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Toshiaki Yoshioka - One of the best experts on this subject based on the ideXlab platform.

  • effects of steam on the thermal Dehydrochlorination of poly vinyl chloride resin and flexible poly vinyl chloride under atmospheric pressure
    Polymer Degradation and Stability, 2015
    Co-Authors: Juan Diego Fonseca, Tomohito Kameda, Guido Grause, Toshiaki Yoshioka
    Abstract:

    Abstract A steam-based treatment for the Dehydrochlorination of poly(vinyl chloride) (PVC) at atmospheric pressure was evaluated. Temperatures ranging from 170 to 250 °C and steam concentrations of up to 75 vol% were applied to PVC resin and flexible PVC. Overall, the addition of steam increased the Dehydrochlorination ratios for both sample types, regardless of temperature. PVC resin reached a maximum Dehydrochlorination ratio of 76% after 1 h of treating at 250 °C and at a steam concentration of 50 vol%; this compares favorably to the 61% achieved under nitrogen. Higher steam concentrations reduced the maximum Dehydrochlorination ratio for PVC resin; this was shown to be the result of a shielding effect due to rapid, superficial Dehydrochlorination. This effect was not observed for flexible PVC, which reached a maximum Dehydrochlorination ratio of 69% after 1 h of treating at 250 °C and at a steam concentration of 75 vol%; again, this is a significant improvement over the 51% value obtained under nitrogen. Moreover, the loss of plasticizer was shown to account for the majority of the flexible PVC weight loss. The reaction kinetics was also investigated. The proposed treatment is of special interest for the treatment of PVC medical equipment, since it could fulfill the needs for both sterilization and Dehydrochlorination which the disposal of this waste requires.

  • Dehydrochlorination of poly vinyl chloride with ca oh 2 in ethylene glycol and the effect of ball milling
    Journal of Polymer Research, 2011
    Co-Authors: Tomohito Kameda, Shintaro Wachi, Guido Grause, Tadaaki Mizoguchi, Toshiaki Yoshioka
    Abstract:

    The Dehydrochlorination behavior of pure and flexible PVC in ethylene glycol was studied in the presence of Ca(OH)2 at temperatures between 170 °C and 190 °C. Although the Dehydrochlorination proceeded slower in Ca(OH)2 than in NaOH, similar Dehydrochlorination yields were obtained. It was assumed that the slower reaction rate was a result of the low solubility of Ca(OH)2 and the larger solvation shell of the Ca2+ ion. The Dehydrochlorination rate and yield were improved by employing a ball mill. Additionally, diisononyl phthalate and CaCO3 were quantitatively separated from flexible PVC during the ball-milling process. The maximum Dehydrochlorination yield of pure PVC after 7 h at 190 °C was 74%. After 8 h at the same temperature, a comparable Dehydrochlorination yield of 77% was achieved for flexible PVC, which could be increased by ball milling to 86%.

  • kinetics of the Dehydrochlorination of poly vinyl chloride in the presence of naoh and various diols as solvents
    Polymer Degradation and Stability, 2009
    Co-Authors: Tomohito Kameda, Guido Grause, Tadaaki Mizoguchi, Katsuaki Imai, Toshiaki Yoshioka
    Abstract:

    Abstract The Dehydrochlorination of PVC in the presence of NaOH was investigated in different diols. Diethylene glycol (DEG), triethylene glycol (TEG), and propylene glycol (PG) were found to be effective in accelerating the dechlorination of PVC. The Dehydrochlorination was promoted in the order TEG > DEG > PG, which was in agreement with the compatibility between PET and the diol. Compatibility resulted in an improved penetration of the PVC particle by the solvent, leading to the acceleration of the Dehydrochlorination. The Dehydrochlorination of PVC in NaOH/diol followed first-order kinetics, confirming the progress of the reaction under chemical reaction control. The apparent activation energies were 82 kJ mol−1, 109 kJ mol−1, and 151 kJ mol−1 for TEG, DEG, and PG, respectively. The lower the activation energy became the faster the Dehydrochlorination of PVC proceeded.

  • Dehydrochlorination and recovery of hydrochloric acid by thermal treatment of a chloride ion intercalated hydrotalcite like compound
    Applied Clay Science, 2007
    Co-Authors: Tomohito Kameda, Toshiaki Yoshioka, Kouji Watanabe, Miho Uchida, Akitsugu Okuwaki
    Abstract:

    Abstract We examined the Dehydrochlorination of a chloride ion-intercalated hydrotalcite-like compound (Cl−-HT) on thermal treatment under water vapor, and the subsequent recovery of hydrochloric acid. The degree of Dehydrochlorination increased with increasing temperature, partial pressure of water vapor, and time, whereas the hydrochloric acid concentration decreased with increasing partial pressure of water vapor and time. Greater than 90% Dehydrochlorination and greater than 20 wt.% recovery of hydrochloric acid could be obtained by thermal treatment of Cl−-HT in the conditions as follows; temperature: 550 °C, time: 0.5 h, water vapor: 7%.

  • Dehydrochlorination behavior of a chloride ion intercalated hydrotalcite like compound during thermal decomposition
    Applied Clay Science, 2007
    Co-Authors: Tomohito Kameda, Toshiaki Yoshioka, Kouji Watanabe, Miho Uchida, Akitsugu Okuwaki
    Abstract:

    Abstract We prepared a chloride ion-intercalated hydrotalcite-like compound (Cl−-HT) in a co-precipitation reaction, and investigated its thermal properties using thermogravimetry-differential thermal analysis (TG–DTA) and simultaneous thermogravimetry-mass spectrometry (TG-MS). In addition, we examined the effects of temperature and atmosphere on the Dehydrochlorination of Cl−-HT during thermal treatment. The thermal decomposition of the Cl−-HT was divided into three stages: the evaporation of surface adsorbed water and interlayer water in the Cl−-HT, the dehydroxylation of the brucite-like octahedral layers in the Cl−-HT, and the elimination of HCl from the Cl−-HT. H2O was produced at four steps: the evaporation of surface adsorbed water and interlayer water in the first stage, two steps of H2O production caused by the dehydroxylation of the parts of Cl−-HT with properties similar to Mg(OH)2 and Al(OH)3, respectively, in the second stage, and H2O production due to the dehydroxylation of the part of Cl−-HT with properties similar to Al(OH)3 in the third stage. HCl was produced at two steps: the Dehydrochlorination of the parts of Cl−-HT with properties similar to AlOCl and Mg(OH)Cl, respectively, in the third stage. Hydrochloric acid was obtained from the Cl−-HT on thermal treatment. The degree of Dehydrochlorination of the Cl−-HT increased with temperature. The degree was greater under water vapor than under nitrogen at all temperatures, indicating that water vapor promoted the Dehydrochlorination of Cl−-HT. However, the concentration of hydrochloric acid obtained under water vapor was lower than that under nitrogen.

Akitsugu Okuwaki - One of the best experts on this subject based on the ideXlab platform.

  • Dehydrochlorination and recovery of hydrochloric acid by thermal treatment of a chloride ion intercalated hydrotalcite like compound
    Applied Clay Science, 2007
    Co-Authors: Tomohito Kameda, Toshiaki Yoshioka, Kouji Watanabe, Miho Uchida, Akitsugu Okuwaki
    Abstract:

    Abstract We examined the Dehydrochlorination of a chloride ion-intercalated hydrotalcite-like compound (Cl−-HT) on thermal treatment under water vapor, and the subsequent recovery of hydrochloric acid. The degree of Dehydrochlorination increased with increasing temperature, partial pressure of water vapor, and time, whereas the hydrochloric acid concentration decreased with increasing partial pressure of water vapor and time. Greater than 90% Dehydrochlorination and greater than 20 wt.% recovery of hydrochloric acid could be obtained by thermal treatment of Cl−-HT in the conditions as follows; temperature: 550 °C, time: 0.5 h, water vapor: 7%.

  • Dehydrochlorination behavior of a chloride ion intercalated hydrotalcite like compound during thermal decomposition
    Applied Clay Science, 2007
    Co-Authors: Tomohito Kameda, Toshiaki Yoshioka, Kouji Watanabe, Miho Uchida, Akitsugu Okuwaki
    Abstract:

    Abstract We prepared a chloride ion-intercalated hydrotalcite-like compound (Cl−-HT) in a co-precipitation reaction, and investigated its thermal properties using thermogravimetry-differential thermal analysis (TG–DTA) and simultaneous thermogravimetry-mass spectrometry (TG-MS). In addition, we examined the effects of temperature and atmosphere on the Dehydrochlorination of Cl−-HT during thermal treatment. The thermal decomposition of the Cl−-HT was divided into three stages: the evaporation of surface adsorbed water and interlayer water in the Cl−-HT, the dehydroxylation of the brucite-like octahedral layers in the Cl−-HT, and the elimination of HCl from the Cl−-HT. H2O was produced at four steps: the evaporation of surface adsorbed water and interlayer water in the first stage, two steps of H2O production caused by the dehydroxylation of the parts of Cl−-HT with properties similar to Mg(OH)2 and Al(OH)3, respectively, in the second stage, and H2O production due to the dehydroxylation of the part of Cl−-HT with properties similar to Al(OH)3 in the third stage. HCl was produced at two steps: the Dehydrochlorination of the parts of Cl−-HT with properties similar to AlOCl and Mg(OH)Cl, respectively, in the third stage. Hydrochloric acid was obtained from the Cl−-HT on thermal treatment. The degree of Dehydrochlorination of the Cl−-HT increased with temperature. The degree was greater under water vapor than under nitrogen at all temperatures, indicating that water vapor promoted the Dehydrochlorination of Cl−-HT. However, the concentration of hydrochloric acid obtained under water vapor was lower than that under nitrogen.

  • TG–MS Analysis of Dehydrochlorination of Poly(vinylidene chloride)
    Chemistry Letters, 2001
    Co-Authors: Tetsuhiro Akama, Toshiaki Yoshioka, Miho Uchida, Toyonobu Suzuki, Akitsugu Okuwaki
    Abstract:

    Poly(vinylidene chloride) (PVDC) was decomposed by thermal treatment to 800 °C under inert atmosphere, using thermogravimetry-mass spectrometry (TG–MS). The evolvement of hydrogen chloride was still observed at 800 °C for the degradation of PVDC. The Dehydrochlorination process was divided into two stages according to difference in the formation rate of hydrogen chloride and trichlorobenzene. Dehydrochlorination was accompanied by the evolvement of trichlorobenzene during the first stage below 380 °C, but trichlorobenzene was not observed during the second stage above 380 °C.

  • analysis of two stages Dehydrochlorination of poly vinyl chloride using tg ms
    Chemistry Letters, 2000
    Co-Authors: Toshiaki Yoshioka, Miho Uchida, Tetsuhiro Akama, Akitsugu Okuwaki
    Abstract:

    Degradation behavior of poly(vinyl chloride) (PVC) was analyzed by means of simultaneous thermogravimetry-mass spectrometry (TG-MS). Weight loss and the production behavior of hydrogen chloride and organic materials with PVC degradation was clearly divided into three stages at lower heating rate. Dehydrochlorination was occurred mainly in the first and second stages. Benzene was formed mainly in the first stage with Dehydrochlorination.

  • Dehydrochlorination behavior of flexible pvc pellets in naoh solutions at elevated temperature
    Journal of Applied Polymer Science, 1998
    Co-Authors: Shun-myung Shin, Toshiaki Yoshioka, Akitsugu Okuwaki
    Abstract:

    Flexible PVC pellets were treated at 150–250°C in 0–7M NaOH solutions for 0–12 h. The degree of Dehydrochlorination of flexible PVC pellets increased with increasing reaction temperature and was about 100% at 250°C over 5 h. A porous char, 2–16 μm in pore size, was produced. The Dehydrochlorination of PVC in the flexible PVC was proceeded by a first-order reaction in alkaline solution. The maximum rate of the Dehydrochlorination for flexible PVC was reached at 5M NaOH. The apparent activation energies were 22–35 kcal/mol in 1–7M NaOH for flexible PVC. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2171–2177, 1998

Yusaku Sakata - One of the best experts on this subject based on the ideXlab platform.

Tomohito Kameda - One of the best experts on this subject based on the ideXlab platform.

  • effects of steam on the thermal Dehydrochlorination of poly vinyl chloride resin and flexible poly vinyl chloride under atmospheric pressure
    Polymer Degradation and Stability, 2015
    Co-Authors: Juan Diego Fonseca, Tomohito Kameda, Guido Grause, Toshiaki Yoshioka
    Abstract:

    Abstract A steam-based treatment for the Dehydrochlorination of poly(vinyl chloride) (PVC) at atmospheric pressure was evaluated. Temperatures ranging from 170 to 250 °C and steam concentrations of up to 75 vol% were applied to PVC resin and flexible PVC. Overall, the addition of steam increased the Dehydrochlorination ratios for both sample types, regardless of temperature. PVC resin reached a maximum Dehydrochlorination ratio of 76% after 1 h of treating at 250 °C and at a steam concentration of 50 vol%; this compares favorably to the 61% achieved under nitrogen. Higher steam concentrations reduced the maximum Dehydrochlorination ratio for PVC resin; this was shown to be the result of a shielding effect due to rapid, superficial Dehydrochlorination. This effect was not observed for flexible PVC, which reached a maximum Dehydrochlorination ratio of 69% after 1 h of treating at 250 °C and at a steam concentration of 75 vol%; again, this is a significant improvement over the 51% value obtained under nitrogen. Moreover, the loss of plasticizer was shown to account for the majority of the flexible PVC weight loss. The reaction kinetics was also investigated. The proposed treatment is of special interest for the treatment of PVC medical equipment, since it could fulfill the needs for both sterilization and Dehydrochlorination which the disposal of this waste requires.

  • Dehydrochlorination of poly vinyl chloride with ca oh 2 in ethylene glycol and the effect of ball milling
    Journal of Polymer Research, 2011
    Co-Authors: Tomohito Kameda, Shintaro Wachi, Guido Grause, Tadaaki Mizoguchi, Toshiaki Yoshioka
    Abstract:

    The Dehydrochlorination behavior of pure and flexible PVC in ethylene glycol was studied in the presence of Ca(OH)2 at temperatures between 170 °C and 190 °C. Although the Dehydrochlorination proceeded slower in Ca(OH)2 than in NaOH, similar Dehydrochlorination yields were obtained. It was assumed that the slower reaction rate was a result of the low solubility of Ca(OH)2 and the larger solvation shell of the Ca2+ ion. The Dehydrochlorination rate and yield were improved by employing a ball mill. Additionally, diisononyl phthalate and CaCO3 were quantitatively separated from flexible PVC during the ball-milling process. The maximum Dehydrochlorination yield of pure PVC after 7 h at 190 °C was 74%. After 8 h at the same temperature, a comparable Dehydrochlorination yield of 77% was achieved for flexible PVC, which could be increased by ball milling to 86%.

  • kinetics of the Dehydrochlorination of poly vinyl chloride in the presence of naoh and various diols as solvents
    Polymer Degradation and Stability, 2009
    Co-Authors: Tomohito Kameda, Guido Grause, Tadaaki Mizoguchi, Katsuaki Imai, Toshiaki Yoshioka
    Abstract:

    Abstract The Dehydrochlorination of PVC in the presence of NaOH was investigated in different diols. Diethylene glycol (DEG), triethylene glycol (TEG), and propylene glycol (PG) were found to be effective in accelerating the dechlorination of PVC. The Dehydrochlorination was promoted in the order TEG > DEG > PG, which was in agreement with the compatibility between PET and the diol. Compatibility resulted in an improved penetration of the PVC particle by the solvent, leading to the acceleration of the Dehydrochlorination. The Dehydrochlorination of PVC in NaOH/diol followed first-order kinetics, confirming the progress of the reaction under chemical reaction control. The apparent activation energies were 82 kJ mol−1, 109 kJ mol−1, and 151 kJ mol−1 for TEG, DEG, and PG, respectively. The lower the activation energy became the faster the Dehydrochlorination of PVC proceeded.

  • Dehydrochlorination and recovery of hydrochloric acid by thermal treatment of a chloride ion intercalated hydrotalcite like compound
    Applied Clay Science, 2007
    Co-Authors: Tomohito Kameda, Toshiaki Yoshioka, Kouji Watanabe, Miho Uchida, Akitsugu Okuwaki
    Abstract:

    Abstract We examined the Dehydrochlorination of a chloride ion-intercalated hydrotalcite-like compound (Cl−-HT) on thermal treatment under water vapor, and the subsequent recovery of hydrochloric acid. The degree of Dehydrochlorination increased with increasing temperature, partial pressure of water vapor, and time, whereas the hydrochloric acid concentration decreased with increasing partial pressure of water vapor and time. Greater than 90% Dehydrochlorination and greater than 20 wt.% recovery of hydrochloric acid could be obtained by thermal treatment of Cl−-HT in the conditions as follows; temperature: 550 °C, time: 0.5 h, water vapor: 7%.

  • Dehydrochlorination behavior of a chloride ion intercalated hydrotalcite like compound during thermal decomposition
    Applied Clay Science, 2007
    Co-Authors: Tomohito Kameda, Toshiaki Yoshioka, Kouji Watanabe, Miho Uchida, Akitsugu Okuwaki
    Abstract:

    Abstract We prepared a chloride ion-intercalated hydrotalcite-like compound (Cl−-HT) in a co-precipitation reaction, and investigated its thermal properties using thermogravimetry-differential thermal analysis (TG–DTA) and simultaneous thermogravimetry-mass spectrometry (TG-MS). In addition, we examined the effects of temperature and atmosphere on the Dehydrochlorination of Cl−-HT during thermal treatment. The thermal decomposition of the Cl−-HT was divided into three stages: the evaporation of surface adsorbed water and interlayer water in the Cl−-HT, the dehydroxylation of the brucite-like octahedral layers in the Cl−-HT, and the elimination of HCl from the Cl−-HT. H2O was produced at four steps: the evaporation of surface adsorbed water and interlayer water in the first stage, two steps of H2O production caused by the dehydroxylation of the parts of Cl−-HT with properties similar to Mg(OH)2 and Al(OH)3, respectively, in the second stage, and H2O production due to the dehydroxylation of the part of Cl−-HT with properties similar to Al(OH)3 in the third stage. HCl was produced at two steps: the Dehydrochlorination of the parts of Cl−-HT with properties similar to AlOCl and Mg(OH)Cl, respectively, in the third stage. Hydrochloric acid was obtained from the Cl−-HT on thermal treatment. The degree of Dehydrochlorination of the Cl−-HT increased with temperature. The degree was greater under water vapor than under nitrogen at all temperatures, indicating that water vapor promoted the Dehydrochlorination of Cl−-HT. However, the concentration of hydrochloric acid obtained under water vapor was lower than that under nitrogen.

N. Lingaiah - One of the best experts on this subject based on the ideXlab platform.