Reactivity of Aliphatic Dicarboxylic Acids in Wet Air Oxidation Conditions

Kaldas, Kristiina; Preegel, Gert; Muldma, Kati; Lopp, Margus

doi:10.1021/acs.iecr.9b01643

Cited by 5 publications

(10 citation statements)

References 50 publications

(113 reference statements)

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“…This indicates that the temperature rise caused faster degradation of the primary oxygenated intermediates. A similar phenomenon was described in our previous work for DCA stability, where we found that at 200 °C, a considerable degradation of DCAs (C4–C10) occured . When the WAO of the oil shale was carried out at lower temperatures, ranging from 150 to 165 °C, the yield of the formed DCAs was less than 6%.…”

Section: Resultsmentioning

confidence: 73%

“…A similar phenomenon was described in our previous work for DCA stability, where we found that at 200 °C, a considerable degradation of DCAs (C4–C10) occured. 33 When the WAO of the oil shale was carried out at lower temperatures, ranging from 150 to 165 °C, the yield of the formed DCAs was less than 6%. In this respect, the temperature range for the acceptable conversion of the oil shale to SO and the formation of DCAs is around 175 °C.…”

Section: Resultsmentioning

confidence: 99%

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Wet Air Oxidation of Oil Shales: Kerogen Dissolution and Dicarboxylic Acid Formation

et al. 2020

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Until now, the oil shale kukersite has been used mainly for energy and oil production. To broaden the possible applications of oil shales, the wet air oxidation of kukersite (an organic-rich sedimentary rock from Estonia) was studied. Kukersite was oxidized with an oxygen-rich gas in water at temperatures up to 200 °C and pressures up to 60 bar. The efficiency of this batch process was evaluated from organic matter conversion, from the amount of solubilized organics obtained, and from the rate of dicarboxylic acid (DCA) formation. The effect of several reaction parameters—pressure, temperature, time, acid/base additives, substrate concentration, the origin of a substrate and its organic matter content, and so forth—was measured. A conversion of 91% in total organic carbon was achieved at 175 °C with 40 bar of the 1:1 oxygen/nitrogen mixture in 3 h without the presence of any additives. Under basic conditions, high yields (up to 50%) of dissolved organic matter were obtained with 8% of DCA; the best results are obtained with K 2 CO 3 and KOH. The highest DCA outcome (12%) within the 3 h reaction time was obtained in the presence of acetic acid. It was found that temperatures higher than 185 °C, pressures over 30 bar of pO 2 , and long reaction times in the acidic media caused a considerable decrease in the DCA outcome. It was also found that the same process can be applied to shales of different origins, although with lower DCA yields.

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Section: Resultsmentioning

confidence: 73%

Section: Resultsmentioning

confidence: 99%

Wet Air Oxidation of Oil Shales: Kerogen Dissolution and Dicarboxylic Acid Formation

et al. 2020

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“…For K-70 and K-90, the amount of C6-C10 DCAs was 14% and 7%, respectively [24]. It has also been demonstrated that pure DCAs are relatively stable in water up to 175 °C or higher, but the presence of bases or organic co-oxidants induces their decomposition [32]. Therefore, the decomposition of the formed products is an essential factor when adapting the WAO process to oil shale to obtain DCA.…”

Section: Dca Destruction In the Presence Of Oil Shalementioning

confidence: 99%

Aspects of kerogen oxidative dissolution in subcritical water using oxygen from air

Kaldas¹,

Lopp²,

Muldma³

et al. 2021

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Society's growing demands on everyday products and materials are increasingly difficult to meet in an environment that seeks to avoid petroleumbased processes. Instead of abandoning fossil materials altogether, more research should be done on their efficient and clean conversion. One option for this is the oxidative dissolution of kerogen in water under conditions that satisfy the subcritical range (T = 150-200 °C, pO 2 = 0.5-4 MPa). The resulting mixture contains a substantial amount of various aliphatic carboxylic and dicarboxylic acids. Both batch and semi-continuous processes were set up to find the main factors and optimal conditions for the kerogen dissolution process. The rate of transformation of organic carbon to dissolved organic compounds was mainly influenced by elevated temperature and oxygen partial pressure. To obtain high yields of organic carbon dissolution and to avoid the formation of excess CO 2 , the oxidation of kerogen should be carried out fast (< 1 h) and under high oxygen pressure. By employing a temperature of 175 °C and O 2 pressure of 2 MPa, over 65% of the initial organic carbon dissolves in about one hour. Prolonged reaction times or harsher oxidation conditions resulted in a rapid degradation of dissolved matter and also of the valuable products formed. The organic matter content of the initial oil shale had a direct effect on the further degradation of dicarboxylic acid and consequently on the overall yield. The suitability of using a trickle-bed reactor for kerogen dissolution is discussed in detail on the basis of experimental results.

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“…This treatment offers a high versatility and efficiency in the degradation of different nonbiodegradable organic pollutants, using air or oxygen gas as oxidants under moderate to high temperature (below 200 °C) and pressure (5–50 bar) conditions. , Furthermore, the catalytic process (CWAO) improves the degradation of the pollutant, being able to operate at milder conditions in a real-scale scenario . Generally, the pollutants are totally oxidized to carbon dioxide, water, short-chain organic acids, and nonhazardous compounds to the environment …”

Section: Introductionmentioning

confidence: 99%

“…26 Generally, the pollutants are totally oxidized to carbon dioxide, water, short-chain organic acids, and nonhazardous compounds to the environment. 27 The main challenge in the development of a catalyst is to provide a high resistance to the deactivation within the catalytic oxidative process. Generally, supported catalysts based on noble metals such as palladium, platinum, ruthenium, rhodium, etc.…”

Section: Introductionmentioning

confidence: 99%

Highly Efficient Ru Supported on Carbon Nanosphere Nanoparticles for Ciprofloxacin Removal: Effects of Operating Parameters, Degradation Pathways, and Kinetic Study

Serra-Pérez

Ferronato

Giroir‐Fendler

et al. 2020

Ind. Eng. Chem. Res.

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In this work, the capability of the catalytic wet air oxidation process (CWAO) using a ruthenium-carbon nanosphere catalyst (CNS-Ru) for the degradation of the widely spread antibiotic ciprofloxacin (CPF) has been investigated. The effect of the operating conditions on oxidative process, as well as different loads of ruthenium in the catalyst (1–10 wt %), reusability of the solid, reaction kinetics, and the pollutant degradation mechanism were investigated. The complete degradation of the pollutant was achieved at only 90 min reaction time within the following operation conditions: 140 °C, 20 bar, [CPF]0 = 20 mg·L–1, [CNS-Ru] = 0.67 g·L–1, 2 wt % of ruthenium, and initial pH 7.0. The catalyst was stable and could be successfully reused within three consecutive cycles with no loss of active phase. Two potential kinetic models were used for simulating the kinetic behavior of CPF in noncatalytic and catalytic processes. Finally, a degradation pathway involving 12 compounds was proposed.

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Reactivity of Aliphatic Dicarboxylic Acids in Wet Air Oxidation Conditions

Cited by 5 publications

References 50 publications

Wet Air Oxidation of Oil Shales: Kerogen Dissolution and Dicarboxylic Acid Formation

Wet Air Oxidation of Oil Shales: Kerogen Dissolution and Dicarboxylic Acid Formation

Aspects of kerogen oxidative dissolution in subcritical water using oxygen from air

Highly Efficient Ru Supported on Carbon Nanosphere Nanoparticles for Ciprofloxacin Removal: Effects of Operating Parameters, Degradation Pathways, and Kinetic Study

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