Silicate anion intercalated cobalt-aluminium hydrotalcite (CoAl-HT-Si): a potential catalyst for alcohol oxidation

Baskaran, Thangaraj; Kumaravel, R.; Christopher, J.; Sakthivel, Ayyamperumal

doi:10.1039/c3ra46703a

Cited by 40 publications

(30 citation statements)

References 92 publications

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“…In all the cases, excellent conversions with selective formation of carbonyl compounds were observed and the results are comparable with literature [30]. In addition, cobalt oxide supported on silica and alumina was also studied under identical conditions, which yielded only 23 and 12 % conversion with an exclusive formation of carbonyl compound [23]. Thus, the presence of cobalt complex on the surface of SBA-15 with uniform distribution favors better activity.…”

Section: Resultssupporting

confidence: 80%

“…It is clear from the table that the conversion of alcohol reduced from 87 to 44 % in presence of radical scavenger. The above facts supports that the reaction precedes through radical mechanism on cobalticinim complex grafted SBA-15, which is similar to that of the cobalt based catalyst [23,42]. …”

Section: Resultssupporting

confidence: 67%

“…Heterogenization of various transition metal based homogenous catalysis with salen, acac, and cyclopentadienyl-based ligands are shown very good catalytic ability for several oxidation reactions [16][17][18][19][20][21]. In this regard, cobalt based catalysts also shown comparable activity towards various organic transformations, such as hydroformylation, hydrosilylation, Fisher-Tropsch synthesis, hydroxylation, reforming, and various redox processes [22][23][24][25][26][27][28][29][30][31]. For example, cobalt-polyaniline nanostructure hosted SBA-15 shown as a capable catalyst for oxidation process [29].…”

Section: Introductionmentioning

confidence: 95%

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Synthesis and Heterogenization of Siloxane Functionalized Cobalt Complex: Potential Catalyst for Oxidation of Alcohols

et al. 2015

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Cobalticinium complex containing siloxane moiety on ligand center was first time synthesized, characterized and heterogenized on the surface of SBA-15 molecular sieves. FT-IR and 29 Si-MAS-NMR spectrum evidence the successful grafting of the cobalt complex on the surface of SBA-15. N 2 sorption isotherm of cobalticinium complex grafted sample showed the decrease in surface area, pore volume, further confirms the presence of complex inside the channel of mesoporous SBA-15. The heterogenized complex exhibited promising activity for oxidation of alcohols with good selectivity of ketone. Further the catalytic activity remains intact after two recycles. Graphical Abstract Cobalticinium complex possessing siloxane functionality was prepared first time and heterogenized on SBA-15 surface. The resultant materials showed as promising recyclable heterogeneous catalyst for oxidation of alcohols.

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Section: Resultssupporting

confidence: 80%

Section: Resultssupporting

confidence: 67%

Section: Introductionmentioning

confidence: 95%

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Synthesis and Heterogenization of Siloxane Functionalized Cobalt Complex: Potential Catalyst for Oxidation of Alcohols

et al. 2015

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“…It is quite understandable that hydrogen peroxide can be activated either by cobalt [20] or silanol groups [44] 41 containing silanol groups as well as Co(II) yields mixture of products 2 and 3. Increment of OH-groups with increase in cobalt content in CoMCM-41 can lead to proton extraction both from benzylic carbon as well as from phenolic substrate.…”

Section: Catalyst Ch Cn H Omentioning

confidence: 99%

“…Cobalt(II) present in the catalyst, interacts with the hydrogen peroxide yielding hydroxyl radical [43,44]. Subsequently, the reaction proceeds in two possible pathways, the hydroxy radical formed either abstracts a phenolic hydrogen atom from the phenolic substrate (1) (path-1) and produces a reactive phenoxy radical (4) or it abstracts a proton from the benzylic carbon (path-2), forming the reactive radical (6).…”

Section: Catalyst Ch Cn H Omentioning

confidence: 99%

Catalytic Conversion of Lignin: Studies on Oxidation of Lignin Model Phenolic Monomer over CoMCM-41 and CoMCM-48 Catalysts

Sadual¹,

Badamali²

2018

Asian J. Chem.

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INTRODUCTIONLignin is an integral component of plants and is most abundant aromatic biopolymer in earth which can serve as a renewable resource of chemical feedstock. It is suggested that catalytic oxidation of lignin or lignin derived fragments is interesting as it is expected to yield functionalized chemicals which can be employed in fine chemical synthesis [1]. In this subject, several reports have been appeared in literature largely focused on catalytic reactions of lignin model compounds which could provide useful information for the development of selective and high yield processes of lignin oxidation namely the conversion of lignin to aromatic monomers catalyzed by triflic acid [2], depolymerization of oxidized lignin to aromatics by formic acid [3], oxidation of phenolic and non-phenolic compounds in presence of metal chlorides in ionic liquid medium [4] are some of the significant achievements in the area of lignin valorization. Among the lignin model phenolic monomers, apocynol, 1-(4-hydroxy-3-methoxyphenoxy)-ethanol is commonly studied over many catalysts. Recently, much attention is focussed on the catalytic oxidation of lignin derived fragments to fine chemicals. Wozniak et al. [5] have studied the liquid phase oxidation of apocynol over potassium nitrosodisulfonate (Fremy's salt) and corresponding benzo- The present study focussed on investigation of the potentiality of cobalt containing mesoporous material (M41S) as a robust heterogeneous catalyst for the oxidation of lignin model phenolic compound. Cobalt containing MCM-41 and MCM-48 were prepared under hydrothermal condition and characterized by various spectroscopic and analytical techniques. Formation of well ordered hexagonal and cubic mesopore structures of MCMs, containing cobalt in the silicate framework was inferred from XRD, TG-DTA and N2 adsorption-desorption studies. DR UV-visible spectral analysis revealed existence of Co(II) and Co(III) in the tetrahedral framework. The oxidative ability of CoMCMs were studied for the lignin model phenolic monomer, 1-(4-hydroxy-3-methoxyphenoxy)-ethanol, under mild conditions using environmentally benign H2O2 as the oxidant. The catalytic results showed that under optimum reaction conditions, apocynol undergoes selective oxidation yielding 2-methoxybenzoquinone and acetovanillone. CoMCM-41 was found to be more selective towards acetovanillone, on the contrary, CoMCM-48 was better catalyst for 2-methoxybenzoquinone yield.

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Preparation of an MCM‐22/Hydrotalcite Framework Composite and Its Catalytic Application

et al. 2017

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A composite material (MAMCM), possessing both a layered cationic MgAl‐hydrotalcite (MA‐HT) and an anionic MCM‐22 framework, was prepared by a simple coprecipitation method. The resulting composite material has features of both MCM‐22 and the HT layered framework, as shown by powder XRD, FTIR, 29Si and 27Al‐MAS NMR spectroscopy, and SEM studies. Electron microscopy revealed that the layer sheets are arranged in a spherical morphology. The composite material was utilized for the vapor‐phase alkylation of toluene. The MAMCM material showed better toluene conversion than MCM‐22 and MA‐HT materials.

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Silicate anion intercalated cobalt-aluminium hydrotalcite (CoAl-HT-Si): a potential catalyst for alcohol oxidation

Cited by 40 publications

References 92 publications

Synthesis and Heterogenization of Siloxane Functionalized Cobalt Complex: Potential Catalyst for Oxidation of Alcohols

Synthesis and Heterogenization of Siloxane Functionalized Cobalt Complex: Potential Catalyst for Oxidation of Alcohols

Catalytic Conversion of Lignin: Studies on Oxidation of Lignin Model Phenolic Monomer over CoMCM-41 and CoMCM-48 Catalysts

Preparation of an MCM‐22/Hydrotalcite Framework Composite and Its Catalytic Application

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