Enhancement of Proton Mobility in Extended-Nanospace Channels

2012 ◽  
Vol 51 (15) ◽  
pp. 3573-3577 ◽  
Author(s):  
Hiroyuki Chinen ◽  
Kazuma Mawatari ◽  
Yuriy Pihosh ◽  
Kyojiro Morikawa ◽  
Yutaka Kazoe ◽  
...  
Keyword(s):  
Proton Mobility ◽  
Extended Nanospace

Enhancement of Proton Mobility in Extended-Nanospace Channels

2012 ◽  
Vol 124 (15) ◽  
pp. 3633-3637 ◽  
Author(s):  
Hiroyuki Chinen ◽  
Kazuma Mawatari ◽  
Yuriy Pihosh ◽  
Kyojiro Morikawa ◽  
Yutaka Kazoe ◽  
...  
Keyword(s):  
Proton Mobility ◽  
Extended Nanospace

Innenrücktitelbild: Enhancement of Proton Mobility in Extended-Nanospace Channels (Angew. Chem. 15/2012)

2012 ◽  
Vol 124 (15) ◽  
pp. 3785-3785 ◽  
Author(s):  
Hiroyuki Chinen ◽  
Kazuma Mawatari ◽  
Yuriy Pihosh ◽  
Kyojiro Morikawa ◽  
Yutaka Kazoe ◽  
...  
Keyword(s):  
Proton Mobility ◽  
Extended Nanospace

Inside Back Cover: Enhancement of Proton Mobility in Extended-Nanospace Channels (Angew. Chem. Int. Ed. 15/2012)

2012 ◽  
Vol 51 (15) ◽  
pp. 3723-3723
Author(s):  
Hiroyuki Chinen ◽  
Kazuma Mawatari ◽  
Yuriy Pihosh ◽  
Kyojiro Morikawa ◽  
Yutaka Kazoe ◽  
...  
Keyword(s):  
Proton Mobility ◽  
Back Cover ◽  
Extended Nanospace

Proton Acidity and Proton Mobility in ECR-40, a Silicoaluminophosphate That Violates Löwenstein’s Rule

2019 ◽  
Author(s):  
Michael Fischer
Keyword(s):  
Density Functional ◽  
Water Clusters ◽  
Computational Study ◽  
Acid Catalyst ◽  
Ab Initio Molecular Dynamics ◽  
Brønsted Acidity ◽  
Hydrothermal Route ◽  
Proton Mobility ◽  
Brönsted Acidity ◽  
A Minor

<p>The silicoaluminophosphate zeotype ECR-40, which has the MEI topology, contains linkages of AlO<sub>4</sub> tetrahedra via a common oxygen atom, thereby violating the famous “Löwenstein’s rule”. Due to the proven existence of Al-O-Al linkages in this material, it constitutes an ideal model system to study the acidity and mobility of protons associated with such unusual linkages. In addition, their properties can be directly compared to those of protons associated with more common Si-O-Al linkages, which are also present in ECR-40. In this work, static density functional theory (DFT) calculations including a dispersion correction were employed to study the preferred proton sites as well as the Brønsted acidity of the framework protons, followed by DFT-based ab-initio molecular dynamics (AIMD) to investigate the proton mobility in guest-free and hydrated ECR-40. Initially, two different proton arrangements were compared, one containing both H[O6] protons associated with Al-O-Al linkages and H[O10] protons at Si-O-Al linkages, the other one containing only H[O10] protons. The former model was found to be thermodynamically favoured, as a removal of protons from the Al-O-Al linkages causes a local accumulation of negative charge. Calculations of the deprotonation energy showed a moderately higher Brønsted acidity of the H[O10] protons, at variance with previous empirical explanations, which attributed the exceptional performance of ECR-40 as acid catalyst to the presence of Al‑O‑Al linkages. The AIMD simulations (<i>T</i> = 298 K) delivered no appreciable proton mobility for guest-free ECR-40 and for low levels of hydration (one H<sub>2</sub>O per framework proton). Under saturation conditions, framework deprotonation occurred, leading to the formation of protonated water clusters in the pores. Pronounced differences between the two types of framework protons were observed: While the H[O10] protons were always removed from the Si-O-Al linkages, the Al-O-Al linkages remained mostly protonated, but deprotonation did occur to a minor extent. The observation of a degree of framework deprotonation of Al-O-Al linkages differs from the findings reported in a recent computational study of hydrated aluminosilicate zeolites with such linkages (Heard et al., <i>Chem. Sci.</i> <b>2019</b>, <i>10</i>, 5705), pointing to an influence of the overall framework composition. Further inspection of the AIMD results showed that a coordination of water molecules to framework Al atoms occurred in many cases, especially in the vicinity of the Al-O-Al linkages, sometimes resulting in a pronounced modification of the linkages through additional bridging oxygen atoms. Given the changes in the local structure, it can be expected that such modified linkages are especially prone to break upon dehydration. Thus, in addition to elucidating the deprotonation behaviour of protons associated with different types of linkages, the calculations also provide insights into possible reasons for the instability of Al-O-Al linkages, clarifying why Löwenstein’s rule is mostly obeyed in materials that are formed via a hydrothermal route.</p>

scholarly journals The Hydration Characteristics, Structural Properties and Volatile Profile of Squid (Symplectoteuthis oualaniensis) Mantle Muscle: Impacts of Steaming, Boiling, and Sous Vide Cooking

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1646
Author(s):  
Hong Xiao ◽  
Nannan Li ◽  
Longtao Yan ◽  
Yong Xue
Keyword(s):  
Structural Properties ◽  
Cooking Methods ◽  
Volatile Components ◽  
Volatile Profile ◽  
Proton Mobility ◽  
Water Binding ◽  
Damage Degree ◽  
Application Potential ◽  
Sous Vide ◽  
Hydration Characteristics

Herein, the effects of boiling (BO), steaming (ST), and sous vide (SV) on the hydration characteristics, structural properties, and volatile profile of squid (Symplectoteuthis oualaniensis) mantle muscle (SMM) were investigated. Three cooking methods resulted in a dramatic decrease in proton mobility and freedom of protons, the relaxation time T2 decreased after cooking, and the water binding in the SMM was closer, but the SV treatment could retain more water in the SMM. SV resulted in a lower cooking loss (10.8%) than ST (49.0%) and BO (36.7%). Samples treated with SV had a better color and texture, the secondary structure β-fold of the squid protein was damaged by cooking to a certain extent, and the damage degree was BO > ST > SV. Compared with BO and ST, SV treatment caused more damage to the myosin heavy chain, paramyosin, and actin in SMM, improved the tenderness of SMM, and resulted in more regular internal reticular structures and less formation of fibrous structures. Cooking methods can significantly affect the volatile components of SMM, resulting in increasing volatile components or generating new volatile components in SMM including 2-methylbutanal, ethyl 2-methylpropanoate, acetic acid, and propyl methyl ketone in ST and BO samples and 2-methylbutanal, hexanal, and 2,3-pentanedione in SV samples. Therefore, SV resulted in the best quality squids and has substantial industrial application potential.

Investigating the role of GeO2 in enhancing the thermal stability and proton mobility of proton-conducting phosphate glasses

2021 ◽  
Author(s):  
Takahisa Omata ◽  
Aman Sharma ◽  
Takuya Kinoshita ◽  
Issei Suzuki ◽  
Tomohiro Ishiyama ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Phosphate Glasses ◽  
Proton Mobility ◽  
Proton Conducting

In this study, the effect of GeO2 on the thermal stability and proton mobility (μH) of proton-conducting phosphate glasses was experimentally investigated using 22HO1/2−3NaO1/2−(12−x)LaO3/2−xGeO2−63PO5/2 glasses. Increasing glass transition temperature (Tg)...

LIMITING CONDUCTANCE OF LYONIUM AND LYATE IONS

1959 ◽  
Vol 37 (1) ◽  
pp. 173-177 ◽  
Author(s):  
Martin Kilpatrick
Keyword(s):  
Mixed Solvents ◽  
Direct Determination ◽  
Solvent Mixture ◽  
Dielectric Constants ◽  
Proton Mobility ◽  
Anhydrous Hydrogen Fluoride ◽  
Ice Leads ◽  
Hydrogen Bonded Systems ◽  
High Dielectric ◽  
Strong Acids

The problem of proton mobility has been considered in H2O–CH3OH, H2O–D2O, and H2O–H2O2 solvents from the current viewpoint of the mechanism of proton mobility for aqueous solutions. Mixed solvents are more complicated in that one must consider the relative basicity and acidity of the species competing for the protons. It is concluded that for dilute solutions of HClO4, where water is replaced by hydrogen peroxide, the decrease in equivalent conductance relative to that of KCl in the same solvent mixture is due to the partial elimination of the proton transfer process.For highly acidic non-aqueous solvents of high dielectric constants such as HF, HCN, and HCOOH, the problem of the weakness of the usual "strong" acids of aqueous solution makes a direct determination of the limiting equivalent conductances difficult. In the case of anhydrous hydrogen fluoride the available experimental evidence indicates that the limiting conductance of the lyonium ion is approximately the same as that of the potassium ion but the lyate ion has a higher limiting conductance than other stable anions.The higher proton mobility in ice leads one to expect that hydrogen-bonded systems may be found where the conductivity may approach that of electronic semiconductors.

scholarly journals Relationship of Moisture Status and Quality Characteristics of Fresh Wet Noodles Prepared from Different Grade Wheat Flours from Flour Milling Streams

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Li Li ◽  
Na Wang ◽  
Sen Ma ◽  
Songzhu Yang ◽  
Xuehua Chen ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Frozen Storage ◽  
Bound Water ◽  
Intermediate Water ◽  
Proton Mobility ◽  
Flour Milling ◽  
Low Field ◽  
Relationship Of ◽  
Wheat Flours

This study was performed to investigate the quality of fresh wet noodles made from flour milling streams. The basic composition, texture properties, cooking characteristics, and moisture status were measured to evaluate the qualities of noodles. The results indicated that as storage time increased, the springiness of fresh wet noodles gradually decreased, but the hardness increased. Additionally, the cooking loss rate was increased obviously, and the water absorption rate generally decreased. The relaxation times T21 and T22, analyzed by low-field nuclear magnetic resonance, showed a downward trend that proton mobility became poor and bound water changed into intermediate water. Noodles made from reduction flour exhibited better quality. Compared to that with ambient temperature storage, the wet noodles under frozen storage showed better quality. The relaxation time T21, and T22 showed a positive correlation with noodle quality.

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