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In the heterogeneous catalysis, adsorption and desorption behaviors of reactants and products on the surface of catalysts can remarkably impact their catalytic activities and product selectivities. Here, series of Ru‐based catalysts supported on Zn‐incorporated Li−Al layered double hydroxides (Ru/LDH) were developed and employed in the selective benzene hydrogenation to produce cyclohexene without the use of any additional zinc salt additives. It was demonstrated that as‐constructed supported Ru catalyst bearing a Zn/(Li+Zn) molar ratio of 0.075 in the LDH support gave a higher cyclohexene yield of 43.2 % than those over other Ru‐based ones. Combining structural characterizations and catalytic hydrogenation reactions with temperature‐programmed desorption and in situ Fourier transform infrared spectroscopy of benzene and cyclohexene, it was revealed that the generation of appropriate surficial/interfacial Ru0/Ruδ+−O−Zn structures, as well as the existence of abundant hydroxyl groups on LDH supports, could facilitate the benzene adsorption and the cyclohexene desorption, thereby remarkably promoting the formation of cyclohexene. The present findings not only give a profound insight into the roles of surface‐interface structures of supported Ru catalysts for efficient benzene hydrogenation to produce cyclohexene but also simultaneously provide a promising guide to design high‐performance Ru‐based catalysts. [ABSTRACT FROM AUTHOR]

Enantioselective formal carbo [3+3] cycloaddition reaction of isopropylidenemalononitrile (1) and α,β‐unsaturated aldehyde, catalyzed by diphenylprolinol silyl ether, was developed. The reaction is a domino Michael/aldol‐type reaction, followed by Al2O3‐mediated dehydration to afford 5‐substituted cyclohexene derivatives possessing a methylene‐malononitrile moiety, with excellent enantioselectivity. [ABSTRACT FROM AUTHOR]

We undertake silver cyanide (AgCN) powder for its catalytic epoxidation of cyclohexene or styrene in CH3CN with variable substrate‐to‐solvent volume ratios using H2O2(aq) at 60 °C. The reaction mixtures can facilely separate into organic and aqueous layers. Cyclohexene oxide can be produced in the organic layer with 100 % selectivity from the substrate cyclohexene, while styrene oxide was identified with 80 % selectivity against benzaldehyde in styrene oxidation. After reactions, we can recycle the AgCN particles with comparable bulk property clarified via XRD, XPS, XAS, FT‐IR, and 13C‐SS NMR spectroscopy. Using H218O2 as the oxidant, both epoxide products and acetamide are highly enriched with 18O‐atom, indicating that the π bond‐activation is essential for forming the cyclohexene/styrene oxides in the organic and acetamide in the aqueous layers. The oxidation of cyclohexene/styrene catalyzed by AgCN powder through surface activation by H2O2(aq) and assisted by the non‐innocent CH3CN‐originated acetamide can achieve highly selective π‐bond activation with high reactivity. [ABSTRACT FROM AUTHOR]

A copper-iron mixed oxide was deposited by the washcoating procedure over cordierite honeycomb monoliths for its use as a heterogeneous catalyst in organic synthesis processes. In particular, the prepared catalyst, characterized by techniques such as X-ray fluorescence, X-ray diffraction, SEM-EDS, laser granulometry, adherence tests, Temperature-Programmed Oxidation and Temperature-Programmed Reduction, showed an excellent yield and stability in the selective production of the allylic ester derived from the Kharasch-Sosnovsky oxidation of cyclohexene with benzoic acid. The use of a structured catalyst here proposed opens up an interesting alternative to homogeneous catalysis in the field of synthetic chemistry. [Display omitted] • Copper-iron mixed oxide as structured heterogeneous catalyst for organic synthesis. • High yield in Kharasch-Sosnovsky oxidation of cyclohexene with benzoic acid. • Cordierite honeycomb monolith as support provides excellent catalyst stability. • Proposed formulation for the active phase is more active than separate pure oxides. • Applicable to other benzoic acid derivatives and with potential to reaction scaling. [ABSTRACT FROM AUTHOR]

MOF-74 is probably the MOF material that best combine three key features for catalytic applications: compositional versatility, the presence of open metal sites and the possibility of becoming nanocrystalline, thus avoiding or minimizing any reactants/products diffusion problems within their pores. This work describes, for the first time, the room-temperature preparation of bimetallic nanocrystalline MOF-74 materials and their catalytic performance in the solvent-free oxidation of cyclohexene using oxygen as oxidant. Although the preparation of oligo-metallic MOF-74 has been already published and even certain catalytic and adsorption metallic synergism has been made clear, this work shows that the room temperature synthesis approach provides some further possibilities for controlling the metal distribution by two different strategies: (i) changing the order of metal addition and/or (ii) by synthesis time. The nanocrystalline Me-MOF-74 catalysts based on metal with redox behavior (Mn, Co, Cu) are significantly active in the aerobic oxidation of cyclohexene, whereas Zn is rather an inhibitor. In spite of such inhibitor role of Zn-MOF-74, the bimetallic Zn-M2-MOF-74 samples (M2 = Mn, Co, Cu) show catalytic performance similar to that of the monometallic counterparts M2-MOF-74, and therefore their turnover is considerably increased. The system Cu-Mg-MOF-74 was selected to study effect of different metal distribution within the crystal on their catalytic activity: Longer synthesis time and consecutive addition of Cu and then Mg (the reverse order did not lead to pure MOF-74 phase) favors the catalytic activity of the resultant materials. Finally, the CoMn combination of two of the three most active metals (samples CuMn, CoMn and CuCo) lead to a bimetallic catalyst with higher catalytic performance than the corresponding monometallic samples. [Display omitted] • Nanocrystalline bimetallic MOF-74 instantaneously prepared at room temperature. • Order of addition of metal controls the metal distribution within MOF crystals. • Catalytic synergism could be reached with metals able to form isostructural MOF-74. [ABSTRACT FROM AUTHOR]

In this study, we synthesized a poly(cyclohexene carbonate) (PCHC) through alternative ring-opening copolymerization of CO2 with cyclohexene oxide (CHO) mediated by a binary LZn2OAc2 catalyst at a mild temperature. A two-dimensional Fourier transform infrared (2D FTIR) spectroscopy indicated that strong intramolecular [C–H···O=C] hydrogen bonding (H-bonding) occurred in the PCHC copolymer, thereby weakening its intermolecular interactions and making it difficult to form miscible blends with other polymers. Nevertheless, blends of PCHC with poly(vinyl phenol) (PVPh), a strong hydrogen bond donor, were miscible because intermolecular H-bonding formed between the PCHC C=O units and the PVPh OH units, as evidenced through solid state NMR and one-dimensional and 2D FTIR spectroscopic analyses. Because the intermolecular H-bonding in the PCHC/PVPh binary blends were relatively weak, a negative deviation from linearity occurred in the glass transition temperatures (Tg). We measured a single proton spin-lattice relaxation time from solid state NMR spectra recorded in the rotating frame [T1ρ(H)], indicating full miscibility on the order of 2–3 nm; nevertheless, the relaxation time exhibited a positive deviation from linearity, indicating that the hydrogen bonding interactions were weak, and that the flexibility of the main chain was possibly responsible for the negative deviation in the values of Tg. [ABSTRACT FROM AUTHOR]

Chemical recycling of polymers to true monomers is pivotal for a circular plastics economy. Here, the first catalyzed chemical recycling of the widely investigated carbon dioxide derived polymer, poly(cyclohexene carbonate), to cyclohexene oxide and carbon dioxide is reported. The reaction requires dinuclear catalysis, with the di‐MgII catalyst showing both high monomer selectivity (>98 %) and activity (TOF=150 h−1, 0.33 mol %, 120 °C). The depolymerization occurs via a chain‐end catalyzed depolymerization mechanism and DFT calculations indicate the high selectivity arises from Mg‐alkoxide catalyzed epoxide extrusion being kinetically favorable compared to cyclic carbonate formation. [ABSTRACT FROM AUTHOR]

One‐step synthesis of well‐defined block copolymer is of great fundamental and practical values. Here, an aromatic‐aliphatic block copolyester is one‐step synthesized from the mixture of phthalic anhydride (PA), cyclohexene oxide (CHO), and δ‐valerolactone (δ‐VL) at room temperature in the presence of a metal‐free Lewis pair catalyst consisting of triethylborane and excess phosphazene base. Alcohol‐initiated ring‐opening alternating copolymerization of PA and CHO occurs first and selectively because of the overwhelmingly higher activity of PA than CHO and δ‐VL toward the reaction with base‐activated hydroxy species. Only after full conversion of PA is reached can ring‐opening polymerization of δ‐VL occur from the terminus of the aromatic polyester so that a well‐defined (AB)nCm type block copolyester is formed. The two polymerizations are both highly chemoselective without homopolymerization of CHO or extensive transesterification reactions. Owing to the sequence‐selective and living characteristics of the terpolymerization, hepta‐ and undecablock copolyesters with controlled molar mass and low dispersity are obtained through addition of the three‐component monomer mixture in batches. Applicability of the method to propylene oxide and ε‐caprolactone is also examined. [ABSTRACT FROM AUTHOR]

A new chitosan derivative (CS-CHO) was successfully synthesized based on chitosan (CS) and cyclohexene oxide (CHO). It proved that CHO was successfully grafted onto the amino group of CS by N-alkylation reaction through the characterization of FTIR, XRD and DSC-TGA. The mechanical properties (tensile strength, folding endurance, tearing strength), optical properties (whiteness, glossiness) of the CS-CHO coated paper sample were tested. The results showed that the mechanical properties of the paper treated with 10 % CS-CHO increased significantly without changing the appearance of the paper. The paper permanence (tensile strength, folding endurance, tearing strength and pH) of the treated paper samples tested by dry-heat aging test. The results showed that the permanence of the treated paper samples was significantly improved compared with the blank aged paper samples, which indicated that CS-CHO had the function of deacidification while reinforcing the paper samples, providing the possibility for deacidification and reinforcement in one-step method and playing a positive role in the paper preservation. [ABSTRACT FROM AUTHOR]

Adipic acid (hexadioic acid) is a bulk chemical presently produced using highly polluting processes. Herein, we discuss the catalytic evaluation of CuNPs on a hybrid PLA/TiO2 particle brush in the selective liqud-phase oxidation of cyclohexene to adipic acid using H2O2 as green oxidant. Various reaction conditions including effect of solvent, temperature, time and catalyst concentration were optimized in the reaction protocol. The recyclability as well as the stability of the catalyst was studied and a mechanism proposed for the observed results. Products and reaction evolution was tracked by GC–MS, 1H NMR and FT-IR.

Cyclohexanol is an organic chemical intermediate product widely used in chemical industry and commonly produced by cyclohexene hydration. Because of the low mutual solubility of cyclohexene and water, the reaction is limited by chemical equilibrium, which has the disadvantage of low conversion of cyclohexene. In this paper, the hydration reaction of cyclohexene catalysed by A-36 cation exchange resin catalyst was analysed by Aspen Plus V8.6 simulation software in the presence of isophorone as cosolvent. The process model of synthesising cyclohexanol by catalytic distillation was verified by process experiments. The simulation experiments were carried out using the process model, and suitable operating conditions of the catalytic distillation column were obtained. These are: ketene feed ratio 1.5, alkene/water ratio 0.5, distillation stage trays 5, reaction stage trays 12, stripping stage trays 6, cyclohexene feed at the 18th tray, water and isophorone feed at the 5th tray, reflux ratio 3, feed ratio (D/F) 0.25. Under these operating conditions, the conversion of cyclohexene can reach 40.63 %.

New "olefin–alcohol" pairs were involved in the non-catalytic (α-hydroxy)alkylation process at 350 °C – the addition reaction of MeOH, EtOH or 2-PrOH to styrene, cyclohexene, 1-heptene, and limonene to produce carbon-chain elongated alcohols. The contribution of different side reactions (transfer hydrogenation, alcohol dehydration, C-alkoxylation, etc.) was described for the first time, and the chemo- and regio-selectivity was evaluated for each pair. As proof-of-concept, the ability of an olefinic precursor to participate in a two-step elimination–(α-hydroxy)alkylation tandem reaction with alcohols was confirmed: isobutylene generated in situ from tert-butanol at 350 °C reacted with MeOH to give two isomeric alcohols (isoamyl and neopentyl alcohols) with 34% selectivity. [ABSTRACT FROM AUTHOR]

In the last three decades, invasive fungal infections caused by Candida species have become an important public health problem, because they are associated with high rates of morbidity and mortality in immunocompromised and hospitalized patients. The diagnosis and treatment of candidiasis are difficult and usually inefficient. Accordingly, a diversity of available drugs, currently employed to attack candidiasis, frequently induce resistance in patients promoting toxicity due to long-term treatments. Therefore, development of accurate diagnoses and novel antifungals is of high priority to improve life's quality and expectancy of individuals infected with this pathogen. Plants are invaluable sources of new biologically active compounds. Among the plants used in Mexico in traditional herbolary medicine which have empirically been demonstrated to have antifungal activity are Pedilanthus tithymaloides, Thymus vulgaris, and Ocimum basilicum. In the present study, we analyzed whether these plants contain metabolites with antifungal activity against five Candida species. The extracts from the different plant organs were obtained by macerating them in ethyl alcohol or hexane and filtering. The obtained extracts were preserved in amber flasks at 4°C until used. The minimum inhibitory concentrations (MICs) of the active compound were determined by a microdilution assay. In addition, the following secondary metabolites were identified: linalool (3,7-dimethylocta-1,6-dien-3-ol), eugenol (4-allyl-2-methoxyphenol), limonene (1-methyl-4-(1-methylethenyl)-cyclohexene), and borneol ([(2R)-1,7,7-trimethyl-2-bicyclo[2.2.1]heptanyl] formate). All these compounds were found in the three plants, traditionally used in everyday life, and proved to be effective against Candida species and therefore a viable alternative to conventional antifungals. [ABSTRACT FROM AUTHOR]

The coordination chemistry of Fe2+ ions in combination with a monodentate siloxide ligand Ph3SiO− (L) was investigated. Using a Fe/L stoichiometry of 1 : 3 the complex [Na(DME)][FeL3], 2, with the iron center in a trigonal ligand environment was isolated and through decreasing the siloxide amount fraction 2 was shown to form via a unique example of a dinuclear complex, where one of the iron ions has a quasi‐trigonal and the other one a tetrahedral coordination sphere, namely [Na(DME)][Fe2L5], 1. If, however, 4 equivalents of L are employed, the tetrasiloxido ferrate(II) anion with a tetrahedral structure is generated, so that the product [Na(DME)]2[FeL4], 3, can be isolated. 2 reacts instantly with O‐atom transfer reagents, also at low temperatures, but no reaction intermediate could be identified. From the product mixture the iron(III) siloxide complex [Na(DME)3][FeL4], 4, could isolated by crystallization as the main product. Likewise, the reaction with dioxygen proceeded rather fast and added substrates did not intercept any intermediate upon its formation. However, in the presence of cyclohexene oxidation products were observed. They correspond to the typical radical‐chain‐derived products of cyclohexene suggesting, that initially a reactive FeOx species is generated that via an H atom abstraction from cyclohexene triggers its autoxidation. [ABSTRACT FROM AUTHOR]

A major drawback for practical application of halohydrin dehalogenase HheG in biocatalysis is its rather low thermal stability and low organic solvent tolerance. We therefore pursued a stabilization of HheG via immobilization as cross‐linked enzyme crystals. Since glutaraldehyde inactivates HheG, we introduced a cysteine residue in the crystal interface, which enabled thiol‐specific cross‐linking at well‐defined cross‐linking sites. Variant HheG D114C displayed improved crystallizability and yielded stable and catalytically active CLECs using bis‐maleimidoethane as cross‐linker. Effective cross‐linking at the predefined site could be confirmed via the CLEC crystal structure. Compared to soluble enzyme, the CLECs displayed significantly improved stability and activity at higher temperatures, lower pH values and in the presence of water‐miscible organic solvents, which enabled their reuse over 21 days in the azidolysis of cyclohexene oxide. [ABSTRACT FROM AUTHOR]

Porous Fe carboxylates are amongst the most promising MOF-based materials due to their low price, low toxicity, metal environments (including open metal sites) and remarkable (meso)porosity variety. Fe-MOFs based on the cluster [Fe 3 O(X)(solvent) 2 ]6+, that is, MIL-101(Fe), MIL-100(Fe) and semiamorphous Fe-BTC, are of particular interest. These three materials are quite related each other: (i) MIL-100(Fe) and MIL-101(Fe) have the same zeolitic topology MTN and two types of mesocavities, whereas (ii) Fe-BTC and MIL-100(Fe) form an unprecedented semiamorphous / fully-crystallized pair, having in common the metal cluster, the composition, one mesocavity, etc but without becoming a nano- / micro-crystalline pair. This work describes the room-temperature synthesis, characterization and catalytic performance in the aerobic cyclohexene oxidation of the semiamorphous Fe-BDC, which together with MIL-101(Fe) would form the second semiamorphous / crystallized pair in MOFs. Unfortunately, Fe-BDC could not be prepared in water as solvent, but in either ethanol or in N,N-dimethylformamide. It possesses relatively high textural properties (above 500 m2g-1) and key common features with MIL-101(Fe): XRD reflections at the same 2θ positions, similar thermal stability, almost equal linker conformations, etc. Fe-BDC became quite active in the solvent-free aerobic oxidation of cyclohexene under mild conditions, surpassing the activity performance of the well-known commercial Fe-BTC catalyst in the same reaction under the same mild conditions. [Display omitted] • A new semiamorphous Fe-MOF, the so-called Fe-BDC, is described. • It is highly related to the semiamorphous Fe-BTC and to the mesoporous MIL-101(Fe). • Fe-BDC and MIL-101(Fe) form a semiamorphous/crystallized pair of MOFs. • Fe-BDC is an active heterogeneous catalyst in the aerobic oxidation of cyclohexene. [ABSTRACT FROM AUTHOR]

The aim of this study is to obtain Ti-containing Periodic Mesoporous Organosilica (PMO) materials with catalytic activity in epoxidation reactions. Characterization of the PMO materials using X ray diffraction, N 2 sorption isotherms, chemical analysis (ICP-OES) and UV–vis spectroscopy reveals that the Ti-PMO materials possess ordered 2-dimensional hexagonal mesostructures, high surface areas (593–944 m2/g), uniform pore sizes (4.5–11 nm), large pore volumes (0.59–1.62 cm3/g), and tetrahedrally incorporated Ti(IV) species on the surface of the pore walls. The PMO materials with fiber-like particle morphology, which may hinder the diffusion of substrates, have been compared with those of plate-like morphology in which diffusion problems may be avoided. The catalytic activities of these materials were tested in epoxidation of cyclohexene with an optimum conversion rate of 30.5% and good epoxide selectivity (93.8%). Selected Ti-PMO materials were also effective for the epoxidation of vernonia oil, a naturally expoxidized triglyceride oil, using tert-butyl hydroperoxide as an oxidant. Epoxidation of vernonia oil using Ti containing PMO [Display omitted] • Direct synthesis of Ti-PMO using titanocene using P123 and PE104 surfactants. • PE104 leads to short channels particles while P123 forms fibers like in SBA-15. • Catalytic activity tested in epoxidation of cyclohexene. • Optimum conversion rate of 30.5% and good epoxide selectivity (93.8%). • Selected Ti-PMO materials were also effective for the epoxidation of vernonia oil. [ABSTRACT FROM AUTHOR]

BACKGROUND The separation of olefins and alkanes remains one of the most challenging industrial processes due to their similar structure and boiling points. Traditional industrial methods are limited as a consequence of high equipment cost and energy consumption. Ionic liquids (ILs) for olefin separation systems have been developed in recent years. This study aimed to synthesize silver (Ag+) IL and apply it in both extraction and membrane processes to enhance the separation performance. RESULTS: Quantum chemical calculation results show that the interaction energy between the IL and cyclohexene is much larger than the values for interactions between the IL and alkanes. The highest selectivities for cyclohexene in the extraction process were 33.4 and 51.9 in the presence of cyclohexane and hexane, respectively. The gel membrane was prepared by casting a mixture of 12HSA and Ag+ IL solution onto the PVDF membrane. In vapor permeation, high separation performance was obtained together with a stable membrane phase when the 12HSA content was 1.50% and the operating temperature was 45 °C. With the increase of the mole fraction of cyclohexene, the permeation flux gradually increased and the separation factor was maintained at >9. CONCLUSION: Reversible π‐complex formation between Ag+ ions and cyclohexene can effectively enhance the separation performance in both extraction and membrane process. This study presents a promising alternative to conventional technology for olefin and alkane separations. © 2021 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Nanocrystalline Ti−Beta zeolite with high hydrophilicity and a Ti−rich exterior was successfully prepared via a dissolution–recrystallization method. With the post−treatment of tetraethylammonium hydroxide (TEAOH) solution at elevated temperature, the Si and Ti species within the Ti−Beta matrix were partially dissolved and recrystallized on the outer surface of crystals, resulting in the Ti−rich exterior and higher hydrophilicity, which improved the accessibility of the active Ti sites and the enrichment of H2O2. Simultaneously, some of the closed Ti(OSi)4 species were transformed to more active open Ti(OSi)3OH or Ti(OSi)2(H2O)2(OH)2 species. The modified Ti−Beta zeolite exhibited greatly enhanced catalytic performance in the epoxidation of cyclohexene in comparison to the parent Ti−Beta. [ABSTRACT FROM AUTHOR]

Herein, the catalysts of ruthenium and molybdenum oxide nanoparticles supported on activated carbon (AC) were synthesized by precursor stepwise impregnation and employed for the hydrodeoxygenation (HDO) of lignin oil. The XRD, TEM, XPS and NH 3 -TPD-MS result of RuMoO x /AC catalysts confirm that the method of loading molybdenum precursor before ruthenium precursor is advantageous for the MoO x and Ru nanoparticles high dispersion and the reduction of MoO x species enhance the amount of acidity of catalyst. Meanwhile, the reduction temperature of RuMoO x /AC-1-T catalysts could effectively regulate the MoO x species that determine the activity and product distribution of HDO. The conversion of aromatic monomers/dimers were up to 96% with high selectivity of hydrocarbon over RuMoO x /AC-1-350 catalyst at 160 °C and 30 bar H 2. Which is attributed to the MoO 3 and Ru species possess the excellent activity of benzene ring deep hydrogenation, ether bond breaking and acid dehydration. The RuMoO x /AC-1-350 catalyst effectively converted lignin oil (from the depolymerization of cornstalk hydrolysis residue) into hydrocarbons (56.9 wt%) and cyclohexanol/ethers (18.7 wt%) under 280 °C and 3 bar H 2. The durability of the RuMoO x /AC-1-350 catalyst for HDO of lignin oil was also investigated and showed that the RuMoO x /AC-1-350 catalyst had good stability, regenerability and repeatability. [ABSTRACT FROM AUTHOR]

Bis(amidinate) tin(II) complex (1) was reported as active catalyst for ring‐opening copolymerization of cyclic anhydrides and epoxides via a binary catalyst system. Polymerizations of six combinations of epoxides and cyclic anhydrides were carried out giving highly alternating poly(anhydride‐alt‐epoxide) with narrow dispersities, except for cyclohexene oxide where significant amount of ether linkage up to 62 % was observed. This ether linkages could be diminished by increasing the amount of cocatalyst to over 3 equiv. Six well‐known cocatalysts were screened where PPNCl was found to be the best cocatalyst. [ABSTRACT FROM AUTHOR]

A flexible approach to both type II and III lepadin alkaloids is developed for the first time. A key Diels–Alder reaction based on a novel chiral ketolactone dienophile is employed to obtain the desirable all- cis -trisubstituted cyclohexene with excellent regio- and stereoselectivity. As the subsequent closure of the piperidine ring is devised at the N1 and C2 position via an intramolecular nucleophilic amination, the two stereochemical types of lepadin frameworks with the opposite configuration at C2 can be conveniently accessible from a common intermediate. By the approach, lepadins D, E (type II) and F (type III) are stereo-selectively synthesized from ethyl l -lactate. [ABSTRACT FROM AUTHOR]

In this manuscript, H-La-Y and La-H-Y molecular sieves with different La loadings had been prepared by way of impregnation-ion exchange method, and the acidity and pore structure of the molecular sieves were characterized. The catalytic overall performance of modified molecular sieves for the catalytic alkylation of benzene and cyclohexene used to be investigated, and the introduction of La framework and cation exchange product make the H-Y molecular sieve produce extra strong acid centres, and the acid strength of the molecular sieves and the conversion of cyclohexene had been significantly improved. The study located that La-H-Y(2) molecular sieve has higher activity. Alkylation of benzene and cyclohexene was used to be carried out below optimal conditions, this alkylation response demonstrated a 98.27% conversion of cyclohexene with 97.63% selectivity of cyclohexylbenzene. Besides, thermogravimetric (TG) analysis contrast before and after the reaction confirmed that the weight loss of the catalyst previously than and after the reaction used to be by and large due to the removal of the adsorbed water, and a small quantity of organic by-products stayed in the pore channel after the reaction. The regeneration through the usage of calcining after the use of the catalyst can additionally lead to the partial destruction of the molecular sieve's skeleton structure. [ABSTRACT FROM AUTHOR]

In the present study, the allylic oxidation of cyclohexene is investigated using molecular oxygen as an oxidant under environment-friendly conditions in the presence of rGO-dithiooxamide/Au hybrid nanocatalyst (rGO $=$ reduced graphene oxide). This hybrid catalyst comprises nanometric spherical gold particles supported on dithiooxamide-functionalized rGO. The structure of the prepared hybrid catalyst was characterized using FT-IR, XRD, SEM and TEM techniques. The catalytic activity results were found to be dependent on pressure, the amount of hybrid nanocatalyst, reaction time, and temperature. In addition, an 85% conversion and 85% selectivity to 2-cyclohexene-1-one were obtained under optimized reaction conditions. The catalytic activity over a recycled catalyst (rGO-dithiooxamide/Au) remained at a satisfactory state after at least five cycles.

Acidic poly(ionic liquid)s (PILs) with swelling ability were synthesized by free radical copolymerization of N-vinylimidazolium ionic liquids, divinylbenzene (DVB) and sodium acrylate (NaAA), and further acidification by sulfuric acid. The swelling ability of acidic PILs was greatly affected by cross-linker content and chain length of 3-alkyl-substituents on imidazolium. Cross-linked network structures could be observed from the cryogenic scanning electron microscopy (cryo-SEM) images of the swollen acidic PILs in formic acid. Acidic PILs with network structures in swollen state exhibited excellent activities in the esterification of cyclohexene and formic acid, and the catalytic activities were in positive correlation with their swelling abilities. Acidic PIL with 3-octyl-substituent and 2.5 mol% DVB (PIL-C8-2.5DVB-HSO4) had the highest swelling ability in formic acid and exhibited comparable catalytic activities with homogeneous catalysts such as sulfuric acid and p-toluenesulfonic acid.

Monoterpenes, the second most abundant biogenic volatile organic compounds globally, are crucial in forming secondary organic aerosols, making their oxidation mechanisms vital for addressing climate change and air pollution. This study utilized cyclohexene as a surrogate to explore first-generation products from its ozonolysis through laboratory experiments and mechanistic modeling. We employed proton transfer reaction mass spectrometry with NH 4 + ion sources (NH 4 ) and closed-shell species. Under near-real atmospheric conditions in a Potential Aerosol Mass-Oxidation Flow Reactor, we identified 30 ozonolysis products, expanding previous data sets of low-oxygen compounds. Combined with simulations based on the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere and relevant literature, our results revealed that OH dominates over ozone in cyclohexene oxidation at typical atmospheric oxidant levels with H-abstraction contributing 30% of initial RO + -CIMS) and a custom-built OH calibration source to quantify organic peroxy radicals (RO 2 ) and closed-shell species. Under near-real atmospheric conditions in a Potential Aerosol Mass-Oxidation Flow Reactor, we identified 30 ozonolysis products, expanding previous data sets of low-oxygen compounds. Combined with simulations based on the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere and relevant literature, our results revealed that OH dominates over ozone in cyclohexene oxidation at typical atmospheric oxidant levels with H-abstraction contributing 30% of initial RO 2 radicals. Highly oxidized molecules primarily arise from RO 2 autoxidation initiated by ozone, and at least 15% of ozone oxidation products follow the overlooked nonvinyl hydroperoxides pathway. Gaps remain especially in understanding RO 2 cross-reactions, and the structural complexity of monoterpenes further complicates research. As emissions decrease and afforestation increases, understanding these mechanisms becomes increasingly critical.

Reaction of benzaldehyde (5a) with defined quantities of ethyl cyanoacetate (6) in presence of piperidine was studied. In a neat condition, hexasubstituted cyclohexeneamine (7a) with three ester substituents was formed along with ethyl acrylate (9a); occasionally the triesters (7) were transformed to diesters (8). (7) and (8) had uniquely defined stereochemistry. Many substituted aromatic aldehydes and pyridine-3 and 4-aldehydes exhibited this reaction. Cyclohexenes were also formed in solutions. Mass spectral evidence showed the presence of small percentage of isomeric tri and diesters. Mechanistic and other aspects are discussed. Richly substituted cyclohexene amine esters are attractive substrates for medicinal chemistry.

The cyclohexene motif is ubiquitous in nature and specialty chemicals. A straightforward selective access to chiral cyclohexenes from unactivated dienes and dienophiles is not feasible by classical Diels–Alder reaction and constitutes an unsolved synthetic challenge. We report a mild and enantioselective iron‐catalyzed cross‐[4+2]‐cycloaddition of unactivated dienes providing access to chiral 1,3‐substituted vinyl‐cyclohexenes. The development of bis‐dihydroisoquinoline ligands was vital to obtain iron complexes that display high reactivities and excellent chemo‐, regio‐ and enantioselectivities towards the targeted cyclohexenes. A range of diene substrates is well accommodated including feedstocks like butadiene, isoprene and myrcene. The structures of different iron complexes are mapped by X‐ray crystallographic analysis and linked to their performance. [ABSTRACT FROM AUTHOR]

• Desilication process was used to investigate adsorption desulphurization over NaY zeolite. • Desilication using mixture of TPAOH and NaOH improves the desulphurization performance. • Impregnated metal ions on the mesoporous adsorbent of NaY zeolite increase the thiophene and dibenzothiophene uptake. • By increasing the temperature, the adsorption capacity of thiophene has been increased and reached its maximum at 55 °C. • Adsorption capacity reduction of sulfur was in order of Cu-0.5R˃CuCe-0.5R˃Ce-0.5R in the presence of toluene and cyclohexene. The presence of sulfur compounds in transportation fuels have always been one of the most important issues discussed in scientific and industrial associations. In recent years, due to the adoption of global policies to address environmental problems, the study of efficient systems for desulfurization of fuels has attracted much attention. In this study, the effects of alkaline treatment with NaOH and NaOH/TPAOH mixtures with different concentrations on adsorption desulfurization of NaY adsorbent were investigated. The adsorbents were characterized by XRD, FE-SEM, BET, EDX, ICP-OES and FT-IR techniques. It was found that alkaline treatment in the NaOH/TPAOH solution with TPAOH/(TPAOH + NaOH) = 0.5 had the highest total surface area followed by the highest adsorption capacity among the desilicated adsorbents. In order to increase the adsorption capacity, copper and cerium metals were impregnated individually and in pairs on this adsorbent at 80 °C. The results showed that impregnating of metal ions increases the adsorption capacity of adsorbents so that CuCe-0.5R adsorbent with values of 21.02 and 24 mg/g had the highest adsorption capacity of thiophene and dibenzothiophene sulfur compounds, respectively. In this regard, the competitive adsorption of toluene and cyclohexene was also investigated in different model fuels containing isooctane as a solvent. The adsorption capacity reduction of sulfur compounds for different adsorbents was in order of Cu-0.5R > CuCe-0.5R > Ce-0.5R, respectively, in the presence of toluene and cyclohexene. Thermodynamics studies showed that the adsorption process is endothermic. The kinetic models in adsorbing the sulfur compounds followed the pseudo-second-order equation. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Catalytic enantioselective ring‐opening of oxa‐ and aza‐bicyclic alkenes with readily available accessible alkenylboronic acids, promoted by a chiral phosphine–Co complex, is reported. Such a process represents the unprecedented Co‐catalyzed introduction of various alkenyl groups onto the oxa‐ and aza‐bicyclic alkenes, affording a wide range of multisubstituted functionalized cyclohexenes in up to 98% yield and 99.5 : 0.5 er. [ABSTRACT FROM AUTHOR]

Implementing large-scale synthesis of nanoporous PtNi/C catalysts for hydrogenation processes of unsaturated organic compounds under atmospheric pressure at temperatures below 100 °C is an urgent task. In this paper, a nanoporous SPE-PtNi/C membrane electrode is prepared by ion beam sputtering, ultrasonic-assisted electrochemical dealloying, and hotpressing. Special attention is paid to the analysis of the electrochemical properties, phase structure, surface morphology, active constituent distribution, and catalytic efficiency for cyclohexene hydrogenation of the produced electrode in comparison with those of commercial Pt/C catalysts. The results show that the ultrasonic-assisted electrochemical etching temperature exerts the most significant effect on the catalytic activity of the catalyst under consideration. In particular, the treatment of PtNi/C in 0.7 mol/L HClO 4 for 1.5 h at the optimized temperature of 50 °C enables one to increase the catalytic activity by 25.20% at decreasing the Pt-loading content by 88.85% compared with commercial Pt/C. Furthermore, the nanoporous structure of the PtNi/C surface allows the binding energy of Pt 4f 7/2 to be reduced by 0.23 eV due to the Ni loss and the crystal plane shrinkage from NiPt, which enhances the compressive strain of the lattice structure of exposed Pt and increases the number of active sites. Finally, the use of a nanoporous SPE-PtNi/C membrane electrode could increase the yield of cyclohexene during the hydrogenation reaction by 179% at simultaneously improving the current efficiency by 69%. The nanoporous SPE-PtNi/C film electrode prepared by ion beam sputtering and ultrasound-assisted electrochemical de-alloying has low Pt loading, high specific surface area, in addition to good low-temperature catalytic hydrogenation activity, and has promising applications in hydrogen storage. [Display omitted] • Preparation of Pt-based nanocrystalline catalysts by ion beam sputtering. • Nanoporous catalysts prepared by ultrasound-assisted electrochemical dealloying. • The nanoporous PtNi/C membrane electrode has good catalytic activity. [ABSTRACT FROM AUTHOR]

Examination of the reactions of σ‐type quinolinium‐based triradicals with cyclohexane in the gas phase demonstrated that the radical site that is the least strongly coupled to the other two radical sites reacts first, independent of the intrinsic reactivity of this radical site, in contrast to related biradicals that first react at the most electron‐deficient radical site. Abstraction of one or two H atoms and formation of an ion that formally corresponds to a combination of the ion and cyclohexane accompanied by elimination of a H atom ("addition‐H") were observed. In all cases except one, the most reactive radical site of the triradicals is intrinsically less reactive than the other two radical sites. The product complex of the first H atom abstraction either dissociates to give the H‐atom‐abstraction product and the cyclohexyl radical or the more reactive radical site in the produced biradical abstracts a H atom from the cyclohexyl radical. The monoradical product sometimes adds to cyclohexene followed by elimination of a H atom, generating the "addition‐H" products. Similar reaction efficiencies were measured for three of the triradicals as for relevant monoradicals. Surprisingly, the remaining three triradicals (all containing a meta‐pyridyne moiety) reacted substantially faster than the relevant monoradicals. This is likely due to the exothermic generation of a meta‐pyridyne analog that has enough energy to attain the dehydrocarbon atom separation common for H‐atom‐abstraction transition states of protonated meta‐pyridynes. [ABSTRACT FROM AUTHOR]

A series of Brønsted–Lewis acids bifunctionalized heteropolyacid based ionic liquids hybrid solid acid catalysts (BLA-HPA-ILs) were synthesized by combining the Brønsted acidic ionic liquid [Bis–Bs–BDMAEE]HPW12O40 with metallic oxide in different composition ratios and applied in the esterification of cyclohexene to cyclohexyl acetate. Among the synthesized catalysts, the 1/2Cu[Bis–Bs–BDMAEE]HPW12O40 catalyst with Brønsted and Lewis acidities shown the most excellent catalytic performance for the esterification of cyclohexene with acetic acid. The BLA-HPA-ILs catalysts were characterized by elemental analysis, FT-IR, Py-IR, TG, 1H NMR, SEM and EDX. The effects of reaction temperature, catalyst dosage, and initial reactant molar ratio has been investigated in detail. A pseudohomogeneous (PH) kinetic model was used to correlate the kinetic data in the temperature range of 333.15–363.15 K, and the kinetic parameters were estimated, indicating the results calculated by the kinetic model are well coincidence with the experimental results. Moreover, as a heterogeneous reaction catalyst, 1/2Cu[Bis–Bs–BDMAEE]HPW12O40 could be easily recovered by a simple treatment and reused six times without any obvious decrease in catalytic activity, displaying good reusability. [ABSTRACT FROM AUTHOR]

A new method for cyclopropanation of olefins with the BuLi—AlCl3—CH2I2 reagent system was developed. The reaction is tolerant of a wide range of unsaturated alkyl- and aryl-substituted hydrocarbons of linear and cyclic structure (octene-1, decene-1, tetradecene-1, styrene, 1-vinylnaphthalene, cyclohexene, cyclooctene, myrcene) and gives high yields (63–87%) of the corresponding cyclopropanation products. The reactions involving the sterically hindered olefins (2-cyclobutylideneadamantane, 2,2′-bi(adamantylidene)) produce cyclopropane-containing polycyclic hydrocarbons in 40–45% yields. [ABSTRACT FROM AUTHOR]

La1−xSrxCoO3 (x=0, 0.1, 0.2, 0.3, 0.4) nanoparticles were prepared by spray‐flame synthesis and applied in the liquid‐phase oxidation of cyclohexene with molecular O2 as oxidant under mild conditions. The catalysts were systematically characterized by state‐of‐the‐art techniques. With increasing Sr content, the concentration of surface oxygen vacancy defects increases, which is beneficial for cyclohexene oxidation, but the surface concentration of less active Co2+ was also increased. However, Co2+ cations have a superior activity towards peroxide decomposition, which also plays an important role in cyclohexene oxidation. A Sr doping of 20 at. % was found to be the optimum in terms of activity and product selectivity. The catalyst also showed excellent reusability over three catalytic runs; this can be attributed to its highly stable particle size and morphology. Kinetic investigations revealed first‐order reaction kinetics for temperatures between 60 and 100 °C and an apparent activation energy of 68 kJ mol−1 for cyclohexene oxidation. Moreover, the reaction was not affected by the applied O2 pressure in the range from 10 to 20 bar. In situ attenuated total reflection infrared spectroscopy was used to monitor the conversion of cyclohexene and the formation of reaction products including the key intermediate cyclohex‐2‐ene‐1‐hydroperoxide; spin trap electron paramagnetic resonance spectroscopy provided strong evidence for a radical reaction pathway by identifying the cyclohexenyl alkoxyl radical. [ABSTRACT FROM AUTHOR]

Difunctionalization of strained cyclic alkynes presents a powerful strategy to build richly functionalized cyclic alkenes in an expedient fashion. Herein we disclose an efficient and flexible approach to achieve carbohalogenation, dicarbofunctionalization, aminohalogenation and aminocarbonation of readily available cyclohexenyl triflates. We have demonstrated the novel use of zincate base/nucleophile system for effective formation of key cyclohexyne intermediates and selective addition of various carbon and nitrogen nucleophiles. Importantly, leveraging the resulting organozincates enables the incorporation of a broad range of electrophilic partners to deliver structurally diverse cyclohexene motifs. The importance and utility of this method is also exemplified by the modularity of this approach and the ease in which even highly complex polycyclic scaffolds can be accessed in one step. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heterogeneous polyoxometalates were obtained after calcinations at 600 °C without loss of Keggin structure. • Both higher acidity and concentration of surface (W-O-W)/W species were associated to cyclohexene oxidation to adipic acid. • Acetonitrile and acetic acid roles were investigated. • The products distribution by time was investigated and a reaction mechanism was suggested taking these results into account. One-step oxidative cleavage of cyclohexene to adipic acid using H 2 O 2 as oxidizing agent and heteropolysalts as heterogeneous catalysts was successfully performed, without the use of additives, such as organic or inorganic acids. The K 3 PW 12 O 40 , K 3 PMo 12 O 40 , Cs 3 PW 12 O 40 and Cs 3 PMo 12 O 40 heteropolysalts were synthesized by ion exchange of the respective heteropolyacids using cesium and potassium carbonates. The catalysts were thermally treated at 200 or 600 °C and characterized by Raman spectroscopy, thermogravimetric analysis, X-ray fluorescence (XRF) and photoelectronic X-ray spectroscopy (XPS). Raman results showed that the Keggin structure of the polyoxometalates was successfully obtained for both heteropolyacids and heteropolysalts and remained stable even after thermal treatment at 600 °C. XRF analysis confirmed the insertion of the cations (Cs+ and K+) into the heteropolysalt structures. All catalysts completely converted cyclohexene within 24 h and they were selective to adipic acid. The best catalyst, K 3 PW 12 O 40 calcined at 600 °C (KPW-600), achieved the highest adipic acid yield (83 %). In this work, we associate the best activity of the KPW-600 heteropolysalt not only to its greater acidity, but also to the higher concentration of (W-O-W)/W species (identified by XPS). Both properties are fundamental for the oxidation reaction of cyclohexene to adipic acid under the experimental conditions used. The results showed that the presence of peroxide species is essential, mainly to favor oxidation reactions, such as the Baeyer-Villiger rearrangement reaction. A reaction scheme for the oxidation of cyclohexene to adipic acid with the best catalyst (KPW-600), was proposed based on our kinetic studies and literature results. In addition to the main route of adipic acid formation from the direct oxidation of cyclohexene, undesirable parallel reactions of the rearrangement of 1,2 - cyclohexanediol and allyl oxidation were also observed. The influence of reaction conditions was also investigated, as well as the reuse of the most promising catalyst. [ABSTRACT FROM AUTHOR]

In the fused tetra­cyclic system of the title compound, C29H36O9, the five-membered dioxolane ring adopts a twist conformation; the two adjacent C atoms deviate alternately from the mean plane of the other three atoms by −0.252 (6) and 0.340 (6) Å. The cyclo­hexane, cyclo­hexene and central cyclo­octane rings show chair, half-chair and boat-chair forms, respectively. There are three intra­molecular C—H···O inter­actions supporting the mol­ecular conformation, with one S(6) and two S(7) graph-set motifs. In the crystal, inter­molecular O—H···O hydrogen bonds connect the mol­ecules into a helical chain running along the c-axis direction, generating a C(7) graph-set motif. The chains are further linked by inter­molecular C—H···O inter­actions to construct a three-dimensional network. There is no valid C—H···π inter­action. [ABSTRACT FROM AUTHOR]

The work aimed at the mechanistic investigation of the catalytic hydrogenation of cyclohexene by a newly synthesized ruthenium(III) Schiff base complex, [RuLCl(H 2 O)], where L represents tetradentate N 2 O 2 naphthaldiimine. Several physicochemical methods were used to characterize the target complex. Furthermore, it was observed that the catalytic activity relies mainly on solvent composition. On the other hand, the density functional theory (DFT) was applied to explore the mechanistic story of the catalytic reaction. The findings showed that the complex has two stable isomers (trans and cis), which serve as platforms for the destination toward the hydrogenation journey through the in-situ generation of the active catalysts. Accordingly, one can imagine them as robust and weak machines for cyclohexane production in the reaction vessel. Interestingly, the experimental and the theoretical total activation energies are so comparable which supports the validity of the mechanistic insights. Based on the DFT findings, one can imagine two active catalysts being generated in situ from the cis and trans -isomers of the Ru (III) pre-catalyst combined to serve as weak and robust machines for the hydrogenation of cyclohexene, respectively. The strength of the two machines can be evaluated from the overall activation energy barrier of the rate-determining step, 27.99 kcal/mol, and 25.25 kcal/mol, which represents the H 2 heterolysis and proton transfer events, respectively. [Display omitted] • The work introduces a newly synthesized ruthenium (III) N 2 O 2 Schiff base complex for the hydrogenation of cyclohexene. • The catalytic activity of the complex depends mainly on the solvent/co-solvent composition. • Two in-situ catalysts with cis and trans configurations are generated to accelerate the hydrogenation of cyclohexene. • The H 2 heterolysis or intramolecular proton transfer are the slow steps in the catalytic mechanisms. • The monohydride ruthenium (III) complexes is highly recommended for hydrogenation of alkene at room temperature. [ABSTRACT FROM AUTHOR]

The effect of organic solvents on the rate of ethylene oxidation with p-benzoquinone to acetaldehyde in aqueous organic solutions of palladium cationic complexes has been studied. It was found that the reaction rate increased when the acceptor number of the solvent increased and the donor number decreased. The oxidation of ethylene and cyclohexene in binary (N-methylpyrrolidone–H2O) and ternary (acetonitrile–N-methylpyrrolidone–H2O) solvents was studied in more detail. In contrast to the acetonitrile–Н2О system, in the N-methylpyrrolidone–Н2О binary solvent hydrogen peroxide oxidizes ethylene to acetaldehyde in the presence of Pd(II) cationic complexes. The use of a solvent N-methylpyrrolidone acceptable for cyclohexene (CH) oxidation technology leads to a decrease in the rate and selectivity of cyclohexanone synthesis. [ABSTRACT FROM AUTHOR]

Developing biomass-based strategies for liquid bio-fuels production is promising for the reduction of the aftereffects of fossil fuels. The conversion of lignin-derived intermediates such as cyclohexanone is currently of a great deal of interest. The current study aims to evaluate the molybdenum-based hydrotreating catalysts for the conversion of cyclohexanone in the presence of hydrogen. Catalytic experiments at 400 °C, 15 bar, and a range of WHSV were developed. The experiments reveal that catalyst type and reaction WHSV affect the cyclohexanone conversion, product distribution, deoxygenation efficiency, total hydrocarbon production capacity, and heating value of the product blend. The main products include C6 cyclic and aromatic hydrocarbons and oxygenates. Cyclohexane, cyclohexene, benzene, cyclohexanol, and phenol are major products. Small quantities of methylcyclopentane and bicyclic hydrocarbons and oxygenates are also reported in some cases. Increasing WHSV reduced the cyclohexanone conversion. Cyclohexanone conversions up to 89% were observed at the lowest WHSVs over a cobalt-molybdenum sample. The highest hydrocarbon production capacity (99.53%) was managed at WHSV = 5.240 gcyclohexanone/gcat h over a cobalt-molybdenum sample, while the highest deoxygenation efficiency, i.e. 81.29% degree of deoxygenation and 5.35 C/O ratio enhancement were achieved at WHSV = 0.262 gcyclohexanone/gcat h by a nickel-molybdenum sample. The heating values would be enhanced by up to 22.7% when cyclohexanone is converted over the utilized catalysts. The larger heating value (44.90 MJ/kg, 22.7% enhancement) was obtained over a nickel-molybdenum catalyst, which is comparable to the energy density of the conventional fuels. The results reveal that the catalysts are efficient in the conversion of cyclohexanone to liquid bio-fuels. [ABSTRACT FROM AUTHOR]

A series of porous confined ionic liquid phosphotungstate were synthesized by encapsulated of N-(3-sulfopropyl)morpholinium phosphotungstate ([C3SO3Hnhm]3 -PW12O40) into MIL-101. Then the aforementioned porous confined ionic liquid phosphotungstate as heterogeneous catalyst will be used together with H2O2 for the catalytic synthesis of adipic acid from cyclohexene. During the experiment, the effect of weight content of [C3SO3Hnhm]3PW12O40 on the catalytic performance was investigated in detail. And the chemical structure of the catalyst was also characterized by XRD, FT-IR, 1H-NMR, SEM–EDX and N2 adsorption–desorption isotherms. Experimental results revealed that the desired products has been successfully prepared, and the best catalytic performance (81.2% yield of the adipic acid) was obtained under the dose of [C3SO3Hnhm]3PW12O40 was 31wt%, which was almost close to the catalytic activity of original [C3SO3Hnhm]3PW12O40 (85.3% yield of the adipic acid), which was also proved the strategy of packaging ionic liquid phosphotungstate with MIL-101 in this research is feasible. Furthermore, recycled catalytic performance of the catalyst under repeat 6 times was evaluated and the result revealed that the yield in adipic acid was still higher than 80.0%, which also proved that the catalytic active component was stable in the catalyst. [ABSTRACT FROM AUTHOR]

The required amount of abscisic acid containing 4 – 5 D atoms ([2H]ABA) in the cyclohexene fragment of the molecule was produced via isotope exchange in 100% deuterated D2O at 220°C in the presence of diisopropyl ethylamine. The yield of labeled compound was 45 – 80%. A complex of biological studies was carried out using the D-labeled preparation. It was established that [2H]ABAserved as a growth substrate for soil bacteria, which included the isotopic label in the composition of cell metabolites. The characteristics of D-labeled metabolites allowed their reliable identification in mass spectra of the total bacterial metabolome. Three intermediates of a new metabolic pathway of microbial degradation of this phytohormone were identified using the developed technique. [ABSTRACT FROM AUTHOR]

Bagasse cellulose, an industrial waste byproduct of sugar production, was demonstrated to be a viable solid support for a solid-phase ionic oxidation catalyst enabling organic solvent-free aqueous reaction conditions and facile catalyst recovery. Bagasse cellulose-supported quaternary ammonium peroxyphosphotungstate was synthesized from bagasse cellulose-supported quaternary ammonium chloride, phosphotungstic acid, and hydrogen peroxide. The chemical structure of this material was characterized by SEM, XRD, FT-IR, XPS, and 13C NMR, revealing stability of the cellulose matrix to the catalyst loading conditions and effective dispersion of the acicular catalyst crystals throughout the matrix. High catalytic activity of this synthetic complex was demonstrated in the oxidation of cyclohexene to 1,2-cyclohexanediol with hydrogen peroxide in the absence of solvent. Optimized conditions providing trans -1,2-cyclohexanediol with 86.2 % selectivity were 12 wt% catalyst and 4 mL/g 30 % H 2 O 2 (vs. cyclohexene) at 50 °C for 10 h. [ABSTRACT FROM AUTHOR]

The presence of dimagnesium catalyst residues strongly influences the thermal stability and degradation mechanism of poly(cyclohexene carbonates). [Display omitted] • Residues of dimetallic catalyst reduce the thermal stability of poly(cyclohexene carbonates). • Specific purification procedures are necessary to significantly remove the catalyst. • The degradation temperature and mechanism can be tuned by adequately changing the amount of catalyst residue. Three poly(cyclohexene carbonates) with molecular weights ranging from 4.9 to 9.4 kg/mol were synthesized from cyclohexene oxide and CO 2 using macrocyclic phenolate dimetallic catalysts and purified by conventional purification procedure. A decrease in thermal stability of approximately 100 °C was observed in comparison to poly(cyclohexene carbonates) with similar molecular weights synthesized using salen metal catalysts. This decrease derives from the presence of traces of dimetallic catalyst which is able to promote the depolymerisation of poly(cyclohexene carbonate) to CO 2 and cyclohexene oxide in contrast to the usual backbiting mechanism that leads to cyclic carbonate. The onset of the degradation can be precisely tuned by changing the amount of residual dimetallic catalyst or including species with functional groups that can reduce the availability of the catalytic centers. Therefore, the possibility of controlling the thermal stability of poly(cyclohexene carbonates) by varying the concentration of the catalyst and the surrounding chemical environment paves the way for the use of these polymers as components in self-sacrificial materials of interest for advanced applications. [ABSTRACT FROM AUTHOR]

• The DFT study proposes the 13-TMC bound Mn-complex as an efficient catalyst for alkene epoxidation. • The epoxidation proceeds predominantly via MnIII-OOH in the absence of additives. • Incorporation of additives engages multiple oxidants viz. MnIII-OOH and MnIV-O˙. • The inclusion of additives significantly enhances the kinetic feasibility of epoxidation. The epoxidation of cyclohexene using the metal-based oxidants, viz. 13-TMC bound MnIII-O 2 (1), MnIII-OOH (2), MnIV-O (3) and MnV-O (4) are computed in the absence and presence of additives. The thermodynamic stability of these oxidants is examined based on the formation free energy (ΔG R.E) from its precursor (i.e. 2 from 1; 3 & 4 from 2). In the absence of additives, 2 hs/ls (ΔG R. E = -3.8/-14.0 kcal/mol) is found to be thermodynamically more stable than 3 hs/ls (ΔG R. E = +18.1/+10.6 kcal/mol) and 4 is/ls (ΔG R. E = +88.3/+76.5 kcal/mol). Also, due to the lesser ΔG R.E associated with 2 hs , the interconversion of 2 hs and 1 hs is energetically feasible. Therefore, in the absence of additives, MnIII-OOH (2 hs/ls) and MnIII-O 2 (1 hs/ls) are proposed as the active oxidants to mediate cyclohexene epoxidation. Among the proposed oxidants, the epoxidation efficacy of 2 hs is higher than 2 ls and 1 hs/ls by +9.5 to +33.6 kcal/mol. Further, the effect of additive (X) is investigated in 2 hs (X = AcOH (2a hs), H 2 O (2b hs), H 2 SO 4 (2c hs)). In contrast to 4 , the incorporation of additive significantly enhances the thermodynamic stability of MnIV-O˙/MnV-O (4a is -4c is , ΔG R. E = +2.0 to +11.9 kcal/mol). Herein, the 4a is -4c is (S = 1) is thermodynamically more preferred over 4a hs -4c hs (S = 2) by +6.3 to +10.0 kcal/mol. Notably, the formation of 4a is -4c is is found to be kinetically feasible, which is evidenced by the ΔG‡ of ∼ +13.4 kcal/mol via additive-assisted O OH cleavage step from 2a hs -2c hs. Therefore, the computed energetics suggest that in the presence of additives, MnIII-OOH (2a hs -2c hs) and MnIV-O˙(4a is -4c is) are the plausible oxidants to medicate cyclohexene epoxidation. Importantly, the epoxidation efficacy of additive incorporated 2a hs (ΔG‡ = +10.0 kcal/mol) is found to be higher than 2 hs by 50 %. Similarly, the additive incorporated 4a is -4c is exhibits facile epoxidation (ΔG‡ = ∼ +1.3 kcal/mol) with the rate - determining O OH cleavage step. Herein, the comparison of the ΔG‡ of 4a is -4c is with that of 2 hs clearly shows that the epoxidation efficacy of 4a is -4c is is also superior over 2 hs (by 42 %). Overall, the computed results tend to propose that the incorporation of additives facilitates the epoxidation efficacy of 13-TMC bound Mn-complex by invoking both MnIII-OOH and MnIV-O˙ as active oxidants. Using the DFT method, the epoxidation efficacy of 13-TMC bound Mn-species has been investigated by invoking various metal-based oxidants in the presence and absence of additives. In the absence of additives, the MnIII-OOH (ΔG‡ = +20.0 kcal/mol) is proposed as the active oxidant to mediate the cyclohexene epoxidation. In the presence of additive (e.g. AcOH), the MnIII-OOH and MnIV-O˙ species act as the active oxidants. Notably, the incorporation of additive enhances the epoxidation efficacy of MnIII-OOH by 50 % and also facilitates the formation of MnIV-O˙ which undergoes facile epoxidation. [Display omitted] [ABSTRACT FROM AUTHOR]

12 Mitra, S., Kandambeth, S., Biswal, B. P., Khayum, M. A., Choudhury, C. K., Mehta, M., Kaur, G., Banerjee, S., Prabhune, A., Verma, S., Roy, S., Kharu, U. K., Banerjee, R. Self-exfoliated guanidinium-based ionic covalent organic nanosheets (iCONs). Keywords: 2190507 EN 2190507 903 905 3 08/25/22 20221001 NES 221001 Table 1 contains crystallographic data and Table 2 contains the list of the atoms including atomic coordinates and displacement parameters. All H-atoms were placed geometrically and refined using a riding model with common isotropic displacement factors I U i SB iso sb (H) = 1.2 or 1.5 I U i SB eq sb (parent C-atom). [Extracted from the article]

12 Mitra, S., Kandambeth, S., Biswal, B. P., Khayum, M. A., Choudhury, C. K., Mehta, M., Kaur, G., Banerjee, S., Prabhune, A., Verma, S., Roy, S., Kharu, U. K., Banerjee, R. Self-exfoliated guanidinium-based ionic covalent organic nanosheets (iCONs). Keywords: 2190507 EN 2190507 903 905 3 08/25/22 20221001 NES 221001 Table 1 contains crystallographic data and Table 2 contains the list of the atoms including atomic coordinates and displacement parameters. All H-atoms were placed geometrically and refined using a riding model with common isotropic displacement factors I U i SB iso sb (H) = 1.2 or 1.5 I U i SB eq sb (parent C-atom). [Extracted from the article]

A series of ruthenium-based catalysts supported on acid-activated montmorillonite (PILC) and interspersed with titanium (Ru/Ti-PILCs) were prepared with various amounts of ruthenium. Their catalytic performances in the selective oxidation of cyclohexene, using tert-butylhydroperoxide (TBHP) as oxidant were checked. The clay structure modification by acid activation and impregnation of transition metals resulted in an enhanced Lewis and Bronsted acidities. The Ru/Ti-PILCs materials were characterized using X-ray diffraction (XRD), surface area and pore volume measurements, surface acidity followed by Fourier transform infrared (FTIR) spectroscopy, chemical analysis, and Scanning Electron Microscopy (SEM). It was found that all catalysts can selectively oxidize cyclohexene through allylic oxidation leading mainly to 2-cyclohexene-1-one (Enone) as the major product, and 2-cyclohexene-1-ol (Enol) as secondary product. With the 5 %Ru/Ti-PILC, it was possible to reach 59 % cyclohexene total conversion, and 87 % selectivity into 2-cyclohexene-1-one and 13 % selectivity into 2-cyclohexene-1-ol.

Tin (antimony) substituted and lacunar Dawson phosphotungstomolybdates (a1-K10P2W12Mo5ÿO61, a1-K8P2W12Mo5SnO61 and a-Cs4SnP2W12Mo6O62,and a-Cs3SbP2W12Mo6O62) were synthesized and characterized by Fourier Transform Infra Red (FTIR), nuclear magnetic resonance (31P NMR), Visible Ultra Violet (UV-Vis) spectroscopy, and X-ray diffraction (XRD). Their catalytic properties were examined in the oxidation reaction of cyclohexanone at 90 °C and that of cyclohexene at 70 °C to adipic acid (AA), in presence of hydrogen peroxide and in free solvent. The effects of catalyst/substrate molar ratios, hydrogene peroxide flow rate, heteropolysalt composition, and cyclohexanol addition on AA yields were studied. The Cs4SnP2W12Mo6O62 (the most efficient) led to 61 % of AA yield from the cyclohexanone oxidation using a catalyst/substrate molar ratio of 13.3×10-4, H2O2 flow rate of 0.5 mL/h, and a reaction time of 20 h.