Styrenes Research Articles

Effect of SiO2/Al2O3 ratios of HZSM-5 zeolites on the formation of light aromatics during lignite pyrolysis

In this study, the effects of HZSM-5 zeolites with different SiO2/Al2O3 ratios on the formation and distribution of light aromatics (mainly BTEXN) were systematically investigated by in situ pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS), and model compounds were used to analyze the catalytic routes of HZSM-5 zeolites for the formation of light aromatics during the pyrolysis of coal. Results revealed that the role played by HZSM-5 zeolites for the catalytic upgrading of uncondensed coal tar from the pyrolysis of coal is strong related to the Brönsted and Lewis acid sites and pore structure. HZ-25 zeolite (HZSM-5 zeolite with a SiO2/Al2O3 mole ratio of 25) with a high content of Brönsted and Lewis acid sites exhibited the best promotion for the catalytic upgrading of coal tar during the pyrolysis of Coal A. Model compounds of anthracene, benzyl phenyl ether, and petroleum ether represented the condensed aromatic ring; C-O bridge bond, and aliphatic structure in coal, respectively, and BTEXN was generated over the HZSM-5 zeolite catalyst. HZ-25 zeolite with a higher content of acid sites and high specific surface area is prone to facilitating the formation of BTEXN during the pyrolysis of petroleum ether, anthracene and benzyl phenyl ether. Notably, the obtained results indicated that HZSM-5 zeolites exhibit a dual promoting role for the aromatization of aliphatic hydrocarbons and catalytic cracking of macromolecular fragments during the pyrolysis of coal.

Photo-polymerization as a new approach to fabricate the active layer of forward osmosis membrane

A novel approach is employed to prepare the active layer of the forward osmosis membrane by the photo-polymerization method. The poly (ethylene glycol) phenyl ether acrylate (PPEA) and methacrylic acid (MAA) are used as monomers. The emphasis is given to analysing the effect of monomer concentration on chemical functional groups of active layer, thermal stability, surface morphology, roughness, interfacial free energy, organic fouling tendency and osmotic flux performance. The functional groups of the active layer are characterized by ATR-FTIR. Furthermore, thermal analysis (TGA/DTG) is performed to calculate grafting density and thermal stability of prepared FO membranes. Surface morphology and roughness are characterized by atomic force microscopy (AFM). Unlike control polyamide active layer membrane that suffered from organic fouling (28.14 ± 3.70% flux decline and 95% flux recovery), the photo-polymerized 75/25 active layer FO membrane demonstrated the low fouling propensity (2.77 ± 0.62% flux decline) and high flux recovery (nearly ~100%). The interfacial free energy and low fouling property of 75/25 FO membrane is also reflected in improved osmotic flux performance with 11.20 ± 0.79 L/g (AL-FS) and 8.41 ± 0.22 L/g (AL-DS) reverse solute flux selectivity (RSFS) (Jw/Js) than control polyamide FO membrane (7.94 ± 0.22 L/g (AL-FS) and 7.64 ± 0.54 L/g (AL-DS)).

Electrodeposition of polymer electrolyte into carbon nanotube tissues for high performance flexible Li-ion microbatteries

Polymer-coated Carbon Nanotube (CNT) tissues are very flexible and lightweight and have high potential as an anode material for flexible Li-ion microbatteries. The electrochemical deposition of p-sulfonated poly(allyl phenyl ether) (SPAPE) polymer electrolyte into CNT tissues has been accomplished using a cyclic voltammetry (CV) technique. When compared to a pristine CNT tissue, the capacity of SPAPE-coated CNT tissue after 10 cycles of CV is improved about 67% at 1C rate. The enhancement of electrochemical performance is obtained when the CNT tissues are coated with the SPAPE polymer electrolyte. The higher capacity of the SPAPE-coated CNT tissue is attributed to the increased surface area and the improved quality of the electrode/electrolyte interfaces between the nanotubes and the polymer electrolyte. The SPAPE-coated CNT tissue delivers a higher reversible capacity of 750 mAh g−1 (276 µAh cm−2) compared to a pristine CNT tissue, which solely provides a reversible capacity of 450 mAh g−1 (166 µAh cm−2) after 110 cycles at 1C rate. Remarkably, the SPAPE-coated CNT tissue reaches a high capacity up to 12C rate while observing that the capacity can be significantly recovered.

Catalytic Cleavage of Ether Bond in a Lignin Model Compound over Carbon-Supported Noble Metal Catalysts in Supercritical Ethanol

Decomposition of lignin-related model compound (benzyl phenyl ether, BPE) to phenol and toluene was performed over carbon-supported noble metal (Ru, Pd, and Pt) catalysts in supercritical ethanol without supply of hydrogen. Phenol and toluene as target products were produced by the hydrogenolysis of BPE. The conversion of BPE was higher than 95% over all carbon-supported noble metal catalysts at 270 ° for 4 h. The 5 wt% Pd/C demonstrated the highest yield (ca. 59.3%) of the target products and enhanced conversion rates and reactivity more significantly than other catalysts. In the case of Ru/C, BPE was significantly transformed to other unidentified byproducts, more so than other catalysts. The Pt/C catalyst produced the highest number of byproducts such as alkylated phenols and gas-phase products, indicating that the catalyst promotes secondary reactions during the decomposition of BPE. In addition, a model reaction using phenol as a reactant was conducted to check the secondary reactions of phenol such as alkylation or hydrogenation in supercritical ethanol. The product distribution when phenol was used as a reactant was mostly consistent with BPE as a reactant. Based on the results, plausible reaction pathways were proposed.

Nb(Ta)-based solid acid modified Pt/CNTs catalysts for hydrodeoxygenation of lignin-derived compounds

Efficient upgrading of lignin bio-oils into oxygen-free liquid alkane fuels is a challenging task owing to the incompatibility of the phenolic feedstock with conventional fuels and the availability of effective hydrotreating catalysts based on the current refinery infrastructure. In this work, a series of solid acid nanosheets (HNbWO6, HNbMoO6, HTaWO6) modified Pt/CNTs bifunctional catalysts were evaluated in hydrodeoxygenation (HDO) of lignin-derived compounds. The effects of types of nanosheets and the synergistic effect between metal sites and acid sites were discussed via HDO of diphenyl ether. Pt/HNbWO6/CNTs catalyst exhibited the most efficient performance for the HDO of diphenyl ether to cyclohexane (conversion: 99.7%, selectivity: 96.4%) at 200 °C, 3.0 MPa. Several lignin aromatic model compounds including phenol, anisole, 2-phenylethyl phenyl ether and guaiacol were also investigated over Pt/HNbWO6/CNTs catalyst. Due to the different bond-dissociation energies of CO bond and steric hindrance effect, guaiacol and phenol are more difficult to be converted than diphenyl ether and anisole based on the yield of cyclohexane. It was found that the Pt/HNbWO6/CNTs catalyst exhibited favorable stability. These results validated that it is desirable to utilize this catalyst in the HDO of actual lignin macromolecules into hydrocarbon fuels.

Release Behavior of Benzimidazole-Intercalated α-Zirconium Phosphate as a Latent Thermal Initiator in the Reaction of Epoxy Resin

The intercalation compound of benzimidazole with α-zirconium phosphate (α-ZrP) was evaluated as a latent thermal initiator in the reaction of glycidyl phenyl ether (GPE) and hexahydro-4-methylphthalic anhydride (MHHPA). No reaction occurred at 60 °C after 1 h. Upon increasing the temperature to 140 °C, the conversion reached 97% after 1 h. The deintercalation ratio of Bim from the intercalation compound of benzimidazole with α-zirconium phosphate (α-ZrP·Bim) was measured in the reaction of the GPE-MHHPA system. The deintercalation ratio increased upon increasing the temperature, reaching 97% at 120 °C after 1 h. The storage stability at 25 °C and 40 °C in the reaction of GPE-MHHPA was tested and was found to be maintained for 14 days at 25 °C. The intercalation compound of α-ZrP·Bim can effectively serve as a latent thermal initiator in the reaction of GPE-MHHPA.

Low‐dielectric‐constant aromatic homopolyimide and copolyimide derived from pyromellitic dianhydride, 4,4′‐oxydianiline, 2,2‐bis[4‐(4‐aminephenoxy)phenyl]propane, 1,4‐bis(4‐aminophenoxy)benzene, or 1,3‐bis(4‐aminophenoxy)benzene

ABSTRACTLow‐dielectric‐constant aromatics, homopolyimide and copolyimide, were introduced. Homopolyimides were prepared by pyromellitic dianhydride (PMDA) as an anhydride monomer and 4,4′‐oxydianiline (ODA), 2,2‐bis[4‐(4‐aminephenoxy)phenyl]propane, 1,4‐bis(4‐aminophenoxy)benzene, or 1,3‐bis(4‐aminophenoxy)benzene as an amine monomer. The copolyimides were prepared with PMDA as an anhydride monomer, ODA as an amine monomer with the addition of 2,2‐bis[4‐(4‐aminephenoxy)phenyl]propane, 1,4‐bis(4‐aminophenoxy)benzene, or 1,3‐bis(4‐aminophenoxy)benzene as another amine monomer. The polyimides were well characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, thermomechanical analysis, dielectric measurements, and tensile testing. The homopolyimide and copolyimides showed lower dielectric constants than the homopolyimide formed by ODA and PMDA. The results also indicate that the interchain distance, the quantities of phenyl ether, and the position of the substitute are factors that not only affected the thermal performance of polyimide by improving the molecular flexibility but also reduced the dielectric constant of polyimide by increasing the free volume of the molecular chain and decreasing the polarization points per unit volume. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47405.

Efficient liquid-phase hydrogenolysis of a lignin model compound (benzyl phenyl ether) using a Ni/carbon catalyst

Efficient liquid-phase hydrogenolysis of benzyl phenyl ether using Ni/CB in an EtOH/H2O co-solvent system.

Facile synthesis of highly conductive PEDOT:PSS via surfactant templates.

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) nanoparticles in powder form with high electrical conductivity were synthesized via chemical oxidative polymerization. In addition, the effects of EDOT : PSS weight ratio, EDOT : Na2S2O8 mole ratio, and surfactant concentration and type, namely hexadecyltrimethylammonium bromide (CTAB), sodium dodecylsulfate (SDS), and polyoxyethylene octyl phenyl ether (Triton X-100) on the properties of PEDOT:PSS were investigated. For the effect of EDOT : PSS weight ratio, at the EDOT : Na2S2O8 mole ratio of 1 : 1, the EDOT : PSS weight ratio of 1 : 11 was the optimal condition to obtain electrical conductivity of 999.74 ± 10.86 S cm−1 due to the high amount of PSS− and SO42− available to interact with the PEDOT chain with a low % PSSNa. For the effect of EDOT : Na2S2O8 mole ratio, at the EDOT : PSS weight ratio of 1 : 11, the EDOT : Na2S2O8 mole ratio of 1 : 2 was the best condition as it provided the highest dopant (PSS− and SO42−) amount, while the % PSSNa was relatively low. For the effect of surfactant type and concentration, at the EDOT : PSS weight ratio of 1 : 11 and EDOT : Na2S2O8 mole ratio of 1 : 2, Triton X-100 at 2.5CMC provided electrical conductivity higher than with CTAB and SDS. The thermal stability of PEDOT:PSS obtained from various conditions was investigated, and PEDOT:PSS without surfactant showed the highest thermal stability since it produced the highest char yield. In this study, the highest electrical conductivity of PEDOT:PSS, which was obtained in the presence of Triton X-100 to reduce the PSSNa amount, was 1879.49 ± 13.87 S cm−1, the highest value reported to date.

3D QSAR Studies on Benzyl Phenyl Ether Diamidine Derivatives with Antiprotozoal Activities

Human African trypanosomiasis (HAT) is a neglected tropical disease, and some drugs treating HAT have been used for even more than 60 years. Currently, a series of benzyl phenyl ether diamidine derivatives are discovered, which exhibit high antiprotozoal activities and low cytotoxicity, leading to good development prospects. The comparative molecular field analysis (CoMFA) and the comparative molecular similarity indices analysis (CoMSIA) are used to study the relationship between the structure and antiprotozoal activities. The established 3D QSAR model shows not only significant statistical quality, but also satisfies predictive ability: the best CoMFA model had r2 = 0.958 and q2 = 0.766, the best CoMSIA model had r2 = 0.957 and q2 = 0.812, the predictive ability of CoMFA and CoMSIA model were further confirmed by a test set which had 11 compounds, giving the correlation coefficient Qext2 of 0.792, 0.873, respectively. The contour maps and contribution maps show important features that can improve the antiprotozoal activity: position 3 from substituent R4 should be a low electronegativity group, position 4 from substituent R4 should have higher electronegativity, substituent R2 should be selected to a low electronegativity and small bulk group. Together these results may offer some useful theoretical information in designing potential inhibitors.

Mixed micellization and surface properties of non-ionic/cationic surfactants

We investigate the surface properties of aqueous binary mixtures of our cationic surfactant O-dodecyl-N,N′-diisopropylisourea hydrochloride (ISO-DIC C12) with commercially available nonionic surfactant polyoxyethylene p-(1,1,3,3-tetramethylbutyl)phenyl ether (TritonX-100) at different temperatures (288 to 303 K). The micellization behavior of the binary systems is studied by determining the surface tension and other important physicochemical parameters, such as the critical micelle concentration (CMC), surface tension at the CMC(γcmc), Krafft Temperature (TK), maximum excess concentration (Γmax), minimum surface area per molecule (Amin), surface pressure at the CMC (Пcmc), and the adsorption efficiency (pC20) at the air/water interface. The study has additionally covered the calculation of thermodynamic parameters of micellization, including the standard Gibbs free energy, the standard enthalpy, the standard entropy, the free energy, and the Gibbs free energy of adsorption at air/water interface. The CMC values of the binary systems determined by experimental data are used to evaluate the micellar composition in the mixed micelle, the interaction parameter β and the activity coefficients f1(ISO-DIC C12) and f2 (polyoxyethylene p-(1,1,3,3-tetramethylbutyl)phenyl ether) using the theoretical treatment proposed by Clint and Rubingh. Our results reveal that the proposed binary systems possess enhanced surface activity compared to those of the individual surfactants.

Biocatalytic methylation and demethylation via a shuttle catalysis concept involving corrinoid proteins

Synthetically established methods for methylation of phenols and demethylation of methyl phenyl ethers rely in general on hazardous reagents or/and harsh reaction conditions and are irreversible. Consequently, alternative regioselective methods for the reversible formation and breakage of C-O-ether bonds to be performed under mild and sustainable conditions are highly desired. Here we present a biocatalytic shuttle concept making use of corrinoid-dependent methyl transferases from anaerobic bacteria. The two-component enzymatic system consists of a corrinoid protein carrying the cofactor and acting as methyl group shuttle, and a methyltransferase catalyzing both methylation and demethylation in a reversible fashion. Various phenyl methyl ethers are successfully demethylated and serve in addition as sustainable methylating agents for the functionalization of various substituted catechols. Therefore, this methyl transfer approach represents a promising alternative to common chemical protocols and a valuable add-on for the toolbox of available biocatalysts.

Pd(OAc)2-catalyzed synthesis of benzyl phenyl ether derivatives with H2O2 as an oxidant in neat water

A new protocol for Pd(OAc)2-catalyzed reactions of different benzyl bromides and various arylboronic acids has been developed to form functionalized benzyl phenyl ethers. This method represents the first instance where arylboronic acid is used as a reaction substrate for benzyl phenyl ether synthesis with H2O2 as the green oxidant under atmospheric oxygen and pure H2O as an environmental friendly solvent without the requirement for phosphine- and N-based ligands, remarkable functional group tolerance, and considerable yield.

Synthesis, Characterization, and Evaluation of Surface and Thermal Properties and Cytotoxicity of 2‐Hydroxy‐3‐Phenoxypropyl Imidazolium Bola‐Type Gemini Amphiphiles

AbstractA library of imidazolium‐based gemini cationic bola amphiphiles was synthesized using a regioselective ring‐opening reaction of glycidyl phenyl ether with imidazole under solvent‐free conditions. The corresponding hexafluorophosphate (PF6−) and tetrafluoroborate (BF4−) counterion‐containing amphiphiles were also synthesized and characterized using nuclear magnetic resonance (NMR) and mass spectroscopy. The micellar and interfacial parameters like the critical micelle concentration (CMC), surface pressure at the CMC (Пcmc), surface tension at CMC ( γcmc), counterion binding (β), maximum surface excess concentration ( Γmax), minimum area per molecule ( Amin), standard free energy of micellization () and adsorption (), and Kraft temperature were evaluated using surface tension and conductometry methods in aqueous solution as well as in buffer solution. Dynamic light scattering (DLS) was used to determine the size of the micelles formed in the aqueous solution. Cytotoxicity tests were carried out on the C6 glioma cancerous brain cell line using the MTT assay (3‐(4, 5‐dimethylthiazole‐2‐yl)‐2, 5‐diphenyltetrazolium bromide) to evaluate the IC50 value of all the synthesized amphiphiles. Thermal stability of these amphiphiles was also evaluated using a thermal gravimetric analyzer (TGA). Economic way of synthesis, moderate thermal stability, a low value of CMC, and cytotoxicity of these amphiphiles will inspire new research in the field of nanobiotechnology and pharmaceutical industries.

Mechanism and Effect of Polar Styrenes on Scandium-Catalyzed Copolymerization with Ethylene.

Copolymerization of ethylene (E) and polar vinyl monomers remains a problem because E propagation is hindered. Herein, for the first time, we report the copolymerization of E and polar styrenes (SR ) by using an oxophilic scandium catalyst that exhibits higher turnover frequencies than both E and SR homopolymerizations when R is an electron-withdrawing group. This positive comonomer effect was elucidated through computing reaction profiles of E/SF copolymerization at the DFT (B3PW91) level of theory. It reveals that the secondary interaction between Sc3+ and phenyl of the last and penultimate inserted SF units leads to a decrease of the E insertion barrier, because the electron-withdrawing substituent enhances the electrophilicity of Sc3+ by an inductive effect mediated by the secondary interaction. After three consecutive insertions of the E units, the secondary interaction is lost and the SF insertion is kinetically preferred over the E insertion. This process is in line with the NMR spectrum analyses which show that the resultant copolymers mainly contain SR (E)x SR sequences where x≤3.

Mechanism and Effect of Polar Styrenes on Scandium‐Catalyzed Copolymerization with Ethylene

AbstractCopolymerization of ethylene (E) and polar vinyl monomers remains a problem because E propagation is hindered. Herein, for the first time, we report the copolymerization of E and polar styrenes (SR) by using an oxophilic scandium catalyst that exhibits higher turnover frequencies than both E and SR homopolymerizations when R is an electron‐withdrawing group. This positive comonomer effect was elucidated through computing reaction profiles of E/SF copolymerization at the DFT (B3PW91) level of theory. It reveals that the secondary interaction between Sc3+ and phenyl of the last and penultimate inserted SF units leads to a decrease of the E insertion barrier, because the electron‐withdrawing substituent enhances the electrophilicity of Sc3+ by an inductive effect mediated by the secondary interaction. After three consecutive insertions of the E units, the secondary interaction is lost and the SF insertion is kinetically preferred over the E insertion. This process is in line with the NMR spectrum analyses which show that the resultant copolymers mainly contain SR(E)xSR sequences where x≤3.

Light-Driven Intermolecular Charge Transfer Induced Reactivity of Ethynylbenziodoxol(on)e and Phenols.

Ethynylbenziodoxol(on)es (EBXs) have been widely used in organic synthesis as electrophilic alkyne-transfer reagents involving carbon- and heteroatom-based nucleophiles. However, potential reactions of EBXs with phenols remain uninvestigated. Here, we present the formation of ( Z)-2-iodovinyl phenyl ethers with excellent regio- and stereoselectivity through the reactivity between EBXs and phenols driven by visible light. We propose that this light-activated transformation proceeds through electron donor-acceptor complexes to enable new reactivity beyond existing mechanisms for alkynylation of carbon- and heteroatom-based nucleophiles. This operationally robust process was employed for the synthesis of diverse ( Z)-2-iodovinyl phenyl ethers through irradiating a solution containing a phenyl-EBX, a phenol, and the base Cs2CO3 with a commercially available blue LED at room temperature. The ( Z)-2-iodovinyl phenyl ether products can be further stereospecifically functionalized to form trisubstituted alkenes, demonstrating the potential of these products en route to chemical complexity.

Metabolism of the Strobilurin Fungicide Mandestrobin in Wheat.

The metabolic fate of a new fungicide, mandestrobin, labeled with 14C at the phenoxy or benzyl ring was examined in wheat after a single spray application at 300 g/ha. Mandestrobin penetrated into foliage over time, with both radiolabels showing similar 14C distribution in wheat, and 2.8-3.3% of the total radioactive residue remained on the surface of straw at the final harvest. In foliage, mandestrobin primarily underwent mono-oxidation at the phenoxy ring to produce 4-hydroxy or 2-/5-hydroxymethyl derivatives, followed by their subsequent formation of malonylglucose conjugates. In grain, the cleavage of its benzyl phenyl ether bond was the major metabolic reaction, releasing the corresponding alcohol derivative, while the counterpart 2,5-dimethylphenol was not detected. The constant RS enantiomeric ratio of mandestrobin showed its enantioselective metabolism to be unlikely on/in wheat.

Descriptor selection evaluation of binary gravitational search algorithm in quantitative structure-activity relationship studies of benzyl phenyl ether diamidine's antiprotozoal activity and Chalcone's anticancer potency

In this work, the effect of various gravitational constant functions, G(t), were evaluated on the performance of the newly proposed binary gravitational search algorithm (BGSA) as a feature selection method for chemical systems. To fulfill this aim, linear, exponential, logarithmic and square root functions were studied. These functions were implemented in the binary gravitational search algorithm computer code sequentially and their performances were evaluated in a quantitative structure-activity relationship (QSAR) study for selection of the most informative descriptors. In the QSAR study, sixty cationic benzyl phenyl ether diamidine derivatives, which had been synthesized and evaluated against acute infection of Trypanosoma brucei rhodesiense (T.b. rhodesiense), were examined. The number and the kind of descriptors, which were selected by the BGSA, were highly dependent on the applied G(t) function. The results of internal and external validation tests indicate that the exponential function was superior to the other gravitational constant functions for applying in the binary gravitational search algorithm. A general model was established using seven descriptors for the ten training and validation sets. Regardless of subsetting, the selected descriptors and generated model can successfully describe experimental variation of antiprotozoal activity of benzyl phenyl ether diamidine derivatives. In addition, in another QSAR study, anticancer potency of a series of 87 Chalcone derivatives was satisfactorily modeled by using the BGSA-BRANN method. Comparison of BGSA results with those obtained by genetic algorithm (GA) indicates superiority of the BGSA.

3D printing a mechanically-tunable acrylate resin on a commercial DLP-SLA printer

Multi-material 3D printing with several mechanically distinct materials at once has expanded the potential applications for additive manufacturing technology. Fewer material options exist, however, for additive systems that employ vat photopolymerization (such as stereolithography, SLA, and digital light projection, DLP, 3D printers), which are more commonly used for advanced engineering prototypes and manufacturing. Those material selections that do exist are limited in their capacity for fusion due to disparate chemical and physical properties, limiting the potential mechanical range for multi-material printed composites. Here, we present an ethylene glycol phenyl ether acrylate (EGPEA)-based formulation for a polymer resin yielding a range of elastic moduli between 0.6 MPa and 31 MPa simply by altering the ratio of monomer and crosslinker feedstocks in the formulation. This simple chemistry is also well suited to form seamless adhesions between mechanically dissimilar formulations, making it a promising candidate for multi-material DLP 3D printing. Preliminary tests with these polymer formulations indicate that variability due to molecular differences between hard and soft formulations is less than 3% of the prescribed model dimensions, comparable to existing commercial DLP and SLA resins, with unique advantages of a wide range of elastomer stiffness and seamless fusion for 3D printing of structurally detailed and mechanically heterogeneous composites.