Destruction of chlorinated organics by hydrotreatment using Ru/TiO2 catalyst

Catalytic hydrodechlorination reactions of p‐chloro‐m‐cresol (PCMC) and p‐chloroaniline (PCA) were investigated in a slurry reactor using a Ru/TiO₂ catalyst. The organic reaction intermediates, m‐cresol and aniline, were further converted into methylcyclohexanol and cyclohexylamine respectively. Kinetics of PCMC hydrogenation was studied over the ranges in temperature, 323–373 K, H₂ partial pressure, 0.34–1.38 MPa, PCMC concentration, 3.5–14 mM and catalyst loading, 0.1–2 kg/m³. The reaction orders with respect to PCMC and H₂ were evaluated as 0.5 and 0.8 respectively. It was found that aniline hydrogenation is the rate‐determining step in the hydrotreatment of PCA. Kinetics of aniline hydrogenation was studied at 343 and 363 K over the ranges in H₂ partial pressure, 0.34–1.38 MPa, aniline concentration, 5.4–21.5 mM and catalyst loading, 0.1–0.6 kg/m³. The reaction orders with respect to aniline and H₂ were found to be 1.3 and 1.0 respectively. © 2012 Canadian Society for Chemical Engineering     

Anthranilic acid assisted preparation of Fe3O4–poly(aniline‐co‐o‐anthranilic acid) nanoparticles

Magnetic Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles were prepared by a novel and simple method: anthranilic acid assisted polymerization. The synthetic strategy involved two steps. First, Fe₃O₄ nanoparticles capped by anthranilic acid were obtained by a chemical precipitation method, and then the aniline and oxidant were added to the modified Fe₃O₄ nanoparticles to prepare well‐dispersed Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles. Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles exhibited a superparamagnetic behavior (i.e., no hysteresis loop) and high‐saturated magnetization (M_s = 21.5 emu/g). The structure of the composite was characterized by Fourier‐transform infrared spectra, X‐ray powder diffraction patterns, and transmission electron microscopy, which proved that the Fe₃O₄–poly(aniline‐co‐o‐anthranilic acid) nanoparticles were about 20 nm. Moreover, the thermal properties of the composite were evaluated by thermogravimetric analysis, and it showed excellent thermal stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1666–1671, 2006     

Preparation and electrochemical capacitance of poly(pyrrole‐co‐aniline)

The copolymer of pyrrole and aniline, poly(pyrrole‐co‐aniline), has been prepared by chemical oxidation of corresponding monomer mixtures with ammonium peroxysulfate. Techniques of FTIR, SEM‐EDS, and BET surface area measurement were used to characterize the structure and morphology of the copolymer. The electrochemical properties of the copolymer were investigated by cyclic voltammetry, galvanostatic charge‐discharge, and electrochemical impedance spectroscopy. The results indicated that poly(pyrrole‐co‐aniline) was about 100–300 nm in diameter and showed better electrochemical capacitive performance than polypyrrole and polyaniline. The specific capacitance of the copolymer electrode was 827 F/g at a current of 8 mA/cm² in 1 mol/L Na₂SO₄ electrolyte. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Highly conductive new aniline copolymers: poly(aniline‐co‐aminoacetophenone)s

Copolymers of aniline and o‐/m‐aminoacetophenone of different compositions were synthesized by oxidative chemical copolymerization. Two different methods were employed, emulsion and inverse emulsion, with different oxidants, ammonium persulphate and benzoyl peroxide, to study the effect of synthesis conditions on the yield, solubility and conductivity of the copolymers. The copolymer compositions were determined using proton NMR spectroscopy. The reactivity ratios determined by the Finemann–Ross method indicate lower reactivity for m‐aminoacetophenone relative to aniline in the emulsion method, while the reverse holds true in the inverse emulsion method. Copolymers formed by the former pathway are random type as determined by the Finemann–Ross method. The copolymers have crystalline/amorphous morphologies and good conductivity. They exhibit enhanced solubility compared with polyaniline. Copyright © 2005 Society of Chemical Industry     

Effect of dopant and oxidant on the electrochemical properties of polyaniline/graphite nanoplate composites

Optimizing the synthesis parameters of polyaniline/graphite nanoplate (PANI/GNP) composite is essential to the final electrochemical performance. Herein, the electrochemical properties of PANI/GNP composites, prepared by in situ chemical polymerization using varying amounts of different oxidants, with or without the addition of 4‐dodecylbenzenesulfonic acid (DBSA) as dopant, were investigated. Cyclic voltammetric results suggested that a stoichiometric amount of the oxidant iron chloride (FeCl₃) was beneficial to the electrochemical properties of the composites. The use of ammonium persulfate (APS) instead of FeCl₃ as oxidant largely increased the actual PANI content, conductivity and specific capacitance of the PANI/GNP composites. The dopant DBSA increased the conductivity of the PANI/GNP composites but did not show a positive effect on the electrochemical behavior. The cyclic voltammograms of the PANI/GNP composites indicated that the pseudocapacitance of PANI contributes more than the electrical double‐layer capacitance of GNP to the capacitance of the composites, while the presence of GNP plays an essential role in the rate capability of the composites. In this study, PANI/GNP (1:1) composite synthesized with an APS to aniline molar ratio of 1 showed a balanced combination of high specific capacitance (180.5 F g^?1 at 20 mV s^?1) and good rate capability (78% retention at 100 mV s^?1). © 2018 Society of Chemical Industry     

Synthesis and characterization of water‐soluble conducting polyaniline by enzyme catalysis

Enzymatic synthesis of a water‐soluble, conducting polyaniline (PANI) was studied, using horseradish peroxidase as the biocatalyst and H₂O₂ as the initiator, in the presence of a poly(vinylsulfonic acid, sodium salt) (PVS) polyanion template. The effects of the buffer, concentration of H₂O₂, and the molar ratio of aniline to PVS on the polymerization were particularly investigated. The products were characterized by UV–vis/near‐IR and FTIR spectroscopy, thermogravimetric analysis, and four‐point probe conductivity measurement. The results showed that PVS could be chosen as a new template in the synthesis of PANI. The proper conditions of polymerization were obtained as follows: pH of the buffer was pH 4.0–5.0, the concentration of H₂O₂ was around 20 mM, and the molar ratio of PVS to aniline was 1–1.5. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 814–817, 2005     

Electrochemical behaviour and electrochemical polymerization of fluoro‐substituted anilines

The electrochemical behaviour of three fluoro‐substituted aniline monomers, 2‐fluoroaniline (2FAN), 3‐fluoroaniline (3FAN) and 4‐fluoroaniline (4FAN), was investigated in aqueous acidic and organic media by means of cyclic voltammetry (CV) studies. Constant potential electrolysis (CPE) of the monomers in acetonitrile–water mixture (1:1 by volume) using NaClO₄ as supporting electrolyte yielded soluble polymers. The mechanism of electrochemical polymerization was investigated using in situ electron spin resonance (ESR) and in situ UV–VIS spectroscopic techniques for one of the monomers (4FAN). Both CV and in situ UV–VIS measurements indicated that the polymers obtained are in the emeraldine base form. In situ ESR studies indicated that electrochemical polymerization involves a radical‐cation as an intermediate. Characterization of polymer products have been carried out using FTIR and NMR spectroscopic techniques, and thermal behaviour was studied using differential scanning calorimetry (DSC). It was found that conductivity can be imparted to as‐synthesized polyfluoroanilines via iodine doping. © 2002 Society of Chemical Industry     

C?C Bond Formation via C?H Activation and C?N Bond Formation via Oxidative Amination Catalyzed by Palladium‐ Polyoxometalate Nanomaterials Using Dioxygen as the Terminal Oxidant

An efficient heterogeneous palladium‐polyoxometalate catalyst with the formula Pd‐H₆PV₃Mo₉O₄₀/C has been successfully developed for carbon‐carbon (C C) bond formation via carbon‐hydrogen (C H) activation and carbon‐nitrogen (C N) bond formation via oxidative amination using oxygen as the terminal oxidant. The coupling processes are simple, and use relatively mild conditions to form the desired products. In addition, less waste is generated as no additional reagents such as organic/inorganic oxidants are required, and water is the only by‐product generated.     

Synthesis and characterization of N‐ and O‐alkylated poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline]

Poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline] was synthesized in an aqueous hydrochloric acid medium with a determined feed ratio by chemical oxidative polymerization. This polymer was used as a functional conducting polymer intermediate because of its side‐group reactivity. To synthesize the alkyl‐substituted copolymer, the initial copolymer was reacted with NaH to obtain the N‐ and O‐anionic copolymer after the reaction with octadecyl bromide to prepare the octadecyl‐substituted polymer. The microstructure of the obtained polymers was characterized by Fourier transform infrared spectroscopy, ¹H‐NMR, and X‐ray diffraction. The thermal behavior of the polymers was investigated by thermogravimetric analysis and differential scanning calorimetry. The morphology of obtained copolymers was studied by scanning electron microscopy. The cyclic voltammetry investigation showed the electroactivity of poly [aniline‐co‐N‐(2‐hydroxyethyl) aniline] and N and O‐alkylated poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline]. The conductivities of the polymers were 5 × 10^?5 S/cm for poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline] and 5 ×10^?7 S/cm for the octadecyl‐substituted copolymer. The conductivity measurements were performed with a four‐point probe method. The solubility of the initial copolymer in common organic solvents such as N‐methyl‐2‐pyrrolidone and dimethylformamide was greater than polyaniline. The alkylated copolymer was mainly soluble in nonpolar solvents such as n‐hexane and cyclohexane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Manipulation of polymer layer characteristics by electrochemical polymerization from mixtures of aniline and ortho‐phenylenediamine monomers

The influence of adding ortho‐phenylenediamine (OPDA) during the polymerization of aniline on the characteristics of the resulting polymer film was examined. When using a platinum electrode, the deposits were obtained from solutions containing 0.1 mol dm^?3 aniline and 1, 5, or 10 mmol dm^?3 OPDA. The deposits were also prepared from solutions containing 0.5 mol dm^?3 aniline and 5, 10, or 50 mmol dm^?3 OPDA. In both cases, 3 mol dm^?3 phosphoric acid solution was used as a supporting electrolyte. The characteristics of the obtained layers were investigated through the catalytic effect of different polymer layers on hydroquinone/quinone (H₂Q/Q) test redox system. The results obtained confirm the earlier established catalytic effect on the potential of the redox reaction by shifting it to more reversible values. However, as the concentration of OPDA was increased, the resulting limiting current decreased, thus indicating in the presence of OPDA a lower population of the available active centers necessary for the catalytic reaction to proceed. The influence of OPDA on polymer characteristics was also studied by using scanning electron microscopy as well as electrochemical impedance spectroscopy. The polymer was synthesized on a stainless steel electrode (13% Cr) from a solution containing 0.5 mol dm^?3 aniline and 5, 10, or 50 mmol dm^?3 OPDA. The layers were tested in chloride‐containing solutions by monitoring the open circuit potential. The results obtained suggest that, by increasing the concentration of OPDA, the time of OCP in the passive region of stainless steel is prolonged. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis,characterization, and thermal stability of azomethine oligomer and its metal complexes

The oxidative polycondensation reaction conditions of N,N′‐bis[(2‐hydroxy‐1‐naphthyl)methylene]urea (2‐HNMU) has been accomplished using NaOCl, H₂O₂, and air O₂ oxidants in an aqueous alkaline medium. The structures of the obtained monomer and oligomer were confirmed by FTIR, UV–vis, ¹H NMR, ¹³C NMR, and elemental analysis. The characterization was made by TG‐DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yield of oligo‐N,N′‐bis[(2‐hydroxy‐1‐naphthyl)methylene]urea (O‐2‐HNMU) was found to be 95% (for air O₂ oxidant), 51% (for H₂O₂ oxidant), 96% (for NaOCl oxidant). According to the SEC analysis, the number‐average molecular weight (M_n), weight‐average molecular weight (M_w), and polydispersity index values of O‐2‐HNMU was found to be 1036, 1225 g/mol, and 1.182, respectively, using H₂O₂, and 765, 1080 g/mol, and 1.412, respectively, using air O₂, and 857, 1105 g/mol, and 1.289, respectively, using NaOCl. TG‐DTA analyses showed that O‐2‐HNMU was more stable than 2‐HNMU. According to TG analyses, the carbonaceous residue of 2‐HNMU and O‐2‐HNMU was found to be 0.49% and 2.11% at 1000°C, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Ultrathin electrospun PANI nanofibers for neuronal tissue engineering

N‐(4‐aminophenyl)aniline oxidative polymerization is optimized to produce polyaniline (PANI) free from carcinogenic and/or polluting coproducts. The resulting polymer is electrospun using polymethyl methacrylate (PMMA) as the supporting polymer, with different weight ratios (1:0, 4:1, 3:1, 2:1, 1:1, and 0.5:1 w/w PANI/PMMA). By rinsing with a selective solvent, PMMA is removed while maintaining the fibrous morphology. Ultrathin (65 ± 14 nm) and defect‐free PANI nanofiber mats are obtained for the blend containing a high relative content of PANI (2:1 w/w, namely F_2:1). Two different solvents are tested to remove PMMA, namely acetone and isopropanol, the former giving better results, as highlighted by infrared spectroscopy (FTIR). X‐ray diffraction (XRD) demonstrates that the electrospun PANI is amorphous. The thin fiber mats are robust and sterilization both by autoclave and UV irradiation can be carried out. UV irradiation is preferred since no modification of the fibrous morphology is detectable. In vitro biocompatibility of the electrospun F_2:1 fibers has been evaluated with SH‐SY5Y neuronal‐like cells. Indirect cytocompatibility tests show that no cytotoxic leachable is released by the electrospun mats at both short and longer times, while direct cytocompatibility investigations indicate that only F_2:1 fibers washed in isopropanol do not reduce cell proliferation rate with respect to controls on tissue culture plates. Globally, these results suggest that the proposed electrospun nanostructures are promising materials for neuronal tissue engineering. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43885.     

Synthesis of soluble and thermally stable polyamides from diamine containing (quinolin‐8‐yloxy) aniline pendant group

A novel diamine monomer having pendant 4‐(quinolin‐8‐yloxy) aniline group was successfully synthesized via aromatic substitution reaction of 8‐quinolinol with p‐fluoronitrobenzene followed by Pd/C catalyzed hydrazine reduction, amidation reaction between 4‐(quinolin‐8‐yloxy) aniline and 3,5‐dinitrobenzoylcholoride followed by Pd/C catalyzed hydrazine reduction. The diamine monomer was fully characterized by using FTIR, ¹H‐NMR, ¹³C‐NMR, and elemental analysis. The diamine monomer was polymerized with various aromatic and aliphatic dicarboxylic acids to obtain the corresponding polyamides. The polyamides had inherent viscosity in the range of 0.30–0.41 dL/g and exhibited excellent solubility in the polar aprotic solvents such as DMAc, NMP, N,N‐dimethylformamide, Pyridine, and DMSO. The glass transition temperatures (T_g) of the polymers are high (up to 313°C) and the decomposition temperatures (T_i) range between 200 and 370°C, depending on the diacids residue in the polymers backbone. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

On the kinetics of the autoxidation of fats: influence of pro‐oxidants,antioxidants and synergists

The influence of minor amounts of pro‐ and anti‐oxidants on the kinetics of the autoxidation of fat has been evaluated. The reaction rates of oxygen with the substrates were found to follow the same basic equation, hitherto established for pure substrates. There is evidence that the surface of the reaction vessel also acts as a reaction catalyst and its effect is proportional to the area of glass in contact with lipids. Oxidation is enhanced by trace metal ions as well as by surface‐active compounds (e.g. hydroperoxides and sterols). Antioxidants such as α‐tocopherol and butylated hydroxyanisole inhibit the oxidation by delaying the start of oxygen consumption (the induction period) while retarders like amino acids only decrease the rate of oxidation. Thus pro‐ and anti‐ oxidants affect either the start or the rate of oxygen consumption. The empirical formula dx/dt = k [O₂] (1‐x/n) f′(t) was found applicable to the different stages of oxidation.     

Electrical conductivity and thermal properties of poly(m‐aminophenyl acetic acid) and its copolymers with aniline

Poly(m‐aminophenyl acetic acid) was synthesized under different conditions from the respective monomer, using ammonium persulfate as oxidizing agent in both the presence and the absence of CuCl₂ in HCl(aq). Moreover, the copolymers between aniline and m‐aminophenyl acetic acid were prepared at several feed mol ratios (f₁) of aniline. Copper was introduced by the Batch method in the homo‐ and copolymers of different compositions. The polymers were characterized by FTIR and UV‐vis spectroscopy, elemental analysis, thermal analysis, and electrical conductivity. The thermal stability and the content of copper increased as the content of aniline was increased in the copolymers. Moreover, the copolymers showed a high thermal stability; at 400°C a weight loss < 10% was observed. The electrical conductivity was increased with a higher content of aniline in the copolymers, achieving semiconduction values. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1484–1492, 2003     

Electrochemical polymerization and characterization of polyether‐substituted aniline derivatives

New compounds consisting of aniline units linked by polyether bridges have been synthesized and their electrochemical polymerization was performed via constant potential electrolysis and cyclic voltammetry in an aqueous solution containing 3.0 mol L^?1 H₂SO₄. Chemical polymerization was carried out using (NH₄)₂S₂O₈ as oxidizing agent. It was found that both methods gave the same polymer product without any cleavage of the polyether bridge between aniline rings. The polymers were characterized using the Fourier transform infrared spectroscopic technique and the thermal behavior of electrochemically prepared polymers was investigated using thermogravimetric analysis. Spectroelectrochemical properties of the films were investigated using the in situ UV‐visible spectroscopic technique. Copyright © 2007 Society of Chemical Industry     

Selective catalytic oxidation of aniline to azoxybenzene over titanium silicate molecular sieves

The oxidation of aniline using aqueous H₂O₂ and titanium silicates, TS-1 and TS-2 as catalysts was carried out in a batch reactor in the temperature range 333–353 K. TS-1 catalyzes aniline selectively to azoxybenzene and is superior to TS-2. The influence of different solvents, concentration of H₂O₂ and the catalyst in the reaction mixture on the conversion and product distribution has been studied. Acetonitrile is a suitable solvent in this reaction, while acetone is not. For the TS-1 catalyzed oxidation reaction,t-butyl hydroperoxide is not a suitable oxidant. At optimum conditions, a H₂O₂ efficiency of about 100% for aniline conversion is obtained with a selectivity of 97% to azoxybenzene in the product.     

Self‐assembled centimetre‐sized rods obtained in the oxidation of o‐phenylenediamine and aniline

Morphologically well‐defined rods of approximately 1 cm in length are effectively and economically obtained by mixing ortho‐phenylenediamine (30 mmol L^?1) with ammonium persulfate (12.5 mmol L^?1) in an acidic solution (0.37 mol L^?1 HCl) at room temperature with and without the presence of 50 mmol L^?1 aniline. These self‐assembled, morphologically uniform products can be potentially scaled up and used as morphological templates to fabricate well‐defined structures of other materials such as conducting polymers. The products were characterized using Raman, UV‐visible, high‐resolution NMR (¹H and ¹³C) and mass spectroscopies, X‐ray diffraction, scanning electron microscopy and elemental analysis. Apart from certain differences in visual appearance and in X‐ray diffractograms, other analytical data suggest that there are no structural changes upon addition of aniline into the reaction mixture. NMR and mass spectra imply that all syntheses carried out either with or without aniline result in a mixture of two products, attributed to 2,3‐phenazinediamine and 3‐aminophenazin‐2‐ol. A formation mechanism based on hydrogen bonding and π–π stacking has been proposed. © 2015 Society of Chemical Industry     

Aniline and some of its derivatives as corrosion inhibitors for nickel in 1 M HCl solution

The inhibiting action of aniline and some of its derivatives (o‐, m‐ and p‐anisidine) towards the corrosion behaviour of nickel in 1 M HCl solution has been studied using weight loss and polarization techniques. These compounds were found to retard the corrosion rate of nickel. At constant temperature, the corrosion rate decreases with increasing inhibitor concentration. On the other hand, at any inhibitor concentration, the increase in temperature leads to an increase in the corrosion rate. The activation energy, ΔE_a, the equilibrium constant, k, as well as the other thermodynamic parameters (ΔG, ΔH and ΔS) for inhibitor process were calculated and analysed. The inhibitor efficiencies calculated from both weight loss and polarization methods are in good agreement and were found to be in the order: p‐anisidine > o‐anisidine > m‐anisidine > aniline. The inhibitive action of these compounds was attributed to the adsorption of molecular species and their inhibitive efficiencies depend on the relative position of the  OCH₃ group in the aniline ring. © 1999 Society of Chemical Industry     

Preparation and characterization of core‐shell polystyrene/polyaniline/Pd composites and their catalytic properties for the reduction of 4‐nitrophenol

Herein, polystyrene/polyaniline/Pd (PS/PANI/Pd) core‐shell composite catalysts were prepared by a facile swelling‐diffusion‐interfacial polymerization method. PS microparticles were firstly prepared by dispersion polymerization and were swollen by aniline monomer without any surface modification. H₂PdCl₄ acid was used as palladium precursor. The was adsorbed on the surface of aniline‐swollen PS microparticles because of the electrostatic attraction between and anilinium positive ions protonated by H⁺, which was diffused from the aniline‐swollen PS microparticles. Then HCl solution was added to control the diffusion rate of anilinium positive ions and ammonium persulfate (APS) was used to polymerize the anilinium ions to get PANI shell. Due to the redox activity between PANI and Pd ions, Pd nanoparticles can be in situ formed on the surfaces of PS. Therefore, the core‐shell PS/PANI/Pd composite catalysts were obtained. The morphology and structure of the obtained composites was characterized by TEM, FT‐IR and EDX. Results showed that the products presented excellent catalytic properties for the reduction of 4‐nitrophenol (4‐NP) to 4‐aminophenol (4‐AP) in the presence of NaBH₄ by virtue of the interaction between Pd nanoparticles and conducive PANI shell. The catalytic reaction obeyed the pseudo‐first‐order reaction equations and the reaction rate constants were also calculated in this article. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44812.