simulation results showed that acetone has a weak impact on accelerating the aging process, while acetic acid has a significant effect, consistent with previous experimental studies. By tracking the simulation trajectories, both acetic acid and acetone produced small active free radicals to further react with other fragment products, thus accelerating the aging process. The first reaction step of acetic acid is often the shedding of the H atom on the hydroxyl group, while the reaction of acetone is often the shedding of the H atom or the methyl. The latter requires higher energy at lower temperatures. This is why the acceleration effect of acetone for the thermo-oxidative aging of PP was not so significant compared to acetic acid in the experimental temperature (383.15 K).

The Behavior of Surface Hydroxyl Group of Magnetic Iron Oxide Particles

Ferrites ◽  
1982 ◽  
pp. 545-547
Author(s):  
Hiroshi Sugihara ◽  
Yasuta Taketomi ◽  
Tatsuo Uehori ◽  
Yasuo Imaoka
Keyword(s):  
Iron Oxide ◽  
Hydroxyl Group ◽  
Iron Oxide Particles ◽  
Magnetic Iron Oxide ◽  
Surface Hydroxyl ◽  
Oxide Particles

Biocompatibility and Functional Performance of a Polyethylene Glycol Acid-Grafted Cellulosic Membrane for Hemodialysis

2000 ◽  
Vol 23 (6) ◽  
pp. 356-364 ◽  
Author(s):  
V. Sirolli ◽  
S. Di Stante ◽  
S. Stuard ◽  
L. Di Liberato ◽  
L. Amoroso ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Functional Performance ◽  
Sialyl Lewis X ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Dialysis Session ◽  
Cellulose Diacetate ◽  
Activation Markers ◽  
Surface Hydroxyl ◽  
Cellular Expression

In order to improve the biochemical reactivity of the cellulose polymer, which is mainly attributed to the presence of surface hydroxyl groups, derivatized cellulosic membranes have been engineered replacing or masking some or all of the hydroxyl groups in the manufacturing process of the membrane. The present study was set up to analyze both biocompatibility and functional performance of two different derivatized cellulosic membranes (cellulose diacetate; polyethylene glycol, PEG, acid-grafted cellulose) as compared to a synthetic membrane (polymethylmethacrylate, PMMA). Cellulose diacetate is prepared by substituting hydroxyl groups with acetyl groups; PEG cellulose is obtained by grafting PEG chains onto the cellulosic polymer with a smaller amount of substitution than cellulose diacetate. While the three dialyzers provided similar urea and creatinine removal, the dialyzer containing cellulose diacetate showed a reduced ability to remove β2-microglobulin compared to that containing PEG cellulose or PMMA. A transient reduction in leukocyte count was observed for both derivatized cellulosic membranes. The neutrophil and monocyte counts throughout the entire dialysis session showed a closer parallelism with the cellular expression of the adhesive receptor CD15s (sialyl-Lewis x molecole) than with CD11b/CD18 expression. Platelet activation, as indicated by the percentage of cells expressing the activation markers CD62P (P-selectin) and CD63 (gp53), occurred with all membranes at 15 min of dialysis and also with PMMA at 30 min. An increased formation of platelet-neutrophil and platelet-monocyte coaggregates was found at 15 and 30 min during dialysis with cellulose diacetate and PMMA but not with PEG cellulose. Generally in concomitance with the increase in platelet-neutrophil coaggregates, an increased hydrogen peroxide production by neutrophils occurred. Our results indicate that derivatizing cellulose may represent a useful approach to improve the biocompatibility of the cellulose polymer, though some homeostatic reactions remain activated. Our results also indicate that there may be a great variability in the biocompatibility profile of derivatized cellulosic membranes which most likely stem from the different type of structural modification rather than from the degree of hydroxyl group replacement.

Measurement of vibrational energy relaxation of a surface hydroxyl group by ultrashort tunable infrared pulses

1993 ◽  
Vol 283 (1-3) ◽  
pp. A242
Author(s):  
Chiaki Hirose ◽  
Yasumasa Goto ◽  
Naotoshi Akamatsu ◽  
Junko Kondo ◽  
Kazunari Domen
Keyword(s):  
Vibrational Energy ◽  
Energy Relaxation ◽  
Hydroxyl Group ◽  
Vibrational Energy Relaxation ◽  
Surface Hydroxyl

Measurement of vibrational energy relaxation of a surface hydroxyl group by ultrashort tunable infrared pulses

1993 ◽  
Vol 283 (1-3) ◽  
pp. 244-247 ◽  
Author(s):  
Chiaki Hirose ◽  
Yasumasa Goto ◽  
Naotoshi Akamatsu ◽  
Junko Kondo ◽  
Kazunari Domen
Keyword(s):  
Vibrational Energy ◽  
Energy Relaxation ◽  
Hydroxyl Group ◽  
Vibrational Energy Relaxation ◽  
Surface Hydroxyl

Ab-Initio Hartree-Fock Study of Surface Hydroxyl Group on Lithium Oxide

1996 ◽  
Vol 30 (3P2A) ◽  
pp. 874-878 ◽  
Author(s):  
Masaki Taniguchi ◽  
Satoru Tanaka
Keyword(s):  
Ab Initio ◽  
Lithium Oxide ◽  
Hydroxyl Group ◽  
Surface Hydroxyl ◽  
Hartree Fock

The efficiency and mechanism of γ-alumina catalytic ozonation of 2-methylisoborneol in drinking water

2006 ◽  
Vol 6 (3) ◽  
pp. 43-51 ◽  
Author(s):  
L. Chen ◽  
F. Qi ◽  
B. Xu ◽  
Z. Xu ◽  
J. Shen ◽  
...  
Keyword(s):  
Drinking Water ◽  
Ph Value ◽  
Relative Concentration ◽  
Catalytic Ozonation ◽  
Hydroxyl Group ◽  
Ozone Decomposition ◽  
Group Status ◽  
Remarkable Effect ◽  
Surface Hydroxyl ◽  
Ozonation Process

The efficiency and mechanism in degradation of 2-methylisoborneol (MIB) as a taste and odour compound in drinking water were studied under the condition where γ-alumina catalysed ozonation. As a result, γ-alumina can show distinct activity in enhancing the efficiency of ozonation of MIB. Tert-butyl alcohol had a remarkable effect on the removal efficiency of catalytic ozonation of MIB. The surface charge status, surface hydroxyl group status of γ-alumina, and pH values of the solution can be linked together. When the pH value of the solution was near the pHzpc of γ-Al2O3, there was observable activity in the catalysed ozonation process. Rct, which denoted the relative concentration of hydroxyl radical (·OH), was much higher in the catalysed ozonation process than in the ozonation process. This result further illuminated that γ-Al2O3 can promote ozone decomposition to produce ·OH. Finally, the effect of rP/I on catalysed ozone decomposition and ozone decomposition was investigated.

The structure of an intercalated ordered kaolinite — a Raman microscopy study

Clay Minerals ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 587-596 ◽  
Author(s):  
R. L. Frost ◽  
T. H. Tran ◽  
J. Kristof
Keyword(s):  
Raman Band ◽  
Low Frequency ◽  
Potassium Acetate ◽  
Microscopy Study ◽  
Raman Microscopy ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Inner Surface ◽  
Order Of Magnitude

AbstractChanges in the molecular structure of a highly ordered kaolinite, intercalated with urea and potassium acetate, have been studied using Raman microscopy. A new Raman band, attributed to the inner surface hydroxyl groups strongly hydrogen bound to the acetate, is observed at 3605 cm-1 for the potassium acetate intercalate with the consequential loss of intensity in the bands at 3652, 3670, 3684 and 3693 cm-1. Remarkable changes in intensity of the Raman spectral bands of the low-frequency region of the kaolinite occurred upon intercalation. In particular, the 144 and 935 cm-1 bands increased by an order of magnitude and were found to be polarized. These spectroscopic changes provide evidence for the inner surface hydroxyl group-acetate bond being at an angle approaching 90° to the 001 face. Decreases in intensity of the bands at 243, 271 and 336 cm-1 were observed. The urea intercalate shows additional Raman bands at 3387, 3408 and 3500 cm-1 which are attributed to N-H vibrations after formation of the urea-kaolinite complex. Changes in the spectra of the inserting molecules were also observed.

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