Depolymerization of polyethylene terephthalate to monomers with supercritical methanol.

Sako, Takeshi; Sugeta, Tsutomu; Otake, Katsuto; Nakazawa, Noriaki; Sato, Masahito; Namiki, Kunihiro; Tsugumi, Masayuki

doi:10.1252/jcej.30.342

Cited by 103 publications

(73 citation statements)

References 2 publications

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“…The purpose of depolymerization is to depolymerize PET to form BHET monomer. Available PET depolymerization method to date are hydrolysis [9], glycolysis [10], methanolysis [11], aminolysis [12] and ammonolysis [13]. The BHET produced from depolymerization reaction can be purified via crystallization, deionization, decoloring, distillation and many others.…”

Section: Introductionmentioning

confidence: 99%

Time, Temperature and Amount of Distilled Water Effects on the Purity and Yield of Bis(2-hydroxyethyl) Terephthalate Purification System

Goh

Salmiaton

Abdullah

et al. 2015

Bull. Chem. React. Eng. Catal.

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Polyethylene terephthalate (PET) bottle is one of the common plastic wastes existed in the municipal solid waste in Malaysia. One alternative to solve the abundant of PET wastes is chemical recycling of the wastes to produce a value added product. This technology not only can decrease the PET wastes in landfill sites but also can produce many useful recycled PET products. Bis(2-hydroxyethyl) terephthalate (BHET) obtained from glycolysis reaction of PET waste was purified using crystallization process. The hot distilled water was added to glycolysis product followed by cooling and filtration to extract BHET in white solid form from the product. The effect of three operating conditions namely crystallization time, crystallization temperatures and amount of distilled water used to the yield of crystallization process were investigated. The purity of crystallization products were analyzed using HPLC and DSC. The optimum conditions of 3 hours crystallization time, 2 °C crystallization temperature and 5:1 mass ratio of distilled water used to glycolyze solid gave the highest yield and purity of the crystallization process.

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Section: Introductionmentioning

confidence: 99%

Time, Temperature and Amount of Distilled Water Effects on the Purity and Yield of Bis(2-hydroxyethyl) Terephthalate Purification System

Goh

Salmiaton

Abdullah

et al. 2015

Bull. Chem. React. Eng. Catal.

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“…In the former instance, 8 PET was almost completely decomposed in methanol in 30 min under the supercritical conditions at 300˚C and various pressures over 8.1 MPa. In this case, the ester linkages clove to give dimethyl terephthalate and ethylene glycol, although oligomeric products such as 4-methoxycarbonyl(2-hydroxyethyl)benzoate were also produced with the yield of 40 -50%.…”

Section: Introductionmentioning

confidence: 97%

“…On the other hand, supercritical fluids such as supercritical methanol have been utilized to depolymerize intractable polymers such as poly(ethylene terephthalate) (PET) 8 The cross-linking structure of the ultra violet (UV)-cured resin prepared from dipentaerithritol hexacrylate (DPHA) was characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) combined with supercritical methanolysis. The MALDI-mass spectrum of the decomposition products obtained by supercritical methanolysis contained a series of peaks of sodium-cationized methyl acrylate (MA) oligomers up to around m/z = 4000 formed through selective cleavage and methylation occurred at ester linkages in UV-cured DPHA.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, supercritical fluids such as supercritical methanol have been utilized to depolymerize intractable polymers such as poly(ethylene terephthalate) (PET) 8 and phenol resin 9 mainly for the purpose of plastic recycling. In the former instance, 8 PET was almost completely decomposed in methanol in 30 min under the supercritical conditions at 300˚C and various pressures over 8.1 MPa.…”

Section: Introductionmentioning

confidence: 99%

“…This approach, however, was limited for the loosely cross-linking polymer composed of the hydrophilic monomers and oligomers suitable for biodegradable applications. Such materials should be much easier to be hydrolyzed than practical UV-cured resins in the industrial fields with rigidly cross-linking structure essential for high chemical resistance and heat resistance.On the other hand, supercritical fluids such as supercritical methanol have been utilized to depolymerize intractable polymers such as poly(ethylene terephthalate) (PET) 8 The cross-linking structure of the ultra violet (UV)-cured resin prepared from dipentaerithritol hexacrylate (DPHA) was characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) combined with supercritical methanolysis. The MALDI-mass spectrum of the decomposition products obtained by supercritical methanolysis contained a series of peaks of sodium-cationized methyl acrylate (MA) oligomers up to around m/z = 4000 formed through selective cleavage and methylation occurred at ester linkages in UV-cured DPHA.…”

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confidence: 99%

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Characterization of Cross-linking Structures in UV-cured Acrylic Ester Resin by MALDI-MS Combined with Supercritical Methanolysis

Matsubara¹,

Hata

Kondo

et al. 2006

ANAL. SCI.

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IntroductionUltraviolet (UV) curable acrylic esters are applied to many industrial products such as printing inks, coatings for optical fibers and disks, adhesives, dental materials, photoresist, and three-dimensional stereolithography. [1][2][3][4][5] In order to utilize these in advanced technology, it is often requested to elucidate the cross-linking network structure of the resulting cured resins by UV-irradiation. However, it is not an easy task to analyze cured resins even using advanced spectroscopic methods mainly because of their insoluble nature. Recently, the authors characterized the chain length distribution of network junctions in UV-cured poly(ethylene glycol) diacrylate (PEDA) using pyrolysis-gas chromatography in the presence of tetramethylammonium hydroxide. 6 In this case, methyl acrylate (MA) oligomers formed through thermally assisted hydrolysis and methylation selectively occurred at ester linkages in UVcured PEDA were attributed to the sequences of the network junctions in the cross-linking structure. The chain length distribution of the network junctions composed of up to six acryloyl units in the UV-cured PEDA was estimated from the peak intensities of the corresponding MA oligomers observed in the pyrogram. However, the network structure containing longer sequences comprised of more than seven acryloyl units was not elucidated because the corresponding higher MA oligomers were not observed in the pyrogram, mainly due to their lower volatility.Meanwhile, Burkoth et al. evaluated the kinetic chain length of the network junctions of UV-cured dimethacrylated sebacic anhydride through matrix-assisted laser desorption/ionizationmass spectrometric (MALDI-MS) measurements of its decomposition products. 7 This polymer was readily hydrolyzed in phosphate buffered saline at pH 7.4 and 37˚C during several hours into sebacic acid and poly(methacrylic acid). They observed that poly(methacrylic acid)s reflected the sequences of network junctions in the range between pentamer and 24-mer in the MALDI mass spectra. This approach, however, was limited for the loosely cross-linking polymer composed of the hydrophilic monomers and oligomers suitable for biodegradable applications. Such materials should be much easier to be hydrolyzed than practical UV-cured resins in the industrial fields with rigidly cross-linking structure essential for high chemical resistance and heat resistance.On the other hand, supercritical fluids such as supercritical methanol have been utilized to depolymerize intractable polymers such as poly(ethylene terephthalate) (PET) 8 The cross-linking structure of the ultra violet (UV)-cured resin prepared from dipentaerithritol hexacrylate (DPHA) was characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) combined with supercritical methanolysis. The MALDI-mass spectrum of the decomposition products obtained by supercritical methanolysis contained a series of peaks of sodium-cationized methyl acrylate (MA) oligomers up to around m/z = 4000 formed through...

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Depolymerization of poly(butylene terephthalate) using high-temperature and high-pressure methanol

Shibata

Masuda

Yosomiya

et al. 2000

J. Appl. Polym. Sci.

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Poly(butylene terephthalate) (PBT) was depolymerized in excess methanol at high‐temperature (473–523 K) and high‐pressure (4–14 MPa) conditions. Considering the critical point of methanol (512.6 K, 8.09 MPa), the reaction pressure was varied over the range of 6–14 MPa at the reaction temperature of 513 K. As a result, ca. 20 min was required to recover dimethyl terephthalate and 1,4‐butanediol, quantitatively, at any pressure, indicating that the supercritical state of methanol is not a key factor of degradation of PBT and that the effect of pressure is little. On the contrary, when the reaction temperature was varied over the range of 473–523 K at the pressure 12 MPa, the decomposition rate constant of PBT at the reaction temperatures (503–523 K) higher than the melting temperature of PBT (500 K) was much higher than that at 473–483 K. This result indicates that melting of PBT is an important factor for the short‐time depolymerization of PBT. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3228–3233, 2000

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Depolymerization of polyethylene terephthalate to monomers with supercritical methanol.

Cited by 103 publications

References 2 publications

Time, Temperature and Amount of Distilled Water Effects on the Purity and Yield of Bis(2-hydroxyethyl) Terephthalate Purification System

Time, Temperature and Amount of Distilled Water Effects on the Purity and Yield of Bis(2-hydroxyethyl) Terephthalate Purification System

Characterization of Cross-linking Structures in UV-cured Acrylic Ester Resin by MALDI-MS Combined with Supercritical Methanolysis

Depolymerization of poly(butylene terephthalate) using high-temperature and high-pressure methanol

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