Highly active and spherical natured mesoporous aluminosilicate nanoparticles materialized for t-butylation of phenol

M. Selvaraj

doi:10.1039/c6ra09745f

Deactivation of arenetitanium(II) bromoalane complexes in the cyclotrimerization of butadiene

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19862751 ◽

1986 ◽

Vol 51 (12) ◽

pp. 2751-2759 ◽

Cited By ~ 2

Author(s):

Jindřich Poláček ◽

Helena Antropiusová ◽

Lidmila Petrusová ◽

Karel Mach

Keyword(s):

Catalytic Activity ◽

Catalytic System ◽

Model System ◽

Highly Active ◽

Catalytic Stability

The C6H6.Ti(II)(AlBr4)2 (Ib) catalyst deactivates during the butadiene cyclotrimerization to give a solid containing all titanium (mostly as TiBr3) and a mixture of AlBr3 and RAlBr2 compounds dissolved in benzene. The residual cationic catalytic activity of the deactivated Ib system is due to presence of AlBr3. In contrast to TiCl3, the deactivated Ib system and the model system TiBr3 + AlBr3 are not activated by the addition of EtAlCl2 in the presence of butadiene: the highly active benzenetitanium(II) system is re-constituted only after reduction of TiBr3 with Et3Al followed by the addition of EtAlCl2. The addition of Et2AlBr to Ib accelerates the deactivation of the system. Deactivation products of this system contain mainly Ti(II) species which forms benzenetitanium(II) catalytic system after addition of EtAlCl2. All the EtAlCl2 reactivated systems produce (Z, E, E)-1,5,9-cyclododecatriene with high catalytic stability and considerable selectivity (>90%). This behaviour points to the catalysis by benzenetitanium(II) chloroalane complexes containing only low amount of bromine atoms and ethyl groups.

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Flower-Shaped C-Dots/Co3O4{111} Constructed with Dual-Reaction Centers for Enhancement of Fenton-Like Reaction Activity and Peroxymonosulfate Conversion to Sulfate Radical

Catalysts ◽

10.3390/catal11010135 ◽

2021 ◽

Vol 11 (1) ◽

pp. 135

Author(s):

Zhibin Wen ◽

Qianqian Zhu ◽

Jiali Zhou ◽

Shudi Zhao ◽

Jinnan Wang ◽

...

Keyword(s):

Catalytic Activity ◽

Active Site ◽

High Surface ◽

High Surface Area ◽

Reaction Centers ◽

Organic Radicals ◽

The Other ◽

High Catalytic Activity ◽

High Adsorption ◽

High Turnover

Novel flower-shaped C-dots/Co3O4{111} with dual-reaction centers were constructed to improve the Fenton-like reaction activity and peroxymonosulfate (PMS) conversion to sulfate radicals. Due to the exposure of a high surface area and Co3O4{111} facets, flower-shaped C-dots/Co3O4{111} could provide more Co(II) for PMS activation than traditional spherical Co3O4{110}. Meanwhile, PMS was preferred for adsorption on Co3O4{111} facets because of a high adsorption energy and thereby facilitated the electron transfer from Co(II) to PMS. More importantly, the Co–O–C linkage between C-dots and Co3O4{111} induced the formation of the dual-reaction center, which promoted the production of reactive organic radicals (R•). PMS could be directly reduced to SO4−• by R• over C-dots. On the other hand, electron transferred from R• to Co via Co–O–C linkage could accelerate the redox of Co(II)/(III), avoiding the invalid decomposition of PMS. Thus, C-dots doped on Co3O4{111} improved the PMS conversion rate to SO4−• over the single active site, resulting in high turnover numbers (TONs). In addition, TPR analysis indicated that the optimal content of C-dots doped on Co3O4{111} is 2.5%. More than 99% of antibiotics and dyes were degraded over C-dots/Co3O4{111} within 10 min. Even after six cycles, C-dots/Co3O4{111} still remained a high catalytic activity.

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Highly Dispersed Pd Species Supported on CeO2 Catalyst for Lean Methane Combustion: The Effect of the Occurrence State of Surface Pd Species on the Catalytic Activity

Catalysts ◽

10.3390/catal11070772 ◽

2021 ◽

Vol 11 (7) ◽

pp. 772

Author(s):

Yanxiong Liu ◽

Changhua Hu ◽

Longchun Bian

Keyword(s):

Catalytic Activity ◽

Oxygen Vacancies ◽

Methane Combustion ◽

Pd Nanoparticles ◽

High Concentration ◽

Ch4 Combustion ◽

Highly Active ◽

Δ Phase ◽

Occurrence State ◽

Comprehensive Characterization

The correlation between the occurrence state of surface Pd species of Pd/CeO2 for lean CH4 combustion is investigated. Herein, by using a reduction-deposition method, we have synthesized a highly active 0.5% PdO/CeO2-RE catalyst, in which the Pd nanoparticles are evenly dispersed on the CeO2 nanorods CeO2-R. Based on comprehensive characterization, we have revealed that the uniformly dispersed Pd nanoparticles with a particle size distribution of 2.3 ± 0.6 nm are responsible for the generation of PdO and PdxCe1−xO2−δ phase with –Pd2+–O2−–Ce4+– linkage, which can easily provide oxygen vacancies and facilitate the transfer of reactive oxygen species between the CeO2-R and Pd species. As a consequence, the remarkable catalytic activity of 0.5% Pd/CeO2-RE is related to the high concentration of PdO species on the surface of the catalyst and the synergistic interaction between the Pd species and the CeO2 nanorod.

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A new highly active La2O3–CuO–MgO catalyst for the synthesis of cumyl peroxide by catalytic oxidation

RSC Advances ◽

10.1039/d1ra00176k ◽

2021 ◽

Vol 11 (21) ◽

pp. 12532-12542

Author(s):

HanShuang Liu ◽

KaiJun Wang ◽

XiaoYan Cao ◽

JiaXin Su ◽

Zhenggui Gu

Keyword(s):

Catalytic Activity ◽

Catalytic Oxidation ◽

Highly Active

The La2O3–CuO–MgO catalyst acts on the oxidation of cumene and shows excellent catalytic activity through the coordination of surface and interior.

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Nef Associates with p21-Activated Kinase 2 in a p21-GTPase-Dependent Dynamic Activation Complex within Lipid Rafts

Journal of Virology ◽

10.1128/jvi.78.23.12773-12780.2004 ◽

2004 ◽

Vol 78 (23) ◽

pp. 12773-12780 ◽

Cited By ~ 34

Author(s):

Kati Pulkkinen ◽

G. Herma Renkema ◽

Frank Kirchhoff ◽

Kalle Saksela

Keyword(s):

Catalytic Activity ◽

Lipid Rafts ◽

Lipid Raft ◽

Kinase Activity ◽

Highly Active ◽

Membrane Compartment ◽

Per Se ◽

P21 Activated Kinase ◽

Autoregulatory Mechanism ◽

Pak2 Activation

ABSTRACT We have previously reported that Nef specifically interacts with a small but highly active subpopulation of p21-activated kinase 2 (PAK2). Here we show that this is due to a transient association of Nef with a PAK2 activation complex within a detergent-insoluble membrane compartment containing the lipid raft marker GM1. The low abundance of this Nef-associated kinase (NAK) complex was found to be due to an autoregulatory mechanism. Although activation of PAK2 was required for assembly of the NAK complex, catalytic activity of PAK2 also promoted dissociation of this complex. Testing different constitutively active PAK2 mutants indicated that the conformation associated with p21-mediated activation rather than kinase activity per se was required for PAK2 to become NAK. Although association with PAK2 is one of the most conserved properties of Nef, we found that the ability to stimulate PAK2 activity differed markedly among divergent Nef alleles, suggesting that PAK2 association and activation are distinct functions of Nef. However, mutations introduced into the p21-binding domain of PAK2 revealed that p21-GTPases are involved in both of these Nef functions and, in addition to promoting PAK2 activation, also help to physically stabilize the NAK complex.

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Vanadium-Chromium Oxide: Effective Catalysts for Ammoxidation of 3-Picoline

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.634-638.624 ◽

2013 ◽

Vol 634-638 ◽

pp. 624-627 ◽

Cited By ~ 1

Author(s):

Feng Jiang ◽

Wei Xu ◽

Lei Niu ◽

Guo Min Xiao

Keyword(s):

Raman Spectroscopy ◽

Catalytic Activity ◽

Chromium Oxide ◽

Atmospheric Pressure ◽

High Selectivity ◽

Surface Acidity ◽

N2 Adsorption ◽

Composite Oxide ◽

Highly Active

Bulk vanadium-chromium oxide (VCrO) catalyst was prepared and characterized by N2 adsorption, XRD, NH3-TPD, H2-TPR, and Raman spectroscopy. XRD and Raman results showed that the VCrO catalyst was a kind of VV-CrIII composite oxide mainly consisted of crystalline V2O5 and CrVO4-Ⅲ (orthorhombic). NH3-TPD and H2-TPR results revealed that this catalyst had negligible surface acidity, and was easily reduced due to the formation of CrVO4-Ⅲ. Their catalytic activity was evaluated in the ammoxidation of 3-picoline to nicotinonitrile. Catalytic results showed that the bulk VCrO catalyst was highly active and selective; the nicotinonitrile selectivity and yield was up to 96.1%, 88.2% respectively at atmospheric pressure and 360 °C. The high selectivity was related closely to the low surface acidity of the catalyst.

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Towards highly active heterogeneous catalysts via a sequential noncovalent bonding strategy

New Journal of Chemistry ◽

10.1039/d1nj04303j ◽

2021 ◽

Author(s):

Ruixue Wang ◽

Ying Yue ◽

Huiying Wei ◽

Jinxin Guo ◽

Yanzhao Yang

Keyword(s):

Catalytic Activity ◽

Heterogeneous Catalysts ◽

High Catalytic Activity ◽

Synthetic Route ◽

Surface Ligands ◽

Highly Active ◽

Noncovalent Bonding ◽

Excellent Stability

Here, a novel synthetic route of ceria-based nanocatalysts with high catalytic activity and excellent stability was constructed by utilizing function groups from surface ligands. The surface of ceria nanorods were...

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Catalytic Activity of Oxidation-Reduction Pre-Treated Ni3Al for Methane Steam Reforming

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.89-91.645 ◽

2010 ◽

Vol 89-91 ◽

pp. 645-650 ◽

Cited By ~ 2

Author(s):

Ya Xu ◽

Dong Hyun Chun ◽

Jun Hyuk Jang ◽

Masahiko Demura ◽

Dang Moon Wee ◽

...

Keyword(s):

Catalytic Activity ◽

Steam Reforming ◽

Active Surface ◽

Methane Steam Reforming ◽

Reduction Treatment ◽

Highly Active ◽

Methane Steam ◽

Oxidation Reduction ◽

Pre Treatment ◽

Oxidation In Air

The catalytic activity of oxidation-reduction pre-treated Ni3Al powder for methane steam reforming was examined. The oxidation-reduction pre-treatment consisted of two steps: oxidation in air at various temperatures from 973 to 1373 K, and then followed by reduction in H2 at 873 K. It was found that the oxidation-reduction treatments significantly reduced the onset temperature of activity, i.e., improved the activity of Ni3Al powder at low temperatures. The characterization of Ni3Al surface showed that an outer surface layer of fine NiO particles were formed on the surface of Ni3Al after oxidation. These NiO particles were reduced to metallic Ni by the subsequent reduction treatment, resulting in the high activity for methane steam reforming. These results indicate that the Ni3Al can form highly active surface structure with oxidation-reduction treatment, having excellent heat resistance.

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Numerical analysis of the characteristics ofCorynebacterium diphtheriaestrains isolated in Victoria from 1962 to 1971

Journal of Hygiene ◽

10.1017/s0022172400024487 ◽

1975 ◽

Vol 75 (3) ◽

pp. 413-424

Author(s):

L. F. Gibson

Keyword(s):

Numerical Analysis ◽

Common Ancestor ◽

Corynebacterium Diphtheriae ◽

The State ◽

The Other ◽

Blood Agar ◽

Antigenic Structure ◽

Gradual Change ◽

Biochemical Activity ◽

Highly Active

SUMMARYA study of the incidence of diphtheria in the State of Victoria, Australia, was carried out. Numerical analysis of the characteristics of 264 strains ofCorynebacterium diphtheriaeisolated between 1962 and 1971 placed them into 18 varieties plus six strains which were unique in their combination of reactions to the characteristics examined. During the 10-year period, some varieties appeared inter mittently and were recognized by certain defining characteristics but exhibited a gradual change in their antigenic structure. In contrast, when the outbreaks were examined over shorter periods of time, a number of varieties and single strains were found which differed greatly from each other yet possessed the same major serotype antigen. These findings are discussed in terms of a 'one-parent' concept in which the varieties and single strains represent phases of a common ancestor.By inspection and analysis of the characteristics of the strains, certain associations were apparent. For instance, a correlation was found between the antigenic structure of the organism and the colonial appearance on tellurite blood agar. Similarly, correlation was observed between bacteriophage type, diphthericin type and biochemical activity in that a strain which was highly active in one of the properties was also very active in the other two.

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