Photophysical properties of arylcarbonitrile derivatives: Synthesis, absorption and emission spectra, and quantum chemical studies

A new series of aromatic cyanovinyl compounds were synthesized via one-pot reactions of tri- or tetracyanoethylenes with nucleophilic reagents. The ground-state geometries and UV-vis absorption spectra of the compounds were computationally analyzed by means of density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations, respectively. None of the compounds were fluorescent in solution, but some showed intense emission in the solid state. The first excited singlet states (S₁) potential energy surfaces (PESs) were explored using complete active space SCF (CASSCF) calculations for the compounds in order to elucidate nonradiative decay mechanism that takes into account the involvement of conical intersections (CI).     

Surface functionalization of cotton cellulose with glycidyl methacrylate and its application for the adsorption of aromatic pollutants from wastewaters

Cellulose material C1 was prepared by grafting of glycidyl methacrylate (GMA) in the presence of Fenton-type reagent. This one-pot procedure provided C1 with glycidyl isobutyrate branches. Glycidyl epoxide ring opening with water turned C1–C2 material branched with glycerol isobutyrate. So, C1 surface bears hydrophobic branches ending with the glycidyl group, while C2 surface presents hydrophilic branches ending with the glycerol group. The adsorption of aromatic polluting substances like phenol (Ph), 4-nitrophenol (pNPh), 2,4-dinitrophenol (dNPh), 2,4,6-trinitrophenol (picric acid, tNPh) and 2-naphtol (BN) from their water solutions was tested with C1, C2 and with the untreated cellulose material C0. Phenol adsorption did not occur. All the other aromatic molecules were removed in different amount both by C1 and C2. C1 and C2 showed different affinities towards nitrophenols and 2-naphtol. While C1 was much more effective for removing the hydrophobic 2-naphtol, C2 had higher adsorption capacity towards the hydrophilic nitrophenols, in agreement with their branches polarity, respectively.     

Preparation and characterization of nanoscale aromatic polyamide particles

Aromatic polyamide particles were prepared by reacting m-phthalyl chloride and 4,4′-diaminodiphenyl ether in a dioxane solution with high water content using a precipitation polymerization method. These nanoscale particles were spherical with a narrow size distribution. The morphologies and characteristic features of the polyamide products obtained depended strongly on the water content of this polymerization system. The characteristic features of the polyamide products were correlated with the amount of HCl (generated during polycondensation) complexed with polyamide products. Water was essential for the formation of spherical particles and played an important role in determining the polarity of the reaction solution. Further, water removed HCl from this condensation reaction system and played an important role as a reaction accelerator.     

Mixing properties of isopropyl acetate+aromatic hydrocarbons at 298.15 K: Density,refractive index and isentropic compressibility

We present new experimental data of density, refractive index and speed of sound for the binaries of isopropyl acetate+(toluene, ethylbenzene, p-xylene, mesitylene, isopropylbenzene, butylbenzene, isobutylbenzene, or t-butylbenzene) at T=298.15 K. and standard conditions, and the corresponding computed derived magnitudes (change of isentropic compressibility, change of refractive index on mixing, and excess molar volume). The mixtures show a clear expansive tendency for the highest molar weight compounds and the steric hindrance role of the aromatic chemicals being analyzed to the light of the non-ideality on mixing. A good agreement among experimental data and the values estimated by theoretical procedures was obtained.     

Sorption behaviors of aromatic anions on loess soil modified with cationic surfactant

Modification of soils with hydrophobic cationic surfactants is an effective approach for enhancing the sorptive capabilities of soil in the vadose zone for the purpose of retaining organic contaminants prior to cleanup. The objective of this study was to examine the sorptive behavior of the cationic surfactant-modified loess soil for aromatic anions in the aqueous phase in an attempt to define the sorptive mechanisms. Some dominant factors governing the sorption, such as ionic strength and divalent heavy metal cation, were investigated. The sorption isotherms of 2,4-dinitrophenol (DNP) and benzoic acid (BA) in the modified soil samples were obtained using the batch equilibration method. Under the laboratory conditions, the modified loess soil utilized in this study was prepared by replacing the cations of loess soil with a cationic surfactant—hexadecyltrimethylammonium (HDTMA) bromide. The acidic aromatic compounds, DNP and BA existing as aromatic anions in the natural mixture of loess soil and aqueous phase, were selected as indicator compounds to measured the sorption behaviors of aromatic anions on the HDTMA-modified loess soil. The results confirmed that the sorptive capabilities of aromatic anions in loess soil were greatly enhanced by modification with HDTMA. The increase of ionic strength and the addition of divalent heavy metal cation Zn²⁺ significantly increased the sorption of aromatic anions on the HDTMA-modified loess soil. In binary solute systems, the sorbed amounts either of DNP or BA on the HDTMA-modified loess soil were reduced if two compounds existed simultaneously in the soil. This results indicated that competitive adsorption between the two aromatic anions occurred in soil matrix.     

钪和钇高氯酸盐与2,2′一二喹啉甲烷固体配合物的合成及性质

本文报道了钪和钇高氯酸盐与2,2′—二喹啉甲烷新型固体配合物Sc(Biqm)_3(ClO_4)_3·5H_2O,Y(Biqm)_3(ClO_4)_3的合成,并对配合物的组成及其红外光谱、紫外光谱、差热—热重分析,X光粉末衍射物相分析和摩尔电导等性质进行了研究。     

Development of a bienzyme system based on sugar–lectin biospecific interactions for amperometric determination of phenols and aromatic amines

Bienzyme electrode with horseradish peroxidase (HRP) and glucose oxidase (GOD) multilayers was constructed based on sugar–lectin biospecific interactions for amperometric determination of phenolic compounds and aromatic amines. Atomic force microscopy (AFM) was applied to monitor the uniform layer-by-layer assembly of concanavalin A (Con A) and HRP or GOD on polyelectrolyte precursor film-modified Au electrode. Substituted phenolic compounds and aromatic amines could be determined with in situ generation of H₂O₂ by GOD-catalyzed oxidation of glucose. The parameters of the biosensor including the number of assembled HRP and GOD layer, and the concentrations of glucose were optimized. The linear range for the determination of catechol and p-phenyldiamine was 6.0–60.0 μmol L⁻¹ and 7.6–68.4 μmol L⁻¹ with detection limit of 0.9 μmol L⁻¹ and 0.4 μmol L⁻¹, respectively. The biosensor possessed high sensitivity and fast response for phenolic compounds and 95% of the maximum response could be reached in about 3 s. Glucose, ascorbic acid, tartaric acid, citric acid and starch exhibited no interference for the detection. The biosensor presented high stability due to the design for in situ generation of H₂O₂ with bienzyme system.     

Enhancing the aromatic hydrocarbon yield from the catalytic copyrolysis of xylan and LDPE with a dual-catalytic-stage combined CaO/HZSM-5 catalyst

The high concentration of oxygenated compounds in pyrolytic products prohibits the conversion of hemicellulose to important biofuels and chemicals via fast pyrolysis. Herein CaO and HZSM-5 was developed to convert xylan and LDPE to valuable hydrocarbons by thermogravimetric analysis (TGA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and elucidate the reaction mechanism were also investigated in detail. The results indicated that xylan/LDPE copyrolysis was more complicated than pyrolysis of the individual components. LDPE hindered the thermal decomposition and aromatic hydrocarbon formation from xylan at temperatures under 350 °C and had a synergistic effect at high temperatures. 50% LDPE was proven to be more beneficial than other percentages for the formation of monocyclic aromatic hydrocarbons. Simultaneously, the addition of CaO/HZSM-5 significantly reduced the reaction Ea and increased the reaction rate. CaO can effectively improve the deoxygenation and aromatization reaction, enhancing the yield and selectivity of aromatics to a certain extent. The maximum yield of hydrocarbons (96.01%), mono-aromatic hydrocarbons (88.53%) and S_BTXE (85.79%) were obtained at a CaO/HZSM-5 ratio of 1:2, a pyrolysis temperature of 450 °C, a catalytic temperature of 550 °C, a catalyst dose of 1:2 and a xylan-to-LDPE ratio of 1:1 via an ex situ process. The system was dominated by toluene, xylene and alkyl benzene. Diels-Alder reactions of furans and hydrocarbon pool mechanism of nonfuranic compounds improved aromatic formation. This study provides a fundamental for recovering energy and chemicals from pyrolysis of hemicellulose.     

4,4'-二氨基-3,3',5,5'-四甲基二苯甲酮的合成研究

本文研究了4,4’-二氨基-3,3’,5,5’-四甲基二苯甲酮的合成条件和精制方法,较好的反应条件是：DTD2g和氨醌4g加到40ml乙醇中并在外保护下回流4小时,粗品收率93.5。产品提纯方法是重结晶,溶剂选择是关键。利用DSC、元素分析、IR谱和H’－NMR谱确认了产物的组成和结构。