• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.351-354
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• 2001

Poly(ethylene terephthalate) (PET)는 물리적, 기계적 성질이 우수한 엔지니어링 플라스틱의 하나로 섬유, 필름, 및 여러 가지 용도로 다양하게 사용되고 있다. PET는 DMT(dimethyl terephthalate) 또는 TPA(terephthalic acid)와 EG(ethylene glycol)를 축합 중합하여 제조한다. (중략)

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.615-619
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• 2019

Statistical design of experiments was performed to optimize MOF-235 synthesis process. Concentrations of terephthalic acid (TPA), iron (III) chloride hexahydrate, N,N-dimethylformamide (DMF) and ethanol were important factors to develop the crystal structure of MOF-235. MOF-235 was synthesized with various concentrations of the listed chemicals above and the crystallinity was measured by XRD. The effect of the composition on the synthesis of MOF-235 was evaluated using a statistical analysis. For the variance analysis using F-test, the concentration of ethanol showed the greatest effect on the crystallinity and TPA the least influential. A regression model for predicting the crystallinity of MOF-235 was derived and the prediction results for two synthetic variables were presented using contour plots. Finally, the crystallinity was predicted by a mixture method with $FeCl_3$, ethanol and DMF.

• Journal of the Korean Chemical Society
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• v.42 no.3
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• pp.285-291
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• 1998

Methods to determine EU(Ⅲ) ion in aqueous solution by fluorescence spectrometry based upon the ligand sensitized fluorescence of Eu(Ⅲ)-terephthalic acid (TPA) complex ion have been studied. The effects of excitation wavelength, pH, concentration of TPA and emission wavelength on the fluorescence intensity were investigated. The fluorescence intensity of the Eu(Ⅲ) complex ion was further increased with addition of trioctylphosphine oxide (TOPO). In this case Triton X-100 was used to dissolve TOPO in aqueous solution. The calibration curve for Eu(Ⅲ) was linear over the range from $1.0{\times}10^{-6}M\;to\;4.0{\times}10^{-4}M$ and the detection limit was $1.0{\times}10^{-6}M$ under the experimental conditions of 256 nm, 5.6, $3.5{\times}10^{-4}$M$ and 615 nm for excitation wavelength, pH, concentration of TPA and emission wavelength, respectively. When TOPO was added to the Eu(Ⅲ)-TPA system, the concentration range of linear response and the detection limit were $1.0 {\times}10^{-9}M\;to\;1.0{\times}10^{-4}M,\;1.0{\times}10^{-7}M,$ respectively under the experimental conditions of 284 nm, 4.4 and $1.0{\times} 10^{-4}M$ for excitation wavelength, pH and concentration of TOPO, respectively. Effects of interferences from various cations for the determination of Eu(Ⅲ) ion were also investigated.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.480-486
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• 2006

On account of exchanging main process from chemical precipitation for MLE(Modified Ludzark-Ettinger), an external carbon source was required for supplementation of carbon source shortage that was needed biological denitrification in the S sewage treatment plant(S-STP). In this study, NUR(nitrate uptake rate), OUR(oxygen uptake rate) test and a field application test was conducted for the applicability assessment of Terephtalic acid(TPA) by-product contained about 4.7% acetate as alternative external carbon source. As the results, TPA by-product shows more rapid acclimation than methanol, 8.24 mg ${NO_3}^--N/g$ VSS/hr specific denitrification rate, 3.70 g $COD_{Cr}/g\;NO_3$ C/N ratio and 99.4% readily biodegradable COD contents. In the results of field application, the nutrient removal efficiency was high and effluent T-N concentration is 8.2 mg/L. It is concluded that TPA by-product is the proper alternative external carbon source.

• Fibers and Polymers
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• v.2 no.2
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• pp.86-91
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• 2001

Liquid crystalline (LC) poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate) [copoly(ET/CPT)] was prepared using poly(ethylene terephthalate) (PET) as a flexible spacer, terephthalic acid (TPA), and chlorohydroquinone diacetate (CHQDA). All reactions involved in the copolymerization were investigated using some model compounds: TAP was used for acidolysis, diphenylethyl terephthalate (DPET) for interchange reaction between PET chains, and 야-o-chlorophenyl terephthalate (DOCT) and di-m-chlorophenyl terephthalate (DMCT) for interchange reaction between PET and rigid rodlike segments. Activation energies obtained for the acidolysis of PET with TPA and for interchange reaction of PET with DPET, DOCT, and DMCT were 19.8 kcal/mol, 26.5 kcal/mole, and 45.9 kcal/mole, respectively. This result supports that the copolymerization proceeds through the acidolysis of PET with TPA first and subsequent polycondensation between carboxyl end group and CHQDA or acetyl end group, which is formed from the reaction of CHQDA and TPA. Also, it was found that ester-interchange reaction can be influenced by the steric hindrance. Copoly(ET/CPT)s obtained has ethylene acetate end groups formed from acetic acid hydroxy ethylene end groups and showed almost the random sequence distribution for all compositions.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.335-336
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• 2003

The synthesis of poly(trimethylene terephthalate) (PTT), whose application is being expanded very rapidly to new apparel and carpet materials, was investigated by melt condensation polymerization using 1,3-propanediol (PDO) and terephthalic acid (TPA). No catalyst was used in the 1st step reaction (esterification), but tetrabutyl titanate(TBT) was used as a polyesterification catalyst ranging from 25 to 75 ppm based on the weight of TPA used in the 2nd step reaction (polyesterification). The molar ratio of PDO to TPA was set as 2.2:1. The effect of reaction conditions on the color and intrinsic viscosity of the final product was investigated. (omitted)

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.59-64
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• 2002

A facile and precise batch oxidation reaction system allows continuous monitoring of the oxidation rate and cumulated oxygen conversion of xylenes, and the side reactions to carbon monoxide and carbon dioxide may also be studied. The oxidation reaction can be analyzed precisely with the rate and amount of oxygen consumed. The reaction reveals that 4-carboxybenzaldehyde is an unstable intermediate of p-xylene oxidation as the reaction proceeds instantaneously from p-toluic acid to TPA (terephthalic acid). The alkali metals accelerate oxidation, even though they retard the reaction initially. The oxidation rate increases with decreasing water concentration. However, in the later part of reaction, the reactivity decreases a bit if the water concentration is very low. This retarding effect of water can be overcome partly by the addition of potassium. The oxidation of o-xylene, compared with the oxidation of p-xylene and m-xylene, proceeds quite fast initially, however, the oxidation rate of xylene isomers in the later stage of reaction is in the order of p-xylene > mxylene > o-xylene.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.714-721
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• 2008

Chemical plants which consume lots of energy are not operating in the best conditions due to their own peculiar nonlinearity, instability, and diverse disturbances. In order to improve this, the plant wide optimization was performed. It is important to select the most appropriate number of decision variables which strongly affect the operating cost because there are too many decision variables which economically have an effect on plant wide. For instance, if all decision variables which can economically affect are applied in optimization and then the result of the optimization is applied to operation, a lot of operating conditions should be going to be changed. As a result of changing a plenty of operating conditions, the cost of the change will absolutely increase. Thus, in this study, the method of selecting the most appropriate decision variables which can influence on saving operation costs was presented in order to optimize plant wide. TPA (Terephthalic-acid) plant is considered as a case study. In other word, after modeling, the most proper decision variables was selected by examining the degree which decision variables influence on operating costs through sensitivity analysis. In TPA process, the three decision variables were selected by the presented method in this study. Then the plant was optimized by selected the decision variables. Consequently, it was seen that the plant are expected to save the 350 million won of energy annually without additional investment for facilities or remodeling of the plant.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.92-92
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• 2003

poly(trimethylene terephthalate) (PTT) was synthesized via condensation polymerization using different molar ratios of 1,3-propane diol (PDO)/terephthalic acid (TPA) in the presence of tetraisopropyl titanate (TiPT) as a polyesterifi-cation catalyst. The effect of reaction conditions on the characteristics of as-polymerized PTT was investigated.

• Applied Chemistry for Engineering
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• v.3 no.2
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• pp.280-287
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• 1992

Aromatic liquid crystalline polyesters were synthesized from terephthalic acid(TPA), biphenyl dicarboxylic acid(BPA) and hydroquinone(HQ) by solution polymerization. Effects of TPA/BPA ratio(by mole %) on the thermal properties, thermal stability and textures of mesophases were investigated with DSC, TGA, cross-polarized microscopy and X-ray diffractometer. The synthesized polymers in this study were thermotropic and showed nematic textures. Melting temperature($T_m$) and isotropization temperature($T_i$) of polymer increased and thermal stabilities of polymer were improved with the content of BPA. Most of the polymers in this study had crystallinity more than 30%.