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

Li, Meng; Niu, Fenghui; Zuo, Xinxin; Metelski, Peter D.; Busch, Daryle H.; Subramaniam, Bala

doi:10.1016/j.ces.2013.09.004

Cited by 43 publications

(36 citation statements)

References 62 publications

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“…Therefore, it is highly desirable to develop efficient and sustainable technology for obtaining TPA with low content of CBA directly at the oxidation step to remove the step of high temperature catalytic hydropurification. An interesting solution to the problem of one‐step production of pure TPA was found in designing of a spray reactor as promising alternative to conventional stirred reactor . In this study, we demonstrate another approach to synthesis of TPA with low content of CBA.…”

Section: Figurementioning

confidence: 69%

An Improved Synthetic Approach for Obtaining High‐Quality Terephthalic Acid: Eliminating the Need for Purification

et al. 2017

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The large‐scale production of terephthalic acid (TPA) is currently based on the two‐step technology, with oxidation of p‐xylene in an acetic acid solution containing a Co/Mn/Br catalyst, followed by the purification of the crude product containing the impurity p‐carboxybenzaldehyde (CBA). Here we offer a simple and robust route to the target product, which makes it possible to avoid the tedious and energy‐consuming hydropurification of TPA to remove CBA. We demonstrate that addition of ammonium acetate and ionic liquids to the acetic acid solution changes the reaction medium to improve solubility of TPA and CBA and accelerates oxidation of CBA to TPA. Efficient combinations of the additives and appropriate oxidation conditions have been selected to attain nearly complete oxidation of CBA to TPA over the reaction time and formation of the oxidation product with content of CBA less than 25 ppm without the hydropurification step.

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Section: Figurementioning

confidence: 69%

An Improved Synthetic Approach for Obtaining High‐Quality Terephthalic Acid: Eliminating the Need for Purification

et al. 2017

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“…By altering the ligand environment of either or both the catalyst and promoter, it caused over-oxidation to both IPA and the coupling product C 16 H 16 O 2 . It is known that water also affects the oxidation mechanism by forming the [RCH 2 Á ÁÁÁH 2 O] complex [22,23]. This complex is less reactive than RCH 2 Á or RCO Á for the termination reaction with Co 3?…”

Section: Scheme 1 Lumped Kinetics Of M-xylene Oxidationmentioning

confidence: 98%

“…A typical process for xylene oxidation consists of the homogeneous oxidation of PX to TPA in acetic acid (HAc) using soluble Co and/or Mn salts activated by promoters (e.g., bromide salts, aldehydes) that overcome the problems of acid decarboxylation by rapid electron transfer from cobalt to promoter to peroxy radical [3,4,6,[15][16][17]. The process is typically conducted at 120-200°C and 1.0-3.0 MPa using the so called AMOCO process [1,3,4,6,15,[18][19][20][21][22]. The yield to TPA along with other desired products can reach 85-97 % in 3 h using a combination of Co, Mn, Br, Ce or Zr salts [1,3,4,15,[18][19][20][21]23].…”

Section: Introductionmentioning

confidence: 99%

Waste-Reducing Catalytic Oxidation of m-Xylene to m-Toluic Acid

2016

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Catalytic performances of soluble Co, Co/Mn, Co/Mn/Br, and Co/Mn/Ce catalysts for m-xylene (MX) oxidation without acetic acid (HAc) solvent were studied, comparing with Co/HAc catalysts. In m-toluic acid (MTA) production, a Ce-salt promoter could effectively substitute for bromide salts and the recycle alcohol/aldehyde liquid mixture acts as a more efficient promotor than either peroxides or MTA itself. The Co/Mn/Ce system, free of acetic acid and Br -, was a superior catalyst in terms of activity and selectivity to MTA. Just as for p-xylene oxidation using Co/Mn/Br catalysts, both the MX reaction rate and the MTA selectivity increased with temperature when using Co/Mn/Ce catalysts. Unlike p-xylene oxidation however, MX oxidation resulted in more coupling products. For MX oxidation catalyzed by a supported Co-imide complex in supercritical CO 2 , the activity was lower by more than an order of magnitude, but the MTA selectivity was greater.Graphical Abstract The selectivity behavior of the catalyst systems indicate that the Co/Mn/Ce system, free of acetic acid solvent and corrosive Br -, was a superior catalyst, both in terms of overall activity and selectivity for MTA.

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“…1. p-Xylene has been in badly deficit relative to the market demand, thus, the routes to convert toluene selectively to p-Xylene, such as the acid catalyzed toluene disproportionation and methylation, have been the focus of industrial and academic research for the last few decades [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Detonation and deflagration characteristics of p-Xylene/gaseous hydrocarbon fuels/air mixtures

Zhang

Xiu

Chen

et al. 2015

Fuel

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

Cited by 43 publications

References 62 publications

An Improved Synthetic Approach for Obtaining High‐Quality Terephthalic Acid: Eliminating the Need for Purification

An Improved Synthetic Approach for Obtaining High‐Quality Terephthalic Acid: Eliminating the Need for Purification

Waste-Reducing Catalytic Oxidation of m-Xylene to m-Toluic Acid

Detonation and deflagration characteristics of p-Xylene/gaseous hydrocarbon fuels/air mixtures

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