Manuel Sánchez-Sánchez - Academia.edu (original) (raw)

Papers by Manuel Sánchez-Sánchez

Studies in Surface Science and Catalysis, 1994

The aluminophosphate glasses were prepared by the melting-quenching technique and their optical a... more The aluminophosphate glasses were prepared by the melting-quenching technique and their optical and structural properties were investigated. The 56P2O5-20Al2O3 glass exhibits unique blue emission at 406 nm due to the phosphorus defect in the glass matrix. Addition of SiO2, ZnF2, or Li2O to 56P2O5-20Al2O3 glass matrix has different influence on formation of phosphorus defect resulting in different intensities of blue emission at 406 nm, though SiO2, ZnF2 or Li2O mostly enters the glass network as modifier. Structural analysis of P2O5-Al2O3 based aluminophosphate glasses by positron annihilation lifetime spectroscopy indicates that values of positron lifetimes and the corresponding intensities may be connected with the sizes and number of structural defects. Under excitation of 251 nm, a broad blue emission band and a red emission band were observed in the Mn-doped 56P2O5-20Al2O3-15SiO2-10ZnF2 glass, indicating the operation of energy transfer from the phosphorus defect to octahedrally coordinated Mn in the glass host.

Studies in Surface Science and Catalysis, Dec 31, 2004

Aluminosilicate ZSM-5 is produced directly from high-silica zeolite Y or zeolite β by a simple hy... more Aluminosilicate ZSM-5 is produced directly from high-silica zeolite Y or zeolite β by a simple hydrothermal treatment of the alkali hydroxide treated starting zeolite material and without using any structure directing organic agent. NMR and FTIR results clearly suggest that majority of the Al (III) species is present in the framework yielding Brønsted acid sites. Addition of appropriate template such as tetrapropylammonium bromide or tetrabutylammonium bromide directs the formation of ZSM-5 and ZSM-11, respectively. ...

Zeolites and Metal-Organic Frameworks

Enzyme-based processes are gaining ground in applied industrial catalysis. The exploitation of th... more Enzyme-based processes are gaining ground in applied industrial catalysis. The exploitation of the biocatalytic activity of enzymes in a massive context ineludibly implies their heterogeneization and/or immobilization on solid supports whereas their catalytic efficiency is maintained at some extent. Since the catalytic role of enzymes is directly related to their quaternary/tertiary structure, the non-covalent immobilization strategies normally become more effective. This Chapter deals with several methods for encapsulating enzymes within porous materials developed by our group in the last decade. Apart from the non-covalent nature of the enzyme-support interaction, the encapsulation of enzymes provides some extra key advantages: (i) the resultant solid biocatalysts can take advantage of the size sieving of the reactants and products provided by the supports; (ii) the both kinds of studied supports, i.e. SiO2-or organosilica-based ordered mesoporous materials (OMM) and metal-organic framework (MOF) materials, can be easily and controllably functionalized by organic groups favoring the immobilization efficiency and preventing the enzyme leaching; (iii) the pore arrangement of the supports can be tailored to the enzyme requirements, such as the use of cage/window mesoporous system allowing the in-situ encapsulation of enzymes with no subsequent leaching at all. All these strategies have been widely and successfully developed for OMMs materials, although it is recommendable to optimize the physicochemical properties of the OMM support for any particular enzyme. On the contrary, the use of MOFs as supports of enzymes is relatively new, especially the universal approaches in which the MOF materials do not need to have pore larger than the enzyme to be immobilized. The very rich compositional, structural and functionalization versatility of these porous supports entails a very promising future for the enzyme immobilization.

Methods in Molecular Biology

Microporous and Mesoporous Materials

Journal of Solid State Chemistry

Microporous and Mesoporous Materials

Catalysts

Metal-organic framework (MOF) materials possess the widest versatility in structure, composition,... more Metal-organic framework (MOF) materials possess the widest versatility in structure, composition, and synthesis procedures amongst the known families of materials. On the other hand, the extraordinary affinity between MOFs and enzymes has led to widely investigating these materials as platforms to support these catalytic proteins in recent years. In this work, the MOF material NH2-MIL-53(Al) has been tested as a support to immobilize by one-step methodology (in situ) the enzyme lipase CaLB from Candida antarctica by employing conditions that are compatible with its enzymatic activity (room temperature, aqueous solution, and moderate pH values). Once the nature of the linker deprotonating agent or the synthesis time were optimized, the MOF material resulted in quite efficient entrapping of the lipase CaLB through this in situ approach (>85% of the present enzyme in the synthesis media) while the supported enzyme retained acceptable activity (29% compared to the free enzyme) and ha...

Frontiers in Chemistry

Loading of active metals, metal clusters, and/or metal nanoparticles in Metal Organic Frameworks ... more Loading of active metals, metal clusters, and/or metal nanoparticles in Metal Organic Frameworks (MOFs) is an emergent field with applications in sensors, catalysis, medicine, and even in the polymeric industry. In the present work, MIL-100(Fe) has been synthesized and reacted with AgNO 3 through liquid and incipient wetness, and also through solid-state reaction or solid grinding. The aim of this study is to evaluate whether the MIL-100 would uptake metal particles using a similar principle as that of the ion exchange in zeolites, or else, their inherent humidity would favor the "dissolution" of the metal salt, thus yielding very small metal particles. The immobilization of Ag nanoparticles inside the MOF pores was identified by C s-corrected scanning transmission electron microscopy (C s-corrected STEM) techniques.

Dalton transactions (Cambridge, England : 2003), Jan 9, 2018

A greener synthesis of Cu-MOF-74 was obtained, for the first time, in methanol as the unique solv... more A greener synthesis of Cu-MOF-74 was obtained, for the first time, in methanol as the unique solvent and at room temperature. Full characterisation of the MOF material showed its purity and also its nanocrystalline nature. Complete activation (150 °C for 1 h and 10bar) of Cu-MOF-74 afforded unsaturated Cu metal sites and this was corroborated by in situ DRIFT spectroscopy. The access to these Cu open metal sites was tested for the catalytic transformation of trans-ferulic acid to vanillin (yield of 71% and 97% selectivity) and a plausible catalytic reaction mechanism was postulated based on quantum chemical calculations.

Catalysis Today

This work reports the ionothermal synthesis of SAPO-34 material, which is the perexcellence catal... more This work reports the ionothermal synthesis of SAPO-34 material, which is the perexcellence catalyst in the methanol-to-olefins (MTO) process. The direct addition of Si sources to the aluminophosphate and ionic liquid (1-ethyl-3-methyl imidazolium) mixture gave rise to the undesired AEL-structured materials. Therefore, some other strategies were necessary to apply. In particular, two unexplored strategies have been developed: (i) the addition of further heteroatom ions able to direct CHA materials, V ions being particularly efficient; and (ii) to carry out the synthesis in open systems rather than in autoclaves under autogenous pressure. Interestingly, the combination of both strategies led to V 4+-free SAPO-34 samples, so any Brönsted acidity of the samples should be assigned to the incorporated Si atoms. These materials, far from being conventional SAPO-34, have triclinic CHA structure, which provides some structural singularities and has not been tested as catalyst in the MTO reaction yet. Despite their conversion level achieved was lower than that given by conventional SAPO-34, probably because of the scarce optimization of the physicochemical properties of the material, the selectivity towards the different olefins is interestingly different, favoring C4 olefins at the expense of ethylene and propylene.

ChemCatChem

Metal-organic frameworks (MOFs) are a family of porous solids combining organic and inorganic moi... more Metal-organic frameworks (MOFs) are a family of porous solids combining organic and inorganic moieties with tunable porosity. Their particular structural parameters have converted MOFs into suitable compounds for gas storage or drug delivery. However, despite the excellent crystallinity they tend to exhibit their analysis through transmission electron microscopy is extraordinarily complicated due to the high instability under the electron beam irradiation. In here, high-resolution Cs-corrected STEM imaging has been used for the observation of the building units of MIL-100(Fe) paying special attention to the electron beam current. In addition, MIL-100(Fe) has been reacted with AgNO3 through a solid-state reaction technique, which has resulted into the formation of metal nanoparticles on the surface. The incorporation of Ag into the porous network has been also investigated.

Nanomaterials (Basel, Switzerland), Jan 16, 2017

The activity and recyclability of Cu-MOF-74 as a catalyst was studied for the ligand-free C-O cro... more The activity and recyclability of Cu-MOF-74 as a catalyst was studied for the ligand-free C-O cross-coupling reaction of 4-nitrobenzaldehyde (NB) with phenol (Ph) to form 4-formyldiphenyl ether (FDE). Cu-MOF-74 is characterized by having unsaturated copper sites in a highly porous metal-organic framework. The influence of solvent, reaction temperature, NB/Ph ratio, catalyst concentration, and basic agent (type and concentration) were evaluated. High conversions were achieved at 120 °C, 5 mol % of catalyst, NB/Ph ratio of 1:2, DMF as solvent, and 1 equivalent of K₂CO₃ base. The activity of Cu-MOF-74 material was higher than other ligand-free copper catalytic systems tested in this study. This catalyst was easily separated and reused in five successive runs, achieving a remarkable performance without significant porous framework degradation. The leaching of copper species in the reaction medium was negligible. The O-arylation between NB and Ph took place only in the presence of Cu-MOF...

Crystal Growth & Design, 2017

The real industrial establishment of MOFs requires significant advances in economic and chemical ... more The real industrial establishment of MOFs requires significant advances in economic and chemical sustainability. This work describes a novel and simple method to prepare one of the most widely studied MOF material, i.e. MIL-100(Fe), which significantly improves the sustainability of the conventional process in several aspects. Interestingly, the only difference in the preparation method of MIL-100(Fe) compared with that of semi-amorphous Fe-BTC (MOF material commercialized as Basolite F300 having the same metal and linker, and which can be also prepared under similar sustainable conditions), is to start from Fe(II) or Fe(III) sources, respectively, which opens certain versatility options in the room temperature synthesis procedures of MOF materials. The prepared samples were characterized using XRD, TGA, N 2 adsorption/ desorption isotherms, Cs-aberration corrected STEM and UV-Vis DRS. These two room-temperature-made Fe-BTC materials were tested in the industrially-demanded photocatalytic degradation of methyl orange under both ultraviolet and solar light radiation. MIL-100(Fe) was a very active photocatalyst in comparison with its homologue. That difference was mainly attributed to the presence of larger cavities within its structure.

Microporous and Mesoporous Materials, 2017

By using asymmetric di-substituted imidazolium molecules (1-Butyl-3-methylimidazolium (BMIM) and ... more By using asymmetric di-substituted imidazolium molecules (1-Butyl-3-methylimidazolium (BMIM) and 1-Ethyl-3-methylimidazolium (EMIM) bromide) as the structure directing agents, in combination with simple changes in silica source or sodium/water content it is possible to prepare three pure phase microporous 10-ring siliceous zeolitic structures. The crystallizations are comparatively rapid with fully crystalline material resulting in 1-3 days at 443 K. In contrast to many recipes reported for pure silica materials, the synthesis is performed without the use of HF or without the need to alter the properties of the SDA, while significantly lower amounts of both ionic liquid and mineralizing agent are required. The results obtained indicate that effective phase control can be achieved from a primary gel composition by minor changes to either the silica source or the water/sodium content, with a strong specificity in the formation of topologies with interconnected 10-rings.

Journal of Visualized Experiments, 2016

Vanillin (4-hydoxy-3-methoxybenzaldehyde) is the main component of the extract of vanilla bean. T... more Vanillin (4-hydoxy-3-methoxybenzaldehyde) is the main component of the extract of vanilla bean. The natural vanilla scent is a mixture of approximately 200 different odorant compounds in addition to vanillin. The natural extraction of vanillin (from the orchid Vanilla planifolia, Vanilla tahitiensis and Vanilla pompon) represents only 1% of the worldwide production and since this process is expensive and very long, the rest of the production of vanillin is synthesized. Many biotechnological approaches can be used for the synthesis of vanillin from lignin, phenolic stilbenes, isoeugenol, eugenol, guaicol, etc., with the disadvantage of harming the environment since these processes use strong oxidizing agents and toxic solvents. Thus, eco-friendly alternatives on the production of vanillin are very desirable and thus, under current investigation. Porous coordination polymers (PCPs) are a new class of highly crystalline materials that recently have been used for catalysis. HKUST-1 (Cu3(BTC)2(H2O)3, BTC = 1,3,5-benzene-tricarboxylate) is a very well known PCP which has been extensively studied as a heterogeneous catalyst. Here, we report a synthetic strategy for the production of vanillin by the oxidation of trans-ferulic acid using HKUST-1 as a catalyst.

Microporous and Mesoporous Materials, 2016

Topics in Catalysis, 2015

ChemCatChem, 2015

ABSTRACT In some aspects, the potential of metal–organic framework (MOF) materials as heterogeneo... more ABSTRACT In some aspects, the potential of metal–organic framework (MOF) materials as heterogeneous catalysts has been realized, at least in an academic context. However, one of their most promising catalytic properties, that is, the presence of open metal sites, is far from understood properly. In this work, a series of M–MOF-74 (M=Mn, Co, Ni, Cu, Zn) materials, prepared under sustainable conditions, was tested systematically in the oxidation of cyclohexene, which can proceed by either radical or epoxidation routes. Under the optimized reaction conditions, the radical route is spontaneous to some extent and it is enhanced in the presence of any M–MOF-74 that has a metal with a redox character but not Zn. However, the epoxidation of cyclohexene is also promoted by a redox catalyst in such a way that the conversion correlates qualitatively with the redox potential of the metal. Thus, for the first time, a chemical property of M is correlated with the catalytic activity of the M–MOF-74 family.

Studies in Surface Science and Catalysis, 1994

The aluminophosphate glasses were prepared by the melting-quenching technique and their optical a... more The aluminophosphate glasses were prepared by the melting-quenching technique and their optical and structural properties were investigated. The 56P2O5-20Al2O3 glass exhibits unique blue emission at 406 nm due to the phosphorus defect in the glass matrix. Addition of SiO2, ZnF2, or Li2O to 56P2O5-20Al2O3 glass matrix has different influence on formation of phosphorus defect resulting in different intensities of blue emission at 406 nm, though SiO2, ZnF2 or Li2O mostly enters the glass network as modifier. Structural analysis of P2O5-Al2O3 based aluminophosphate glasses by positron annihilation lifetime spectroscopy indicates that values of positron lifetimes and the corresponding intensities may be connected with the sizes and number of structural defects. Under excitation of 251 nm, a broad blue emission band and a red emission band were observed in the Mn-doped 56P2O5-20Al2O3-15SiO2-10ZnF2 glass, indicating the operation of energy transfer from the phosphorus defect to octahedrally coordinated Mn in the glass host.

Studies in Surface Science and Catalysis, Dec 31, 2004

Aluminosilicate ZSM-5 is produced directly from high-silica zeolite Y or zeolite β by a simple hy... more Aluminosilicate ZSM-5 is produced directly from high-silica zeolite Y or zeolite β by a simple hydrothermal treatment of the alkali hydroxide treated starting zeolite material and without using any structure directing organic agent. NMR and FTIR results clearly suggest that majority of the Al (III) species is present in the framework yielding Brønsted acid sites. Addition of appropriate template such as tetrapropylammonium bromide or tetrabutylammonium bromide directs the formation of ZSM-5 and ZSM-11, respectively. ...

Zeolites and Metal-Organic Frameworks

Enzyme-based processes are gaining ground in applied industrial catalysis. The exploitation of th... more Enzyme-based processes are gaining ground in applied industrial catalysis. The exploitation of the biocatalytic activity of enzymes in a massive context ineludibly implies their heterogeneization and/or immobilization on solid supports whereas their catalytic efficiency is maintained at some extent. Since the catalytic role of enzymes is directly related to their quaternary/tertiary structure, the non-covalent immobilization strategies normally become more effective. This Chapter deals with several methods for encapsulating enzymes within porous materials developed by our group in the last decade. Apart from the non-covalent nature of the enzyme-support interaction, the encapsulation of enzymes provides some extra key advantages: (i) the resultant solid biocatalysts can take advantage of the size sieving of the reactants and products provided by the supports; (ii) the both kinds of studied supports, i.e. SiO2-or organosilica-based ordered mesoporous materials (OMM) and metal-organic framework (MOF) materials, can be easily and controllably functionalized by organic groups favoring the immobilization efficiency and preventing the enzyme leaching; (iii) the pore arrangement of the supports can be tailored to the enzyme requirements, such as the use of cage/window mesoporous system allowing the in-situ encapsulation of enzymes with no subsequent leaching at all. All these strategies have been widely and successfully developed for OMMs materials, although it is recommendable to optimize the physicochemical properties of the OMM support for any particular enzyme. On the contrary, the use of MOFs as supports of enzymes is relatively new, especially the universal approaches in which the MOF materials do not need to have pore larger than the enzyme to be immobilized. The very rich compositional, structural and functionalization versatility of these porous supports entails a very promising future for the enzyme immobilization.

Methods in Molecular Biology

Microporous and Mesoporous Materials

Journal of Solid State Chemistry

Microporous and Mesoporous Materials

Catalysts

Metal-organic framework (MOF) materials possess the widest versatility in structure, composition,... more Metal-organic framework (MOF) materials possess the widest versatility in structure, composition, and synthesis procedures amongst the known families of materials. On the other hand, the extraordinary affinity between MOFs and enzymes has led to widely investigating these materials as platforms to support these catalytic proteins in recent years. In this work, the MOF material NH2-MIL-53(Al) has been tested as a support to immobilize by one-step methodology (in situ) the enzyme lipase CaLB from Candida antarctica by employing conditions that are compatible with its enzymatic activity (room temperature, aqueous solution, and moderate pH values). Once the nature of the linker deprotonating agent or the synthesis time were optimized, the MOF material resulted in quite efficient entrapping of the lipase CaLB through this in situ approach (>85% of the present enzyme in the synthesis media) while the supported enzyme retained acceptable activity (29% compared to the free enzyme) and ha...

Frontiers in Chemistry

Loading of active metals, metal clusters, and/or metal nanoparticles in Metal Organic Frameworks ... more Loading of active metals, metal clusters, and/or metal nanoparticles in Metal Organic Frameworks (MOFs) is an emergent field with applications in sensors, catalysis, medicine, and even in the polymeric industry. In the present work, MIL-100(Fe) has been synthesized and reacted with AgNO 3 through liquid and incipient wetness, and also through solid-state reaction or solid grinding. The aim of this study is to evaluate whether the MIL-100 would uptake metal particles using a similar principle as that of the ion exchange in zeolites, or else, their inherent humidity would favor the "dissolution" of the metal salt, thus yielding very small metal particles. The immobilization of Ag nanoparticles inside the MOF pores was identified by C s-corrected scanning transmission electron microscopy (C s-corrected STEM) techniques.

Dalton transactions (Cambridge, England : 2003), Jan 9, 2018

A greener synthesis of Cu-MOF-74 was obtained, for the first time, in methanol as the unique solv... more A greener synthesis of Cu-MOF-74 was obtained, for the first time, in methanol as the unique solvent and at room temperature. Full characterisation of the MOF material showed its purity and also its nanocrystalline nature. Complete activation (150 °C for 1 h and 10bar) of Cu-MOF-74 afforded unsaturated Cu metal sites and this was corroborated by in situ DRIFT spectroscopy. The access to these Cu open metal sites was tested for the catalytic transformation of trans-ferulic acid to vanillin (yield of 71% and 97% selectivity) and a plausible catalytic reaction mechanism was postulated based on quantum chemical calculations.

Catalysis Today

This work reports the ionothermal synthesis of SAPO-34 material, which is the perexcellence catal... more This work reports the ionothermal synthesis of SAPO-34 material, which is the perexcellence catalyst in the methanol-to-olefins (MTO) process. The direct addition of Si sources to the aluminophosphate and ionic liquid (1-ethyl-3-methyl imidazolium) mixture gave rise to the undesired AEL-structured materials. Therefore, some other strategies were necessary to apply. In particular, two unexplored strategies have been developed: (i) the addition of further heteroatom ions able to direct CHA materials, V ions being particularly efficient; and (ii) to carry out the synthesis in open systems rather than in autoclaves under autogenous pressure. Interestingly, the combination of both strategies led to V 4+-free SAPO-34 samples, so any Brönsted acidity of the samples should be assigned to the incorporated Si atoms. These materials, far from being conventional SAPO-34, have triclinic CHA structure, which provides some structural singularities and has not been tested as catalyst in the MTO reaction yet. Despite their conversion level achieved was lower than that given by conventional SAPO-34, probably because of the scarce optimization of the physicochemical properties of the material, the selectivity towards the different olefins is interestingly different, favoring C4 olefins at the expense of ethylene and propylene.

ChemCatChem

Metal-organic frameworks (MOFs) are a family of porous solids combining organic and inorganic moi... more Metal-organic frameworks (MOFs) are a family of porous solids combining organic and inorganic moieties with tunable porosity. Their particular structural parameters have converted MOFs into suitable compounds for gas storage or drug delivery. However, despite the excellent crystallinity they tend to exhibit their analysis through transmission electron microscopy is extraordinarily complicated due to the high instability under the electron beam irradiation. In here, high-resolution Cs-corrected STEM imaging has been used for the observation of the building units of MIL-100(Fe) paying special attention to the electron beam current. In addition, MIL-100(Fe) has been reacted with AgNO3 through a solid-state reaction technique, which has resulted into the formation of metal nanoparticles on the surface. The incorporation of Ag into the porous network has been also investigated.

Nanomaterials (Basel, Switzerland), Jan 16, 2017

The activity and recyclability of Cu-MOF-74 as a catalyst was studied for the ligand-free C-O cro... more The activity and recyclability of Cu-MOF-74 as a catalyst was studied for the ligand-free C-O cross-coupling reaction of 4-nitrobenzaldehyde (NB) with phenol (Ph) to form 4-formyldiphenyl ether (FDE). Cu-MOF-74 is characterized by having unsaturated copper sites in a highly porous metal-organic framework. The influence of solvent, reaction temperature, NB/Ph ratio, catalyst concentration, and basic agent (type and concentration) were evaluated. High conversions were achieved at 120 °C, 5 mol % of catalyst, NB/Ph ratio of 1:2, DMF as solvent, and 1 equivalent of K₂CO₃ base. The activity of Cu-MOF-74 material was higher than other ligand-free copper catalytic systems tested in this study. This catalyst was easily separated and reused in five successive runs, achieving a remarkable performance without significant porous framework degradation. The leaching of copper species in the reaction medium was negligible. The O-arylation between NB and Ph took place only in the presence of Cu-MOF...

Crystal Growth & Design, 2017

The real industrial establishment of MOFs requires significant advances in economic and chemical ... more The real industrial establishment of MOFs requires significant advances in economic and chemical sustainability. This work describes a novel and simple method to prepare one of the most widely studied MOF material, i.e. MIL-100(Fe), which significantly improves the sustainability of the conventional process in several aspects. Interestingly, the only difference in the preparation method of MIL-100(Fe) compared with that of semi-amorphous Fe-BTC (MOF material commercialized as Basolite F300 having the same metal and linker, and which can be also prepared under similar sustainable conditions), is to start from Fe(II) or Fe(III) sources, respectively, which opens certain versatility options in the room temperature synthesis procedures of MOF materials. The prepared samples were characterized using XRD, TGA, N 2 adsorption/ desorption isotherms, Cs-aberration corrected STEM and UV-Vis DRS. These two room-temperature-made Fe-BTC materials were tested in the industrially-demanded photocatalytic degradation of methyl orange under both ultraviolet and solar light radiation. MIL-100(Fe) was a very active photocatalyst in comparison with its homologue. That difference was mainly attributed to the presence of larger cavities within its structure.

Microporous and Mesoporous Materials, 2017

By using asymmetric di-substituted imidazolium molecules (1-Butyl-3-methylimidazolium (BMIM) and ... more By using asymmetric di-substituted imidazolium molecules (1-Butyl-3-methylimidazolium (BMIM) and 1-Ethyl-3-methylimidazolium (EMIM) bromide) as the structure directing agents, in combination with simple changes in silica source or sodium/water content it is possible to prepare three pure phase microporous 10-ring siliceous zeolitic structures. The crystallizations are comparatively rapid with fully crystalline material resulting in 1-3 days at 443 K. In contrast to many recipes reported for pure silica materials, the synthesis is performed without the use of HF or without the need to alter the properties of the SDA, while significantly lower amounts of both ionic liquid and mineralizing agent are required. The results obtained indicate that effective phase control can be achieved from a primary gel composition by minor changes to either the silica source or the water/sodium content, with a strong specificity in the formation of topologies with interconnected 10-rings.

Journal of Visualized Experiments, 2016

Vanillin (4-hydoxy-3-methoxybenzaldehyde) is the main component of the extract of vanilla bean. T... more Vanillin (4-hydoxy-3-methoxybenzaldehyde) is the main component of the extract of vanilla bean. The natural vanilla scent is a mixture of approximately 200 different odorant compounds in addition to vanillin. The natural extraction of vanillin (from the orchid Vanilla planifolia, Vanilla tahitiensis and Vanilla pompon) represents only 1% of the worldwide production and since this process is expensive and very long, the rest of the production of vanillin is synthesized. Many biotechnological approaches can be used for the synthesis of vanillin from lignin, phenolic stilbenes, isoeugenol, eugenol, guaicol, etc., with the disadvantage of harming the environment since these processes use strong oxidizing agents and toxic solvents. Thus, eco-friendly alternatives on the production of vanillin are very desirable and thus, under current investigation. Porous coordination polymers (PCPs) are a new class of highly crystalline materials that recently have been used for catalysis. HKUST-1 (Cu3(BTC)2(H2O)3, BTC = 1,3,5-benzene-tricarboxylate) is a very well known PCP which has been extensively studied as a heterogeneous catalyst. Here, we report a synthetic strategy for the production of vanillin by the oxidation of trans-ferulic acid using HKUST-1 as a catalyst.

Microporous and Mesoporous Materials, 2016

Topics in Catalysis, 2015

ChemCatChem, 2015

ABSTRACT In some aspects, the potential of metal–organic framework (MOF) materials as heterogeneo... more ABSTRACT In some aspects, the potential of metal–organic framework (MOF) materials as heterogeneous catalysts has been realized, at least in an academic context. However, one of their most promising catalytic properties, that is, the presence of open metal sites, is far from understood properly. In this work, a series of M–MOF-74 (M=Mn, Co, Ni, Cu, Zn) materials, prepared under sustainable conditions, was tested systematically in the oxidation of cyclohexene, which can proceed by either radical or epoxidation routes. Under the optimized reaction conditions, the radical route is spontaneous to some extent and it is enhanced in the presence of any M–MOF-74 that has a metal with a redox character but not Zn. However, the epoxidation of cyclohexene is also promoted by a redox catalyst in such a way that the conversion correlates qualitatively with the redox potential of the metal. Thus, for the first time, a chemical property of M is correlated with the catalytic activity of the M–MOF-74 family.