Methyl acetate: by-product in the terephthalic acid production process. Mechanisms and rates of formation and decomposition in oxidation

Roffia, P.; Calini, Pierangelo; Tonti, S.

doi:10.1021/ie00077a008

Cited by 16 publications

(14 citation statements)

References 3 publications

(5 reference statements)

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“…The stability of FDCA was further studied in the presence of HMF because the free radicals generated by substrate oxidation might attack the product and cause it to decompose, as has been observed in solvent decomposition. 54 Thus, two reactions were carried out based on which the recovery of FDCA can be estimated. The first experiment involves the oxidation of 352 mg HMF at 180 °C and 60 bar and yielded 324 mg FDCA.…”

Section: Benchmark Of Semicontinuous Oxidation At 160 °Cmentioning

confidence: 99%

Optimization of Co/Mn/Br-Catalyzed Oxidation of 5-Hydroxymethylfurfural to Enhance 2,5-Furandicarboxylic Acid Yield and Minimize Substrate Burning

Zuo

Venkitasubramanian

Busch

et al. 2016

ACS Sustainable Chem. Eng.

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2,5-furandicarboxylic acid (FDCA) is a valuable non-phthalate biomass-based plastic precursor with the potential to replace terephthalic acid (TPA) in a variety of polymer applications. In this work, the Co/Mn/Br catalyzed semi-continuous oxidation of 5hydroxymethylfurfural (HMF) to FDCA has been carried out at temperatures lower than those of the traditional Mid-Century (MC) process. As HMF is more susceptible to side reactions (e.g. the over-oxidation to CO and CO 2 ), lower temperatures compared to the MC process are typically used to prevent substrate burning. However, lower temperatures afford much decreased FDCA yield compared to that of TPA in p-xylene oxidation. Therefore, optimization of other operating variables such as catalyst composition, water concentration in the acetic acid solvent and pressure are essential to maximize FDCA yield. Using such optimization, we show that the FDCA yield can be enhanced to 90% at 1/0.015/0.5 molar ratio of Co, Mn and Br, 7% (v/v) water, 30 bar (CO 2 /O 2 = 1/1, mol/mol) and 180 o C, the highest value reported for HMF oxidation using Co/Mn/Br catalyst. The use of Zr(IV) as co-catalyst facilitates FDCA formation, but only at lower temperatures (120-160 °C) where the FDCA yield is compromised. These findings broaden the scope of the application of the industrial MC catalytic process for FDCA production. use) by 65%. As a result, FDCA has been identified by DOE as one of the top twelve building blocks for the future green chemicals industry. 12, 13 The oxidation of HMF to FDCA was originally carried out in presence of strong oxidants, such as nitric acid or KMnO 4 . 2,14 Apart from environmental concerns, these systems produced only modest FDCA yield owing to substrate destruction under the harsh oxidizing conditions. Alternatively, oxidation with molecular oxygen, a much milder and cleaner oxidant, has been developed, employing noble metals such as platinum, 15-20 gold 21-27 and Pd 28-33 as active catalysts.During the past five years, these heterogeneous catalytic systems have been extensively studied and shown to provide nearly quantitative FDCA yield at relatively mild reaction temperatures (65-130 °C). However, because of its low solubility in the reaction medium, FDCA tends to precipitate out in the course of reaction, which might not only deactivate the catalysts by blocking the active sites but also causes separation problems. For this reason, sodium hydroxide is added in some cases to convert the diacid product into its sodium salt, which, after removal of the catalysts, must be treated with a strong acid for recovery of FDCA. 18,23,24 More recently, several base-free processes have been reported by using hydrotalcite-supported gold nanoparticles, 25 carbon nanotube-supported gold-palladium alloy nanoparticles 34 , covalent triazine supported ruthenium 35 and magnetic Fe 3 O 4 −CoO x 36 as catalysts. Nevertheless, even in these cases, the substrate (HMF) concentration needs to be maintained very low to avoid FDCA precipitation. The potential for practical appl...

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Section: Benchmark Of Semicontinuous Oxidation At 160 °Cmentioning

confidence: 99%

Optimization of Co/Mn/Br-Catalyzed Oxidation of 5-Hydroxymethylfurfural to Enhance 2,5-Furandicarboxylic Acid Yield and Minimize Substrate Burning

Zuo

Venkitasubramanian

Busch

et al. 2016

ACS Sustainable Chem. Eng.

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“…[17] There is a close association of the rate of decomposition of the acetic acid to the rate of formation of methanol and methyl acetate. [18] The mechanisms of formation of these species are rationalized by the following set of reactions: ð2Þ ð3Þ Figure 2. Rate of reaction of dioxygen and rate of formation of carbon monoxide, carbon dioxide, and methyl 3,4-DMbenzoate.…”

Section: Some Possible Mechanisms For the Unusual Behaviormentioning

confidence: 99%

The Unusual Characteristics of the Aerobic Oxidation of 3,4‐Dimethoxytoluene with Metal/Bromide Catalysts

Partenheimer

2004

Adv Synth Catal

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DMtoluene (3,4-dimethoxytoluene; DM ¼ 3,4-dimethoxy), a model compound for lignin oxidation, can be autoxidized in acetic acid using a Co/Mn/ Br catalyst to its benzaldehyde in 51 mol % yield, and to its acid in 85 -92 mol % yield. This synthesis is unusual because a number of unprecedented phenomena occur. 1) The rate of molecular oxygen reacting with the substrate is bi-phasic, i.e., two maximum in the rate of reaction are observed. 2) In the first phase, all of the 3,4-dimethoxytoluene is converted to intermediates, but very little to the carboxylic acid. 3) During the second maximum of activity, virtually all the intermediates are converted to the carboxylic acid with 95 -100% mass accountability. 4) The rate of carbon monoxide and carbon dioxide formation is considerably higher during the second phase during which 5) 9 -12% of methyl 3,4-dimethoxybenzoate (the methyl ester of the benzoic acid) is formed. Mechanisms are suggested for these unusual phenomena.

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“…1.3). Roffia et al [41] studied the formation of methyl acetate and found that methyl acetate can be conveniently hydrolyzed over ion exchange catalysts, for example, to convert methyl acetate to methanol and acetic acid, which is then recycled.…”

Section: Px Oxidationmentioning

confidence: 99%

A spray reactor concept for catalytic oxidation of p-xylene to produce high-purity terephthalic acid

Niu

Zuo

et al. 2013

Chemical Engineering Science

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Methyl acetate: by-product in the terephthalic acid production process. Mechanisms and rates of formation and decomposition in oxidation

Cited by 16 publications

References 3 publications

Optimization of Co/Mn/Br-Catalyzed Oxidation of 5-Hydroxymethylfurfural to Enhance 2,5-Furandicarboxylic Acid Yield and Minimize Substrate Burning

Optimization of Co/Mn/Br-Catalyzed Oxidation of 5-Hydroxymethylfurfural to Enhance 2,5-Furandicarboxylic Acid Yield and Minimize Substrate Burning

The Unusual Characteristics of the Aerobic Oxidation of 3,4‐Dimethoxytoluene with Metal/Bromide Catalysts

A spray reactor concept for catalytic oxidation of p-xylene to produce high-purity terephthalic acid

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