European Journal of Organic Chemistry, Nov 26, 2018
These reactions also occurred with a very good selectivity to the targeted products. These perfor... more These reactions also occurred with a very good selectivity to the targeted products. These performances are in line with the basicity of these catalysts demonstrated from CO2 chemisorption measurements. The effect of the nano-size and the interaction of the nano-particles with the graphene are also important to achieve this high activity.
Bimodal porous Al–UVM-7 system materials with different Si-to-Al ratios were prepared using the A... more Bimodal porous Al–UVM-7 system materials with different Si-to-Al ratios were prepared using the Atrane route. These were converted in strong acid heterogeneous AlTf-based catalysts after the treatment with methanolic solutions of triflic acid. The materials so obtained were used as catalysts for the conversion of ethylene glycol (EG) and propylene glycol (PG) with octanol under solvent-free conditions. The process is
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Collection of Czechoslovak Chemical Communications, Apr 5, 2013
ABSTRACT Postsynthetic modification of [Cu2(mand)2(hmt)] (mand=mandelic acid, hmt=hexamethylenete... more ABSTRACT Postsynthetic modification of [Cu2(mand)2(hmt)] (mand=mandelic acid, hmt=hexamethylenetetramine) with a chiral, dimeric chromium(III)–salen complex led to a robust structure. Characterization of this new material showed that it perfectly preserved the textural and structural properties of the parent metal–organic framework (MOF). Although epoxidation of trans-methyl cinnamate with hydrogen peroxide led to copper leaching of 2–3 %, experiments performed with N-methylmorpholine-N-oxide indicated no leaching, even after 72 h of exposure. The obtained chiral MOF is an effective catalyst for the enantioselective epoxidation of trans-methyl cinnamate and leads to (2R,3S)-phenylglycidate with a high enantiomeric excess at room temperature.
The catalytic hydrotreatment of humins, the solid byproduct produced from the conversion of C6 su... more The catalytic hydrotreatment of humins, the solid byproduct produced from the conversion of C6 sugars (glucose, fructose) to 5-hydroxymethylfurfural (HMF), using supported Pd@zeolite (Beta, Y, and USY) catalysts with different amounts of Pd (i.e., 0.5, 1.0 and 1.5 wt%) was investigated under molecular hydrogen pressure. The highest conversion of humins (52.0%) was obtained on 1.5Pd@USY catalyst while the highest amount of humins oil (27.3%) was obtained in the presence of the 1Pd@Beta zeolite sample, at PH2 = 30 bars and T = 250 °C. The major compounds in the humins oil evidenced by GC-MS are alcohols, organic acids, ethers, and alkyl-phenolics. However, although all these classes of compounds are obtained regardless of the nature of the catalyst used, the composition of the mixture differs from one catalyst to another. Furanic compounds were not identified in the reaction products. A possible explanation may be related to their high reactivity under the reaction conditions, in the ...
Pyrolysis of chitosan films containing Au 3+ renders 1.1.1 oriented Au nanoplatelets (20 nm later... more Pyrolysis of chitosan films containing Au 3+ renders 1.1.1 oriented Au nanoplatelets (20 nm lateral size, 3-4 nm height) on few layers N-doped graphene (Au ̅̅̅̅ /fl-G), while the lateral sides were 0.0.1 oriented. Comparison of the catalytic activity of Au ̅̅̅̅ /fl-G films with powders of unoriented Au NPs supported on few layer graphene showed that Au ̅̅̅̅ /fl-G films exhibit six orders of magnitude enhancement for three Au-catalyzed reactions, namely, the Ullmannlike homocoupling, the C-N cross coupling and the oxidative coupling of benzene to benzoic acid as result of the defined morphology, facet orientation of Au nanocrystals and strong Augraphene interaction. Catalysis by supported metal nanoparticles (MNPs) has been a very active field of research in the last thirty years. Remarkable examples of highly active and selective MNP catalysts for organic transformations including aerobic oxidations, couplings and rearrangements have been reported. Catalysis by gold constitutes one ...
Bimodal porous Al–UVM-7 system materials with different Si-to-Al ratios were prepared using the A... more Bimodal porous Al–UVM-7 system materials with different Si-to-Al ratios were prepared using the Atrane route. These were converted in strong acid heterogeneous AlTf-based catalysts after the treatment with methanolic solutions of triflic acid. The materials so obtained were used as catalysts for the conversion of ethylene glycol (EG) and propylene glycol (PG) with octanol under solvent-free conditions. The process is selective to short ethoxylated structures resulting in the corresponding monoethers. While the conversion of EG and PG was very high (>94%) irrespective of the support characteristics, 1-octanol was transformed only in low degree (3–35%), and its conversion depends on both the Si/Al molar ratio and the catalyst texture (Al–UVM-7 or AlTf–UVM-7). Recyclable experiments showed the catalysts are stable and the reuse occurred without changes in the chemical composition.
Nanometer-thick films of antimony oxide nanoparticles grafted on defective graphenes as heterogen... more Nanometer-thick films of antimony oxide nanoparticles grafted on defective graphenes as heterogeneous base catalysts for coupling reactions,
∞3[Cu2(mand)2(hmt)]·H2O (where mand is totally deprotonated mandelic acid (racemic mixture) and h... more ∞3[Cu2(mand)2(hmt)]·H2O (where mand is totally deprotonated mandelic acid (racemic mixture) and hmt is hexamethylenetetramine) proved to be a stable metal–organic framework (MOF) structure under thermal activation and catalytic conditions, as confirmed by both the in situ PXRD (Powder X-ray diffraction) and ATR–FTIR (Attenuated total reflection-Fourier-transform infrared spectroscopy) haracterization. The non-activated MOF was completely inert as catalyst for the Henry reaction, as the accessibility of the substrates to the channels was completely blocked by H-bonded water to the mand entities and CO2 adsorbed on the Lewis basic sites of the hmt. Heating at 140 °C removed these molecules. Only an insignificant change in the relative ratios of the XRD facets due to the capillary forces associated to the removal of the guest molecules from the network has been observed. This treatment afforded the accessibility of nitromethane and various aldehydes (4-bromobenzaldehyde, 4-nitrobenzald...
The compounds [2-(Me 2 NCH 2)C 6 H 4 ] 2 SbL (L = ONO 2 (2), OSO 2 CF 3 (3)) and [PhCH 2 N(CH 2 C... more The compounds [2-(Me 2 NCH 2)C 6 H 4 ] 2 SbL (L = ONO 2 (2), OSO 2 CF 3 (3)) and [PhCH 2 N(CH 2 C 6 H 4) 2 ]SbL (L = ONO 2 (5), OSO 2 CF 3 (6)) were prepared by reacting [2-(Me 2 NCH 2)C 6 H 4 ] 2 SbCl (1) and [PhCH 2 N(CH 2 C 6 H 4) 2 ]SbCl (4), respectively, with the appropriate silver(I) salt in a 1:1 molar ratio. The new species 2-6 were structurally characterized in solution using multinuclear NMR and in the solid state using infrared spectroscopy. The solid-state structures for compounds 2, 4 and 6, as well as for the hydrolysis ionic product [{2-(Me 2 N + HCH 2)C 6 H 4 }{2-(Me 2 NCH 2)C 6 H 4 }SbOH][CF 3 SO 3 ] − (3h) were determined using single-crystal X-ray diffraction. Medium to strong intramolecular N! Sb interactions were observed in all these four compounds, thus resulting in hypercoordinated organoantimony(III) species 14-Sb-6 in 2 and 10-Sb-4 in the cation of 3h and in 4 and 6. Compounds 1-6 and the starting amines PhCH 2 NMe 2 and PhCH 2 N(CH 2 C 6 H 4 Br-2) 2 were investigated as catalysts in the Henry (nitroaldol) addition of nitromethane to benzaldehyde. The activity of compounds 1-6 resulted as an effect of the cooperation of the positively charged antimony with the negatively charged nitrogen.
The catalytic potential of triflate-based activated carbon composites has been investigated in ph... more The catalytic potential of triflate-based activated carbon composites has been investigated in phenprocoumon (C3-alkylated compound) synthesis, through the alkylation of 4-hydroxycoumarin with phenyl-ethyl-carbinol. The main reaction products are O-and C3-alkylated compounds. However, O-alkylated product is more easily produced to the detriment of the C3-alkylated compound, the selective synthesis of the last being a challenge in these conditions. Both the conversion of 4-hydroxycoumarin and the selectivity to C3-alkylated compound is highly influenced by the physico-chemical characteristics of the catalysts and the reaction conditions. The highest 4-hydroxycoumarin conversions (16.0-30.0%) and selectivity to phenprocoumon (94.0-99.7%) were achieved with triflate-based activated carbon composites, characterized by the existence of strong Brønsted acid sites, optimal Lewis/Brønsted acid ratio, and bimodal micro-/mesoporosity.
Few-layered graphene-supported 1.1.1 and 2.0.0 oriented Au and Cu2O nanoplatelets were prepared b... more Few-layered graphene-supported 1.1.1 and 2.0.0 oriented Au and Cu2O nanoplatelets were prepared by one-step pyrolysis of the corresponding metal salts embedded in chitosan at 900 C under inert atmosphere. These nanometric films containing oriented nanoplatelets were investigated in a series of reactions as Ullmann-type homocoupling, C-N cross-coupling and Michael addition. The catalysts exhibited turnover numbers (TONs) three to six orders of magnitude higher than those of analogous graphene-supported unoriented metal nanoparticles. In addition it has been found that oriented Cu2O and Au nanoplatelets grafted on defective graphene also exhibit activity to promote the Michael addition of compounds with active methylene and methine hydrogens to conjugated ketone. An exhaustive characterization of these materials using spectroscopic and electron microscopy analyses has been carried out. CO2 thermoprogrammed desorption measurements show that films of these two graphene supported catalysts exhibit some basicity that can explain their activity to promote Michael addition.
N-doped defective graphene [(N)G] obtained by pyrolysis at 900 o C of chitosan contains about 3.7... more N-doped defective graphene [(N)G] obtained by pyrolysis at 900 o C of chitosan contains about 3.7 % of residual N atoms, distributed as pyridinic, pyrrolic and graphitic N atoms. It has been found that (N)G acts as basic catalyst promoting two classical CC bond forming nucleophilic additions in organic chemistry, such as the Michael and the Henry additions. Computational calculations at DFT level of models corresponding to the various N atoms leads to the conclusion that N atoms are more stable at the periphery of the graphene sheets and that H adsorption on these sites is a suitable descriptor to correlate with the catalytic activity of the various sites. According to these calculations the most active sites are pyridinic N atoms at zigzag edges of the sheets. In addition, N as dopant changes the reactivity of the neighbour C atoms. Water was found a suitable solvent to achieve high conversions in both reactions. In this solvent the initial distribution of N atoms is affected due to the easy protonation of the NPy to NPyH sites. As an effect, C edge sites adjacent at NPyH with an appropriate reactivity towards the α-C-H bond breaking are formed. The present results show the general activity of Ndoped graphene as base catalysts and illustrate the potential of carbocatalysis to promote reactions of general interest in organic synthesis.
Highlights Chemo-and diastereoselective hydrogenation of Formoterol intermediate. The influen... more Highlights Chemo-and diastereoselective hydrogenation of Formoterol intermediate. The influence of the metal@zeolite catalysts characteristics upon the catalysts performances. The influence of the metal particles dispersion and reduction degree upon chemo-and diastereoselectivity. H-BEA has an essential role as a selectivity-promoting support. Hydrogenation reaction is sensitive to the catalyst structure.
The one-pot production of HMF from glucose in biphasic water/MIBK solvent using Nb(0.02 and 0.05m... more The one-pot production of HMF from glucose in biphasic water/MIBK solvent using Nb(0.02 and 0.05moles%)-Beta zeolites occurs with a selectivity to HMF of 84.3% for a glucose conversion of 97.4%. Highlights Niobium-Beta zeolites were prepared via a post synthesis methodology Efficient one-pot transformation of glucose to 5-hydroxymethylfurfural (HMF) The catalysts are stable in hot water, at 180C Working in biphasic water/MIBK solvent improves the selectivity to HMF
Michael and Henry addition reactions have been investigated using mono (Au and Cu2O) and bimetall... more Michael and Henry addition reactions have been investigated using mono (Au and Cu2O) and bimetallic nanoplatelets (Au/Cu2O) grafted onto few‐layers graphene (fl‐G) films as heterogeneous catalysts by comparison with homogeneous NaOH and K2CO3 ones. In the presence of the heterogeneous catalysts, these reactions occurred in the absence of any extrinsic (NaOH and K2CO3) base with turnover numbers (TONs) at least four orders of magnitude higher. While the homogeneous catalysts provided TONs close to the unity for Au/Cu2O/fl‐G this was of the order of 107. These reactions also occurred with a very good selectivity to the targeted products. These performances are in line with the basicity of these catalysts demonstrated from CO2 chemisorption measurements. The effect of the nanosize and the interaction of the nanoparticles with the graphene are also important to achieve this high activity.
European Journal of Organic Chemistry, Nov 26, 2018
These reactions also occurred with a very good selectivity to the targeted products. These perfor... more These reactions also occurred with a very good selectivity to the targeted products. These performances are in line with the basicity of these catalysts demonstrated from CO2 chemisorption measurements. The effect of the nano-size and the interaction of the nano-particles with the graphene are also important to achieve this high activity.
Bimodal porous Al–UVM-7 system materials with different Si-to-Al ratios were prepared using the A... more Bimodal porous Al–UVM-7 system materials with different Si-to-Al ratios were prepared using the Atrane route. These were converted in strong acid heterogeneous AlTf-based catalysts after the treatment with methanolic solutions of triflic acid. The materials so obtained were used as catalysts for the conversion of ethylene glycol (EG) and propylene glycol (PG) with octanol under solvent-free conditions. The process is
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Collection of Czechoslovak Chemical Communications, Apr 5, 2013
ABSTRACT Postsynthetic modification of [Cu2(mand)2(hmt)] (mand=mandelic acid, hmt=hexamethylenete... more ABSTRACT Postsynthetic modification of [Cu2(mand)2(hmt)] (mand=mandelic acid, hmt=hexamethylenetetramine) with a chiral, dimeric chromium(III)–salen complex led to a robust structure. Characterization of this new material showed that it perfectly preserved the textural and structural properties of the parent metal–organic framework (MOF). Although epoxidation of trans-methyl cinnamate with hydrogen peroxide led to copper leaching of 2–3 %, experiments performed with N-methylmorpholine-N-oxide indicated no leaching, even after 72 h of exposure. The obtained chiral MOF is an effective catalyst for the enantioselective epoxidation of trans-methyl cinnamate and leads to (2R,3S)-phenylglycidate with a high enantiomeric excess at room temperature.
The catalytic hydrotreatment of humins, the solid byproduct produced from the conversion of C6 su... more The catalytic hydrotreatment of humins, the solid byproduct produced from the conversion of C6 sugars (glucose, fructose) to 5-hydroxymethylfurfural (HMF), using supported Pd@zeolite (Beta, Y, and USY) catalysts with different amounts of Pd (i.e., 0.5, 1.0 and 1.5 wt%) was investigated under molecular hydrogen pressure. The highest conversion of humins (52.0%) was obtained on 1.5Pd@USY catalyst while the highest amount of humins oil (27.3%) was obtained in the presence of the 1Pd@Beta zeolite sample, at PH2 = 30 bars and T = 250 °C. The major compounds in the humins oil evidenced by GC-MS are alcohols, organic acids, ethers, and alkyl-phenolics. However, although all these classes of compounds are obtained regardless of the nature of the catalyst used, the composition of the mixture differs from one catalyst to another. Furanic compounds were not identified in the reaction products. A possible explanation may be related to their high reactivity under the reaction conditions, in the ...
Pyrolysis of chitosan films containing Au 3+ renders 1.1.1 oriented Au nanoplatelets (20 nm later... more Pyrolysis of chitosan films containing Au 3+ renders 1.1.1 oriented Au nanoplatelets (20 nm lateral size, 3-4 nm height) on few layers N-doped graphene (Au ̅̅̅̅ /fl-G), while the lateral sides were 0.0.1 oriented. Comparison of the catalytic activity of Au ̅̅̅̅ /fl-G films with powders of unoriented Au NPs supported on few layer graphene showed that Au ̅̅̅̅ /fl-G films exhibit six orders of magnitude enhancement for three Au-catalyzed reactions, namely, the Ullmannlike homocoupling, the C-N cross coupling and the oxidative coupling of benzene to benzoic acid as result of the defined morphology, facet orientation of Au nanocrystals and strong Augraphene interaction. Catalysis by supported metal nanoparticles (MNPs) has been a very active field of research in the last thirty years. Remarkable examples of highly active and selective MNP catalysts for organic transformations including aerobic oxidations, couplings and rearrangements have been reported. Catalysis by gold constitutes one ...
Bimodal porous Al–UVM-7 system materials with different Si-to-Al ratios were prepared using the A... more Bimodal porous Al–UVM-7 system materials with different Si-to-Al ratios were prepared using the Atrane route. These were converted in strong acid heterogeneous AlTf-based catalysts after the treatment with methanolic solutions of triflic acid. The materials so obtained were used as catalysts for the conversion of ethylene glycol (EG) and propylene glycol (PG) with octanol under solvent-free conditions. The process is selective to short ethoxylated structures resulting in the corresponding monoethers. While the conversion of EG and PG was very high (>94%) irrespective of the support characteristics, 1-octanol was transformed only in low degree (3–35%), and its conversion depends on both the Si/Al molar ratio and the catalyst texture (Al–UVM-7 or AlTf–UVM-7). Recyclable experiments showed the catalysts are stable and the reuse occurred without changes in the chemical composition.
Nanometer-thick films of antimony oxide nanoparticles grafted on defective graphenes as heterogen... more Nanometer-thick films of antimony oxide nanoparticles grafted on defective graphenes as heterogeneous base catalysts for coupling reactions,
∞3[Cu2(mand)2(hmt)]·H2O (where mand is totally deprotonated mandelic acid (racemic mixture) and h... more ∞3[Cu2(mand)2(hmt)]·H2O (where mand is totally deprotonated mandelic acid (racemic mixture) and hmt is hexamethylenetetramine) proved to be a stable metal–organic framework (MOF) structure under thermal activation and catalytic conditions, as confirmed by both the in situ PXRD (Powder X-ray diffraction) and ATR–FTIR (Attenuated total reflection-Fourier-transform infrared spectroscopy) haracterization. The non-activated MOF was completely inert as catalyst for the Henry reaction, as the accessibility of the substrates to the channels was completely blocked by H-bonded water to the mand entities and CO2 adsorbed on the Lewis basic sites of the hmt. Heating at 140 °C removed these molecules. Only an insignificant change in the relative ratios of the XRD facets due to the capillary forces associated to the removal of the guest molecules from the network has been observed. This treatment afforded the accessibility of nitromethane and various aldehydes (4-bromobenzaldehyde, 4-nitrobenzald...
The compounds [2-(Me 2 NCH 2)C 6 H 4 ] 2 SbL (L = ONO 2 (2), OSO 2 CF 3 (3)) and [PhCH 2 N(CH 2 C... more The compounds [2-(Me 2 NCH 2)C 6 H 4 ] 2 SbL (L = ONO 2 (2), OSO 2 CF 3 (3)) and [PhCH 2 N(CH 2 C 6 H 4) 2 ]SbL (L = ONO 2 (5), OSO 2 CF 3 (6)) were prepared by reacting [2-(Me 2 NCH 2)C 6 H 4 ] 2 SbCl (1) and [PhCH 2 N(CH 2 C 6 H 4) 2 ]SbCl (4), respectively, with the appropriate silver(I) salt in a 1:1 molar ratio. The new species 2-6 were structurally characterized in solution using multinuclear NMR and in the solid state using infrared spectroscopy. The solid-state structures for compounds 2, 4 and 6, as well as for the hydrolysis ionic product [{2-(Me 2 N + HCH 2)C 6 H 4 }{2-(Me 2 NCH 2)C 6 H 4 }SbOH][CF 3 SO 3 ] − (3h) were determined using single-crystal X-ray diffraction. Medium to strong intramolecular N! Sb interactions were observed in all these four compounds, thus resulting in hypercoordinated organoantimony(III) species 14-Sb-6 in 2 and 10-Sb-4 in the cation of 3h and in 4 and 6. Compounds 1-6 and the starting amines PhCH 2 NMe 2 and PhCH 2 N(CH 2 C 6 H 4 Br-2) 2 were investigated as catalysts in the Henry (nitroaldol) addition of nitromethane to benzaldehyde. The activity of compounds 1-6 resulted as an effect of the cooperation of the positively charged antimony with the negatively charged nitrogen.
The catalytic potential of triflate-based activated carbon composites has been investigated in ph... more The catalytic potential of triflate-based activated carbon composites has been investigated in phenprocoumon (C3-alkylated compound) synthesis, through the alkylation of 4-hydroxycoumarin with phenyl-ethyl-carbinol. The main reaction products are O-and C3-alkylated compounds. However, O-alkylated product is more easily produced to the detriment of the C3-alkylated compound, the selective synthesis of the last being a challenge in these conditions. Both the conversion of 4-hydroxycoumarin and the selectivity to C3-alkylated compound is highly influenced by the physico-chemical characteristics of the catalysts and the reaction conditions. The highest 4-hydroxycoumarin conversions (16.0-30.0%) and selectivity to phenprocoumon (94.0-99.7%) were achieved with triflate-based activated carbon composites, characterized by the existence of strong Brønsted acid sites, optimal Lewis/Brønsted acid ratio, and bimodal micro-/mesoporosity.
Few-layered graphene-supported 1.1.1 and 2.0.0 oriented Au and Cu2O nanoplatelets were prepared b... more Few-layered graphene-supported 1.1.1 and 2.0.0 oriented Au and Cu2O nanoplatelets were prepared by one-step pyrolysis of the corresponding metal salts embedded in chitosan at 900 C under inert atmosphere. These nanometric films containing oriented nanoplatelets were investigated in a series of reactions as Ullmann-type homocoupling, C-N cross-coupling and Michael addition. The catalysts exhibited turnover numbers (TONs) three to six orders of magnitude higher than those of analogous graphene-supported unoriented metal nanoparticles. In addition it has been found that oriented Cu2O and Au nanoplatelets grafted on defective graphene also exhibit activity to promote the Michael addition of compounds with active methylene and methine hydrogens to conjugated ketone. An exhaustive characterization of these materials using spectroscopic and electron microscopy analyses has been carried out. CO2 thermoprogrammed desorption measurements show that films of these two graphene supported catalysts exhibit some basicity that can explain their activity to promote Michael addition.
N-doped defective graphene [(N)G] obtained by pyrolysis at 900 o C of chitosan contains about 3.7... more N-doped defective graphene [(N)G] obtained by pyrolysis at 900 o C of chitosan contains about 3.7 % of residual N atoms, distributed as pyridinic, pyrrolic and graphitic N atoms. It has been found that (N)G acts as basic catalyst promoting two classical CC bond forming nucleophilic additions in organic chemistry, such as the Michael and the Henry additions. Computational calculations at DFT level of models corresponding to the various N atoms leads to the conclusion that N atoms are more stable at the periphery of the graphene sheets and that H adsorption on these sites is a suitable descriptor to correlate with the catalytic activity of the various sites. According to these calculations the most active sites are pyridinic N atoms at zigzag edges of the sheets. In addition, N as dopant changes the reactivity of the neighbour C atoms. Water was found a suitable solvent to achieve high conversions in both reactions. In this solvent the initial distribution of N atoms is affected due to the easy protonation of the NPy to NPyH sites. As an effect, C edge sites adjacent at NPyH with an appropriate reactivity towards the α-C-H bond breaking are formed. The present results show the general activity of Ndoped graphene as base catalysts and illustrate the potential of carbocatalysis to promote reactions of general interest in organic synthesis.
Highlights Chemo-and diastereoselective hydrogenation of Formoterol intermediate. The influen... more Highlights Chemo-and diastereoselective hydrogenation of Formoterol intermediate. The influence of the metal@zeolite catalysts characteristics upon the catalysts performances. The influence of the metal particles dispersion and reduction degree upon chemo-and diastereoselectivity. H-BEA has an essential role as a selectivity-promoting support. Hydrogenation reaction is sensitive to the catalyst structure.
The one-pot production of HMF from glucose in biphasic water/MIBK solvent using Nb(0.02 and 0.05m... more The one-pot production of HMF from glucose in biphasic water/MIBK solvent using Nb(0.02 and 0.05moles%)-Beta zeolites occurs with a selectivity to HMF of 84.3% for a glucose conversion of 97.4%. Highlights Niobium-Beta zeolites were prepared via a post synthesis methodology Efficient one-pot transformation of glucose to 5-hydroxymethylfurfural (HMF) The catalysts are stable in hot water, at 180C Working in biphasic water/MIBK solvent improves the selectivity to HMF
Michael and Henry addition reactions have been investigated using mono (Au and Cu2O) and bimetall... more Michael and Henry addition reactions have been investigated using mono (Au and Cu2O) and bimetallic nanoplatelets (Au/Cu2O) grafted onto few‐layers graphene (fl‐G) films as heterogeneous catalysts by comparison with homogeneous NaOH and K2CO3 ones. In the presence of the heterogeneous catalysts, these reactions occurred in the absence of any extrinsic (NaOH and K2CO3) base with turnover numbers (TONs) at least four orders of magnitude higher. While the homogeneous catalysts provided TONs close to the unity for Au/Cu2O/fl‐G this was of the order of 107. These reactions also occurred with a very good selectivity to the targeted products. These performances are in line with the basicity of these catalysts demonstrated from CO2 chemisorption measurements. The effect of the nanosize and the interaction of the nanoparticles with the graphene are also important to achieve this high activity.
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Papers by Natalia Candu