Studies in pyrolysis. Part IV. Model systems for the pyrolysis of poly(ethylene terephthalate) and allied polyesters

Allan, R. J. P.; Forman, R. L.; Ritchie, P. D.

doi:10.1039/jr9550002717

Cited by 33 publications

(13 citation statements)

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“…At constant density the total number of molecules decreases if a comonomer with a higher molecular mass than ethylene is added. On the other hand, we can expect more gaseous decomposition products Ž from the comonomers than from ethylene Albert, 1998;Bamford and Tipper, 1972;Allan et al, 1955;Forman et al, . 1968 .…”

Section: Maximum Explosion Pressurementioning

confidence: 95%

Thermal decomposition of ethylene–comonomer mixtures under high pressure

Albert

Luft

1999

AIChE Journal

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Section: Maximum Explosion Pressurementioning

confidence: 95%

Thermal decomposition of ethylene–comonomer mixtures under high pressure

Albert

Luft

1999

AIChE Journal

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“…Radical V formed in equation I would further thermally decompose to radical VII (eq 7), which in turn couples with the phenyl radical to give the 1,2-bis( 4-carboxyphenyl)ethane derivative (Ill) (eq 8). The direct decarboxylation of ester is very rare, but has been shown to occur in the pyrolysis of vinyl benzoate to styrene 17 Although the mechanism of polycondensation of BHET in the presence of tungsten catalyst is not clear, it would be possible to assume a complex similar to that of Mn, Co, and Zn, because tungsten is also a transition metal and is able to make a complex with OH-groups of alcohol. 18 · 19 …”

Section: Mechanism Of Side Reactionsmentioning

confidence: 99%

“…15 • 16 As a result the thermal decomposition of the alkyloxygen bond of2-alkoxyethyl ester would be accelerated (eq3). 17 For the phenyl radical, which was formed by the thermal decomposition of complex VI, followed by decarboxylation 6 (eq 4), two pathways of reaction are avaiable. 6 Path I is a simple coupling of two phenyl radicals to give the 4,4' -biphenyldicarboxylic acid derivative (I) (eq 5), which was the most abundant by-product in the polycondensation.…”

Section: Mechanism Of Side Reactionsmentioning

confidence: 99%

Formation of Aromatic Compounds as Side Reactions in the Polycondensation of Bis(2-hydroxyethyl) Terephthalate

Kamatani

Kuze

1979

Polym J

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ABSTRACT:Studies on the side reactions in the polycondensation of bis(2-hydroxyethyl) terephthalate were performed in the presence of catalysts (Mn, Co, Zn, W). 4,4'-Biphenyldicarboxylic acid, l,2-bis(4-carboxyphenyl)ethane, and 2,4',5-biphenyltricarboxylic acid were found as major aromatic by-products in the reaction. The yield of these by-products was very poor in the absence of these catalysts, and remarkably increased in the presence of catalysts in the following order: Mn< Co< Zn <1; W. This order was in accord with that of the activity of catalysts for polycondensation of bis(2-hydroxyethyl) terephthalate. The side reactions were suppressed with the addition of radical inhibitor, indicating that the side reactions occurred with a radical mechanism; this was supported from ESR studies. The side reactio'ls are probably initiated by the alkyl radical ( -C6 H4 COOC2H4 ·) obtained from the reaction ofbis(2-hydroxyethyl) terephthalate with the metal of catalysts.KEY WORDS Bis(2-hydroxyethyl) Terephthalate / Poly(ethylene terephthalate) / Polycondensation / 4,4'-Biphenyldicarboxylic Acid / l,2-Bis(4-carboxyphenyl)ethane / 2,4',5-Biphenyltricarboxylic Acid / ESR / Free EXPERIMENT A-L MaterialsSeveral side reactions such as etherification 1 · 2 and thermal degradation 3 -6 have been observed in the polycondensation of bis(2-hydroxyethyl) terephthalate (BHET) or its oligomer. We found that 4,4'-biphenyldicarboxylic acid, 2,4' ,5-biphenyltricarboxylic acid, and 1,2-bis( 4-carboxyphenyl)ethane were obtained as by.products in the polycondensation of BHET. The side reactions sometimes lead to the deterioration of the physical and chemical properties of the poly(ethylene terephthalate) (PET) obtained. 2 · 3 · 7 In order to manufacture PET of high quality, details of the side reactions in the polycondensation must be investigated.BHET was prepared by the reaction of terephthalic acid with ethylene oxide. 9One of the present authors previously identified the mechanism of the polycondensation of BHET in the presence of catalysts (Co, Mn, Zn). 8 In this research, aromatic compounds formed by the side reactions in the polycondensation of BHET were determined quantitatively in the presence of a catalyst (Mn, Co, Zn, W); the mechanisms for the side reactions are discussed here.Catalysts (commercially available guaranteed grade) and a radical inhibitor, 1,3,4, Shell Fine Chemicals), were used without further prufication. Polycondensation of BHETPolycondensation ofBHET (1.5 mol) was carried out in a 1.0 dm 3 autoclave in the presence of a catalyst (0.3 mmol) at 273°C under reduced pressure. 8 Samples for the study of by-products were taken out of the autoclave at regular time intervals 8 and were subjected to methanolysis. Thermooxidative Degradation of PETThe polymer containing a polycondensation catalyst was powdered and heated for I h in an oven at 300°C under an air stream 4 -6 and was subjected to 787

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“…2 To assure adequate storage stability, leadcorrosion losses may not exceed 25 and 150 mg/in. 2 after 48 and 168 hours, respectively, at 185 0 F. In the present study the storage test was further accelerated by raising the test temperature to 230 0 F. PE-301 containing 0.01 percent water and 1.0 percent phenyla-naphthylamine as the antioxidant was the reference fluid. The effects of added water, TCP, and an aliphatic amine (2,6-ditertlarybAoyl-a-dimethylamino-p-cresol) on the storage stability of the reference polyol are shown in Table 8.…”

Section: Jnteraction Of Tcp Polyol Esters and Watermentioning

confidence: 99%

“…For these and related reasons the pyrolysis of esters of differeni structures haL received significant research attention in recent years (2)(3)(4)(5)(6).…”

Section: Neopentyl Polyol Ft•sers For Jet Engine Lubricants -Effect mentioning

confidence: 99%

Neopentyl polyol esters for jet engine lubricants—effect of tricresyl phosphate on thermal stability and corrosivity

1968

Wear

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Studies in pyrolysis. Part IV. Model systems for the pyrolysis of poly(ethylene terephthalate) and allied polyesters

Cited by 33 publications

References 0 publications

Thermal decomposition of ethylene–comonomer mixtures under high pressure

Thermal decomposition of ethylene–comonomer mixtures under high pressure

Formation of Aromatic Compounds as Side Reactions in the Polycondensation of Bis(2-hydroxyethyl) Terephthalate

Neopentyl polyol esters for jet engine lubricants—effect of tricresyl phosphate on thermal stability and corrosivity

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