Synthesis and helix-sense-selective polymerization of a novel phenylacetylene having a trisiloxanyl group and two hydroxyl groups and enantioselective permeability of the resulting chiral polymeric membrane: Effect of the trisiloxanyl group on the polymerization and enantioselective permeability

Polymer ◽  
2010 ◽  
Vol 51 (12) ◽  
pp. 2460-2464 ◽  
Author(s):  
Lijia Liu ◽  
Yoshiyuki Oniyama ◽  
Yu Zang ◽  
Shingo Hadano ◽  
Toshiki Aoki ◽  
...  
Keyword(s):  
Polymeric Membrane ◽  
Hydroxyl Groups ◽  
Membrane Effect

Bleaching ability of pre-hydrolyzed pulps in the context of a biorefinery mill

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 49-53 ◽  
Author(s):  
CHRISTINE CHIRAT ◽  
LUCIE BOIRON ◽  
DOMINIQUE LACHENAL
Keyword(s):  
Carbon Content ◽  
Acid Hydrolysis ◽  
13C Nmr ◽  
Kraft Lignin ◽  
Kappa Number ◽  
Hydroxyl Groups ◽  
Kraft Pulps ◽  
Quaternary Carbon ◽  
Oxygen Delignification

Autohydrolysis and acid hydrolysis treatments were applied on mixed softwood chips. The cooking ability was studied by varying the alkali and duration of the cook. Pulps with kappa numbers varying from 30 to 70 were obtained. The bleaching ability of these pulps was studied and compared to control kraft pulps. The prehydrolyzed pulps were shown to be more efficiently delignified by oxygen than the control kraft pulps starting from the same kappa number. Furthermore, the final bleaching was also easier for these pulps. It was also shown that extensive oxygen delignification applied on high-kappa pre-hydrolyzed pulps could be a way to improve the overall yield, which is a prerequisite for the development of such biorefinery concepts. Lignin was isolated from the control kraft and the two pre-hydrolyzed kraft pulps and analyzed by 13C NMR. Lignins from pre-hydrolyzed kraft pulps had similar free phenolic groups content to the control kraft lignin, but their aliphatic hydroxyl groups and β-O-4 content were lower than for the control lignin. The quaternary carbon content was the same for all the samples.

Synthesis and antimicrobial properties of oligomeric silsesquioxanes containing quaternized nitrogen atoms and hydroxyl groups in organic shell

2017 ◽  
Vol 39 (3) ◽  
pp. 188-194
Author(s):  
M.A. Gumenna ◽  
◽  
N.S. Klimenko ◽  
A.V. Stryutsky ◽  
D.M. Hodyna ◽  
...  
Keyword(s):  
Antimicrobial Properties ◽  
Hydroxyl Groups ◽  
Organic Shell

QM/MM Simulations of Organic Phosphorus Adsorption at the Diaspore-Water Interface

2019 ◽  
Author(s):  
Prasanth Babu Ganta ◽  
Oliver Kühn ◽  
Ashour Ahmed
Keyword(s):  
Interaction Energy ◽  
Dynamics Simulation ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Water Interface ◽  
Mineral Surfaces ◽  
Soil Mineral ◽  
Phosphorus Adsorption ◽  
Covalent Bonds ◽  
Binding Mechanisms

The phosphorus (P) immobilization and thus its availability for plants are mainly affected by the strong interaction of phosphates with soil components especially soil mineral surfaces. Related reactions have been studied extensively via sorption experiments especially by carrying out adsorption of ortho-phosphate onto Fe-oxide surfaces. But a molecular-level understanding for the P-binding mechanisms at the mineral-water interface is still lacking, especially for forest eco-systems. Therefore, the current contribution provides an investigation of the molecular binding mechanisms for two abundant phosphates in forest soils, inositol hexaphosphate (IHP) and glycerolphosphate (GP), at the diaspore mineral surface. Here a hybrid electrostatic embedding quantum mechanics/molecular mechanics (QM/MM) based molecular dynamics simulation has been applied to explore the diaspore-IHP/GP-water interactions. The results provide evidence for the formation of different P-diaspore binding motifs involving monodentate (M) and bidentate (B) for GP and two (2M) as well as three (3M) monodentate for IHP. The interaction energy results indicated the abundance of the GP B motif compared to the M one. The IHP 3M motif has a higher total interaction energy compared to its 2M motif, but exhibits a lower interaction energy per bond. Compared to GP, IHP exhibited stronger interaction with the surface as well as with water. Water was found to play an important role in controlling these diaspore-IHP/GP-water interactions. The interfacial water molecules form moderately strong H-bonds (HBs) with GP and IHP as well as with the diaspore surface. For all the diaspore-IHP/GP-water complexes, the interaction of water with diaspore exceeds that with the studied phosphates. Furthermore, some water molecules form covalent bonds with diaspore Al atoms while others dissociate at the surface to protons and hydroxyl groups leading to proton transfer processes. Finally, the current results confirm previous experimental conclusions indicating the importance of the number of phosphate groups, HBs, and proton transfers in controlling the P-binding at soil mineral surfaces.

Composition of low molecular weight impurities in dimethylmethylpheylsiloxane rubbers with terminal hydroxyl groups

2020 ◽  
Vol 86 (11) ◽  
pp. 20-27
Author(s):  
A. M. Filippov ◽  
N. Yu. Semenkova ◽  
S. M. Gorelov ◽  
T. I. Shulyatieva ◽  
P. A. Storozhenko
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Hydroxyl Groups
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