Terephthalic Acid, Dimethyl Terephthalate, and Isophthalic Acid

Sheehan, Richard J.

doi:10.1002/14356007.a26_193

Cited by 45 publications

(77 citation statements)

References 10 publications

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“…Particle size determines the flow and the handling of the crystal TPA product as well as the viscosity of the slurry when mixed with ethylene glycol. lists the quantitative TPA product specifications on impurity levels, color and particle size [42].…”

Section: Product Quality Specificationsmentioning

confidence: 99%

“…A perfectly pure TPA sample will have an acid number of 675.5 mg KOH/g, but the extremely low impurity levels make the acid number meaningless as a quantitative indication of purity, and it is being phased out [42]. c The color of TPA crystals is measured in terms of a tristimulus color scale such as the CIE L*a*b scale [43].…”

Section: Product Quality Specificationsmentioning

confidence: 99%

“…Gaseous emissions from the TPA process are mostly the oxygen-depleted air from the oxidation step [83]. Volumes are large and the vent gas contaminated with VOCs (volatile organic compounds), CO x and NO x must be cleansed via catalytic combustion followed by scrubbing to meet the most demanding regulations for process vents.…”

Section: Off-gas Treatmentmentioning

confidence: 99%

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A spray reactor concept for catalytic oxidation of p-xylene to produce high-purity terephthalic acid

Niu

Zuo

et al. 2013

Chemical Engineering Science

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Section: Product Quality Specificationsmentioning

confidence: 99%

Section: Product Quality Specificationsmentioning

confidence: 99%

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A spray reactor concept for catalytic oxidation of p-xylene to produce high-purity terephthalic acid

Niu

Zuo

et al. 2013

Chemical Engineering Science

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“…Plastics and fibers are two important classes of synthetic products, most of them deriving from highly-purified terephthalic acid (PTA) and its esters. 1 About 50% of all PTA are used to make polyester fibers for tire cord, industrial filament, and protective apparel. The fastest growing use of PTA is, however, in the synthesis of polyethylene terephthalate (PET), better known as the number "1" recyclable material used in drink containers.…”

Section: Introductionmentioning

confidence: 99%

“…2 Terephthalic acid is produced industrially by oxidation of p-xylene in acetic acid medium under the effect of a catalyst system based on Co, Mn and Br, at high temperatures ( Figure 1). 1 The oxidation is a stepwise reaction involving several intermediates, whose presence as impurities in the final product is highly dependent upon the process parameters. Several side products have been reported and classified by means of their structural features.…”

Section: Introductionmentioning

confidence: 99%

Analysis of impurities in crude and highly-purified terephthalic acid by capillary electrophoresis

Moraes¹,

Rubim²,

Realpozo³

et al. 2004

J. Braz. Chem. Soc.

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Neste trabalho, foi desenvolvido um método simples e rápido, utilizando eletroforese capilar (CE), para a análise simultânea de 4-carboxibenzaldeído (4-CBA), ácido p-toluóico (pTOL) e ácido benzóico (BZ), em lotes industriais de ácido tereftálico cru (CTA) e purificado (PTA). As condições eletroforéticas de análise foram: tampão tetraborato a 20 mmol L -1 (pH 9), injeção hidrodinâmica (5 s, 17 kPa), tensão aplicada de +30 kV e detecção direta em 200 nm.Foram analisados cinco lotes de CTA e quatro lotes de PTA nos teores de 4-CBA e pTOL pela metodologia proposta e as metodologias utilizadas na empresa Tereftalatos Mexicanos S.A. (TEMEX), que são cromatografia gasosa para pTOL e polarografia para 4-CBA, mostrando concordância entre os valores encontrados. Os níveis de BZ foram determinados apenas pela metodologia CE, apresentando no CTA, valores compreendidos entre 60 e 300 ppm, enquanto que no PTA, 5 a 7 ppm. Várias impurezas derivadas da oxidação incompleta do p-xileno foram investigadas, constatando-se a presença do ácido 4-hidroximetilbenzóico por comparação com padrões.In this work, a simple and fast capillary electrophoresis method for the simultaneous analysis of 4-carboxybenzaldehyde (4-CBA), p-toluic acid (pTOL) and benzoic acid (BZ) in industrial batches of crude (CTA) and highly-purified (PTA) terephthalic acid was developed. The electrophoretic conditions comprise: 20 mmol L -1 tetraborate buffer at pH 9, hydrodynamic injection (5 s/17 kPa), applied voltage of +30 kV and direct UV detection at 200 nm.The concentrations of 4-CBA and pTOL in five batches of CTA and four batches of PTA as determined by the proposed CE methodology were in agreement with the results from gas chromatography and polarography methods in current use in Tereftalatos Mexicanos S.A. (TEMEX). Levels of BZ were determined only by the CE methodology and ranged from 60 -300 ppm in CTA and 5 -7 ppm in PTA. Several impurities deriving from the incomplete oxidation of p-xylene were investigated. So far the positive identification of 4-hydroxymethylbenzoic acid was accomplished by comparison with pure standards.

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One-dimensional and comprehensive two-dimensional gas chromatographic approaches for the characterization of post-consumer recycled plastic materials

Hochegger

Pantò²,

Jones³

et al. 2023

Anal Bioanal Chem

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In September 2022, the European Commission published its new regulation on recycled plastic materials for food contact. It allows newly developed, non-authorized technologies and approaches, or so-called novel technologies, to be deployed in the field to generate the data needed for establishing regulatory and/or fit for purpose processes. The data shall be generated by using suitable methods, but the regulation does not give a more detailed description on those. In this study, commercially purchased buckets made of post-consumer recycled polypropylene were screened, using a number of different analytical approaches. Sample preparation methods, analysis techniques, and the data and information generated were compared. The results clearly demonstrate the need for a detailed characterization of such materials and the advantages and disadvantages of the analysis using conventional gas chromatography with flame ionization detection and mass spectrometery as well as two-dimensional comprehensive gas chromatography with time of flight mass spectrometry. Graphical Abstract

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Terephthalic Acid, Dimethyl Terephthalate, and Isophthalic Acid

Cited by 45 publications

References 10 publications

A spray reactor concept for catalytic oxidation of p-xylene to produce high-purity terephthalic acid

A spray reactor concept for catalytic oxidation of p-xylene to produce high-purity terephthalic acid

Analysis of impurities in crude and highly-purified terephthalic acid by capillary electrophoresis

One-dimensional and comprehensive two-dimensional gas chromatographic approaches for the characterization of post-consumer recycled plastic materials

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