Nitric acid decomposition kinetics in mixed acid and their use in the modeling of aromatic nitration

Somma, Ilaria Di; Marotta, Raffaele; Andreozzi, Roberto; Caprio, V.

doi:10.1016/j.cej.2013.04.100

Cited by 17 publications

(6 citation statements)

References 8 publications

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“…After being formed in the organic phase, Ph is transferred into the acid phase where it should be nitrated to MNPs. However, despite the expected Ph depletion from the reaction medium, this was not observed most probably due to a variety of situations: (i) low nitric acid content (<900 ppm 30 min after the reaction beginning and <260 ppm at the reaction end), reason that could explain the low extent of Ph nitration; (ii) Bz oxidation to Ph by nitrogen oxides (NO x ) known to be formed by nitric acid decomposition (which yields potential oxidants 27,28 Typically, in Bz nitration studies, only the di-and trinitrated phenolic byproducts are accounted for. As Ph and MNPs have less nitro groups (−NO 2 is a powerfull ring deactivating group), they are more reactive than DNPs and TNP.…”

Section: Industrial and Engineering Chemistry Researchsupporting

confidence: 90%

Phenol in Mixed Acid Benzene Nitration Systems

Afonso

Ribeiro²,

Araújo³

et al. 2018

Ind. Eng. Chem. Res.

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Phenol was detected for the first time in the mononitrobenzene production process by benzene adiabatic nitration, supporting the theory that proposes phenol as the precursor of nitrophenols, unwanted byproducts. For that, analytical procedures (based in liquid and gas chromatographic techniques) have been developed and improved that aim to detect these chemical species both in the industrial nitration process as well as in laboratory tests at different reaction conditions. The obtained results confirmed the proposed and accepted mechanism for the nitrophenols formation during benzene nitration, showing that phenol is indeed the nitrophenolic byproducts precursor. Moreover, it is shown the phenol's high reactivity even at smooth reaction conditions (namely low temperature and low sulfuric acid concentration), which explains the difficulty of detecting this compound within the reaction medium using the analytical techniques applied for monitoring benzene nitration process. In this study, it was also discovered that 4-mononitrophenol had higher affinity into the aqueous acid phase when compared to the other nitrophenolic byproducts (2-mononitrophenol; 2,4-dinitrophenol; 2,6-dinitrophenol; and 2,4,6-trinitrophenol) that have more affinity into the organic phase. Phenol distribution between both reaction phases was found to be similar to the majority of the nitrophenols, i.e., it is present in higher concentration in the organic phase.

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Section: Industrial and Engineering Chemistry Researchsupporting

confidence: 90%

Phenol in Mixed Acid Benzene Nitration Systems

Afonso

Ribeiro²,

Araújo³

et al. 2018

Ind. Eng. Chem. Res.

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“…However, this kind of wastewater often contains only 5–10 wt % free hydrogen chloride, which is extremely difficult to remove . Several techniques including neutralization, roasting, extraction, − evaporation, distillation, and membrane separation have been reported to remove hydrogen chloride. Although these methods show good separation selectivity, some disadvantages, including secondary pollution, high cost, and energy consumption, make them commercially unfeasible.…”

Section: Introductionmentioning

confidence: 99%

Alkoxy-Group-Functionalized UiO-66 as Highly Efficient Adsorbents for Hydrogen Chloride Removal from Aqueous Solution

et al. 2018

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A series of alkoxy group-functionalized UiO-66 were designed for hydrogen chloride adsorption from aqueous solution, which were characterized by various methods to verify the structures and study the adsorption mechanism. A volcano-shaped change of adsorption capacity was discovered. UiO-66-C 2 exhibited the highest adsorption capacity and excellent structure stability. The adsorption kinetics, isotherms, and thermodynamics were studied. It was found that the pseudo-second-order kinetic model fit the experimental data well in kinetic studies. Meanwhile, both Henry and Freundlich models fitted the isotherm experiment data well. The thermodynamics parameters further confirmed that hydrogen chloride adsorption on UiO-66-C 2 was a spontaneous and exothermic physisorption process. Regeneration experiment demonstrated that UiO-66-C 2 has high regeneration efficiency and no significant change in adsorption capacity was confirmed after recycles. All the results substantiated that UiO-66-C 2 could be an efficient solution to treatment of acidic wastewater.

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“…For instance, there are , and unionized, molecular nitric acid in mixed acids. [37][38][39] It can be seen from the structural formula of nitric acid that the most easily broken bonds are the H-O bond and N-O bond, by which H + and are generated via acidic ionization and basic ionization, respectively. Sulfuric acid is referred to as a nitration activator.…”

Section: 52mentioning

confidence: 99%

Determination of the kinetics of chlorobenzene nitration using a homogeneously continuous microflow

Deng

et al. 2021

Preprint

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The nitration of chlorobenzene with concentrated mixed acids is a fast and highly exothermic process, which suffers from considerable mass transfer resistance and poor heat transfer rates. The reaction kinetics has not been thoroughly reported before. In this work, a continuous-flow microreactor system and a homogeneous reaction condition were proposed to obtain accurate chlorobenzene nitration kinetics data at high mixed acid concentrations. A general model for predicting the observed reaction rate constants was established. With a new method for estimating the equilibria associated with HNO3 in aqueous sulfuric acid, the rate constants based on nitronium ion and activation energies were obtained. Compared with batch reactors, the continuous-flow microreactor system allows for a sufficient heat transfer efficiency and accurate residence time control, making it possible to study the reaction performance more quickly and sensitively. This work may provide a reliable reference for the kinetic study of similar processes.

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Nitric acid decomposition kinetics in mixed acid and their use in the modeling of aromatic nitration

Cited by 17 publications

References 8 publications

Phenol in Mixed Acid Benzene Nitration Systems

Phenol in Mixed Acid Benzene Nitration Systems

Alkoxy-Group-Functionalized UiO-66 as Highly Efficient Adsorbents for Hydrogen Chloride Removal from Aqueous Solution

Determination of the kinetics of chlorobenzene nitration using a homogeneously continuous microflow

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