scholarly journals Interaction of Refractory Dibenzothiophenes and Polymerizable Structures

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Jose L. Rivera ◽  
Pedro Navarro-Santos ◽  
Roberto Guerra-Gonzalez ◽  
Enrique Lima
Keyword(s):  
Hydrogen Bonds ◽  
First Principles ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
First Principles Calculations ◽  
Amino Groups ◽  
Hydrogen Atoms ◽  
Methylene Groups ◽  
Monomeric Structure ◽  
Additional Hydrogen

We carried out first principles calculations to show that polymerizable structures containing hydroxyl (alcoholic chain) and amino groups are suitable to form stable complexes with dibenzothiophene (DBT) and its alkyl derivates. These sulfur pollutants are very difficult to eliminate through traditional catalytic processes. Spontaneous and exothermic interactions at 0 K primarily occur through the formation of stable complexes of organosulfur molecules with monomeric structures by hydrogen bonds. The bonds are formed between the sulfur atom and the hydrogen of the hydroxyl group; additional hydrogen bonds are formed between the hydrogen atoms of the organosulfur molecule and the nitrogen atoms of the monomers. We vary the number of methylene groups in the alcoholic chain containing the hydroxyl group of the monomer and find that the monomeric structure with four methylene groups has the best selectivity towards the interaction with the methyl derivates with reference to the interaction with DBT. Even this study does not consider solvent and competitive adsorption effects; our results show that monomeric structures containing amino and hydroxyl groups can be used to develop adsorbents to eliminate organosulfur pollutants from oil and its derivates.

scholarly journals Molecular interactions in nanocellulose assembly

2017 ◽  
Vol 376 (2112) ◽  
pp. 20170047 ◽  
Author(s):  
Yoshiharu Nishiyama
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Molecular Modelling ◽  
Hydroxyl Group ◽  
Enthalpy Of Sublimation ◽  
Dispersion Force ◽  
Hydroxyl Groups ◽  
Range Interaction ◽  
Simple Arithmetic ◽  
London Dispersion

The contribution of hydrogen bonds and the London dispersion force in the cohesion of cellulose is discussed in the light of the structure, spectroscopic data, empirical molecular-modelling parameters and thermodynamics data of analogue molecules. The hydrogen bond of cellulose is mainly electrostatic, and the stabilization energy in cellulose for each hydrogen bond is estimated to be between 17 and 30 kJ mol −1 . On average, hydroxyl groups of cellulose form hydrogen bonds comparable to those of other simple alcohols. The London dispersion interaction may be estimated from empirical attraction terms in molecular modelling by simple integration over all components. Although this interaction extends to relatively large distances in colloidal systems, the short-range interaction is dominant for the cohesion of cellulose and is equivalent to a compression of 3 GPa. Trends of heat of vaporization of alkyl alcohols and alkanes suggests a stabilization by such hydroxyl group hydrogen bonding to be of the order of 24 kJ mol −1 , whereas the London dispersion force contributes about 0.41 kJ mol −1  Da −1 . The simple arithmetic sum of the energy is consistent with the experimental enthalpy of sublimation of small sugars, where the main part of the cohesive energy comes from hydrogen bonds. For cellulose, because of the reduced number of hydroxyl groups, the London dispersion force provides the main contribution to intermolecular cohesion. This article is part of a discussion meeting issue ‘New horizons for cellulose nanotechnology’.

scholarly journals Relationship between the Behavior of Hydrogen and Hydrogen Bubble Nucleation in Vanadium

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 322
Author(s):  
Zhengxiong Su ◽  
Sheng Wang ◽  
Chenyang Lu ◽  
Qing Peng
Keyword(s):  
Hydrogen Atom ◽  
First Principles ◽  
Bound States ◽  
Hydrogen Molecule ◽  
Vacancy Cluster ◽  
Bubble Nucleation ◽  
Hydrogen Bubble ◽  
First Principles Calculations ◽  
Hydrogen Atoms ◽  
Macroscopic Deformation

Hydrogen plays a significant role in the microstructure evolution and macroscopic deformation of materials, causing swelling and surface blistering to reduce service life. In the present work, the atomistic mechanisms of hydrogen bubble nucleation in vanadium were studied by first-principles calculations. The interstitial hydrogen atoms cannot form significant bound states with other hydrogen atoms in bulk vanadium, which explains the absence of hydrogen self-clustering from the experiments. To find the possible origin of hydrogen bubble in vanadium, we explored the minimum sizes of a vacancy cluster in vanadium for the formation of hydrogen molecule. We show that a freestanding hydrogen molecule can form and remain relatively stable in the center of a 54-hydrogen atom saturated 27-vacancy cluster.

scholarly journals Rectifying Performance of Heterojunction Based on α-Borophene Nanoribbons with Edge Passivation

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Guoliang Yu ◽  
Wence Ding ◽  
Xianbo Xiao ◽  
Xiaobo Li ◽  
Guanghui Zhou
Keyword(s):  
Electronic Transport ◽  
First Principles ◽  
First Principles Calculations ◽  
Zigzag Edge ◽  
Hydrogen Atoms ◽  
Rectification Effect ◽  
Structural Details ◽  
Potential Applications ◽  
Matching Degree ◽  
The Right

Abstract We propose a planar model heterojunction based on α-borophene nanoribbons and study its electronic transport properties. We respectively consider three types of heterojunctions. Each type consists of two zigzag-edge α-borophene nanoribbons (Z αBNR), one is metallic with unpassivated or passivated edges by a hydrogen atom (1H-Z αBNR) and the other is semiconducting with the edge passivated by two hydrogen atoms (2H-Z αBNR) or a single nitrogen atom (N-Z αBNR). Using the first-principles calculations combined with the nonequilibrium Green’s function, we observe that the rectifying performance depends strongly on the atomic structural details of a junction. Specifically, the rectification ratio of the junction is almost unchanged when its left metallic ribbon changes from ZBNR to 1H-Z αBNR. However, its ratio increases from 120 to 240 when the right semiconducting one varies from 2H-Z αBNR to N-Z αBNR. This rectification effect can be explained microscopically by the matching degree the electronic bands between two parts of a junction. Our findings imply that the borophene-based heterojunctions may have potential applications in rectification nano-devices.

AN INVESTIGATION OF THE CHLORINATION OF SPRUCE WOOD AND OF THE RESULTING CHLOROLIGNIN

1937 ◽  
Vol 15b (7) ◽  
pp. 279-294 ◽  
Author(s):  
G. V. Jansen ◽  
J. W. Bain
Keyword(s):  
Methyl Alcohol ◽  
Ring Structure ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Hydrogen Atoms ◽  
Chlorine Atoms ◽  
Spruce Wood ◽  
Simple Substitution ◽  
Homogeneous Fraction ◽  
Acid Reduction

Spruce sawdust was chlorinated under various conditions in an attempt to procure a homogeneous lignin chloride. Success finally attended the use of methyl alcohol as a medium for chlorination. The lignin chloride, which was dissolved by the alcohol during the chlorination and subsequently precipitated by the addition of water, was cream white in color, and analysis showed it to be an alcohol lignin.A homogeneous fraction (No. 2) was obtained from the re-chlorinated product, and it proved to be a chlorinated analogue of Hibbert's monomethylated methyl alcohol lignin, the formulas of the two products being C42H22O6Cl13(OH)2(OCH3)7, and C42H32O6(OH)3(OCH3)7. The molecular weight and the presence of the two hydroxyl groups were confirmed by acetylation, when 2.0 acetyl groups entered the molecule. Eleven of the chlorine atoms in Fraction 2 have evidently replaced ten hydrogen atoms and one hydroxyl group by simple substitution in methyl alcohol lignin, leaving two chlorine atoms which have apparently entered to saturate a double bond. Seven of these chlorine atoms have been shown to be readily removable either by an alkali or by acid reduction. The other six, because of their stable union with the molecule, are surmised to be joined to an aromatic nucleus or at least to some type of ring structure. The product has been shown to react stoichiometrically within limits as narrow as could be expected for such a large molecule.

scholarly journals First Principles Study of Reactions in Alucone Growth: the Role of the Organic Precursor

2020 ◽  
Author(s):  
Arbresha Muriqi ◽  
Michael Nolan
Keyword(s):  
Ethylene Glycol ◽  
First Principles ◽  
Molecular Layer ◽  
Triethylene Glycol ◽  
Detailed Comparison ◽  
Hydroxyl Group ◽  
Tetraethylene Glycol ◽  
Hydroxyl Groups ◽  
Reaction Products ◽  
Organic Precursor

Organic-inorganic hybrid materials are a unique class of materials with properties driven by the organic and inorganic components, making them useful for flexible devices. Molecular layer deposition (MLD) offers novel pathways for the fabrication of such hybrids by using inorganic metal precursors and the vast range of organic molecules with tunable properties. To investigate and understand the mechanism of growth a combination of theoretical and experimental data is needed. In this contribution, we present a first principles investigation of the molecular mechanism of the growth of hybrid organic−inorganic thin films of aluminium alkoxides, known as “alucones” grown by MLD. We explore the interactions between precursors by analyzing the MLD reaction products of the alumina surface terminated with Al(CH<sub>3</sub>) groups after the trimethyl aluminium pulse; this yields monomethyl-Al<sub>2</sub>O<sub>3</sub> (Al-CH<sub>3</sub>-Al<sub>2</sub>O<sub>3</sub>) and dimethyl- Al<sub>2</sub>O<sub>3</sub> (Al(CH<sub>3</sub>)<sub>2</sub>- Al<sub>2</sub>O<sub>3</sub>) terminated surfaces. The organic precursors are ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG) and tetraethylene glycol (FEG). A detailed comparison with alucones grown with ethylene glycol (EG) and glycerol (GL) precursors is presented to assist the interpretation of experimental findings regarding the differences in the hybrid films grown by EG and GL. The results show that Al-O formation with release of methane is favorable for all precursors. EG and GL can lie flat and create so-called double reactions through the reaction of the two terminal hydroxyl groups with the surface fragments. This phenomenon removes active hydroxyl sites for EG. However, for GL the third hydroxyl group is available and growth can proceed. This analysis shows the origin of differences in thickness of alucones found for EG and GL.

scholarly journals SIGNIFICANCE OF THE HYDROXYL GROUPS OF STEROIDS IN PROMOTING GROWTH

1954 ◽  
Vol 100 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Charles Huggins ◽  
Elwood V. Jensen
Keyword(s):  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Critical Importance ◽  
Hydrogen Atoms ◽  
Albino Rat ◽  
Ketone Group ◽  
Related Compounds

The presence of a 17ß-hydroxyl group endows the simple androstane molecule with the ability to produce growth of the uterus, vagina, and prostate of the female hypophysectomized albino rat. It appears that hydrogen atoms at position 17 are of critical importance since related compounds with a ketone group at this site are inactive. Monofunctional steroids with a hydroxyl or a ketone group at position 3 likewise are devoid of activity. If a phenolic A-ring is present in monofunctional steroids the 17ß-hydroxyl group is not obligatory for growth. Proliferation of the uterus and vagina were found to follow the administration of 17-desoxyestradiol.

scholarly journals Porous Si Partially Filled with Water Molecules—Crystal Structure, Energy Bands and Optical Properties from First Principles

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 396
Author(s):  
Ya. Shchur ◽  
O. Pavlyuk ◽  
A.S. Andrushchak ◽  
S. Vitusevich ◽  
A.V. Kityk
Keyword(s):  
Optical Properties ◽  
Hydrogen Bonds ◽  
First Principles ◽  
Energy Band ◽  
Visible Range ◽  
Band Spectrum ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Porous Si ◽  
Oh Groups

The paper reports the results on first-principles investigation of energy band spectrum and optical properties of bulk and nanoporous silicon. We present the evolution of energy band-gap, refractive indices and extinction coefficients going from the bulk Si of cubic symmetry to porous Si with periodically ordered square-shaped pores of 7.34, 11.26 and 15.40 Å width. We consider two natural processes observed in practice, the hydroxylation of Si pores (introduction of OH groups into pores) and the penetration of water molecules into Si pores, as well as their impact on the electronic spectrum and optical properties of Si superstructures. The penetration of OH groups into the pores of the smallest 7.34 Å width causes a disintegration of hydroxyl groups and forms non-bonded protons which might be a reason for proton conductivity of porous Si. The porosity of silicon increases the extinction coefficient, k, in the visible range of the spectrum. The water structuring in pores of various diameters is analysed in detail. By using the bond valence sum approach we demonstrate that the types and geometry of most of hydrogen bonds created within the pores manifest a structural evolution from distorted hydrogen bonds inherent to small pores (∼7 Å) to typical hydrogen bonds observed by us in larger pores (∼15 Å) which are consistent with those observed in a wide database of inorganic crystals.

Activation of the Hydrogen-Terminated Diamond [100] by Hydrogen Atoms and Hydroxyl Groups

2020 ◽  
Vol 996 ◽  
pp. 151-156
Author(s):  
Xiao Gang Jian ◽  
Ji Bo Hu ◽  
Xin Huang ◽  
Pei Kang Yang ◽  
Jun Peng Wang
Keyword(s):  
Hydrogen Atom ◽  
Low Temperature ◽  
Density Functional ◽  
Diamond Surface ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Hydrogen Atoms ◽  
Activation Rate ◽  
Limiting Stage ◽  
Rate Limiting

The process of producing active vacancies on a hydrogen-terminated diamond surface is the most important rate-limiting stage in CH4/H2 and CH4/H2/CO2 atmospheres. Hydrogen atom and the hydroxyl group can bone to the hydrogen atom on the diamond surface and create an active vacancy. Density functional theory (DFT) was used to study the extraction reaction by two reactants both hydrogen atom and the hydroxyl group. The result indicated that the hydroxyl group could reduce the energy required for diamond surface activation. What is more, the activation rate of the surface by the hydroxyl group was livelier at low temperature, while the activation rate of the hydrogen atom predicts on the contrary. The scanning electron microscope (SEM) and Raman spectra demonstrated that the introduction of CO2 in the CH4/H2 atmosphere could reduce the deposition temperature and raise the deposition rate at low temperature.

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