S M A Hakim Siddiki

S M A Hakim Siddiki
Tokyo Metropolitan University | TMU · Department of Chemistry

PhD

About

93
Publications
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2,084
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Publications

Publications (93)
Article
Barium (Ba) has been widely and successfully added to three‐way catalysts to effectively control gasoline vehicle emissions. While the introduction of Ba is well‐known to have a very significant impact on three‐way catalysis (TWC) performance, the role of Ba under practical TWC conditions remains insufficiently understood. In this study, we investi...
Article
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Transesterification of ethyl-10-undecenoate (derived from castor oil) with 1,4-cyclohexanedimethanol over a recyclable Cu-deposited V2O5 catalyst afforded 1,ω-diene, the corresponding cyclohexane-1,4-diylbis(methylene) bis(undec-10-enoate), a promising monomer for the synthesis of biobased polyesters, in an efficient manner. Deposition of Cu plays...
Article
We report a cost-effective, green, and acceptorless dehydrogenative one-pot synthesis of triazine from primary alcohols and amidines using alumina-supported Pt nanoparticle catalyst (Pt/Al 2 O 3 ). This reaction proceeds with high atom efficiency...
Article
The reverse water-gas shift (RWGS) reaction is a promising catalytic route for reducing CO2emissions because its product, CO, is a key intermediate in various industrialized catalytic processes that produce fuels and chemicals. We describe herein a MoOx/TiO2-supported Pt catalyst (Pt(3)/MoOx(15)/TiO2; Pt loading = 3 wt%, MoO3loading = 15 wt%) that...
Article
We have constructed and analyzed an updated dataset consisting of 4759 experimental datapoints for the oxidative coupling of methane (OCM) reaction based on literature data reported before 2020 (~2019) using machine learning (ML) methods. Several ML methods, including random forest regression (RFR), extra trees regression (ETR), and gradient boosti...
Article
Hydrolysis of amides to carboxylic acids is an industrially important reaction but is challenging due to the difficulty of cleaving the resonance stabilized amidic C–N bond. Twenty-three heterogeneous and homogenous catalysts were examined in the hydrolysis of acetamide. Results showed that Nb2O5 was the most effective heterogeneous catalyst with t...
Article
Methods have been reported for the preparation of ω-functionalized alkyl maltoside and glycoside detergents via a simple and inexpensive synthetic route. The key step was stannic chloride-mediated glycosylation of long-chain alcohols or thiols with maltose octaacetate at 0 or-10°C, respectively, within a very short time (isolated yield 17-44%), whi...
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We report herein that a commercially available CeO2 is an active and reusable catalyst for the C3-selective alkenylation of oxindole with aldehydes under solvent-free conditions. This catalytic method is generally applicable to different aromatic and aliphatic aldehydes, giving 3-alkyledene-oxindoles in high yields (87%–99%) and high stereoselectiv...
Article
A combined catalyst comprising TiO2‐supported Re (Re(1)/TiO2; Re = 1 wt%) and H‐MOR (SiO2/Al2O3 = 90) was found to promote the methylation of benzene using CO2 and H2. This catalytic system exhibited high performance with regard to the synthesis of methylated benzenes and gave high yields of total methylated products (up to 52% benzene‐based yield...
Chapter
Heterogeneous catalysis as a part of the biorefinery concept is the key technology to connect the divergence between the transformation of biomass-derived platform molecules with value-added compounds including chemicals, biofuels and its precursors, energy by means of aqueous-phase processing and environmentally benign processes. Recent advancemen...
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Cyclic anhydrides, key intermediates of carbon-neutral and biodegradable polyesters, are currently produced from biomass-derived dicarboxylic acids by a high-cost multistep process. We present a new high-yielding process for the direct intramolecular dehydration of dicarboxylic acids using a reusable heterogeneous Lewis acid catalyst, Nb2O5·nH2O. V...
Article
The structure and performance of TiO2-supported Re (Re/TiO2) catalysts for selective hydrogenation of carboxylic acid derivatives have been investigated. Re/TiO2 promotes selective hydrogenation reactions of carboxylic acids and esters that form the corresponding alcohols, and of amides that generate the corresponding amines. These processes are no...
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Transesterification of biomass-derived triglycerides with methanol (methanolysis of triglycerides) is a promising method for the industrial production of the biodiesel fuel, fatty acid methyl esters (FAMEs). Herein, we present a simple heterogeneous catalytic method for the selective transformation of triglycerides into FAMEs. For the methanolysis...
Article
Efficient conversion of CO2 into useful chemicals, exemplified by the development of methods for low-temperature hydrogenation of CO2 to form methanol (CH3OH), is a highly attractive research target. Herein, we report that Pt nanoparticles, loaded on MoOx/TiO2 as a support (Pt(3)/MoOx(30)/TiO2; Pt = 3 wt%, MoO3 = 30 wt%), promote selective hydrogen...
Article
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Invited for the cover of this issue are the groups of Ken‐ichi Shimizu at the Institute for Catalysis, Hokkaido University. The image depicts phenolysis of amides through C−N bond cleavage reaction catalyzed by CeO2. Read the full text of the article at 10.1002/chem.201901446. “We hope that our contributions can stimulate innovative catalyst design...
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The Cover Feature shows transformations of triglycerides into fatty amines, amides, and nitriles using NH3 and H2. More information can be found in the Full Paper by Jamil et al.
Article
CeO2 catalyzed C−N bond cleavage reaction of amides is reported. This catalytic system overcomes the typical stability issue of amides and phenols and thus offers a straightforward route to the synthesis of phenolic esters. Compared to previously reported catalytic methods for the phenolysis of activated amides, this method offers advantages of cat...
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The direct catalytic esterification of amides that leads to the construction of C–O bonds through the cleavage of amide C–N bonds is a highly attractive strategy in organic synthesis. While aliphatic alcohols can be readily used for the alcoholysis of activated and unactivated amides, the introduction of aromatic alcohols such as phenols is more ch...
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Hydrogenation of carbon dioxide (CO2) to methanol (CH3OH) is an effective strategy for CO2 utilization. Due to a low equilibrium conversion of CO2 at high temperature, development of efficient catalytic CO2 hydrogenation processes that operate under low reaction temperature is of extreme importance. Herein, we report that TiO2-supported Re (Re(1)/T...
Article
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The use of triglycerides as an important class of biomass is an effective strategy to realize a more sustainable society. Herein, we present three types of heterogeneous catalytic methods for the selective one‐pot transformation of triglycerides into value‐added chemicals: (i) the reductive amination of triglycerides to fatty amines with aqueous NH...
Article
We report herein the selective N-methylation of amines and nitroarenes with methanol under basic conditions using carbon-supported Pt nanoparticles (Pt/C) as a heterogeneous catalyst. This method is widely applicable to four types of N-methylation reactions: (1) N,N-dimethylation of aliphatic amines under N 2 , (2) N-monomethylation of aliphatic am...
Article
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The Front Cover shows a C−N bond cleavage reaction catalyzed by CeO2. In their Full Paper, T. Toyao et al. demonstrate that CeO2 promotes catalytic alcoholysis reactions of tertiary amides through C−N bond cleavage to form esters. Unlike typical reactions that use homogeneous catalytic systems and require NHC complexes, the new process is operation...
Article
The front cover artwork for our 10th Anniversary Issue is provided by the research groups of Ken‐ichi Shimizu at Hokkaido University and Kazunari Yoshizawa at Kyushu University (Japan). The image shows a C−N bond cleavage reaction catalyzed by CeO2. See the Full Paper itself at https://doi.org/10.1002/cctc.201801098. “Experimental and computational...
Article
We investigated the hydration of hydrophobic epoxides and alkynes in water using 24 types of heterogeneous and homogeneous catalysts and found that Hbeta (Hβ) zeolite with a relatively high Si/Al ratio (Si/Al = 75), Hβ-75, is an effective catalyst. Hβ-75 showed wide substrate scope, good reusability, and applicability in gram-scale synthesis for bo...
Article
This review focuses on catalytic applications of niobium pentoxide (Nb2O5) and niobic acid (Nb2O5∙nH2O). These materials serve as heterogeneous acid catalysts that show excellent activity and selectivity for various types of reactions including hydrations, dehydrations, and oxidations. Most recently, they have been used for dehydration reactions of...
Article
The front cover artwork is provided by the groups of Dr. Pussana Hirunsit (NANOTEC), Prof. Ken‐ichi Shimizu (Hokkaido University), and Prof. Masahiro Ehara (Institute for Molecular Science). The image shows an efficient amidation reaction on Nb2O5 surface whose catalytic activity is correlated to the position of conduction band of active metal site...
Article
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A one-pot, acceptorless dehydrogenative method, using a carbon-supported Pt catalyst (Pt/C) along with KOtBu, has been developed for the synthesis of 2,4,6-trisubstitutedpyrimidines from secondary and primary alcohols, and amidines. The reaction takes place efficiently using a wide range of substrate scopes (32 examples with isolated yields up to 9...
Article
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The Front Cover illustrates DFT calculations that clarified an efficient amidation on Nb2O5 surface whose catalytic activity is correlated to the position of conduction band of active metal sites and the hybridization to substrates. More information can be found in the Article by P. Hirunsit et al.
Article
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The Cover picture shows sustainable hydrogenation processes for utilization of CO2 and biomass. See the Personal Account by K.‐i. Shimizu et al. (DOI: 10.1002/tcr.201800061).
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The development of heterogeneous catalysts for green chemical synthesis is currently a growing area in catalysis and sustainable chemistry. Especially the use of renewable carbon resources such as carbon dioxide (CO2) and biomass‐derived compounds (e. g. carboxylic acids, esters, and amides) represent highly attractive research targets. As these su...
Article
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The Nb2O5 surface catalyzes the amidation of carboxylic acids with amines via Nb5+ Lewis acid activation of the C=O group. In this work, DFT calculations were applied to theoretically investigate the C=O bond activation of a model carboxylic acid (acetic acid) on Al2O3(110), anatase TiO2(101), and T‐Nb2O5(100) surfaces. The adsorption sites, adsorp...
Article
CeO2 has been found to promote ester forming alcoholysis reactions of tertiary amides. The present catalytic system is operationally simple, recyclable, and it does not require additives. The esterification process displays a wide substrate scope (> 45 examples; up to 93% isolated yield). Results of a density functional theory (DFT) study combined...
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Heterogeneous catalysis for the one-pot synthesis of chemicals is a growing area in green chemistry. Among various types of organic transformations promoted by using this approach, acceptorless dehydrogenative couplings (ADC) have been developed as efficient processes that form various organic substances through C–O, C–N, C–S, C–C and C=C bond form...
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A versatile, selective, and recyclable heterogeneous catalytic method for the methylation of C–H bonds in alcohols, ketones, and indoles with a sustainable C1 resource (methanol) under oxidant-free conditions using a Pt-loaded carbon (Pt/C) catalyst in the presence of NaOH is reported. This catalytic system is effective for various methylation reac...
Article
We report herein the first general catalytic system for direct synthesis of N-substituted γ- and δ-lactams by reductive amination/cyclization of keto acids (including levulinic acid) with nitriles and H2 under mild conditions (7 bar H2, 110 °C, solvent-free). The most effective catalyst, Pt and MoOx co-loaded TiO2 (Pt-MoOx/TiO2), shows a wide subst...
Article
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Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, e.g. hydrogenation of esters to alcohols, hydrogenation of amides to amines, and N-methylation of amines using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic...
Article
Various supported metal catalysts are screened for hydrogenation of lauric acid and 2-octanone as model reactions for the transformation of biomass-derived oxygenates to liquid alkanes (biofuels) in a batch reactor under solvent-free conditions. Among the catalysts tested, Pt and MoOx co-loaded TiO2 (Pt-MoOx/TiO2) shows the highest yields of n-alka...
Article
Among various supported metal nanoparticle catalysts, Pt-loaded carbon (Pt/C) catalysts, including a commercial one, showed the highest yield for selective dehydrogenation of glycerol to lactic acid (LA) under oxidant-free, solvent-free, and alkaline conditions. For the reaction with Pt/C, the effects of conditions (type of basic additives, the amo...
Article
Cyclic anhydrides, as key intermediates of carbon-neutral and biodegradable polyesters, are produced from biomass-derived dicarboxylic acids by a high-cost multistep process. We present a new high-yielding process for direct intermolecular dehydration of dicarboxylic acids using a reusable heterogeneous Lewis acid catalyst, Nb2O5∙nH2O. Various dica...
Article
Invited for the cover of this issue are the group of Ken-ichi Shimizu at Hokkaido University and the group of Kazunari Yoshizawa at Kyushu University. The image depicts the latest findings from Hokkaido dealing with selective hydrogenation of carboxylic acids having aromatic moieties to the corresponding alcohols over Re/TiO2. Read the full text of...
Article
Full-text available
TiO2-supported Re (Re/TiO2) enables selective catalytic hydrogenation of carboxylic acids bearing aromatic and aliphatic moieties to the corresponding alcohols under mild conditions. Contrary to typical heterogeneous catalysts, Re/TiO2 does not lead to the formation of dearomatized byproducts. Re/TiO2 is recyclable as a heterogeneous catalyst and d...
Article
TiO2-supported Re, Re/TiO2, has been found to promote selective hydrogenation of aromatic and aliphatic carboxylic acids to alcohols. Re/TiO2 is superior to other transition metal-loaded TiO2 and supported Re catalysts for selective hydrogenation of 3-phenylpropionic acid. This process produces 3-phenylpropanol in a 97% yield under mild condition (...
Article
Direct synthesis of trimethylamine through N-methylation of NH3 or its surrogate (NH4HCO3) with both CO2 and H2 has been achieved by employing Pt and MoOx coloaded TiO2 (Pt-MoOx/TiO2). Pt-MoOx/TiO2 was found to be superior to other supported Pt and transition-metal-loaded MoOx/TiO2 catalysts for the trimethylamine synthesis process.
Article
Title catalyst is used for the dehydrogenation of sulfoxides to sulfides under solvent-free and mild conditions.
Article
Carbon-supported Pt nanoparticles (Pt/C) are established as effective heterogeneous catalysts for the direct Julia olefination of alcohols in the presence of sulfones and KOtBu under oxidant-free conditions.
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Direct synthesis of 2,5-disubstituted pyrroles has been achieved via acceptorless dehydrogenative heterocyclization of 1,2-aminoalcohols and secondary alcohols by utilizing a heterogeneous carbon-supported Pt catalyst (Pt/C). The optimized method gave 92% yield of 2-ethyl-5-phenyl-1H-pyrrole as a desired product from 2-amino-1-butanol and 1-phenyle...
Article
Pt metal nanoparticles loaded on various supports and carbon-supported various metal catalysts are tested for dehydrogenation of 6-methyl-1,2,3,4- tetrahydroquinoline to 6-methyl-quinoline under oxidant-free conditions. In the 20 types of the catalysts screened, carbon-supported Pt catalyst (Pt/C) shows the highest activity. Pt/C is reusable after...
Article
Among a series of heterogeneous catalysts screened, Pt-Nb2O5 shows the highest catalytic activity in the selective hydrogenation of various tertiary amides (I) and caprolactams (III) to the corresponding amines (II) and (IV), resp.
Article
For the hydrogenation of a tertiary amide (N-acetylpiperidine), Lewis acidic support materials (Nb2O5 and MoOx/TiO2) increase the catalytic activity of Pt metal nanoparticles by a factor of >100. In situ infrared (IR) study shows that coordination of the C=O group of amide to surface Lewis acid sites weakens the C=O bond, and the activated amide un...
Article
Carbon-supported Pt nanoparticles (Pt/C) were found to be effective heterogeneous catalysts for the direct Julia olefination of alcohols in the presence of sulfones and KOtBu under oxidant-free conditions. Primary alcohols, including aryl, aliphatic, allyl, and heterocyclic alcohols, underwent olefination with dimethyl sulfone and aryl alkyl sulfon...
Article
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Supported metal nanoparticle catalysts were studied for the hydrodeoxygenation of sulfoxides to sulfides under solvent-free and mild conditions (50–155 °C, 1 or 7 atm H2). The catalytic activity for the model reaction of diphenyl sulfoxide depended on the type of metals, support materials and co-loaded oxides of transition metals (V, Nb, Mo, W, Re)...
Article
The first example of a heterogeneously catalyzed direct amidation of esters with amines is reported.
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Among 28 types of heterogeneous and homogenous catalysts tested, Nb2O5 shows the highest yield for direct amidation of n-dodecanoic acid with a less reactive amine (aniline). The catalytic amidation by Nb2O5 is applicable to a wide range of carboxylic acids and amines with various functional groups, and the catalyst is reusable. A comparison of the...
Article
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This study reports the first example of a heterogeneous catalytic system for the direct amidation of various esters with amines. Of 25 types of catalyst, Nb2O5 shows the highest activity in the amidation of methyl benzoate with aniline. Nb2O5 gives high yields in the amidation of various esters and amines under solvent-free conditions, is reusable,...
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N-Alkylated indoles [(III) and (V)] are regioselectively synthesized by using Pt-loaded H+-exchanged BEA zeolite as catalyst.
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We found the first heterogeneous Pt catalysts (Pt/Nb2O5 and Pt/HBEA) for the synthesis of indoles via acceptorless dehydrogenative cyclization of 2-(2-aminophenyl)ethanol, showing higher turnover number (TON) than previously reported catalysts.