Microcalorimetric adsorption and infrared spectroscopic studies of supported Pd, Ru and Pd–Ru catalysts for the hydrogenation of aromatic rings with carboxyl groups

2021 ◽  
Author(s):  
Shiling Zhao ◽  
Jingxuan Cai ◽  
Qiumei Hou ◽  
Danyang Zhao ◽  
Jianyi Shen
Keyword(s):  
Benzoic Acid ◽  
High Activity ◽  
Chemical Properties ◽  
Spectroscopic Studies ◽  
Carboxyl Groups ◽  
Surface Chemical ◽  
Aromatic Rings ◽  
Ru Catalysts ◽  
Special Surface ◽  
Supported Pd

Pd–Ru/SiO2 showed special surface chemical properties that were totally different from those of Pd/SiO2 and Ru/SiO2 and exhibited high activity and selectivity for the hydrogenation of benzoic acid to cyclohexanecarboxylic acid.

scholarly journals 4-[1-(4-Chlorophenyl)-3-oxobutylamino]benzoic acid

2007 ◽  
Vol 63 (11) ◽  
pp. o4420-o4421
Author(s):  
B. Narayana ◽  
K. Sunil ◽  
B. K. Sarojini ◽  
H. S. Yathirajan ◽  
Michael Bolte
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Benzoic Acid ◽  
Dihedral Angle ◽  
Title Compound ◽  
Carboxyl Groups ◽  
Carboxyl Group ◽  
Amino Group ◽  
Aromatic Rings ◽  
Compound C

Geometric parameters of the title compound, C17H16ClNO3, are in the usual ranges. The two aromatic rings are almost perpendicular, with a dihedral angle of 89.26 (5)°. The carboxyl group is coplanar with the aromatic ring to which it is attached [dihedral angle = 1.70 (17)°]. The packing involves inversion-symmetric dimers bridged via hydrogen bonding of the carboxyl groups. In addition, there is an N—H...O hydrogen bond between the amino group and the carbonyl O atom.

X-ray photoelectron spectroscopic studies on nanoquasicrystalline powders of Al70Cu20Fe10 obtained by mechanical alloying

2002 ◽  
Vol 17 (8) ◽  
pp. 1892-1895 ◽  
Author(s):  
P. Barua ◽  
V. Srinivas ◽  
S. Dhabal ◽  
T. B. Ghosh
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Prolonged Exposure ◽  
Chemical Properties ◽  
Spectroscopic Studies ◽  
Quasicrystalline Phase ◽  
Surface Chemical ◽  
Ambient Conditions ◽  
X Ray ◽  
Ball Milling Technique

Surface chemical properties of nanoguasicrystalline powders of Al–Cu–Fe synthesized by the ball-milling technique have been investigated using x-ray photoelectron spectroscopy (XPS). The samples were exposed to ambient conditions at room temperature as well as higher temperatures. Our XPS results reveal that the surfaces of nanopowders of Al70Cu20Fe10 are coated with an Al2O3 layer within which the quasicrystalline phase resides. It also appears that the thickness of this layer does not increase significantly on either heating below 873 K or prolonged exposure to ambient conditions.

scholarly journals Hydrogenation of benzoic acid derivatives over Pt/TiO2 under mild conditions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Miao Guo ◽  
Xiangtao Kong ◽  
Chunzhi Li ◽  
Qihua Yang
Keyword(s):  
Electron Transfer ◽  
Benzoic Acid ◽  
High Efficiency ◽  
Carboxyl Groups ◽  
Carboxyl Group ◽  
Benzoic Acids ◽  
Catalyst Poisoning ◽  
Benzoic Acid Derivatives ◽  
Mild Conditions ◽  
Transfer Direction

AbstractHydrogenation of benzoic acid (BA) to cyclohexanecarboxylic acid (CCA) has important industrial and academic significance, however, the electron deficient aromatic ring and catalyst poisoning by carboxyl groups make BA hydrogenation a challenging transformation. Herein, we report that Pt/TiO2 is very effective for BA hydrogenation with, to our knowledge, a record TOF of 4490 h−1 at 80 °C and 50 bar H2, one order higher than previously reported results. Pt/TiO2 catalysts with electron-deficient and electron-enriched Pt sites are obtained by modifying the electron transfer direction between Pt and TiO2. Electron-deficient Pt sites interact with BA more strongly than electron-rich Pt sites, helping the dissociated H of the carboxyl group to participate in BA hydrogenation, thus enhancing its activity. The wide substrate scope, including bi- and tri-benzoic acids, further demonstrates the high efficiency of Pt/TiO2 for hydrogenation of BA derivatives.

Unlocking the potential of ruthenium catalysts for nitrogen fixation with subsurface oxygen

2021 ◽  
Author(s):  
Xin Mao ◽  
Zhengxiang Gu ◽  
Cheng Yan ◽  
Aijun Du
Keyword(s):  
Nitrogen Fixation ◽  
High Activity ◽  
Ruthenium Catalysts ◽  
Ru Catalysts ◽  
Subsurface Oxygen

Decorating subsurface oxygen in Ru catalysts to achieve high activity and selectivity for N2 reduction to ammonia.

Effects of chemical treatment as an adjunctive of air‐abrasive debridement on restoring the surface chemical properties and cytocompatibility of experimentally contaminated titanium surfaces

2019 ◽  
Vol 108 (1) ◽  
pp. 183-191 ◽  
Author(s):  
Yuki Ichioka ◽  
Takashi Kado ◽  
Izumi Mashima ◽  
Futoshi Nakazawa ◽  
Kazuhiko Endo ◽  
...  
Keyword(s):  
Chemical Treatment ◽  
Chemical Properties ◽  
Surface Chemical ◽  
Titanium Surfaces

The Construction of New Proteins. II. Design, Synthesis and Conformational Studies of Folding Units with βαβ-Topology

1986 ◽  
Vol 41 (10) ◽  
pp. 1315-1322 ◽  
Author(s):  
Manfred Mutter ◽  
Karl-Heinz Altmann ◽  
Thomas Vorherr
Keyword(s):  
Solid Phase ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Spectroscopic Studies ◽  
General Concept ◽  
Dimensional Structure ◽  
Design Synthesis ◽  
Phase Synthesis ◽  
Conformational Studies ◽  
Conformational Effects

The design, synthesis and preliminary conformational studies of two polypeptides exhibiting βαβ-type folding topologies are presented. In the design of the model peptides the general concept for the construction of new proteins developed in the preceeding paper was applied. According to this strategy, amphiphilic helices and β-sheets are linked together via hydrophilic loops to attain three-dimensional structures of higher order (‘supersecondary structures’). Com­puter-assisted molecular modelling served as a valuable tool for minimizing conformational con­straints within the molecules. The 38-residue peptide MI was synthesized using polyethylene glycol (PEG) as solubilizing polymeric support (‘Liquid-Phase synthesis'). Conformationally in­duced changes in the physico-chemical properties of the growing peptide chain stressed the significance of conformational effects in peptide synthesis reported earlier. Similar observations were made during the solid-phase synthesis of the 35-peptide MII. CD and IR spectroscopic studies revealed a high degree of secondary structure for both folding units. The present data strongly support the adoption of a three-dimensional structure for both models.

Effect of High-Temperature Defibration on the Chemical Structure of Hardwood

Holzforschung ◽  
2002 ◽  
Vol 56 (1) ◽  
pp. 51-59 ◽  
Author(s):  
P. Widsten ◽  
J.E. Laine ◽  
P. Qvintus-Leino ◽  
S. Tuominen
Keyword(s):  
High Temperature ◽  
Lignin Content ◽  
Bulk Composition ◽  
Chemical Properties ◽  
Water Extract ◽  
Fiber Surface ◽  
Phenolic Hydroxyl ◽  
Hydroxyl Groups ◽  
Surface Chemical ◽  
Alkyl Aryl

Summary The present paper aims at elucidating the effect of high-temperature defibration at different temperatures on the bulk and surface chemical properties of defibrated birch, aspen and eucalypt. The results indicate that defibration of these hardwoods results in partial depolymerization of fiber lignin via (homolytic) cleavage of interunit alkyl-aryl (β-O-4) ether bonds. This increases the phenolic hydroxyl content and produces relatively stable (phenoxy) radicals. Syringyl-type lignin is more extensively depolymerized than guaiacyl-type lignin. Defibration generates water-extractable material, which is enriched in hemicellulose-derived carbohydrates and has a substantial content of aromatic compounds rich in phenolic hydroxyl groups. The amount of water-extract and the extent of lignin interunit ether bond cleavage increase with an increase in defibration temperature. The differences between various hardwood species in this respect are small. The surface chemical composition of the fibers differs considerably from their bulk composition, but is not significantly influenced by variations in defibration temperature. Lipophilic extractives cover a large portion of the fiber surface, while the lignin content of lipophilic extractives-free fiber surfaces is 2–3 times as high as the bulk lignin content of the fibers.

New AlPO4-sepiolite systems as acid catalysts, I. Preparation, texture, surface-chemical properties and cyclohexene skeletal isomerization conversion

1990 ◽  
Vol 25 (5) ◽  
pp. 2513-2519 ◽  
Author(s):  
J. M. Campelo ◽  
A. Garcia ◽  
D. Luna ◽  
J. M. Marinas
Keyword(s):  
Chemical Properties ◽  
Skeletal Isomerization ◽  
Acid Catalysts ◽  
Surface Chemical ◽  
Texture Surface

scholarly journals The Flexible Surface: Molecular Studies Explain the Extraordinary Diversity of Surface Chemical Properties

1998 ◽  
Vol 75 (2) ◽  
pp. 161 ◽  
Author(s):  
Gabor A. Somorjai ◽  
Günther Rupprechter
Keyword(s):  
Chemical Properties ◽  
Surface Chemical ◽  
Flexible Surface ◽  
Molecular Studies
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