• Title/Summary/Keyword: 2,6-dimethylphenol

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Determination of total iodide in seawater by gas chromatography-mass spectrometry (Gas chromatography-mass spectrometry를 이용한 해수 중 총 요오드 정량분석)

  • Shin, Ueon-Sang
    • Analytical Science and Technology
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    • v.15 no.5
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    • pp.445-450
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    • 2002
  • A sensitive gas chromatographic method has been established for the determination of total iodide in seawater as their volatile organic derivative. The method is based on the formation of 4-iodo-2,6-dimethylphenol with 2,6-dimethylphenol in matrix and a single-step extraction of the derivative with ethyl ether, which are then measured by gas chromatography-mass spectrometry (selected ion monitoring). Iodate in sea water was completely reduced to iodide with ascorbic acid and acetic acid. The detection limit was 0.1 ng/mL in seawater and the calibration curve showed good linearity with r=0.9997. The method was sensitive, reproducible and simple enough to permit the reliable routine analysis of total iodide in seawater. Total iodide in sea water was found about 30 ng/ml.

Study on Self-Healing Asphalt Containing Microcapsule (마이크로캡슐이 내재된 자기치유 아스팔트에 관한 연구)

  • Kwon, Young-Jin;Hong, Young-Keun
    • Elastomers and Composites
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    • v.48 no.3
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    • pp.232-240
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    • 2013
  • Microcapsules having healing agent were prepared in which 2,6-dimethylphenol (DMP) as a healing agent forms the core and melamine/formaldehyde resin forms the shell. Microcapsule-contained asphalts showed better mechanical properties than non-contained ones. And as the rest time passed the impact strength of microcapsule-contained asphalt was getting higher than that of asphalt without the microcapsule. As the rest time of 15 days passed, the original strength was restored. This tells that microcapsule-contained asphalt had the ability of self-healing. X-ray photos proved that DMP on asphalt fracture surface, which were burst out of the microcapsules when cracks occurred on asphalt, were polymerized to polyphenyleneoxide and this PPO covered the crack and healed the damage.

Evaluation of the Genetic Toxicity of Synthetic Chemicals (X) -In vivo Bone Marrow Micronucleus Assay of 17 Synthetic Chemicals In Mice-

  • Ryu, Jae-Chun;Jeon, Hee-Kyung
    • Environmental Mutagens and Carcinogens
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    • v.24 no.1
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    • pp.25-32
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    • 2004
  • To validate and to estimate the chemical hazard playa very important role to environment and human health. The detection of many synthetic chemicals used in industry that may pose a genetic hazard in our environment is of great concern at present. Since these substances are not limited to the original products, and enter the environment, they have become widespread environmental pollutants, thus leading to a variety of chemicals that possibly threaten the public health. In this resepct, the clastogenicity of 17 synthetic chemicals was evaluated with bone marrow micronucleus assay in mice. The positive control, mitomycin C (2 mg/kg, i.p.) revealed significant induction ratio of percentage of micronucleated polychromatic erythrocytes/1,000 polychromatic erythrocytes compared to solvent controls. The chemicals with relatively high $LD_{50}$ value such as allyl alcohol (CAS No. 107-18-6), 2,4-pentanedione (CAS No. 123-54-6) and 4-chloro-3,5-dimethylphenol (CAS No. 88-04-0) revealed no significant induction of micronucleated polychromatic erythrocytes in mice. From this results, 17 synthetic chemicals widely used in industry have revealed no significant micronucleus induction of clastogenicity in mice in this experiment.

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Highly Selective Amination of o- and p-Alkyl Phenols over Pd/Al2O3-BaO

  • Ma, Jianchao;Wang, Huabang;Sun, Meng;Yang, Fan;Wu, Zhiwei;Wang, Donghua;Chen, Ligong
    • Bulletin of the Korean Chemical Society
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    • v.33 no.2
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    • pp.387-392
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    • 2012
  • A series of Pd-based catalysts were prepared and examined for the amination of 2,6-dimethylphenol in a fixedbed reactor. The best results were obtained for Pd/$Al_2O_3$-BaO with a conversion of 99.89% and a selectivity of 91.16%. These catalysts were characterized using BET, XRD, XPS, TEM and $NH_3$-TPD. Doped BaO not only improved the dispersion of the Pd particles but also decreased the acidity of the catalyst, which remarkably enhanced the selectivity and stability of the catalyst. The generality of Pd/$Al_2O_3$-BaO for this kind of reaction was demonstrated by catalytic aminations of o- and p-alkyl phenols.

Preparation and Characteristics of Poly(phenylene ether)s in Various Reaction Conditions (다양한 반응조건에 따른 폴리페닐렌에테르의 중합 특성)

  • Park, Jong-Hyun;Kim, Nam-Cheol;Kim, Yong-Tae;Nam, Sung-Woo;Kim, Young-Jun;Kim, Ji-Heung
    • Polymer(Korea)
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    • v.35 no.3
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    • pp.244-248
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    • 2011
  • Poly(2,6-dimethyl-1,4-phenylene ether) (PPE) was synthesized by oxidative polymerization using various Cu(I)-amine catalyst system. The effects of catalyst/monomer ratio, different amine ligand, and the content of 2,4,6-trimethylphenol (TMP) additive on the polymer yield and molecular weight were investigated by using gel permeation chromatography. The catalytic activity of various Cu-amine systems on the 2,S-dimethylphenol (DMP) polymerization was monitored and compared each other through oxygen-uptake experiment. In addition, the effect of catalyst removal using aqueous EDTA on the thermal stability of the prepared polymer was elucidated by thermogravimetric analysis.

Nitrosation of U.S. E.P.A. Classified Eleven Priority Pollutant Phenols (미환경청 분류 11종 상위 환경오염 페놀들의 나이트로소화)

  • Chung, Yongsoon;Lee, Seonghoon;Motomizu, Shoji
    • Analytical Science and Technology
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    • v.17 no.5
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    • pp.393-400
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    • 2004
  • Nitrosation of phenol (POH) was studied by adding hydrochloric acid and sodium nitrite to phenol solution with reaction temperature and time change. The optimum condition of nitrosation was found from the effects of hydrochloric acid and sodium nitrite concentration, reaction temperature, and reaction time changes on the production of nitrosophenol (POHNO). As a result, it was found that the optimum conditions were $5.0{\times}10^{-4}{\sim}2.0{\times}10^{-3}M$ range of $NO{_2}^-$ concentration, more than 0.10 M of HCl concentration, temperature of $80^{\circ}C$, and 3 hrs. of reaction time. In this condition, 10 U.S. E.P.A. classified priority environmental pollutant, phenols, were nitrosated. Nitrosated phenols were: POH, 2-Chlorophenol (2ClPOH), 2,4-diChlorophenol (2ClPOH), 2,4-dimethylphenol (24diMPOH), and 4-Chloro -3-methylphenol (4Cl3MPOH), and a small part of 2-nitrophenol (2NPOH). The ${\lambda}_{max}$ values of nitrosated phenols in acidic solution were around 300 nm, and those in basic solution were around 400 nm. Molar absorptivities (${\varepsilon}$) at the 400 nm of the nitrosated phenols in the basic solution were 1.5~2.0 times larger than those at 300 nm in acidic solution. It was also found by Capillary-HPLC chromatograms of the nitrosated phenol solutions that the production of the nitrosophenols were interfered by the excess concentration of nitrite (more than $3.0{\times}10^{-3}M$).