Role of Citric Acid Modification on Hydrodesulfurization of DBT and 4,6 DMDBT in the Presence of Pyridine Over CoMo/Al2O3

In this study, the effect of pyridine as a basic nitrogen compound on HDS activity of DBT and 4,6 DMDBT in treated diesel over modified CoMo/Al2O3 by citric acid has been investigated. It has been obviously found that the modification of CoMo/Al2O3 catalyst by citric acid can inhibit the influence of pyridine on HDS activity of DBT and 4,6 DMDBT. This can be explained that when citric acid was applied in the catalyst preparation, the increasing of total amount of acid sites and the enhancement of HDN activity play an important role in the tolerance of pyridine.

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Understanding the role of surface Lewis acid sites of Sn modified Pd/Al2O3 catalyst in the chemoselective reductive N-acetylation of nitrobenzene

Reaction Kinetics Mechanisms and Catalysis ◽

10.1007/s11144-020-01765-0 ◽

2020 ◽

Vol 130 (1) ◽

pp. 347-362 ◽

Cited By ~ 1

Author(s):

Vishali Bilakanti ◽

Naresh Gutta ◽

Vijay Kumar Velisoju ◽

Mahesh Dumpalapally ◽

Sreedhar Inkollu ◽

...

Keyword(s):

Lewis Acid ◽

Acid Sites ◽

Lewis Acid Sites ◽

Al2o3 Catalyst

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Role of Citric Acid in Preparing Highly Active CoMo/Al2O3 Catalyst: From Aqueous Impregnation Solution to Active Site Formation

Industrial & Engineering Chemistry Research ◽

10.1021/acs.iecr.7b02877 ◽

2017 ◽

Vol 56 (48) ◽

pp. 14172-14181 ◽

Cited By ~ 14

Author(s):

Jianjun Chen ◽

Jinxing Mi ◽

Kezhi Li ◽

Xiqin Wang ◽

Elizabeth Dominguez Garcia ◽

...

Keyword(s):

Citric Acid ◽

Active Site ◽

Site Formation ◽

Highly Active ◽

Al2o3 Catalyst ◽

Impregnation Solution

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Phytoextraction of Lead Using a Hedge Plant [Alternanthera bettzickiana (Regel) G. Nicholson]: Physiological and Biochemical Alterations through Bioresource Management

Sustainability ◽

10.3390/su13095074 ◽

2021 ◽

Vol 13 (9) ◽

pp. 5074

Author(s):

Urooj Kanwal ◽

Muhammad Ibrahim ◽

Farhat Abbas ◽

Muhammad Yamin ◽

Fariha Jabeen ◽

...

Keyword(s):

Citric Acid ◽

Growth Parameters ◽

Cost Effective ◽

Dry Weight ◽

Citric Acid Concentration ◽

Biochemical Alterations ◽

Biomass Plant ◽

Environmentally Friendly Approach ◽

Pb Concentration

Phytoremediation is a cost-effective and environmentally friendly approach that can be used for the remediation of metals in polluted soil. This study used a hedge plant–calico (Alternanthera bettzickiana (Regel) G. Nicholson) to determine the role of citric acid in lead (Pb) phytoremediation by exposing it to different concentrations of Pb (0, 200, 500, and 1000 mg kg−1) as well as in a combination with citric acid concentration (0, 250, 500 µM). The analysis of variance was applied on results for significant effects of the independent variables on the dependent variables using SPSS (ver10). According to the results, maximum Pb concentration was measured in the upper parts of the plant. An increase in dry weight biomass, plant growth parameters, and photosynthetic contents was observed with the increase of Pb application (200 mg kg−1) in soil while a reduced growth was experienced at higher Pb concentration (1000 mg kg−1). The antioxidant enzymatic activities like superoxide dismutase (SOD) and peroxidase (POD) were enhanced under lower Pb concentration (200, 500 mg kg−1), whereas the reduction occurred at greater metal concentration Pb (1000 mg kg−1). There was a usual reduction in electrolyte leakage (EL) at lower Pb concentration (200, 500 mg kg−1), whereas EL increased at maximum Pb concentration (1000 mg kg−1). We concluded that this hedge plant, A. Bettzickiana, has the greater ability to remediate polluted soils aided with citric acid application.

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On the Role of Protonic Acid Sites in Cu Loaded FAU31 Zeolite as a Catalyst for the Catalytic Transformation of Furfural to Furan

Molecules ◽

10.3390/molecules26072015 ◽

2021 ◽

Vol 26 (7) ◽

pp. 2015

Author(s):

Łukasz Kuterasiński ◽

Małgorzata Smoliło-Utrata ◽

Joanna Kaim ◽

Wojciech Rojek ◽

Jerzy Podobiński ◽

...

Keyword(s):

Active Sites ◽

Acid Sites ◽

Bronsted Acid ◽

Brønsted Acid ◽

Brønsted Acid Sites ◽

Protonic Acid ◽

Brönsted Acid ◽

Brönsted Acid Sites ◽

Bronsted Acid Sites

The aim of the present paper is to study the speciation and the role of different active site types (copper species and Brønsted acid sites) in the direct synthesis of furan from furfural catalyzed by copper-exchanged FAU31 zeolite. Four series of samples were prepared by using different conditions of post-synthesis treatment, which exhibit none, one or two types of active sites. The catalysts were characterized by XRD, low-temperature sorption of nitrogen, SEM, H2-TPR, NMR and by means of IR spectroscopy with ammonia and CO sorption as probe molecules to assess the types of active sites. All catalyst underwent catalytic tests. The performed experiments allowed to propose the relation between the kind of active centers (Cu or Brønsted acid sites) and the type of detected products (2-metylfuran and furan) obtained in the studied reaction. It was found that the production of 2-methylfuran (in trace amounts) is determined by the presence of the redox-type centers, while the protonic acid sites are mainly responsible for the furan production and catalytic activity in the whole temperature range. All studied catalysts revealed very high susceptibility to coking due to polymerization of furfural.

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MCM-41 grafted with citric acid: The role of carboxylic groups in enhancing the synthesis of xanthenes and removal of heavy metal ions

Environmental Nanotechnology Monitoring & Management ◽

10.1016/j.enmm.2020.100410 ◽

2021 ◽

Vol 15 ◽

pp. 100410

Author(s):

Mohammed A. Mannaa ◽

Hatem M. Altass ◽

Reda S. Salama

Keyword(s):

Heavy Metal ◽

Citric Acid ◽

Metal Ions ◽

Heavy Metal Ions ◽

Carboxylic Groups ◽

Mcm 41

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Catalytic role of assembled Ce Lewis acid sites over ceria for electrocatalytic conversion of dinitrogen to ammonia

Journal of Energy Chemistry ◽

10.1016/j.jechem.2021.01.016 ◽

2021 ◽

Vol 60 ◽

pp. 249-258

Author(s):

Jiamin Qi ◽

Shulan Zhou ◽

Ke Xie ◽

Sen Lin

Keyword(s):

Lewis Acid ◽

Acid Sites ◽

Lewis Acid Sites ◽

Catalytic Role

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Oxidation of Ethanol in Cu-Faujasites Studied by IR Spectroscopy

Molecules ◽

10.3390/molecules26092669 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2669

Author(s):

Łukasz Kuterasiński ◽

Jerzy Podobiński ◽

Jerzy Datka

Keyword(s):

Ethanol Oxidation ◽

Produced Water ◽

Acid Sites ◽

No Adsorption ◽

Ir Studies ◽

Oxygen Donor ◽

Before And After ◽

Acetate Formation ◽

Back Donation

In this study, IR studies of the coadsorption of ethanol and CO on Cu+ cations evidenced the transfer of electrons from ethanol to Cu+, which caused the lowering of the frequency of the band attributed to CO bonded to the same Cu+ cation due to the more effective π back donation of d electrons of Cu to antibonding π* orbitals of CO. The reaction of ethanol with acid sites in zeolite HFAU above 370 K produced water and ethane, polymerizing to polyethylene. Ethanol adsorbed on zeolite Cu(2)HFAU containing acid sites and Cu+exch also produced ethene, but in this case, the ethene was bonded to Cu+ and did not polymerize. C=C stretching, which is IR non-active in the free ethene molecule, became IR active, and a weak IR band at 1538 cm−1 was present. The reaction of ethanol above 370 K in Cu(5)NaFAU zeolite (containing small amounts of Cu+exch and bigger amounts of Cu+ox, Cu2+exch and CuO) produced acetaldehyde, which was further oxidized to the acetate species (CH3COO-). As oxygen was not supplied, the donors of oxygen were the Cu species present in our zeolite. The CO and NO adsorption experiments performed in Cu-zeolite before and after ethanol reaction evidenced that both Cu+ox and Cu2+ (Cu2+exch and CuO) were consumed by the ethanol oxidation reaction. The studies of the considered reaction of bulk CuO and Cu2O as well as zeolites, in which the contribution of Cu+ox species was reduced by various treatments, suggest that ethanol was oxidized to acetaldehyde by Cu2+ox (the role of Cu+ox could not be elucidated), but Cu+ox was the oxygen donor in the acetate formation.

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