Terephtalic Acid Research Articles

Treatment of Wastewater from Purified Terephtalic Acid (PTA) Production in a Two-stage Anaerobic Expanded Granular Sludge Bed System

ABSTRACT The wastewater treatment with a two-phase expanded granular sludge bed (EGSB) system for anaerobic degradation of acetate, benzoate, terephtalate and p -toluate from purified terephtalic acid (PTA) production was studied. The feasibility and effectiveness of the system was evaluated in terms of organic oxidation by chemical oxygen demand (COD), gas production, bacterial adaptability and stability in the granular sludge. Average removal efficiencies 93.5% and 72.7% were achieved in the EGSB reactors under volumetric loading rates of 1.0–15 kg-COD/m 3 /day and terephtalate and p -toluate of 351–526 mg/L, respectively. Gas production reached total methane production rate of 0.30 L/g-COD under these conditions in the sequential EGSB reactor system. Higher strength influent COD concentration above 4.8 g-COD/L related to field conditions was fed to observe the disturbance of the EGSB reactors. Keywords: Anaerobic treatment, Expanded granular sludge bed (EGSB), Purified terephtalic acid (PTA), Two-phase, Wastewater

Mesoporous Pt-TiO2 thin films: Photocatalytic efficiency under UV and visible light

The preparation, characterization, and photoactivity of mesoporous Pt-TiO2 thin films were investigated. Titania based thin films were prepared by evaporation induced self assembly (EISA) process, Pt being introduced by a non-photochemical process via two different ways. Whatever the synthesis method and the Pt content (between 0.5% and 3%), the prepared films were thin (around 200nm) and mesoporous with an average pore size of 5nm. XPS surface analysis showed that Pt was present in different oxidation states: mainly Pt0 but also Pt2+ and Pt4+. The presence of Pt0 nanoparticles was also clearly evidenced by Transmission Electronic Microscopy. The photocatalytic efficiency of the mesoporous titania films was determined by two different tests under both UV and visible light: the reaction rates and photonic efficiencies were determined for the mineralization of stearic acid (SA) at the gas–solid interface and for the solid–liquid photobleaching of Methylene Blue (MB). In all the cases, Pt-doped titania films were less active than pure TiO2 films under UV light and slightly more active under visible light. Preliminary results on the HO production on the surface of the films were obtained from the reaction of a specific probe (terephtalic acid, TA) in basic aqueous solutions. These results were discussed relative to literature data.

FRI0511 Global metabolite profiling of synovial fluids from different forms of inflammatory arthritis for the identification of putative biomarker in rheumatoid arthritis

BackgroundMetabolomics is the study of unique chemical fingerprints of specific cellular processes. Metabolite profiling is recently applied in identifying biomarkers in medical research including rheumatologic diseases.ObjectivesThe aim is to assess...

Crystal structure of layered metal-organic coordination polymers based on trinuclear zinc carboxylates: [Zn3(DMA)2(bpdc)3]·3DMA and [Zn3(im)2(bdc)3]·1.5H2O

New layered metal-organic coordination polymers [Zn3(bpdc)3(DMA)2]·3DMA (1) (H2bpdc = 4,4′-biphenyldicaboxylic acid, DMA = N,N′-dimethylacetamide) and [Zn3(bdc)3(im)2]·1.5H2O (2) (H2bdc = terephtalic acid, im = imidazole) are synthesized and characterized by X-ray crystallography.

Effects of diamond-FET-based RNA aptamer sensing for detection of real sample of HIV-1 Tat protein

Diamond is a promising material for merging solid-state and biological systems owing to its chemical stability, low background current, wide potential window and biocompatibility. The effects of surface charge density on human immunodeficiency virus type 1 Trans-activator transcription (HIV-1 Tat) protein binding have been investigated on a diamond field-effect transistor (FET) using ribonucleic acid (RNA) aptamers as a sensing element on a solid surface. A change in the gate potential of 91.6mV was observed, whereby a shift in the negative direction was observed at a source-drain current of −8μA in the presence of HIV-1 Tat protein bound to the RNA aptamers. Moreover, the reversible change in gate potential caused by the binding and regeneration cycles was very stable throughout cyclical detections. The stable immobilization is achieved via RNA aptamers covalently bonded to the carboxyl-terminated terephtalic acids on amine sites, thereby increasing the sensitivity of the HIV-1 Tat protein sensor. The reliable use of a real sample of HIV-1 Tat protein by an aptamer-FET was demonstrated for the first time, which showed the potential of diamond biointerfaces in clinical biosensor applications.

Stress-strain relation in the collapse of Langmuir monolayer of a dimer of disk shaped moiety

Langmuir monolayer of a novel molecule containing dimer of disk shaped moiety, viz., terephtalic acid bis-[6-(3,6,7,10,11-pentahexyloxy-triphenylen-2-yloxyl)-hexyl] ester (tp-dimer), was studied at air-water interface. The monolayer of the tp-dimer at air-water interface exhibited the coexistence of condensed and gas phases at large area per molecule which on compression transformed to a uniform condensed phase at lower area per molecule (1.80 nm(2)) and then collapsed at 1.67 nm(2). The monolayer film transferred by Langmuir-Blodgett technique onto a hydrophilic silicon substrate was studied using an atomic force microscope. The topography image showed the film to be of height of about 1.5 nm corresponding to the edge-on configuration of the triphenylene moieties. We have studied the collapse of monolayer at air-water interface as a function of compression rate and temperature. We find that the collapse pressure increased with increase in the compression rate. The surface pressure of the monolayer is considered as stress and compression as strain. The strain rate is related to the collapse pressure by a power law similar to that found in the dendrimers. Our studies on the effect of temperature on the collapse pressure of tp-dimer monolayer showed that the collapse pressure decreased with increase in temperature. We have considered the Arrhenius temperature dependence of the strain rate and calculated the activation energy for the collapse of monolayer. Our analysis of the relative area loss as a function of time in the collapse region suggests that the monolayer collapses by the formation of nuclei of three-dimensional crystallites.

Pyrolysis Process Of Waste Polyethyleneterephtalate

Polyethyleneterephtalate (PET) is one of the most popular plastic materials used for various purposes, mainly for producing of bottles. Recycling of this material is known, but the ratio of recycled material is too low. With the lowering of primary resources, the PET could be used as a secondary source of carbon and hydrocarbons. One of the ways of processing the waste PET is pyrolysis under the specific conditions, which leads to decomposition of this material with two main products. First, it is a mixture of organic acids – terephtalic acid and benzoic acid with a ratio about 10:1. Those acids can be used in the chemical industry; terephtalic acid can be used for producing of brand-new PET. The second product is solid carbon, which can be used for various purposes, for example as the active carbon. Several experiments were accomplished with this carbon material under various conditions of its activation. Conditions of these experiments could affect the specific surface area of active carbon up to 1200 square meters per gram, and also the pore volume as well as the pore diameter.

Thermal Properties and Crystallinity of Thermotropic Liquid Crystalline Copolyesters Prepared from Poly(ethylene terephtalate) (PET) and Rigid Aromatic Units

A series of copolyesters were synthesized by melt‐polycondensation reaction of poly(ethylene terephtalate) (PET) with various proportions of equimolar compositions of p‐acetoxybenzoic acid (p‐ABA), hydroquinone diacetate (HQDA) and terephtalic acid (TPA). Viscosity, liquid crystallinity, thermal properties, degree of crystallinity and thermal stabilitiy of these copolyesters were investigated by Ubbelohde viscometer, hot‐stage polarized light microscopy (PLM), differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD) and thermogravimetric analysis (TGA), respectively. On the basis of viscosity measurement, it was observed that intrinsic viscosity values of the copolyesters are increased regularly with increasing amounts of aromatic units (p‐ABA, HQDA and TPA) in the polymer chain. Thermotropic liquid crystalline behavior was observed in the copolyesters containing over 50 mol% of rigid p‐ABA/HQDA/TPA aromatic units. DSC analysis of the anisotropic copolyesters revealed broad and weak endotherms associated with the nematic phases, and the melting temperatures were found to be in the processable region. As the mol% of PET in the polymer chain increased, the specific enthalpies of fusion and the degree of crystallinity of the copolyesters were also increased regularly.

Influence of acids on the reaction rate of transesterification of dimethyl terephthalate

The reaction rate of transesterification of dimethyl terephtalate by ethylene glycol was investigated in the presence of some organic acids. The reaction rate decreased only slightly in the presence of monocarboxylic acids, usually forming anions of used catalysts; however the decreasing reaciton rate is very strong in presence of dicarboxylic acids. These acids can be present in ethylene glycol (oxalic acid), dimethyl terephtalate (terephtalic acid), or in any modifier. The monoester of terephtalic acid has a similar influence. The decrease of rate constant of a second order reaction during the reaction can be explained by the forming of carboxylic groups in the transesterification.

Occupational exposure to low levels of organic and inorganic substances in a chemical plant for the production of terephtalic acid dimethyl ester

The aim of our study was the evaluation of personal exposure to chemical pollutants in workers employed in a plant for the production of terephtalic acid dimethyl ester. Chemical agents have been included in the monitoring program on the basis of the industrial process. In the plant, the oxidation of p-xylene is performed by air and the resulting acid is esterified with methyl alcohol. Purified terephtalic acid dimethyl ester is then utilized for the production of polyethylene terephtalate. The environmental monitoring included terephtalic acid dimethyl ester, p-toluic acid methyl ester, terephtalic acid, p-xylene, methylacetate, methylbenzoate, formic acid, acetic acid, methanol, and the catalysts cobalt acetate and manganese (II) acetate tetrahydrate. Personal exposure to the cited airborne substances was performed in the breathing zone of six workers. Air samplings were carried out by drawing air through glass fibre filters (terephtalic acid dimethyl ester, p-toluic acid methyl ester and terephtalic acid aerosols), by active adsorption (methanol, formic and acetic acids vapours). p-Xylene, methylacetate and methylbenzoate vapours were collected by passive sampling. Cellulose nitrate filters were used for cobalt and manganese salts samplings. Analyses were performed by UV detection high-performance liquid chromatography (terephtalic acid dimethyl ester, p-toluic acid methyl ester and terephtalic acid), flame ionization detection gas chromatography ( p-xylene, acetic acid methyl ester and benzoic acid methyl ester), ion chromatography (formic and acetic acids) and inductively coupled plasma-mass spectrometry (cobalt and manganese). The results were evaluated according to the threshold limit values (TLVs) of the American Conference of Governmental Industrial Hygienists (ACGIH) and indicated that the environmental levels of the workplace pollutants were well below the threshold limit values-time weighed average (TLV-TWA) adopted by the American Conference of Governmental Industrial Hygienists for 2002, although for three substances the TLVs were not available.

The effect of plastic addition on coal caking properties during carbonization ☆

The recycling process of waste plastics using coke ovens is now being studied. The effect of plastic addition on coal caking property was investigated. It was revealed that thermal decomposition products of plastics interacted with bituminous coal during carbonization in coke ovens. The effect of plastic addition on coal caking property varied with types of plastics. The addition of aliphatic polymers such as polyethylene (PE), polypropylene (PP) and poly(vinyl chloride) (PVC) had only a small effect on coal caking property and coke strength and in some cases PE addition increased coke strength. On the other hand, the addition of polystyrene (PS), poly(ethylene terephthalate) (PET) and terephtalic acid (TFA) inhibited coal expansion and fusion, decreased maximum fluidity and total dilatation, and deteriorated the coke strength. These differences were discussed from the viewpoint of the interaction between thermal decomposition products of plastics and hydrogen in coal. It was suggested that the radical formed as a result of PS or PET thermal decomposition abstracted hydrogen from coal, which resulted in the decrease in coal caking property.

石炭粘結性に及ぼすプラスチック添加の影響

The recycling process of waste plastics using coke ovens is now being studied. The effect of plastic addition on coal caking property was investigated. Thermal decomposition products of plastics interacted with coal during carbonization and the effect of plastic addition on coal caking property varied for kinds of plastics. The addition of polyethylene (PE), polypropylene (PP) and poly vinyl chloride (PVC) had little effect on coal caking property and coke strength. On the other hand, the addition of polystyrene (PS), polyethylene terephthalate (PET) and terephtalic acid (TFA) decreased the maximum fluidity and total dilatation, and deteriorated the coke strength. These differences were explained by the interaction between thermally decomposed products from plastics and coal. It is suggested that the radical formed as a result of PS or PET thermal decomposition may abstract hydrogen from coal, resulting in the decrease in coal caking property.

Simulation of an industrial wastewater treatment plant using artificial neural networks

This work presents a way to predict the environmental properties of the output stream from the wastewater treatment plant at Rhodiaco Ltda, one of the major chemical plants in Brazil. The industrial plant produces purified terephtalic acid and generates wastewater that should be treated in an activated sludge system. The influence of input variables is analyzed, and satisfactory predicted results are obtained for an optimized situation.

Carboxylic Acids of Moroccan Pinus Pinaster Bark Extract

Summary In this work, carboxylic acids of the Moroccan Pinus pinaster bark were studied and analysed by High Performance Liquid Chromatography (HPLC), Thin Layer Chromatography (TLC) and Gas Chromatography coupled with Mass Spectrometry (GC-MS). Several acids, such as gallic, p-hydroxyphenylacetic, 3,4-dihydroxyphenylacetic, salicylic, shikimic, protocatechuic, terephtalic, ferulic, p-coumaric, vanillic, caffeic and isovanillic acids, were detected by direct injection of standard products and by studying the mass spectrum of their trimethylsilyl derivatives.

Comparison of isotropic and anisotropic sensor effects in polymer lightguides

A method for measuring the effective birefringence of polymer lightguides is shown to be a useful tool for chemical sensors. It is demonstrated that the method can be either the nonlinear response of an initially anisotropic lightguide on a linear effect of an in-diffusing compound or a stress induced birefringence in an initially isotropic polymer film. The samples used were polyimide for the anisotropic case and the allyl polymer poly(diallylic terephtalic acid) for the isotropic material.

Genotoxicity tests on the compounds of polyethylene glycol terephthalate (PET): dimethylterephthalate (DMT) and terephtalic acid (TPA)

Dimethylterephthalate (DMT) and terephtalic acid (TPA), the main compounds of polyethylene glycol terephthalate (PET) were evaluated for genotoxicity and mutagenicity in the Ames test, UDS by liquid scintillation counting, and micronuclei induced in binucleate human lymphocytes. Data failed to show that DMT and TPA at different concentrations (0.5, 5, 50 and 500 ug ml‐1 ) had any genotoxic and or mutagenic effects. Further research should be carried on so that in vivo genotoxic properties of the PET precursors can be determined.

Small Angle Light Scattering Studies on Bisphenol Series Thermotropic Liquid Crystalline Wholly Aromatic Polymers

The average domain sizes in sheared nematic mesophases for aromatic copolyesters based on terephtalic acid, isophtalic acid, p-hydroxybenzoic acid and one of the following bisphenols: 4,4'-dihydroxydiphenyl methane, bisphenol A or 4,4'-dihydroxydiphenyl sulfone. A consistent result was obtained between the steric effect of the bridge groups in the bisphenols and the domain sizes

Copolyesters. VII. Thermal transitions of poly(butylene terephthalate‐co‐isophthalate‐co‐adipate)s

AbstractThe copolyesters of 1,4‐butanediol, terephthalic acid, isophthalic acid, and adipic acid with different compositions were prepared by melt polycondensation. The intrinisic viscosity of the copolyesters was controlled to be about 0.7–1.0 dL/g. Their second‐run thermal properties were determined by DSC. The composition was found to be a major factor in the determination of the thermal transitions. The effect of the composition on the glass transition temperature and melt transition temperature was interesting. The glass transition temperature was found to be dependent mainly on the content of adipic acid. As the content of adipic acid increased, the glass transition decreased. When the content of terephthalic acid was not less than 35 mol % based on the total diacid monomers, the melting temperature was dependent mainly on the content of terephtalic acid and increased with incrase of the content of terephthalic acid. When the content of terephthalic acid was less than 35 mol %, the melt temperature of the copolyesters did not follow a simple rule. However, the effect of the composition on their melting enthalpy showed no simple trend. © 1994 John Wiley & Sons, Inc.

Polymerization kinetics of poly(p-phenylene-cis-benzobisoxazole)

The kinetics of polycondensation of terephtalic acid with diaminoresorcinol in the nematic phase appear to be independent of molecular weight, in good agreement with Flory's equal reactivity hypothesis. The results suggest that, for well-mixed reactive mixtures, translational diffusion does not appear to control the polymerization rates

Polycondensation in the presence of a filler as a new way to create polymer multicomponent systems with prespecified properties

The effects of an antifriction filler (graphite and molybdenum disulfide) on the low temperature polycondensation of bis[4-oxy-3-(chlorophenyl)]-2,2'-propane with terephtalic acid dichloride was studied. The filler was found to determine the kinetic parameters of the reaction, the molecular weight and the microstructure of the polymers as well as the properties of the composites produced