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MIL-125 is a metal-organic framework with great potential for the adsorption and separation of xylene isomers. However, MIL-125 is usually synthesized under anhydrous and anaerobic conditions. In this study, homogeneously shaped and highly crystalline MIL-125 was synthesized by introducing water-resistant titanium-containing oligomers into the synthesis process. With the assistance of the novel oligomers, MIL-125 can be synthesized in the presence of water, which meets batch-production requirements. The adsorption separation performance of the obtained highly crystalline MIL-125 was also significantly enhanced. The para-xylene/meta-xylene selectivity can reach 13.5 in mesitylene, which is higher than the selectivity values of most previously reported para-selective adsorbents. The MIL-125 xylene separation performance was verified using both batch adsorption and breakthrough experiments in the liquid phase. In addition, the influence of the solvent effect was evaluated through microcalorimetric experiments, liquid-phase adsorption experiments, and theoretical calculations.

Noyori-Ikariya type [(arene)RuCl(TsDPEN)] (TsDPEN, sulfonated diphenyl ethylenediamine) complexes are widely used C=O and C=N reduction catalysts that produce chiral alcohols and amines via a key ruthenium-hydride intermediate that determines the stereochemistry of the product. Whereas many details about the interactions of the pro-chiral substrate with the hydride complex and the nature of the hydrogen transfer from the latter to the former have been investigated over the past 25 years, the role of the stereochemical configuration at the stereogenic ruthenium center in the catalysis has not been elucidated so far. Using operando FlowNMR spectroscopy and nuclear Overhauser effect spectroscopy, we show the existence of two diastereomeric hydride complexes under reaction conditions, assign their absolute configurations in solution, and monitor their interconversion during transfer hydrogenation catalysis. Configurational analysis and multifunctional density functional theory (DFT) calculations show the λ-(R,R)SRu configured [(mesitylene)RuH(TsDPEN)] complex to be both thermodynamically and kinetically favored over its λ-(R,R)RRu isomer with the opposite configuration at the metal. Computational analysis of both diastereomeric catalytic manifolds show the major λ-(R,R)SRu configured [(mesitylene)RuH(TsDPEN)] complex to dominate asymmetric ketone reduction catalysis with the minor λ-(R,R)RRu [(mesitylene)RuH(TsDPEN)] stereoisomer being both less active and less enantioselective. These findings also hold true for a tethered catalyst derivative with a propyl linker between the arene and TsDPEN ligands and thus show enantioselective transfer hydrogenation catalysis with Noyori-Ikariya complexes to proceed via a lock-and-key mechanism.

Controlled crystallization of fullerene molecules into ordered molecular assemblies is important for their applications. However, the morphology engineering of fullerene[C70 ] assemblies is challenging, and complicated architectures have rarely been reported due to the low molecular symmetry of C70 molecules, which makes their crystallization difficult to control and the low production yield as well. Herein, with the assistance of solvent intercalation, a general reprecipitation approach is reported to prepare morphologically controllable C70 microcrystals with mesitylene as a good solvent and n-propanol as a poor solvent in one solvent system without replacing specific solvents. A series of C70 microcrystals with high uniformity from perfect cubes and defective hoppers to novel cruciform-pillars are obtained by intentionally tuning C70 concentration and the volume ratio of mesitylene to n-propanol. Among them, novel cruciform-pillar-shaped microcrystals are obtained for the first time by further decreasing the amount of mesitylene in the solvent-intercalated microcrystals. Notably, the C70 concentration is a key parameter for the selective growth of C70 hopper, rather than the volume ratio of mesitylene to n-propanol. Interestingly, the hopper-shaped microcrystals exhibit excellent photoluminescence properties relative to those of cubes and cruciform-pillars owing to the enhanced light absorption, proving their potential applications in optoelectronic devices. This study offers new insights into the morphology-controlled synthesis of other micro/nanostructured organic microcrystals and the fine tuning of photoluminescence properties of organic crystals.

Intramolecular addition of a C(sp3)–H bond of the dimethylamino group across the C–C triple bond in 2-alkynyl-N,N-dimethylanilines is effectively catalyzed by a new iridium complex, IrCl(DTBM-SEGPHOS)(C2H4), in mesitylene at 150 °C. The intramolecular C(sp3)–H addition is followed by double-bond isomerization to afford 3-substituted indoles in good to high yields.

A series of imine-linked covalent organic frameworks (COF) are constructed under Sc(OTf)3 catalysis in a 1,4-dioxane/mesitylene mixture. The amount of Sc(OTf)3 catalyst strongly affects the structure of the as-synthesized COFs. When 0.005 equivalent Sc(OTf)3 is used, a crystalline COF with uniform micropores and high surface area is obtained. The as-synthesized COF evolves to a disordered structure with increase in the catalyst amount. Several imine-linked COFs show NH3 sensing ability at room temperature, and the NH3 sensing performance is strongly dependent on their electric conductivity. The imine-linked COF with a disordered structure has better electric conductivity than the crystalline imine-linked COF. The NH3 sensing ability of the imine-linked COF with a disordered structure is far better than that of the imine-linked COF with a crystalline structure. The excellent NH3 sensing ability, including a short response time, large response value and high sensing selectivity, as well as lower sensor baseline resistance were observed on the imine-linked COF with a disordered structure. The imine linkage was recognized as the active site for NH3 adsorption on the imine-linked COF. Both density functional theory (DFT) calculations and an in situ UV-Vis spectra experiment confirm a hydrogen bond formation between NH3 and imine linkage during the NH3 sensing process.

An efficient and versatile zinc oxide-supported iridium (Ir/ZnO) catalyst was developed to catalyze the additive-free N-methylation of amines with methanol. Mechanistic studies suggested that the high catalytic reactivity is rooted in the small sizes (1.4 nm) of Ir nanoparticles and the high ratio (93%) of oxidized iridium species (IrOx, Ir3+ and Ir4+) on the catalyst. Moreover, the delicate cooperation between the IrOx and ZnO support also promoted its high reactivity. The selectivity of this catalytic N-methylation was controllable between dimethylation and monomethylation by carefully tuning the catalyst loading and reaction solvent. Specifically, neat methanol with high catalyst loading (2 mol% Ir) favored the formation of N,N-dimethylated amine, while the mesitylene/methanol mixture with low catalyst loading (0.5 mol% Ir) was prone to producing mono-N-methylated amines. An environmentally benign continuous flow system with a recycled mode was also developed for the efficient production of N-methylated amines. With optimal flow rates and amine concentrations, a variety of N-methylamines were produced with good to excellent yields in this Ir/ZnO-based flow system, providing a starting point for the clean and efficient production of N-methylamines with this cost-effective chemical process.

The alkylation of aromatics is an important reaction for producing valuable petrochemicals and fine chemicals. A dual metal species encapsulated MEL zeolite with an elegant hierarchical architecture was fabricated to tailor the catalytic properties of liquid alkylation between mesitylene and benzyl alcohol. The redox properties of zeolites played a crucial role in determining the activity and selectivity, and the activity of benzyl alcohol and the selectivity of 2-benzyl-1,3,5-trimethylbenzene could be simultaneously maximized by balancing the redox properties of zeolites. The calculated Thiele modulus and effectiveness factor indicated that the resultant mesoporous MEL zeolites achieved a high catalyst utilization degree with negligible diffusion constraints. A novel reaction coordination and diffusion intensification coupling technology was developed by tuning the redox properties of zeolites and mitigating the diffusion limitation, which could accurately modulate the catalytic performance of the catalysts and improve the utilization efficiency of zeolites in the alkylation of aromatics.

ion of a pyridine ligand from Weiss’ reagent ([PhI(Pyr)2]2+) using BF3-Et2O was found to activate Weiss’ reagent towards electrophilic aromatic substitution reactions. The activated species can be isolated when 4-DMAP is used as the pyridine ligand and was determined to be [PhI(4-DMAP)]2+ in solution. The isolated cation was reactive in electrophilic aromatic substitution reactions towards mesitylene, xylene and toluene that Weiss’ reagent itself does not react with.

(Ferrocenylmethyl)phosphane (1) oxidation with hydrogen peroxide, elemental sulfur and grey selenium produced (ferrocenylmethyl)phosphane oxide 1O, sulfide 1S and selenide 1Se, respectively, as the first isolable primary phosphane chalcogenides lacking steric protection. At elevated temperatures, compound 1O disproportionated into 1 and (ferrocenylmethyl)phosphinic acid. In reactions with [(η6 -mes)RuCl2 ]2 , 1O underwent tautomerization into a phosphane complex [(η6 -mes)RuCl2 {FcCH2 PH(OH)-κP}], whereas 1S and 1Se lost their P-bound chalcogen atoms, giving rise to the phosphane complex [(η6 -mes)RuCl2 (FcCH2 PH2 -κP)] (Fc=ferrocenyl, mes=mesitylene). No tautomerization was observed in the reaction of 1O with B(C6 F5 )3 , which instead produced a Lewis pair FcCH2 P(O)H2 -B(C6 F5 )3 . Phosphane oxide 1O added to C=O bonds of aldehydes and ketones and even to cumulenes PhNCE (E=O and S). However, both PH hydrogens were only employed in the reactions with aldehydes and cyanates.

Electrocatalysis plays a vital role in industrial processes like electrohydrodimerization of acrylonitrile, anodic substitution and addition, electrolytic oxidative/reductive coupling and electrolysis of heterocyclic compounds. Electrocatalysts with suitable size and shape selectivity for reactants, reactant intermediates and products increase their selectivity. Zeolites are the most common vehicles for size-/shape-selective heterogeneous catalysts, but their lack of electronic conductivity vitiates their use in electrocatalysis. In this context, we explore the effectiveness of carbon derived from the zeolitic imidazole framework (ZIF), which possesses both electronic conductivity and structural selectivity for electrocatalytic oxidative coupling of mesitylene to bimesityl. Co-ZIF synthesized by facile solvothermal method was heated in an inert atmosphere and acid-leached to remove Co in order to generate C-based structured material. Further, Pd acting as a catalyst was deposited inside the pore walls of the obtained C scaffold by electroless deposition to derive pore sizes ranging between the molecular size of the particular product. Controlling the pore size of metastructured electrocatalyst at ~ 16 A allows only bimesityl formation, and restricts any larger sized by-product. Metastructured electrocatalyst showed ~ 18 times higher selective conversion for the desired bimesityl production than the planar Pd film electrocatalyst, demonstrating the potential of the proposed approach.

A short, enantioselective synthesis of (-)-maximiscin, a structurally intriguing metabolite of mixed biosynthetic origin, is reported. A retrosynthetic analysis predicated on maximizing ideality and efficiency led to several unusual disconnections and tactics. Formation of the central highly oxidized pyridone ring through a convergent coupling at the end of the synthesis simplified the route considerably. The requisite building blocks could be prepared from feedstock materials (derived from shikimate and mesitylene). Strategies rooted in hidden symmetry recognition, C-H functionalization, and radical retrosynthesis played key roles in developing this concise route.

The flexible host framework of a perfluorinated mononuclear copper complex, [Cu(L1 )2 ] (1, HL1 =3-hydroxy-1,3-bis(pentafluorophenyl)-2-propen-1-one), with a CuO4 core reversibly encapsulated several organic guest molecules through electrostatic interactions in its crystals. Hence, the corresponding dinuclear complex, [Cu2 (L2 )2 ] (2, H2 L2 =1,5-dihydroxy-1,5-bis(pentafluorophenyl)-1,4-pentadien-3-one), was prepared to enhance guest recognition and the ability to separate molecular mixtures. Complex 2 comprises a Cu2 O6 core and four pentafluorophenyl groups. In crystal 2, cavities are formed on the axial sites of the metal core that are surrounded by pentafluorophenyl groups. The crystal of 2 encapsulates various guest molecules, that is, benzene (3), toluene (4), xylene (5), mesitylene (6), durene (7), and anisole (8). X-ray crystallographic and thermogravimetric (TG) studies show that three guest molecules are present in the crystal cavities. The number of guest molecules found in complex 2 was higher than that in complex 1, for example, (2)3 ⋅(6)10 >1⋅(6)2 , (2)2 ⋅(7)7 >1⋅7, or 2⋅(8)3 >1⋅(8)2 . Naphthalene (9), was encapsulated in 2 to give 2⋅(9)3 , but not in 1. In the crystal of complex 2, heteromolecular guest encapsulation was confirmed, designated as 2⋅(3)2 ⋅9. TG analysis indicates that the thermal stability of the guest-included crystals of 2 is higher than that of 1.

In the presence of an iridium catalyst bearing DTBM-SEGPHOS as a ligand and tert-butylethylene as a hydrogen scavenger, 2-ethyl-N-methylanilines were converted directly to 3-methylindoles in high yields. The reaction proceeded efficiently in mesitylene at 150 °C through transfer dehydrogenation of the ethyl group and following intramolecular dehydrogenative C–H/C–H coupling of the N-methyl group with the vinyl group formed in situ. The iridium catalyst system was applied to the asymmetric conversion affording enantioenriched indolines bearing a quaternary stereogenic carbon center at the C3 position.

Doped-ZnO nanoparticles, capped with dioctylphosphinate ligands, are synthesised by the controlled hydrolysis of a mixture of organometallic precursors. Substitutional doping of the wurtzite ZnO nanoparticles with 5 mol% Mg(II), Al(III) and Cu(I) is achieved by the addition of sub-stoichiometric amounts of the appropriate dopant [(n-butyl)(sec-butyl)magnesium, triethylaluminium or mesitylcopper] to diethylzinc in the precursor mixture. After hydrolysis, the resulting colloidal nanoparticles (sizes of 2–3 nm) are characterised by powder X-ray crystallography, transmission electron microscopy, inductively-coupled plasma optical emission spectrometry and X-ray photoelectron spectroscopy. A solution of the doped-ZnO nanoparticles and colloidal Cu(0) nanoparticles [M:ZnO : Cu = 1 : 1] are applied as catalysts for the hydrogenation of CO2 to methanol in a liquid-phase continuous flow stirred tank reactor [210 °C, 50 bar, CO2 : H2 = 1 : 3, 150 mL min−1, mesitylene, 20 h]. All the catalyst systems display higher rates of methanol production and better stability than a benchmark heterogeneous catalyst, Cu–ZnO–Al2O3 [480 μmol mmolmetal−1 h−1], with approximately twice the activity for the Al(III)-doped nanocatalyst. Despite outperforming the benchmark catalyst, Mg(II) doping is detrimental towards methanol production in comparison to undoped ZnO. X-Ray photoelectron spectroscopy and transmission electron microscopy analysis of the most active post-catalysis samples implicate the migration of Al(III) to the catalyst surface, and this surface enrichment is proposed to facilitate stabilisation of the catalytic ZnO/Cu interfaces.

A facile and scaled-up synthesis route to efficient and environment-friendly metal oxide catalysts with desirable properties is of great practical importance, owing to their excellent performance as heterogeneous catalysts in organic synthesis. Herein, a novel amorphous Fe2O3 modified Mn3O4 catalyst (Fe5Mn5-100) has been prepared by adopting a simple co-precipitation method following low temperature baking. Fe5Mn5-100 showed exceptionally high catalytic activity for the atom-economic production of imine from benzyl alcohol with aniline, giving a 98% imine yield at 60 °C in only 3 h, which is higher than all of the reported non-noble and noble metal catalysts. Importantly, Fe5Mn5-100 could still exhibit extraordinary catalytic performance on a large-scale reaction without any solvent, including the frequently used toxic mesitylene, xylene or toluene. Interestingly, the amorphous Fe2O3-100 provided no catalytic activity, and pure Mn3O4-100 showed very inferior catalytic activity towards this reaction. Further detailed characterizations and experimental results revealed that amorphous Fe2O3 plays an important role in expediting the [O] transfer cycle of Mn3+/Mn2+ in Mn3O4, and enhances the oxidation ability and acidity of Fe5Mn5-100. This discovery would provide a new avenue for the atom-economic and environment-friendly industrial synthesis of imine.

Layered zeolites, especially MWW, have been used to synthesize pillared micro/mesoporous hybrids with the goal to enhance catalytic activity towards larger molecules. The critical preparation step is expansion of the interlayer space by swelling with cationic surfactants at high pH. Recently reported solutions of MWW monolayers, obtained by exfoliation of the zeolite MCM-56, can be used to prepare analogous materials by flocculation (precipitation) with surfactant solutions. This previously unavailable approach is studied in this work with both high pH (0.2 M, pH > 13.3) and lower pH (0.01 M, pH~12) solutions, and resulted in finding conditions for preparation of catalysts that can be more active than pure microporous layers (zeolite) despite large content of unreactive silica pillars. Both the high and low pH conditions afforded similar expanded surfactant-MWW composites, but their behavior differed during pillaring with TEOS. Well-defined expanded interlayer distances indicated by a low angle reflection in XRD above 3 nm d-spacing was observed only with the high alkalinity preparations. An additional benefit was observed with TEOS treatment in the presence of isopropyl alcohol leading to a product showing high catalytic activity in model alkylation reaction (mesitylene with benzyl alcohol) proceeding faster than with the pure zeolite. The products obtained under different conditions were characterized by textural methods, nitrogen adsorption and QE-TPDA, and FT-IR to investigate acid site parameters. Notably, the MCM-56 used in this work was prepared with addition of aniline as the structure-promoting agent and is the second formulation affording exfoliable MWW materials.

Renewable arenes and aromatic alcohols can be derived from lignocellulose by biorefineries, which has been considered as a sustainable alternative to replace petrochemical feedstocks in the synthesis of monobenzylation products, key industrial intermediates, via benzylation reactions. Zeolites with micropores are the most widely used catalysts in the benzylation of arenes, however, their performance suffers from diffusion limitations in converting large arenes. In this work, mesoporous and microporous H–Beta zeolites were prepared and applied in the systematic study of benzylation of arenes (benzene, toluene, p-xylene and mesitylene) with benzyl alcohol (BA). The porous structure of these zeolites has been confirmed by XRD, BET and TEM techniques. The catalytically active Bronsted acid sites (BAS) were determined by quantitative 1H magic-angle spinning (MAS) nuclear magnetic resonance (NMR) experiments. The benzylation studies have shown that introducing mesopores into H–Beta zeolites can significantly increase the diffusion/access of arenes to surface sites, particularly for bulky arenes (e.g. mesitylene), while micropores are mainly selective for the conversion of small arenes (e.g. benzene). Increasing the nucleophilicity of arenes with more alkyl groups can enhance their catalytic performance in mesopores, however, the increase hinders their conversion in micropores because of the shape selectivity due to their increasing molecular size. Compared to mesopores, micropores promote the conversion of small arenes (e.g. benzene), which can be additionally enhanced by a high Bronsted acidity. Therefore, introducing a suitable porosity balanced with acidity are keys in the tailoring of the catalytic performance of H-Beta zeolites for target benzylation reactions.

Direct exfoliation of layered zeolites into solutions of monolayers has remained unresolved since the 1990s. Recently, zeolite MCM-56 with the MWW topology (layers denoted mww) has been exfoliated directly in high yield by soft-chemical treatment with tetrabutylammonium hydroxide (TBAOH). This has enabled preparation of zeolite-based hierarchical materials and intimate composites with other active species that are unimaginable via the conventional solid-state routes. The extension to other frameworks, which provides broader benefits, diversified activity, and functionality, is not routine and requires finding suitable synthesis formulations, viz. compositions and conditions, of the layered zeolites themselves. This article reports exfoliation and characterization of layers with ferrierite-related structure, denoted bifer, having rectangular lattice constants like those of the FER and CDO zeolites, and thickness of approximately 2 nm, which is twice that of the so-called fer layer. Several techniques were combined to prove the exfoliation, supported by simulations: AFM; in-plane, in situ, and powder X-ray diffraction; TEM; and SAED. The results confirmed (i) the structure and crystallinity of the layers without unequivocal differentiation between the FER and CDO topologies and (ii) uniform thickness in solution (monodispersity), ruling out significant multilayered particles and other impurities. The bifer layers are zeolitic with Bronsted acid sites, demonstrated catalytic activity in the alkylation of mesitylene with benzyl alcohol, and intralayer pores visible in TEM. The practical benefits are demonstrated by the preparation of unprecedented intimately mixed zeolite composites with the mww, with activity greater than the sum of the components despite high content of inert silica as pillars.

Reducing the nitrogen-containing compounds (NCCs) in fuel oils to ultralow level is essential for preventing the oil refining catalysts from being poisoned and for protecting the environment. Adsorptive denitrogenation is proved to be an effective mean to reduce the NCCs content. Herein, a series of N-doped porous carbons (NDPCs) in possession of proper pore structures, large surface area and moderate N species, which is verified through a series of characterization, are synthesized on the basis of the precursor copolymerized between 2,4,6-tris(chloromethyl)mesitylene and ethylenediamine. The NDPC-700 produced from the copolymer carbonization at 700 °C exhibits a record high adsorptive capacity of 7.35 mmol·g−1 for indole in the model oils, and the stable performance on the NCC adsorption is observed after 10 cycles of regeneration and reusage. The excellent adsorption capacity is attributed to the synergistic effect between porosities and N-containing sites. Moreover, the first-principle simulation proves that the N species, in particular the N-5 species, is helpful to the improvement of the adsorption capacity for indole.

A new heterogeneous polymer supported solid phase oxovanadium(IV) catalyst was synthesized successfully. The designed catalyst furnished excellent results in the oxidation reactions of various aromatic alkanes, e.g. toluene, para-xylene, mesitylene. The polymer supported vanadium complex was proved also an efficient catalyst for the oxidation of aromatic alkenes, like substituted styrenes, trans-stilbene, etc. under mild reaction conditions. The supported catalyst was nicely elucidated by SEM-EDAX, TGA, FT-IR and UV–Vis spectral analysis. The catalytic activity was tested in the presence of an environment-friendly oxidant, 30% aqueous H2O2 during the oxidation of broad range of substrates. Another important fact is that the designed oxovanadium(IV) catalyst is heterogeneous in nature. Moreover, the newly synthesized oxovanadium(IV) complex exhibited a notable recoverability and it could be recycled up to six runs devoid of any prominent reduction in catalytic behavior.

Two-dimensional (2D) layered zeolites are new forms of 3D zeolite frameworks. They can be pillared to form more open porous structures with increased access for reactants that are too big for the micropores of zeolites. The current pillaring procedure, however, requires intercalation of pillaring precursors by dispersing 2D zeolite in an alkoxide liquid and hydrolizing entrapped alkoxide to form inorganic oxide pillars in an aqueous alkaline solution. Both steps use excess solvents, generate significant waste, and require multiple synthesis and separation steps. Here we report a vapor-phase pillarization (VPP) process to produce pillared zeolites from 2D layered zeolite structures. The VPP process has ∼100% efficiency of alkoxide usage in the intercalation step, requires less (and, in some cases, zero) water addition in the hydrolysis step, does not require separation for product recovery, and generates no liquid waste. Furthermore, synthesis of pillared zeolites via the VPP process can be accomplished within a single apparatus with one-time operation. The pillared zeolite prepared by the VPP method preserved the zeolitic layered structure as well as acidity and showed enhancement in catalytic alkylation of mesitylene with benzyl alcohol compared to 2D layered zeolite without pillarization treatment.

We reported a strategy to synthesize MFI zeolites with tunable properties by tailoring organic structure-directing agents (OSDAs) under the hydrothermal conditions. The tailored surfactants were obtained by tuning the structure of Gemini-type Cph-10-6-6 and Bola-type BCph-10-6-6, including alkyl tail chains, ammonium groups and alkyl middle chains. The textural property, morphology and acidity of resulting MFI zeolites were characterized by a complementary combination of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption isotherms and FTIR spectra of pyridine adsorption. Moreover, the correlation between the OSDAs’ composition and the inorganic precursor in the fabrication of zeolite framework was investigated by DFT calculations in this study. The catalytic performance of the resulting MFI samples was investigated by the alkylation of mesitylene with benzyl alcohol. The results revealed that the OSDAs without ammonium groups only leaded to form the micro-structure of zeolites, but the OSDAs with ammonium groups can induce the formation of micro- and meso-structure simultaneously, regardless the OSDAs ended with or without alkyl tail chains. In addition, the resulting MFI zeolites showed an improved catalytic activity in alkylation of mesitylene with benzyl alcohol due to the enhanced pore accessibility, the acidity (Bronsted/Lewis) controlled the activation of benzyl alcohol, and the ratio of external surface area (Sext/SBET) governed the selectivity of alkylation reaction. As a result, tailoring the structure of OSDAs can pick another strategy to synthesize MFI zeolites with tunable zeolite structure and catalytic performance.

It has been found that catalytic deoxygenation of triglycerides is a viable pathway for obtaining renewable liquid fuels to contribute to meet the global energy demand. In this study, SBA-15 mesoporous silica was synthesized in a pure form and modified with mesitylene (TMB) as a swelling molecule (SBA15-TMB). Catalysts with 0.5, 1.5 and 3.0 wt% Pd were synthesized and tested by deoxygenation of stearic acid (SA), obtaining initial conversions of 68–98% that decreased to 36–73% after 6 h time-on-stream. The most abundant product was n-heptadecane, with a selectivity of ~ 90%. The most active catalyst evaluated with SA was 3.0 wt% Pd over unmodified SBA-15 (30Pd/SBA-15). Subsequently, fresh and regenerated 30Pd/SBA-15 catalysts were tested with waste cooking oil (WCO) feed, obtaining conversions of 74 and 72%, respectively, but the fresh catalyst allowed a better oxygen removal (91%. Additionally, commercial Pd(10wt %)/C catalyst was evaluated, obtaining results comparable to those for the regenerated 30Pd/SBA-15 catalyst. The main WCO reaction product for all catalysts was a diesel fraction (C12-C21), and the quality of the products was not very different, following the order: Pd(10wt %)/C > 3.0Pd/SBA-15-regenerated > 3.0Pd/SBA-15-fresh. The results obtained indicate that shynthetized catalysts of this study are promising for obtaining renewable diesel from low-cost feeds while using low hydrogen consumption.

The use of silver trifluoromethanesulfonate (silver triflate, AgOTf) as a halide abstraction reagent is pervasive in organometallic chemistry. However, recent reports suggest a “hidden” Bronsted acid lurks within it that may catalyze purported metal-based catalysis. Presented herein are new reactions that are either catalyzed or promoted by the “hidden” acid, generated upon silver triflate degradation. 1-Phenylethanol dehydrates to styrene (1) upon reaction with AgOTf at 90 °C over 24 h, which slowly coverts to the vinyl hydrovinylation product (E)-1,3-diphenyl-1-butene, (2, 64%) over several days. While dehydration was observed with a number of benzylic alcohols to yield Zaitsev selective olefins, only 1-phenylethanol affords vinyl hydrovinylation products. Dehydration was not observed for primary and secondary alcohols, suggesting an acid catalyzed E1elimination reaction mechanism is at play. The degradation of silver triflate was found to be the source of the “hidden” Bronsted acid, which demonstrated a dependence on the presence of light and oxygen. In the absence of light and oxygen, dehydration of 1-phenylethanol was severely stunted and 2 is not formed, but instead the ether product, oxy-bis(ethane-1,1-diyl)dibenzene (3), is afforded. The mesitylene internal standard also reacts with the in situ formed styrene to produce 2-(1-phenylethyl)mesitylene (4) through acid catalyzed electrophilic aromatic substitution. These reactions were monitored (products characterized) by GC-MS and/or 1H NMR spectroscopic methods. We present herein the details of these reactions and our characterization methods.

Meso- and microporous ZSM-5 zeolites were synthesized through combination of the tetrapropylammonium hydroxide (TPAOH) and single quaternary ammonium surfactant (Cph–ph–10–6) as dual templates. The structure-directing ability of Cph–ph–10–6 and TPA+ was investigated by density functional theory (DFT) calculation. By tuning the molar ratios of Cph–ph–10–6/TPAOH from 5/0 to 5/8, the structure-directing effects between Cph–ph–10–6 and TPA+ could be systematically modulated, resulting in the morphology of the mesoporous ZSM-5 zeolites changed from ultrathin nanosheets, through splint-like nanosheets, to condensed packing plates. In addition, the hierarchical ZSM-5 zeolites exhibited a greater catalytic activity in alkylation of mesitylene with benzyl alcohol compared with conventional ZSM-5 zeolite. The fine control of meso- and microporous structures of ZSM-5 zeolites by a simple one-step dual template synthesis approach allows the design of the desired catalysts for a green and sustainable future.

Stereospecific cis-1,4 polymerization of 1,3 butadiene is carried out by using CpTiCl3/MAO and Cp*TiCl3/MAO catalysts in solvents (mesitylene, toluene, benzene, chlorobenzene, m-chlorobenzene, hexafluorobenzene) having different nucleophilicity. The influence of nucleophilicity of used solvent on activity and selectivity of the two considered catalytic systems is evaluated. Catalyst activity is strongly affected by used solvent, while polymer microstructure remains almost unchanged. The formation of a labile specie anti-η3-π-butenyl-Ti coordinated to solvent molecule, able to increase the rate of polymerization reaction, is hypothesized. The effect of two different external electron donors, N(C2H5)3 and P(C6H5)3, in the polymerization environment on activity and selectivity of the two considered catalytic systems is also investigated. Both N(C2H5)3 and P(C6H5)3 induce a sweeping decrease of catalyst activity, but do not cause changes in polymer microstructures.

Carboxyl group functionalized hollow microporous organic nanospheres (HMONs-COOH) were successfully synthesized by hyper-crosslinking reaction between polylactide-b-polystyrene (PLA-b-PS) diblock copolymers and 2,4,6-tris(bromomethyl)mesitylene as well as subsequent alkaline KMnO4 oxidation. The synthesized HMONs-COOH possess the high special surface area, robust organic framework and hierarchically porous structure, which shows highly catalytic activity in the Friedel-Crafts alkylation of indole with aldehydes and outstanding adsorption efficiency toward cationic dyes.

MWW type zeolites are characterized by the presence of zeolitic layers of 2.5 nm thickness, containing 10-member ring sinusoidal channels inside and supercavities with 12-member ring openings located on their surfaces. Expansion and pillaring of layered zeolites increase the access to active sites and can enable or facilitate catalytic activity towards larger reactant molecules. This goal is explored in this work reporting the pillaring of layered zeolite MCM-56 with MWW topology by tetraethylorthosilicate (TEOS) treatment with the assistance of isopropanol, aimed at obtaining hierarchical micro-mesoporous systems. MCM-56 (Si/Al = 12) was synthesized with hexamethyleneimine as a structure-directing and aniline as a structure-promoting agent. Hierarchical porous systems were obtained using two different pillaring methods: (1) with TEOS only and (2) with TEOS mixed with isopropanol. The MWW framework was preserved during swelling/pillaring in both methods. Pillared zeolites obtained via alcohol-assisted pillaring possessed unique intermediate micro-mesopores with the size of about 2 nm. IR study revealed a decrease in the concentration of accessible acid centers upon pillaring. However, the fraction of acid sites on the external surface, accessible for adsorption of large molecules, increased by up to 90%. Catalytic activity was evaluated in the Friedel-Crafts alkylation of mesitylene with benzyl alcohol. Pillaring resulted in reduction of the acid site concentrations, but the materials retained high catalytic activity. Pillaring in the presence of alcohol produced increased turnover frequency values based on the concentrations of the external acid sites.

Zeolite belongs to one of the most important families of solid acid catalysts in chemical industries. It is, however, severely constrained by the diffusion limitation for bulky molecules, a lack of multifunctionality for sequential reactions and pore adaptability toward specific adsorbates due to its small micropore size and simple aluminosilicate framework. Introducing mesopores into a zeolite toward realizing hierarchical zeolites is a prevailing strategy but one that usually suffers from compromised crystallinity as well as insufficient interconnectivity and openness of the mesopores. Herein, a novel acid-redox co-functionalized single-crystalline zeolite with highly open and interconnected mesopores is designed and fabricated. As a proof-of-concept study, we integrate solid acid and Fe-oxy redox sites into a hierarchical MEL zeolite with well-characterized microporosity and mesoporosity. This zeolite exhibits superior activity and stability toward alkylation between mesitylene with benzyl alcohol, arising from greatly facilitated intra-crystal molecular diffusion, mitigated metal leaching and optimized adsorbate-pore wall interactions.

We acknowledge the financial support from the Spanish Ministry of Science and Innovation (CTQ2017-89443-C3-2-R and PDC2021-120835-C21) and the regional Government of the Principality of Asturias (IDI/2018/000116).

Re/Pd-TiO2/SiO2 and Co/Mo-Al2O3/SiO2 aerogel catalysts were synthesized using sol-gel method and supercritical drying in excess solvent, and investigated in the hydrodesulphurisation (HDS) of dibenzothiophene (DBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT). The influence of supercritical drying on the final catalytic properties of the materials was determined by parallel synthesis of aerogels and xerogels for Re/Pd-TiO2/SiO2 catalysts. The sol-gel method and supercritical drying were found to result in amorphous aerogels with relatively high degree of uniformity, of both supports and active phases. Corresponding xerogels were found to be similar to aerogels in terms of composition and structure, but characterized by lower specific surface areas. Catalytic activity of Co/Mo-Al2O3/SiO2 aerogel catalysts in HDS of DBT and 4,6-DMDBT has shown no major improvement in comparison to conventional Co/Mo catalyst. On the other hand, Re/Pd-TiO2/SiO2 aerogels, obtained with the addition of mesitylene or without it, achieved 70 % and 64 % higher conversion of 4,6-DMDBT than conventional Co/Mo catalyst, respectively. Increased catalytic activity can be attributed to well dispersed Re and Pd active phases across the catalyst structure, good incorporation of Ti within silica matrix, increased mesopore volumes and high specific surface areas.

A simple kinetic model based on the zeolite acid strength, the number of Brønsted acid sites, and the catalyst efficiency was developed for the cracking of n-hexane. A series of HY zeolites with a mesopore volume from 0.04 to 0.32 cm3/g was synthesized and characterized by various physical-chemical methods and tested for n-hexane cracking. The generation of mesoporosity influenced several other important parameters, such as acidity and extra-framework aluminum. Zero-length column diffusion measurements for mesitylene showed a large decrease in the characteristic diffusion time upon the introduction of mesoporosity, which changed only slightly with a further increase in mesoporosity. Similar n-hexane physisorption enthalpies were measured for all samples. The highest initial activity for n-hexane cracking per catalyst volume was observed for the sample with an intermediate mesopore volume of 0.15 cm3/g. The three mesoporous H-USY zeolites showed the same value of the intrinsic rate constant and the same activation energy. The difference in initial activity of the mesoporous zeolites was caused by the difference in the number of Brønsted acid sites. The increase in initial activity for the mesoporous zeolites compared to a microporous zeolite was caused by an increase in the acid strength.

SSZ-70 is one of several layered forms of zeolite MMW obtained by direct synthesis with consecutive layers shifted by approximately ±1/3 of a unit cell in the horizontal direction (⟨110⟩), according to the recent structure solution report. Zeolite MWW is a valuable industrial alkylation catalyst and SSZ-70 itself was called by the inventors 'a successful catalytic material'. SSZ-70 shows characteristic powder X-ray diffraction pattern (XRD), containing a unique broad band with a roughly triangular shape and maximum at 8.5–9.0° 2θ (Cu Kα radiation), which can be used to distinguish SSZ-70 from the other MWW materials with different layer arrangements. This work concerns post-synthesis treatments of SSZ-70 to investigate its ability to produce more expanded structures by silylation, swelling and pillaring. Both boron- and aluminum-containing SSZ-70 were investigated. They showed the ability for interlayer expansion by swelling with cationic surfactants and were pillared with silica to produce micro/mesoporous hybrids with increased BET area. Not too surprisingly, the original unique layer stacking of SSZ-70 seems to have become more random and not distinguishable from the swollen forms of the other swellable MWW materials MCM-22 P and the monolayer MCM-56. Calcined SSZ-70 zeolites showed an unusual peak, assigned to (002) reflection, with d-spacing shorter than c-unit cell of the 3D MWW framework, which suggests collapse with formation of the so-called sub-zeolite form. Silylation resulted in different outcomes for B and Al SSZ-70 samples. The former produced interlayer expanded (IEZ) forms of B-SSZ-70 but did not show significant increase in pore volume and BET surface area. Silylation of Al-SSZ-70 did not yield the stabilized (IEZ) form but had a positive effect as it prevented the collapse to sub-zeolite upon calcination. Catalytic testing was carried out for the Al-containing SSZ-70 obtained by direct synthesis and for B-SSZ-70 activated by Al insertion. The former showed much higher concentration of Bronsted acid sites and 5 times faster conversion in a model alkylation reaction between benzyl alcohol and mesitylene. Pillared Al-SSZ-70 showed highest activity despite lower Al concentration due to silica pillars. Both silylation and pillaring had a positive effect on the activity in alkylation reaction with bulky molecules.

The application of different aluminosilicates (MCM-41, MFI, and BEA) to catalyse the gas-phase self-condensation of acetone allows the selective formation of mesitylene regarding the rest of the C9 compounds (relative selectivity up to 80%). Results suggest that mesitylene formation takes place via isophorones instead of via direct dehydration–cyclization of phorones. However, acetic acid and isobutene are also formed (β-scission of C6 compounds). This side reaction has two negative effects: (i) competition with the target reaction decreasing the mesitylene yield and (ii) formation of intermediate acetate species involved in the acetic acid formation, leading to fast deactivation, especially at initial reaction times. This last point was confirmed by DRIFTS analysis. Co-feeding of molecular hydrogen was considered for improving the catalytic stability and the selectivity to aromatics. In fact, the catalytic activity of MCM-41 and BEA is enhanced, with mesitylene yields around 60 and 100% higher with regard to inert operating conditions, respectively. However, supplying H2 entails a drop in the catalytic dehydration activity due to its interaction with active sites. This fact implies lower relative selectivity to mesitylene regarding all the C9 compounds (ca. 50%). Otherwise, the absolute selectivity to mesitylene is improved since the C6 β-scission reaction is largely hindered by the presence of H2.

Zeolite MCM-56 is a high alumina, monolayered form of the commercially useful framework MWW but it is a transient product during crystallization, so many factors influence its state and quality. This work examines properties of a series of MCM-56 and MCM-49 samples synthesized for different times using Aerosil, Ultrasil and Ludox as silica sources, hexamethyleneimine as the structure directing agent and additionally aniline as structure promoting agent. It was found that the most important parameter, governing the catalytic activity in the test reaction of Friedel-Crafts alkylation of mesitylene with benzyl alcohol, was availability of the Bronsted acid centers located at the external surfaces of the crystals. The key role in correlating physical characteristic with activity was played by infrared spectroscopy as it enabled the study of many properties of the tested materials, starting from the total concentration of acid centers, and their type (Bronsted or Lewis acids) through the concentration of centers available for the reagent molecules, to investigating the correlation of acidity with the degree of zeolite crystallinity.

We developed an environmentally friendly iridium-catalyzed direct cyclization of aromatic amines with diols that generates the corresponding N-heterocyclic compounds with water as the sole by-product. Thus, under conditions of 165 °C for 18 hours, the direct cyclization of N-methylanilines with 1,3-propanediol by using an IrCl3 catalyst with rac-BINAP as a ligand in mesitylene afforded the corresponding tetrahydroquinoline derivatives with yields ranging from 73 to 83%. ­Under similar reaction conditions, direct cyclization of anilines with 1,3-propanediol produced the corresponding tetrahydrobenzoquinolizine derivatives with yields ranging from 26 to 76%.

This paper reports a straightforward approach to synthesizing hierarchical beta zeolites by exposing microporous zeolites to hydrothermal conditions amenable for beta crystallization, which simultaneously creates hierarchical pore structure while maintaining crystallinity and framework integrity without the use of organic structure-directing agents, pore-directing agents, or mesoporous templates. The obtained hierarchical beta zeolites possess enlarged mesopores and exhibit improved catalytic performance for the conversion of bulky molecules in the liquid-phase conversion of benzyl alcohol with mesitylene. A sequential hierarchical structure formation and recrystallization mechanism is proposed to elucidate the creation of mesopores in beta zeolites with excellent preservation of acidity and microporosity.

The design of porous materials for the recognition of multiple hydrocarbons is highly desirable for the energy-efficient separation and recognition of chemical feedstock. Herein, three new iso-structural porous discrete metal-organic cages of formula {[Pd3 (NiPr)3 PO]4 (R-AN)6 } (R-AN=anilate linkers) for the selective recognition of substituted aromatic hydrocarbons are reported. The tetrahedral cages 1, 2, and 3 containing anilate, chloranilate, and bromanilate linkers exhibited selective encapsulation of mesitylene, o-xylene, and p-xylene, respectively, over other analogous aromatic hydrocarbons. These selective encapsulations were driven by the variations in the portal diameters present at each of these cages and their interactions with the hydrocarbon guests. These observations are supported by mass spectrometry, NMR studies, and theoretical binding-energy calculations.

A SiC@TiO2/Pt catalytic membrane was fabricated to simultaneously remove volatile organic compounds (VOCs) and nano particulate matter (nano-PM) from industrial fumes. The TiO2 transition layer and Pt nanoparticles were prepared by soaking SiC membrane into the corresponding precursor and then high temperature sintering, respectively. The TiO2 layer decorated on the pore surface of SiC was found to be essential for the effective loading of Pt nanoparticles and improving of catalytic activity. Meanwhile, this modification process has no effect on the gas permeation of the membrane. The mesitylene degradation and PM removal efficiency of SiC@TiO2/Pt catalytic membrane were evaluated. Complete conversion could be obtained for mesitylene with the inlet concentration of 300, 600, and 800 ppm at the residence time of 1.0 s, reaction temperature of 240, 251, and 263 °C, respectively. In the dust and mesitylene coexistence system, the catalytic membrane can completely degrade mesitylene and remove 99.98% of Al2O3...

Arene-stabilized silylium ions react with carbon monoxide rather than carbon monoxide adducts of silylium ions reacting with arenes. This mechanism is supported by quantum-chemical calculations. Even sterically hindered mesitylene and electronically deactivated chlorobenzene engage in this electrophilic aromatic substitution. The silylium ion mediated formylation corresponds to Gattermann-Koch reactions promoted by strong Brønsted acids. The resulting silylcarboxonium ion of the arenecarbaldehyde was crystallographically characterized, for the first time revealing the molecular structure of this synthetically important intermediate.

This study reports the relevance of alkyl substituents on the chemisorption of alkylaromatics on metal surfaces, namely Pt(1 0 0) and Ni(1 0 0). Density functional theory (DFT) based calculations are used to calculate the chemisorption energies of benzene, methylbenzene (toluene), 1,2-, 1,3-, and 1,4-dimethylbenzenes (xylenes), and 1,3,5-trimethylbenzene (mesitylene), and ethylbenzene on Pt and Ni. Removal of hydrogens from the adsorbed benzene substantially reduces the stability of the adsorbed species on both Pt(1 0 0) and Ni(1 0 0) surfaces. Methyl substituents on the benzene ring, i.e., toluene, xylenes and mesitylene, result in exothermic dissociation of a C H bond from each methyl substituent on both Pt and Ni surfaces. This leads to formation of CH2 groups connected to the aromatic ring, resulting in a π-conjugated system stacked over the metal surface, and expanding over the entire molecule. The energy gain associated with dehydrogenation of each hydrogen from the methyl groups cumulates, so that complete π-conjugated configuration by dehydrogenation of the methyl groups of xylenes and mesitylene is expected. Further removal of hydrogen from aromatic rings of the π-conjugated system is always endothermic on both surfaces. The study is extended to ethylbenzene on the same surface, and results suggest that dehydrogenation of methylene group followed by dehydrogenation of the methyl group, leading to formation of adsorbed styrene is favored. These results may justify more explicitly the essential role of cofed (or recycled) hydrogen to produce alkylaromatics in practical applications, enabling to recover sp3 alkyl substituents to desorb the products. Although the actual catalysis involves more complexities on other types of metal sites, such as edges and kinks, the current study already demonstrates one significant aspect of the hydrogenation-dehydrogenation catalysis on metal surfaces.

A noval method for the synthesis of optically active β-hydroxy sulfones was developed. Through a substitution/dynamic kinetic resolution–asymmetric transfer hydrogenation, the presented method was based on one-pot enantioselective organic transformations of α–bromoindenones and sodium arylsulfinate. The protocol employed RuCl2[(S,S)–TsDPEN](mesitylene) as a catalyst, and sodium formate as a hydrogen source, affording various optically pure vicinal stereocenters β-hydroxy sulfones in high yields with excellent enantioselectivities (up to 99%) and diastereomeric ratios (up to 99:1) under mild reaction conditions.

Mesoporous EU-1 zeolites with adjustable mesoporosity have been prepared by employing silanized silica into the starting synthesis gel, based on the hinder effect of organic moiety to crystal growth. The synthesized mesoporous EU-1 zeolites were characterized by XRD, NMR, SEM/TEM and N2 adsorption/desorption at 77 K, showing the persistence of inherent microporous framework structure of EU-1 zeolite and the existence of additional mesopores within the range of 3–10 nm. The generation of mesoporosities is from the intercrystalline voids of nanocrystal aggregates. The introduction of mesopores in EU-1 zeolite increased the adsorption of mesitylene with the kinetics diameter larger than the micropore size, and made it possible for the diffusion pattern of n-heptane from one-dimensional in microporous EU-1 to three-dimensional in mesoporous EU-1. This result together with the enhanced accessibility of acidic sites of mesoporous EU-1 improved greatly the catalytic activity and product yields of cumene cracking reaction involving bulky molecules.

A large number of chemicals including surfactants, nootropic drugs and pesticides contain an N-acylated lactam moiety in their molecular structure. In this work, the direct, catalytic N-acylation of a number of lactams with various unactivated carboxylic acids is reported. Several Lewis acid catalysts were evaluated for their activity in the N-acylation of pyroglutamic acid methyl ester with palmitic acid; the highest activities were observed for zirconium-based catalysts. Yields of up to 97% were obtained utilising 10 mol% Zr(propoxide)4 in mesitylene at reflux temperature, but ZrOCl2·8H2O was determined as the most stable catalyst. The substrate scope was investigated and a number of lactam-carboxylic acid combinations were successfully converted into the desired products in 57–97% yield. This method provides an alternative synthetic pathway towards the drug aniracetam, which can be produced in 84% yield. A plausible catalytic mechanism is presented based on kinetic experiments.

Micromixing of an o-xylene solution of C60 with N-N-dimethylformamide (DMF) at room temperature under continuous flow in a vortex fluidic device (VFD) results in the formation of symmetrical right cones in high yield with diameters 0.5 to 2.5 μm, pitch angle 25° to 55° and wall thickness 120 to 310 nm. Their formation is in the absence of surfactants and any other reagents, and is scalable. The cones are formed at specific operating parameters of the VFD, including rotational speed, flow rate and concentration, and varying these results in other structures such as grooved fractals. Other aromatic solvents in place of o-xylene results in the formation of rods, spicules and prisms, respectively for m-xylene, p-xylene and mesitylene.

Hierarchical mordenite zeolite nano-rods bundles were successfully synthesized by a novel approach of using organosilane functioned fumed silica as silicon source. The organic moiety linked on the surface of fumed silica inhibits the growth of zeolite crystal into large size, leading to the nano-rods assembled bundles. The mordenite nanorods bundles exhibited significantly improved mesitylene adsorption capacity compared with the conventional mordenite. As a catalyst, the hierarchical mordenite nanorods bundles showed remarkable catalytic performance in the benzylation of mesitylene by benzyl chloride, due to the efficient diffusion rate and improved accessibility of the active sites in the hierarchical mordenite nanorods bundles.

The OsVI nitrido complex, OsVI(N)(quin)2(OTs) (1, quin=2-quinaldinate, OTs=tosylate), is a highly selective and efficient catalyst for the ring hydroxylation of alkylbenzenes with H2O2 at room temperature. Oxidation of various alkylbenzenes occurs with ring/chain oxidation ratios ranging from 96.7/3.3 to 99.9/0.1, and total product yields from 93 % to 98 %. Moreover, turnover numbers up to 6360, 5670, and 3880 can be achieved for the oxidation of p-xylene, ethylbenzene, and mesitylene, respectively. Density functional theory calculations suggest that the active intermediate is an OsVIII nitrido oxo species.