scholarly journals AEROGEL CATALYST MODIFICATION TO IMPROVE CATALYTIC STABILITY DURING THE NITROXIDATION OF PROPYLENE

1989 ◽  
Vol 24 (C4) ◽  
pp. C4-7-C4-11
Author(s):  
M. RAHMAN ◽  
R. J. WILLEY ◽  
S. J. TEICHNER
Keyword(s):  
Catalytic Stability ◽  
Catalyst Modification

Catalytic stability of othro-chloronitrobenzene hydrogenation on Ru-Fe/C catalyst

2014 ◽  
Vol 34 (2) ◽  
pp. 391-396
Author(s):  
Xiangsheng XU ◽  
Ao’ang CHEN ◽  
Li ZHOU ◽  
Xiaoqing LI ◽  
Huizi GU ◽  
...  
Keyword(s):  
Catalytic Stability

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

1986 ◽  
Vol 51 (12) ◽  
pp. 2751-2759 ◽  
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.

scholarly journals Steam Reforming of Chloroform-Ethyl Acetate Mixture to Syngas over Ni-Cu Based Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 826
Author(s):  
Qiong Wu ◽  
Chenghua Xu ◽  
Yuhao Zheng ◽  
Jie Liu ◽  
Zhiyong Deng ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Steam Reforming ◽  
Synergetic Effect ◽  
Mixed Oxide Catalysts ◽  
Reforming Catalysts ◽  
Acidic Sites ◽  
Chlorine Poisoning ◽  
Catalytic Stability ◽  
Nickel Species ◽  
Chloride Salts

NiCuMoLaAl mixed oxide catalysts are prepared and applied in the steam reforming of chloroform-ethyl acetate (CHCl3-EA) mixture to syngas in the present work. The pre-introduction of Cl- ions using chloride salts as modifiers aims to improve the chlorine poisoning resistance. Catalytic tests show that KCl modification is obviously advantageous to increase the catalytic life. The destruction of catalyst structure induced by in situ produced HCl and carbon deposits that occurred on acidic sites are two key points for deactivation of reforming catalysts. The presence of Cl− ions gives rise to the formation of an Ni-Cu alloy, which exhibits a synergetic effect on catalyzing reforming along with metallic Ni crystals formed from excess nickel species, and giving an excellent catalytic stability. Less CHCl3 and more steam can also increase the catalytic stable time of KCl-modified NiCuMoLaAl reforming catalyst.

Facile synthesis of sandwich-like MnO2@Pd@MnO2 hollow spheres with superior catalytic stability and activity

2021 ◽  
Vol 870 ◽  
pp. 159415
Author(s):  
Jian Zhang ◽  
Daqian Bian ◽  
Gang Shao ◽  
Hailong Wang ◽  
Changan Wang
Keyword(s):  
Hollow Spheres ◽  
Facile Synthesis ◽  
Catalytic Stability

scholarly journals Control of zeolite microenvironment for propene synthesis from methanol

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Longfei Lin ◽  
Mengtian Fan ◽  
Alena M. Sheveleva ◽  
Xue Han ◽  
Zhimou Tang ◽  
...  
Keyword(s):  
Active Sites ◽  
Inelastic Neutron Scattering ◽  
Sustainable Manufacturing ◽  
Methanol Conversion ◽  
Acid Sites ◽  
Light Olefins ◽  
Carbon Bond ◽  
X Ray ◽  
Carbon Carbon Bond ◽  
Catalytic Stability

AbstractOptimising the balance between propene selectivity, propene/ethene ratio and catalytic stability and unravelling the explicit mechanism on formation of the first carbon–carbon bond are challenging goals of great importance in state-of-the-art methanol-to-olefin (MTO) research. We report a strategy to finely control the nature of active sites within the pores of commercial MFI-zeolites by incorporating tantalum(V) and aluminium(III) centres into the framework. The resultant TaAlS-1 zeolite exhibits simultaneously remarkable propene selectivity (51%), propene/ethene ratio (8.3) and catalytic stability (>50 h) at full methanol conversion. In situ synchrotron X-ray powder diffraction, X-ray absorption spectroscopy and inelastic neutron scattering coupled with DFT calculations reveal that the first carbon–carbon bond is formed between an activated methanol molecule and a trimethyloxonium intermediate. The unprecedented cooperativity between tantalum(V) and Brønsted acid sites creates an optimal microenvironment for efficient conversion of methanol and thus greatly promotes the application of zeolites in the sustainable manufacturing of light olefins.

Design of an MWW zeolite catalyst for linear alkylbenzene synthesis with improved catalytic stability

2016 ◽  
Vol 6 (8) ◽  
pp. 2715-2724 ◽  
Author(s):  
Hsiang-Ting Yen ◽  
Jhao-Jyun Wang ◽  
Siou-Huei Siao ◽  
Seung Hyeok Cha ◽  
Suk Bong Hong ◽  
...  
Keyword(s):  
Zeolite Catalyst ◽  
Linear Alkylbenzene ◽  
Catalytic Stability ◽  
Mww Zeolite

Effect of micro–meso porosity of MWW zeolites on the catalytic linear alkylbenzene synthesis was studied.

The roles of CeyZr1−yO2 in propane dehydrogenation: Enhancing catalytic stability and decreasing coke combustion temperature

2012 ◽  
Vol 443-444 ◽  
pp. 59-66 ◽  
Author(s):  
Bao Khanh Vu ◽  
Eun Woo Shin ◽  
Jeong-Myeong Ha ◽  
Seok Ki Kim ◽  
Dong Jin Suh ◽  
...  
Keyword(s):  
Combustion Temperature ◽  
Propane Dehydrogenation ◽  
Catalytic Stability ◽  
Coke Combustion
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