Dibenzofurans Research Articles

Removal of Dibenzofuran from aqueous solution by sugarcane bagasse-based biochar

Dibenzofuran (DBF) has been considered an environmental risk due to its high toxicity and risks to human health and ecosystems. Among wastewater treatment technologies, the adsorption process has emerged as a potential solution to remove organic pollutants efficiently, including dibenzofuran, in wastewater. The study aims to investigate the feasibility of sugarcane bagasse-based biochar for DBF removal through adsorption. Biochar characteristics showed a high specific surface area of up to 498.97 m2/g and abundant functional groups on the material surface, resulting in high removal performance of DBF with average adsorption efficiency and adsorption capacity reaching maximum values of 98.43% and 96.77 mg/g, respectively. The optimum parameters were suggested for DBF removal: pyrolysis temperature of 700oC, contact time of 50 min, biochar dosage of 0.5 g/L, and DBF concentration of 40 mg/L. Furthermore, the results of adsorption kinetics and adsorption isotherms indicated that the adsorption process benefits DBF removal. Pseudo-second-order model and Langmuir model can describe the DBF removal process due to the best fit to experimental data (R2 > 0.98). Based on these findings, sugarcane bagasse-based biochar could be utilized efficiently to remove DBF from wastewater.

Polycyclic aromatic hydrocarbon derivatives onto polar microplastics of polyurethane: equilibrium, thermodynamics, and kinetics of monolayer-multilayer adsorption.

The study of the adsorption of polycyclic aromatic hydrocarbons on microplastics (MPs) has attracted much attention as to how microplastics can act as carriers of these pollutants. Polyurethane (PU) is one of the MPs found in aquatic environments, containing different functional groups it can interact with polar and nonpolar molecules. PAH derivatives (dPAHs) present different properties and thus can be adsorbed by different interactions; thus, this study investigated the adsorption of fluorene (FLN), dibenzothiophene (DBT), dibenzofuran (DBF), and carbazole (CBZ) onto PU MP. The Langmuir, Freundlich, and BET isotherm models were examined, and the BET model best fitted. The adsorption was a nonspontaneous process, exothermic for mono- and multilayer formation for FLN, DBT, and CBZ, and endothermic for DBF monolayer formation. The adsorption monolayer was formed by van der Waals forces, H─bonding, and π─π interactions, while the formation of the multilayer can be explained by π─π and hydrophobic interactions. The pseudo-second-order model proved to be more consistent for the adsorption of dPAHs. The adsorption in artificial seawater shows no significant differences for the monolayer but favored the adsorption multilayer due to the salting-out effect. Due to the existence of several adsorption mechanisms, PU MP interacts with dPAHs in greater quantities when compared to a MP with a simpler structure.

Enhanced Catalytic Performance of Palladium‐Based Catalysts Modified With the Dibenzofuran Ligand for Acetylene Hydrochlorination

ABSTRACTA new palladium‐based catalyst system modified with dibenzofuran (DBF) was developed for acetylene hydrochlorination. The optimal Pd‐DBF/SAC catalyst with the 0.5 wt% Pd loading and the 15 wt% DBF loading exhibits an elevated performance of 99.9% acetylene conversion and 99.9% vinyl chloride selectivity for more than 400 h. Characterization analysis and density functional theory (DFT) simulations revealed that the presence of oxygen‐containing DBF species of the Pd‐DBF/SAC catalyst prevents the reduction and loss of Pd species, inhibits the carbon deposition and enhances the HCl adsorbability, resulting in superior catalytic activity and stability for acetylene hydrochlorination.

Utilization of Polycyclic Aromatic Solid Additives for Morphology and Thermal Stability Enhancement in Photoactive Layers of Organic Solar Cells.

Volatile solid additives have emerged as a promising strategy for enhancing film morphology and promoting the power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, a series of novel polycyclic aromatic additives with analogous chemical structures, including fluorene (FL), dibenzothiophene (DBT), and dibenzofuran (DBF) derived from crude oils, are presented and incorporated into OSCs. All these additives exhibit strong interactions with the electron-deficient terminal groups of L8-BO within thebulk-heterojunction OSCs. Moreover, they demonstrate significant sublimation during thermal annealing, leading to increase free volumes for the rearrangement and recrystallization of L8-BO. This phenomenon leads to an improved film morphology and an elevated glass-transition temperature of the photoactive layers. Consequently, the PCE of the PM6:L8-BO blend has been boosted from 16.60% to 18.60% with 40 wt% DBF additives, with a champion PCE of 19.11% achieved for ternary PM6:L8-BO:BTP-eC9 OSCs. Furthermore, the prolonged shelf and thermal stability have been observed in OSCs with these additives. This study emphasizes the synergic effect of volatile solid additives on the performance and thermal stability of OSCs, highlighting their potential for advancing the field of photovoltaics.

Preparation, structure and optical properties of TCNB-based charge-transfer cocrystals

Organic charge transfer cocrystals exhibit interesting properties due to their multi-components synergistic and collective effect. Herein, using 1,2,4,5-tetracyanobenzene (TCNB) as electron acceptor, carbazole (CARB), dibenzothiophene (DBZP) and dibenzofuran (DBZF) as electron donors, three charge transfer cocrystals of CARB-TCNB, DBZP-TCNB and DBZF-TCNB were synthesized by solvent evaporation method and solvent-assisted grinding method. These cocrystals were constructed based on the π–π stacking interactions and CH…N hydrogen bonds and confirmed by the SXRD analysis. The stacking modes are consistent with the model that predicted by molecular electrostatic potential analysis (ESP). The IGM and AIM analyses suggested that the π-π stacking and CH…N hydrogen bonds are weak in nature. The purity and homogeneity of cocrystals and grinding products were verified by PXRD analysis. In addition, the IR, UV–vis absorption and luminescent properties were investigated, and the cocrystals and grinding products exhibited different behaviors from that of their precures. In short, this work not only reports the CT complexes synthesized by liquid- and solid- strategies, but also provides an in-depth understanding of the spectral changes caused by the CT interactions.

Molecular organic geochemistry and origin of oil in the Potwar Basin, Pakistan

The Potwar Basin (PTB) is a prominent geological feature located in northern part of Pakistan, and is considered as one of the active and productive regions for petroleum and gas exploration in Pakistan. In this study, eight crude oil specimens originating from three distinct fields within the PTB were comprehensively examined to decipher the environmental conditions, source of organic matter (OM) and oil-oil correlations using gas chromatography coupled with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC–MS). The molecular marker and hierarchical cluster analysis of PTB oils reveal two different crude oil families. Family-I showed relatively low values of Pr/Ph, C19TT/C23TT and C25TT/C24TeT, C27-C29 regular steranes, dibenzothiophene (DBT), fluorene (FL) and dibenzofuran (DBF), as well as C26/C28 TAS (20S) and C27/C28 TAS (20R). These results suggest that Family-I crude oils derived from marine environment of suboxic water bodies with higher contribution from green algae or planktonic microbes. However, Family II contains comparatively high values of the aforementioned molecular parameters, indicating that crude oils mainly originated from a lacustrine environment with a higher contribution of plant organisms under oxidizing conditions. Saturated hydrocarbon maturity parameters such as CPI and OEP, and C3122S/(C3122S + C3122R) and C3222S/(C3222S + C3222R) indicate PTB crude oils are thermally mature, while aromatic indices reveal that Family-II crude oils are high mature. The present research defines that PTB crude oils contributed from mixed organic matter sources of marine and lacustrine majorly from marine sedimentary environment with the bloom of algae and/or higher plants.

Exploring the effects of mono-bromination on hole-electron transport and distribution in dibenzofuran and dibenzothiophene isomers: a first-principles study.

This study delves into hole-electron transport and distribution properties inherent in mono-brominated dibenzofuran (DBF) and dibenzothiophene (DBT) isomers. As determined by frontier molecular orbitals, all brominated structures have narrower bandgaps than their primary structures. The TD-DFT calculation showed that 2BDBT had the highest absorption wavelength of all molecules at 315.35nm. Notably, the study unveils remarkably low electron and hole reorganization energies due to bromine substitution in DBF and DBT molecules. Specifically, the 4BDBF has the lowest hole reorganization energy of all DBF configurations, 0.229eV. In addition, 3BDBF has 0.226eV less electron reorganization energy than all other molecules. Compared to DBT, 3BDBT has the lowest electron reorganization energy of 0.254eV. Overall, this research sheds significant light on the fundamental electronic and hole transport characteristics of bromine-substituted DBF and DBT isomers, highlighting their promising role in polymer design as donors/acceptors for advanced organic electronic applications. Molecular structures were optimized using Density Functional Theory (DFT) B3LYP/6-311 + + G (d, p) level of theory, and the study further elucidates these molecules' energy levels and absorption spectra through Time-Dependent Density Functional Theory TD-DFT; these calculations were performed using Gaussian 09W software package. The key parameters such as reorganization energies, Electron Localization Function map, Laplacian Bond Order, and NCI-RDG were meticulously examined for the molecules with the results of DFT calculations were analyzed and displayed by utilizing the software packages VMD 1.9.4 and Multiwfn 3.8, aiming to comprehend their charge transport and distribution properties.

Changes of Nitrate Activity and Byproduct Distribution Characteristics for Synergistic NOx and Dioxin Abatement over V2O5/AC Catalyst.

The simultaneous removal of NOx and dioxins has been considered an economical and effective technology of controlling multipollutant flue gas in the context of "carbon peaking and carbon neutrality". However, this technology has not yet been implemented in practical situations, because the interactive relationship between the selective catalytic reduction (SCR) reaction and dioxin catalytic oxidation lacks a deep understanding, especially on a carbon-based catalyst. In this research, the influence of NO and NH3 on the oxidation characteristics and byproducts distribution of dibenzofuran (DBF) was studied on V2O5/AC catalyst. Results indicated that NH3 has a stronger inhibition effect for DBF catalytic oxidation than NO due to obvious competitive adsorption between NH3 and DBF on the V2O5/AC catalyst. In addition, although both NO and NH3 inhibit the complete degradation of DBF, their effects on the byproduct distribution are not consistent. NO primarily affects the level of oxygen-containing byproducts, while NH3 primarily affects the level of alkane byproducts. Furthermore, the SCR reaction activity demonstrated a reduction when DBF was present. The occupation of V2O5 sites by DBF and its oxidizing intermediates has hindered the production of monodentate nitrate and the reactivity of bridged nitrate, resulting in a decrease in SCR activity via the L-H mechanism. This work aims to provide theoretical guidance for simultaneous removal of NOx and dioxins in industrial fumes.

Delaying crystallization and anchoring the grain boundaries defects via π-π stacked molecules for efficient and stable wide-bandgap perovskite solar cells

Owing to the easy migration of halogen ions in wide-bandgap perovskite, it will lead to the formation of a large number of uncoordinated Pb2+ to form deep-level defects, which seriously affects the power conversion efficiency (PCE) and stability of wide-bandgap perovskite solar cells (PSCs). The introduction of additives has been recognized as an effective method to improve these defects, especially Lewis acid-base additives. Herein, Lewis base molecule dibenzofuran (DBF) with π-conjugated system, which can form π-π stacked dimer, is used as a perovskite additive. The detailed crystallization process of perovskite main precursor triggered by DBF is measured by using laser scanning confocal microscopy. It is demonstrated that the addition of DBF in perovskite samples resulted in a deceleration of the crystallization process, which is due to the formation of Lewis acid-base complexes between DBF π-π stacked dimer and perovskite, which can obtain perovskite films with reduced defect density. As a result, the champion PCE of the wide-bandgap (1.68 eV) perovskite device reaches 20.18 %, significantly higher than the control device (17.79 %). Additionally, the device with no encapsulation demonstrates better stability, as it maintains over 90 % of the initial PCE under an air environment with 30–40 % relative humidity (RH) and 25 °C for 1200 h.

Novel indolocarbazole-based bipolar host materials for fabricating green phosphorescent organic light-emitting diodes with high efficiency and low roll-off

Herein we report two novel host materials, viz., 2-(dibenzo [b,d]furan-2-yl)indolo [3,2,1-jk]carbazole (ICz-DBF) and 3-(indolo [3,2,1-jk]carbazol-2-yl)furo [2,3-b:5,4-b']dipyridine (ICz-PFP), for fabricating highly stable and efficient organic light-emitting diodes (OLEDs). Green phosphorescent OLEDs (PhOLEDs) based on ICz-DBF and ICz-PFP exhibited less efficiency roll-off than those based on 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) host, and especially, the ICz-DBF-based device achieved a high external quantum efficiency (EQE) of 20.5 %. Bipolar hosts composed of indolocarbazole (ICz) exhibit strong molecular rigidity, high triplet energy, and fast electron transport properties; therefore, they act as acceptors, but dibenzofuran (DBF) and dipyridofuran (PFP) substitutions endow them with controlled electron-donating characteristics. The bipolar properties of the new host materials were demonstrated by single-carrier device analysis, confirming the effectiveness of our research strategy for developing hosts for high-quality OLEDs.

Crystal growth, HOMO-LUMO engineering and charge-transfer emission of TCNB-based donor-acceptor cocrystals

Using carbazole (CARB), dibenzothiophene (DBZP) and dibenzofuran (DBZF) as electron donors, 1,2,4,5-tetracyanobenzene (TCNB) as electron acceptor, three typical types of luminescent organic cocrystals were synthesized by a simple supramolecular assembly strategy. The cocrystals exhibit interesting optical properties for its charge transfer (CT) interactions. Meanwhile, a series of three-component (CARB)x (DBZP)1-x (TCNB) crystalline microtubes comprising organic CT interactions have been prepared by the self-assembly with poor solvent co-precipitating method. DFT calculations were used to predict the CT interactions and the binding patterns of donor and acceptor, which suggest that the CT interactions can largely influence the energy level and orbital distributions. Moreover, the SXRD analyses verified the cocrystals are constructed by π-π stacking with a face-to-face model. The solid-state cocrystals and microtubes were well characterized by PXRD, UV absorption spectra, emission spectra, fluorescence lifetime and quantum yield analyses. The obvious red-shift in UV–vis absorption spectra and emission spectra with respect to the free monomer indicate the formation of CT interactions. The emission colors of the mixed microtubes can be tailored from green to orange as well as associated photophysical properties with the increasing of dopant concentrations. Therefore, by the combination of experimental and theoretical studies on the cocrystals and microtubes, this work not only reports the new types of crystalline micro-nano materials, but also provides an in-depth understanding of the relationship between structure and fluorescence effect.

Interaction of fluorene and its analogs with high-density polyethylene microplastics: An assessment of the adsorption mechanism to establish the effects of heteroatoms in the molecule

The threat of microplastics (MP) pollution in aquatic ecosystems can be even more severe for they are able to interact with organic pollutants that can migrate to adjacent environments. The presence of heteroatoms in organic pollutants can directly influence adsorption onto MP. This research evaluated the adsorption of fluorene (FLN) and its heteroatom analogs dibenzothiophene (DBT), dibenzofuran (DBF) and carbazole (CBZ) onto high-density polyethylene (HDPE) MP from residual (HDPEres) and commercial (HDPEcom) sources. The Langmuir isotherm showed a better fit, while DBT showed higher maximum adsorption capacity (19.2 and 15.8 μmol g−1) followed by FLN (13.4 and 11.7 μmol g−1), and DBF (13.5 and 10.3 μmol g−1) to the HDPEcom and HDPEres, respectively, which indicates a direct correlation with the hydrophobicity of the molecules determined by Log Kow. In contrast, CBZ showed no significant interaction with MP, due to their polar characteristic, thus, no kinetic and thermodynamic parameters could be determined. The adsorption process of all PAH was determined to be exothermic and spontaneous, with low temperatures favoring the process. The pseudo-second-order kinetic models have fitted to the adsorption onto both HDPE; intraparticle diffusion was also observed. Computational studies, physical characterization techniques and batch adsorption experiments demonstrated that the mechanism is governed by hydrophobic interactions, with van der Waals forces as a secondary effect in the adsorption of FLN, DBT and DBF onto HDPEres and HDPEcom. Thus, allowing a deeper understanding of the interactions between HDPE MP and FLN as well with its derivatives.

Low-Temperature Cross-Linkable Hole Transport Materials for Solution-Processed Quantum Dot and Organic Light-Emitting Diodes with High Efficiency and Color Purity.

Cross-linkable hole transport materials (HTMs) are ideal for improving the performance of solution-processed quantum dot light-emitting diodes (QLEDs) and phosphorescent light-emitting diodes (OLEDs). However, previously developed cross-linkable HTMs possessed poor hole transport properties, high cross-linking temperatures, and long curing times. To achieve efficient cross-linkable HTMs with high mobility, low cross-linking temperature, and short curing time, we designed and synthesized a series of low-temperature cross-linkable HTMs comprising dibenzofuran (DBF) and 4-divinyltriphenylamine (TPA) segments for highly efficient solution-processed QLEDs and OLEDs. The introduction of divinyl-functionalized TPA in various positions of the DBF core remarkably affected their chemical, physical, and electrochemical properties. In particular, cross-linked 4-(dibenzo[b,d]furan-3-yl)-N,N-bis(4-vinylphenyl)aniline (3-CDTPA) exhibited a deep highest occupied molecular orbital energy level (5.50 eV), high hole mobility (2.44 × 10-4 cm2 V-1 s-1), low cross-linking temperature (150 °C), and short curing time (30 min). Furthermore, a green QLED with 3-CDTPA as the hole transport layer (HTL) exhibited a notable maximum external quantum efficiency (EQEmax) of 18.59% with a remarkable maximum current efficiency (CEmax) of 78.48 cd A-1. In addition, solution-processed green OLEDs with 3-CDTPA showed excellent device performance with an EQEmax of 15.61%, a CEmax of 52.51 cd A-1, and outstanding CIE(x, y) color coordinates of (0.29, 0.61). This is one of the highest reported EQEs and CEs with high color purity for green solution-processed QLEDs and OLEDs using a divinyl-functionalized cross-linked HTM as the HTL. We believe that this study provides a new strategy for designing and synthesizing practical cross-linakable HTMs with enhanced performance for highly efficient solution-processed QLEDs and OLEDs.

Stepwise deforestation during the Permian-Triassic boundary crisis linked to rising temperatures

Although the trajectory of the marine mass extinction at the ∼252-Ma Permian-Triassic (P-Tr) boundary has been well studied, details of the coeval collapse of terrestrial ecosystems remain murky. Here, we use hydrocarbon biomarker compositions and other geological records (i.e., organic carbon isotopes (δ13Corg), charcoal abundance, and Hg content) from a tropical peatland succession in southwestern China to reconstruct in detail the history of terrestrial ecosystem collapse during the P-Tr crisis. Our high-resolution hydrocarbon biomarker records reveal that this collapse proceeded in a stepwise manner with increasing intensity as the crisis unfolded. We recognize three discrete crisis stages: Stage I within the uppermost Xuanwei Formation and Stages II and III within the lowermost Kayitou Formation. Stage I, the early crisis stage, is marked by a significant decline in terrestrial biomass (continuing into the later stages), as recorded by reduced C29 steranes relative to total steranes and a concomitant reduction in the ratio of pristane to phytane (Pr/Ph). Stage II, the main crisis stage, records intensified soil erosion and sediment flux as revealed by rising dibenzofuran (DBF) content and high hopane/sterane ratios, the disappearance of coal seams, a sharp negative shift in δ13Corg, and peak concentrations of charcoal reflecting increased wildfire incidence. Stage III, the late crisis stage characterized by enhanced soil erosion, corresponds to peak values of Hg and Hg/TOC but no charcoal peak, suggesting intensified volcanism and a return to a humid climate. These stages closely follow temperature records, which show a stepwise rise during the crisis interval, implying that the deforestation process was strongly influenced by punctuated rises in temperature and/or its attendant effects (e.g., climate aridification). This P-Tr transition scenario suggests that global warming can trigger deforestation and reduce terrestrial carbon storage, thus serving as a positive climate feedback, with important implications for present-day climate change.

Unravelling the impacts of sulfur dioxide on dioxin catalytic decomposition on V2O5/AC catalysts

Dioxins are high chlorine, toxic, and persistent organic pollutants that exert significant pressure on both human and the environment. From the analysis of current pollutant removal of the whole life cycle, such as integrated removal of NOx, SO2 and dioxins in a system, the dioxins oxidation activity as well as the distribution of oxidation products in the presence of SO2 are still a challenge. In this study, dibenzofuran (DBF) was regarded as a model dioxin compound, and V2O5/AC was used as a catalyst to investigate the impact of SO2 on degradation activity and the degradation path of DBF. Various characterization results showed that SO2 could promote the transformation of DBF to intermediates through a reaction with lattice oxygen and lower the apparent activated energy of DBF catalytic oxidation on V2O5/AC catalysts. The density functional theory (DFT) calculations confirmed that SO2 improved the oxidation ability of lattice oxygen on V2O5/AC. The ethyl hydrogen fumarate intermediate decreased and the small-molecule byproducts increased, providing further evidence that SO2 accelerates the degradation of DBF and its intermediates. However, the formation of VOSO4 would inevitably deteriorate the adsorption and oxidation abilities of V2O5/AC. A model is pioneered to describe the relationship between SO2 promotion and VOSO4 inhibition on DBF catalytic oxidation on a V2O5/AC catalyst. This study is expected to provide theoretical guidance for the collaborative abatement of multi-pollutants in flue gas.

Oxygenated graphitic carbon nitride based electrochemical sensor for dibenzofuran detection

Dibenzofuran (DBF) is one of the carcinogenic species which is stamped among the ‘pollutants of concern’ by international environmental protection agencies. This tenacious Persistent, Bioaccumulate and Toxic (PBT) compound is generated as a result of industrial effluents, agricultural wastes, aqueous chlorination and by-products of various pharmaceutical processes. Prolonged exposure to DBF results in significant degradation of environment quality and human health, as it has a slower decomposition capability. Furthermore, there are no relevant technologies in the market which can efficiently detect the presence of DBF due to which numerous human lives are being lost because of its after-effects/complications. Thus, the development of an efficient sensor platform for the trace quantification of this highly toxic species is essential and of utmost requirement which then is the novelty of this work. The current study is focused on the development of an electroanalytical sensing platform, based on oxygenated graphitic carbon nitride (O-gCN) nanostructures, for the detection of DBF in water. The electroanalytical activity of O-gCN is studied using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV). The developed sensor exhibited a Limit of Detection (LoD) of 1.58 pM, and is found to be selective in the presence of interferants with shelf life of 50 days; thereby demonstrating a huge potential to be translated towards on-field applications.

Fine tuning the optoelectronic properties of Dibenzo[b,d]Furan-Centered linear hole transporting materials for perovskite solar cells

Perovskite solar cells (PSCs) have received a lot of interest recently due to their high efficiency, affordable manufacture, and band gap turn capacity. Reports on PSCs efficiency rose dramatically from its initial value of 3.8% in 2009 to 24% in 2022. The absence of suitable materials for hole transportation is a significant barrier to further improving efficiency. To be used as potential components of photovoltaic systems, we have designed a series of small molecules serving as hole transport materials (HTMs) namely MT1, MT2, MT3, MT4, MT5, and MT6 having dibenzo furan based donor core with end capped acceptor moieties linked by thiophene as a bridge. The photovoltaic and optoelectronic properties of the molecules have been investigated by comparing them to a reference molecule (R). All of the designed molecules (MT1-MT6) showed lower bandgaps (1.98 eV–2.61 eV) than reference molecule (3.81 eV), indicating improved electron density transfer. All designed molecules (MT1-MT6) have high open-circuit voltage (1.28 V–1.41 V) and downshifted peak occupied molecular orbital energies (−5.41 eV to −5.28 eV) when electron-withdrawing acceptor moieties are chosen. High dipole moments (5.18 D to 21.70 D) proved that designed molecules (MT1-MT6) are highly soluble and are anticipated to make it easier to fabricate multilayered films. All designed molecules have effective charge transport capabilities, as evidenced by the reorganization energy values. All HTMs (MT1-MT6) have higher FF (0.9032–0.9102) and superior power conversion efficiency of 27.40%–30.42% compared to R (24.62%). This study established the viability of fabricating high performance PSCs using all proposed molecules (MT1-MT6).

Extractive Catalytic Oxidative Deoxygenation of Model Fuels Catalyzed by a Vanadium-Substituted Heteropolyacid and Molecular Oxygen

Extractive catalytic oxidative deoxygenation (ECODO) completes extractive catalytic oxidative desulfurization (ECODS) and extractive catalytic oxidative denitrogenation by removing organic oxygen from fuels. This is particularly necessary for renewable fuels to make them more stable and efficient. In ECODO, compounds such as cresol, furan, and their derivatives could be completely oxidized under oxygen at 20 bar and 120 °C using an aqueous heteropolyacid catalyst solution. The oxidation products were separated in situ in the three-phase process, either as CO2 or CO in the gas phase or as water-soluble organic acids like formic and acetic acid as well as acetone. In the case of stable dibenzofuran (DBF), the conversion could be drastically increased from only 27% to above 50% by tuning the reaction conditions and optimizing the catalyst loading by a design of experiment. Moreover, the amount of oxygen in the gas phase could be drastically reduced from 20 to 4 bar operating in 20 bar of synthetic air without limiting the performance of the catalyst. Furthermore, it could be shown that the parallel ECODS in the presence of an oxygenate like DBF leads to better desulfurization of model gasoline than without. The ECODO therefore offers a potential alternative to the classical hydrodeoxygenation, which is not only more energy-efficient but also replaces the expensive hydrogen with cheap air and avoids additional unit operations for fuel cleaning.

Synthesis and Studies of Dibenzofuran Embedded Bis‐(Calix)‐Pentaphyrins

AbstractCondensation of dibenzofuran based tripyrrane with dipyrroethene diol under acid catalyzed porphyrin forming conditions resulted in the formation of dibenzofuran embedded calix pentaphyrins with two meso‐sp3 carbons instead of expected fully conjugated dibenzofuran (DBF) embedded pentaphyrins. Three examples of DBF embedded calix pentaphyrins have been synthesized by adopting the [3+2] condensation methodology and characterized by various spectroscopic and theoretical methods. The NMR studies that include COSY, NOESY, HMBC and HSQC clearly confirmed the molecular structures of DBF embedded bis‐(calix)‐pentaphyrins. The optimized structures showed that the DBF embedded bis‐(calix)‐pentaphyrin macrocycles adopted figure eight conformation due to presence of two sp3 carbon atoms (C1 and C22) at meso positions which obstructed the conjugation throughout the macrocycle. The absorption spectra of macrocycles showed non‐aromatic features with a sharp strong band at 480 nm and a broad band in the region of 600–800 nm which were significantly red shifted with distinct colour change in protonated derivatives of DBF embedded bis‐(calix)‐pentaphyrins.

Removal efficiency of dibenzofuran using CuZn-zeolitic imidazole frameworks as a catalyst and adsorbent

Abstract Dioxins/furans are classified as highly toxic chemicals that seriously affect human health. To remove dioxin residues from contaminated water, CuZn-ZIFs, a material from bimetallic zeolitic imidazolate frameworks (ZIFs) has been synthesized and explored its efficacy treatment with dibenzofuran (DBF). The pristine structure of CuZn-ZIFs was confirmed using powder X-ray diffraction, Fourier-transform infrared, thermogravimetric analysis, energy-dispersive X-ray, Brunauer–Emmett–Teller, and scanning electron microscopy. CuZn-ZIFs exhibited its role as a heterogeneous catalyst promoting H2O2 oxidation and as an adsorbent in DBF treatment. Herein, at room temperature, more than 86% of DBF adsorbed and 90% of DBF degraded in the presence of H2O2 with 10 mg catalyst dosage, 30 ppm of DBF within 40 and 60 min, respectively. Remarkably, the CuZn-ZIFs’ reusability of each process showed a high efficacy removal with over 80% after five cycles. Therefore, CuZn-ZIFs synthesized could be a prospective candidate for the indirect or direct degradation of dioxins/DBF derivatives from contaminated water.