Trimellitic Acids Research Articles

Primary and secondary organic aerosol in an urban/industrial site: Sources, health implications and the role of plastic enriched waste burning

PM10 samples were collected from an urban/industrial site nearby Athens, where uncontrolled burning activities occur. PAHs, monocarboxylic, dicarboxylic, hydroxycarboxylic and aromatic acids, tracers from BVOC oxidation, biomass burning tracers and bisphenol A were determined. PAH, monocarboxylic acids, biomass burning tracers and bisphenol A were increased during autumn/winter, while BSOA tracers, dicarboxylic- and hydroxycarboxylic acids during summer. Regarding aromatic acids, different sources and formation mechanisms were indicated as benzoic, phthalic and trimellitic acids were peaked during summer whereas p-toluic, isophthalic and terephthalic were more abundant during autumn/winter. The Benzo[a]pyrene-equivalent carcinogenic power, carcinogenic and mutagenic activities were calculated showing significant (p < 0.05) increases during the colder months. Palmitic, succinic and malic acids were the most abundant monocarboxylic, dicarboxylic and hydrocarboxylic acids during the entire sampling period. Isoprene oxidation was the most significant contributor to BSOA as the isoprene-SOA compounds were two times more abundant than the pinene-SOA (13.4 ± 12.3 and 6.1 ± 2.9 ng/m3, respectively). Ozone has significant impact on the formation of many studied compounds showing significant correlations with: isoprene-SOA (r = 0.77), hydrocarboxylic acids (r = 0.69), pinene-SOA (r = 0.63),dicarboxylic acids (r = 0.58), and the sum of phthalic, benzoic and trimellitic acids (r = 0.44). PCA demonstrated five factors that could explain sources including plastic enriched waste burning (30.8%), oxidation of unsaturated fatty acids (23.0%), vehicle missions and cooking (9.2%), biomass burning (7.7%) and oxidation of VOCs (5.8%). The results highlight the significant contribution of plastic waste uncontrolled burning to the overall air quality degradation.

Mild oxidative degradation of spent auricularia auricular substrate and molecular composition of carboxylic acids in the resulting soluble portion

Spent auricularia auricular substrate (SAAS) was oxidatively degraded with aqueous hydrogen peroxide (AHPO)/acetic anhydride (AAH) to produce carboxylic acids (CAs) under mild conditions. The results show that up to 53.6% of the organic matter in SAAS was converted to the soluble species (SSs). In total 122 CAs were detected in the SSs by the analysis with a gas chromatograph/mass spectrometer, which can be classified into 29 group components, mainly being aliphatic acids and along with small amount of aromatic acids. Among the aliphatic acids, normal alkanedioic acids are the most abundant. The detected aromatic acids include benzoic acids, phthalic acids, trimellitic acids, pyromellitic acids, and their derivatives. The synergistic oxidation and the released OH, CH 3 COO , and HOO induced by AHPO/AAH play crucial roles in oxidatively degrading SAAS. • SAAS can be degraded to produce CAs, which consists of aliphatic acids and aromatic acids. • Aliphatic acids represent the predominant species, and NADAs are the most abundant. • AHPO/AAH ratio and temperature have impact on the composition and yield of CAs. • OH, CH 3 COO , and HOO play crucial roles in the SAAS oxidative degradation.

Gd3+ Adsorption over Carboxylic- and Amino-Group Dual-Functionalized UiO-66

Owing to the growing industrial demand worldwide and limited mineral deposits, the recovery of low-concentration rare earth elements (REEs) from waste sources is being considered, which also helps to reduce water pollution. In this work, the adsorption of gadolinium ions (Gd3+) in aqueous solutions over a functionalized metal–organic framework (MOF), UiO-66, was investigated. Initially, the MOF structure was synthesized solvothermally using a ligand mixture of terephthalic and trimellitic acids to produce coordination-free −COOH groups on the UiO-66 framework. Subsequently, the −COOH group was reacted with ethylenediamine to introduce additional −NH2 groups onto the MOF. The optimized product (denoted as UiO-66-COOH-ED) showed an equilibrium adsorption capacity of 79 mg/g for Gd3+ compared with 16 mg/g by pristine UiO-66. This improvement in adsorption by a factor of 4.9 was a consequence of the coordination of Gd3+ ions with the electron-abundant oxygen and nitrogen atoms of −COOH and −NH2 groups. A solu...

Electro-Fenton Degradation of Trimellitic and Pyromellitic Acids: Kinetics and Mechanism

This paper describes the application of electro-Fenton technology to decontaminate waters containing trimellitic and pyromellitic acids. In this technique, the electrogeneration of hydroxyl radicals (•OH) leads to the oxidative degradation of the benzene polycarboxylic acids until their total mineralization. The effect of the operating parameters on the trimellitic acid removal was studied. Under the optimal conditions (C0 = 2.10−4 M, [Fe2+] = 0.3 mM, I = 300 mA, [Na2SO4] = 0.05 M, pH = 3), the mineralization of pyromellitic and trimellitic acid solutions was followed by chemical organic demand (COD) measurements after 4 and 5 h of electrolysis time, respectively. The highest disappearance rate of the pyromellitic acid is due to its greater reactivity compared to the trimellitic acid towards the hydroxyl radicals. The products resulting from degradation of pyromellitic acid were identified by using UPLC/MS. The identified by-products allowed proposing a degradation pathway for the pyromellitic and trimellic acids.

A combined experimental and DFT investigation of the adsorption of humic acid by-products on polypyrrole

ABSTRACTThis study sheds light on the removal of humic acid by-products (trimellitic and pyromellitic acids; TMA and PMA, respectively) from aqueous solution using conducting polypyrrole (PPy) as an effective adsorbent. The effects of experimental factors including contact time, solution pH, initial concentration, adsorbent dose, and temperature were systematically investigated. The pseudo-second-order kinetic model provides the best correlation with adsorption experimental data. The equilibrium adsorption was well described by the Langmuir model with maximum mono-layer adsorption capacities of 47.62 and 71.43 mg g−1 for TMA and PMA, respectively. The analysis of thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic in nature. In addition, we investigated the adsorption mechanism using the density functional theory (DFT) calculations. The TMA and PMA were physisorbed on the PPy surface through the formation of hydrogen bonds between carboxylic groups of adsorbate molecules and the amino group of the adsorbent. The calculated theoretical data were in good agreement with experiments.

High-performance nanostructure chiral poly(amide–imide)s containing benzamide and amino acid linkages: Preparation, characterization and ultrasonic effect on the morphology

In this research work, several novel optically active nanostructure poly(amide–imide)s (PAIs) were synthesized from the direct polycondensation reaction of 3,5-diamino- N-(pyridin-3-yl) benzamide with chiral diacids based on trimellitic anhydride-derived dicarboxylic acids containing different natural amino acids such as l-methionine, S-valine, l-alanine and l-isoleucine in green medium consisting of molten tetrabutylammonium bromide. The diamine was synthesized by a two-step reaction. At first, 3,5-dinitro- N-(pyridin-3-yl)benzamide was prepared from the reaction of one equimolar of 3-amino pyridine and one mole of 3,5-dinitrobenzoyl chloride. In the next step, the obtained dinitro was reduced by Pd/C and hydrazine hydrate. The new thermally stable optically active PAIs with inherent viscosity ranging from 0.31 to 0.46 dL g−1 were obtained with high yield. The synthesized polymers were characterized with Fourier transform infrared, proton-nuclear magnetic resonance spectroscopy, specific rotation measurements, thermogravimetric analysis, x-ray diffraction, field emission scanning electron microscopy (FE-SEM) and elemental analysis techniques. Morphological study by FE-SEM showed that these new PAIs were noncrystalline and nanostructure polymers with particle size between 50 and 70 nm. The effect of ultrasonic radiation on the obtained nanostructured polymers showed that the size of polymeric nanoparticles was reduced to about 30–45 nm.

Pseudo-poly(amino acid)s: study on construction and characterization of novel chiral and thermally stable nanostructured poly(ester-imide)s containing different trimellitylimido-amino acid-based diacids and pyromellitoyl-tyrosine-based diol

A new class of chiral and potentially biodegradable poly(ester-imide)s (PEI)s as pseudo-poly(amino acid)s (PAA)s bearing natural amino acids in the main chain was synthesized. In this investigation, N,N′-(pyromellitoyl)-bis-(L-tyrosine dimethyl ester) as a biodegradable optically active diphenol and synthesized trimellitic anhydride-derived dicarboxylic acids containing different natural amino acids such as S-valine, L-methionine, L-leucine, L-isoleucine, and L-phenylalanine were used for direct polyesterification. With the aim of tosyl chloride/pyridine/N,N′-dimethylformamide system as a condensing agent, the new optically active PEIs were obtained in good yields and moderate inherent viscosity up to 0.42 dL/g. The obtained polymers were characterized with FT-IR, 1H-NMR, X-ray diffraction (XRD), field emission scanning electron microscopy, elemental, and thermogravimetric analysis techniques. These polymers show high solubility in organic solvents, such as N,N′-dimethyl acetamide, N-methyl-2-pyrrolidone, and sulfuric acid at room temperature, and are insoluble in solvents, such as methylene chloride, cyclohexane, and water. Morphology probes showed these pseudo-poly(amino acid)s were noncrystalline and nanostructured polymers. On the basis of thermogravimetric analysis data, such PAAs are thermally stable and can be classified as self-extinguishing polymers. In addition due to the existence of amino acids in the polymer backbones these pseudo-PAAs not only are optically active but also are expected to be biodegradable and therefore could be classified under eco-friendly polymers.

Extraction properties of phthalic acid and aromatic polycarboxylic acids using various solvents

BACKGROUND: To explore the extraction properties of aromatic acids produced in the oxidation of coal, the extraction equilibrium of phthalic acid (as a typical product) was studied using three solvents, 1-octanol, 50% tributylphosphate (TBP)/kerosene, and 10% trialkylphosphine oxide (TRPO)/kerosene, and the feasibility of separating phthalic, [1,1′-biphenyl]-2,2′-dicarboxylic and trimellitic acids is discussed. RESULTS: Phthalic acid extraction followed the sequence: 10% TRPO > 50% TBP > 1-octanol, with recoveries from the TRPO and TBP systems being much larger than that for 1-octanol. The stoichiometry of formation of the complexes of TBP and TRPO with phthalic acid was 1:1. The apparent extraction equilibrium constant for TRPO is much larger than that for TBP. The distribution coefficient of [1,1′-biphenyl]-2,2′-dicarboxylic acid is much larger than that of the other two acids using 1-octanol as the extractant and this acid could be removed by 1-octanol from a mixture of the three acids. The extraction equilibrium correlations obtained for the individual acid component systems can be used to predict that of the acid mixture. CONCLUSION: The extent of phthalic acid extraction by the three solvents investigated is as follows: 10% TRPO > 50% TBP > 1-octanol. The stoichiometry of the complex formation of TBP or TRPO and phthalic acid is 1:1, and the apparent extraction equilibrium constant for TRPO is much larger than that for TBP. 1-octanol shows a good extractive selectivity for [1,1′-biphenyl]-2,2′-dicarboxylic acid as compared with phthalic and trimellitic acids. Copyright © 2011 Society of Chemical Industry

Influence of functional groups on the adsorption behaviour of substituted benzoic acids at the α-alumina/water interface

Adsorption kinetics of hemimellitic and trimellitic acids at a fixed initial concentration of 0.30 mM onto α-alumina surfaces were carried out in batch method in the presence of 0.05 mM NaCl(aq) at pH 5 and 288.15, 298.15, 303.15, and 313.15 K. The experimental data were significantly better fitted to pseudo-second-order kinetic equation of non-linear form in the entire time duration. The state of equilibration time of benzenetricarboxylic acids at 298.15 K follows the sequence: hemimellitic acid < trimellitic acid < trimesic acid. Adsorption isotherms of hemimellitic and trimellitic acids were carried out at 298.15 K, pH 5–10, and 0.05 mM NaCl(aq) by varying acid concentration. The adsorption data were fitted to Langmuir adsorption model. Adsorption density of benzenetricarboxylic acids follows the sequence: trimesic acid < trimellitic acid < hemimellitic acid. Comparison of the adsorption densities of benzenetricarboxylic acids with dihydroxybenzoic and monohydroxybenzoic acids indicates that (i) in benzenetricarboxylic acids the position and equally the number of –COOH groups, (ii) the two phenolic –OH groups at any two position in the benzene ring of dihydroxybenzoic acids, and (iii) the phenolic –OH groups at ortho position in the benzene ring of monohydroxybenzoic acids are the governing parameters for yielding higher adsorption density onto α-alumina surface. Exception is the 2,4-dihydroxybenzoic acid amongst dihydroxybenzoic acids series, which yields highest adsorption density due to ortho and para position of the phenolic –OH groups. The thermodynamic data indicate that the adsorption process is spontaneous for both the systems. The magnitude of shifting of ν s(–COO −) and ν as(–COO −) after adsorption of trimellitic and hemimellitic acids onto α-alumina surface indicate that both acids form outer-sphere surface complexes.

Electrochemical behavior of benzenepolycarboxylic acids on solid electrodes in aqueous and mixed solutions

Electrochemical behavior of biologically active benzenepolycarboxylic (trimellitic, trimesic, pyromellitic, mellitic) acids is studied by a voltammetry method on Pt, Cu, Ta, and Cu-Hg in aqueous media and water mixtures with ethanol and pyridine. In all cases, voltammograms for the acids display waves corresponding to the discharge of hydrogen ions. In the case of Cu-Hg, voltammograms for trimellitic, trimesic, and pyromellitic acids additionally exhibit poorly pronounced prewaves. Concentrations of ionized and non-ionized forms in dilute solutions of the acids are calculated. Apparent dissociation constants K a II and K a III for mellitic acid are calculated from the voltammetry data.

Formation of 2,6-Naphthalenedicarboxylic Acid by the Co–Mn–Br-Catalyzed Autoxidation of 2,6-Diethylnaphthalene in Acetic Acid

Abstract In order to elucidate the reaction mechanism and the optimum reaction conditions for the formation of 2,6-naphthalenedicarboxylic acid (NDCA), the Co(OAc)2–Mn(OAc)2–NaBr-catalyzed oxidation of 2,6-diethylnaphthalene by molecular oxygen was carried out in acetic acid. The oxidation of the ethyl groups to carboxyl groups proceeded mainly via acetyl groups and partly via 1-hydroxyethyl and 1-acetoxyethyl groups. A synergistic catalytic effect due to Co and Mn acetates was observed not only on the rate of oxidation but also on the selective formation of NDCA. The rate of oxidation was strongly retarded at higher concentrations of the substrate, showing that the naphthalene nucleus terminates the chain reaction step of the oxidation. A high concentration of metal catalyst resulted in an increase of acetoxyethylnaphthoic acid. At the optimum reaction conditions, a nearly 90% yield of NDCA was obtained along with small amounts of substituted naphthoic and trimellitic acids. The differences in the yield of NDCA from 2,6-dimethyl, 2,6-diethyl, and 2,6-diisopropylnaphthalenes were compared under similar reaction conditions and are discussed.

Novel regular network polyester films from benezenetricarboxylic acids and glycols

AbstractNovel regular network polyester films were prepared from benzenetricarboxylic acids of trimesic (Y) and trimellitic (Z) acids, and glycols of ethylene (2G), tetramethylene (4G), and hexamethylene (6G) glycols. Prepolymers prepared by melt polycondensation for a short period within 1 h were cast from a DMF solution and successively post‐polymerized at various temperatures and times to form a network. The resultant films were transparent, flexible, and insoluble in any solvents. Distortion temperature measured by a penetration mode of thermomechanical analysis (TMA) increased with increasing post polymerization time and temperature, and leveled out at 222, 168, 125 and 75°C, for the 2GY, 2GZ, 4GY, and 6GY films, respectively. Temperatures close to 400°C at which the probe had completely penetrated corresponded to the thermal decomposition temperature of these films. Two broad but strong peaks in the x‐ray diffraction curves appears for the 2GY, 4GY, and 6GY, suggesting the formation of some ordered supramolecular structure owing to the regular network formed by symmetrical trimesic acid moiety, and the intensity of diffraction peaks became higher with increasing length of the methylene chain of the glycol monomer. Densities of the 2GY and 2GZ films decreased with increasing post‐polymerization time and temperature. Tensile strength and Young's modulus increased and elongation decreased with increasing network formation. These tensile properties was affected by the chemical structure of the network films.

Synthesis and properties of some alkyds of more complex carboxyl functionality

Syntheses are described where dimer fatty acid (C36), or anhydrides of trimellitic, or pyromellitic, or dodecenylsuccinic acids are substituted in part for components of a model polymer derived from 1 mole each phthalic anhydride and glycerol, and 0.4 mole of linoleic acid. These polymers are compared at several degrees of polyesterification with respect to endgroup analysis, melt and intrinsic viscosity, and fractionation and emulsification behavior in water-solvent mixtures. The data suggest that predictions of the gel point in terms of functionality concepts are of general value only for defining the reaction degrees where insoluble molecules can first appear. The experimental event of gelatification can be delayed to varying degrees by different types and concentrations of inert solvent. The extent of reaction where molecular complexity can give a gellable polymer in the absence of solvency retardation occurs near the theoretical gel point and can be located by inspection of functions relating either melt or intrinsic viscosity to molecular weight. Significant differences in polymer structure have a very small effect on this parameter, nor is there much evidence to show preferential reactivity of similar functional groups associated with different structures. Other data here cited demonstrate some practically useful facts regarding how composition and molecular weight affect solvency behavior; however, no general correlations were found which relate solubility behavior to quantities here miasured.