Formation of Phthalic Anhydride by Diels–Alder Reaction During n-Pentane Oxidation on VPO Catalysts and Control of the Process Selectivity

Zazhigalov, V. A.; Kiziun, O.V.

doi:10.1007/s11237-017-9515-9

Cited by 4 publications

(1 citation statement)

References 10 publications

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“…Zazhigalov and Kiziun in 2017 reported PA production by Diels–Alder reaction during n -pentane oxidation on vanadium phosphorus oxide (VPO) catalyst. 24 Kim and Yang in 2000 studied the synthesis of maleic and phthalic anhydrides from the mixture of cyclopentene and 1-pentene via their selective oxidations under different reaction parameters. 25 …”

Section: Introductionmentioning

confidence: 99%

Phthalic anhydride (PA): a valuable substrate in organic transformations

Nikoofar,

Sadathosainy

2023

RSC Adv.

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Section: Introductionmentioning

confidence: 99%

Phthalic anhydride (PA): a valuable substrate in organic transformations

Nikoofar,

Sadathosainy

2023

RSC Adv.

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Activation of C–H bonds of normal alkanes in sulfuric acid solutions of Mn(III)/Mn(II)

Volkova¹,

Opeida²

2021

Kataliz ta naftohimia

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One of the most important directions of establishing the mechanisms of activation of C–H bonds, both in saturated and aromatic hydrocarbons in aqueous and sulfuric acid solutions of oxidants, metal complexes and radicals, is to study the kinetics of reactions and the influence of temperature, environment, nature of reagents, etc. The study of mechanisms is important for the development of technologies for processing hydrocarbons into products with high added value. In this work, to determine the nature of limiting stages and mechanisms of reactions of one group of saturated hydrocarbons, normal alkanes, we use the dependences of substrate selectivity (relative rate constants) on their characteristics: ionization potentials, energy and number of primary and secondary C–H bonds. To determine the nature of the limiting stages of reactions of normal alkanes, the correlations between the logarithms of substrate selectivity of alkanes reactions in H2SO4 solutions with one of the most active manganese(III) ions and molecule properties or C–H bond type were studied by the method of correlation analysis. Comparison of the obtained results with quantum-chemically calculated enthalpy changes of different possible variants of the course of this elementary reaction allowed to clarify the mechanism and propose tests to perform the mechanism of the slow limiting stage. It is shown that for alkanes (ethane, pentane, hexane, heptane, octane) the linear dependence with the ionization potential is most accurately performed, the least accurate is the correlation with the number of secondary C–H bonds, which indicates the electron abstraction in the slow limiting stage. For the shorter pentane – octane series, correlation dependences on both the number of secondary C–H bonds and the ionization potentials are performed with almost equal accuracy, which makes it impossible to establish the nature of the slow stage. The results of quantum-chemical calculations of hexane reactions in Mn(III)/Mn(II)–H2SO4 solutions showed that the most favorable are the electron abstraction by manganese(III) and subsequent proton transfer or homolysis of the C–H bond under the action of bisulfate radical, which is likely formed in the oxidation of sulfuric acid by manganese(III).

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The pathways of the phthalic anhydride selectivity and yield increase at C4-C5-hydrocarbons oxidation

Kiziun¹,

Zazhigalov²

2022

Kataliz ta naftohimia

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The investigation of n-butane and n-pentane oxidation in system with two consecutive reactors confirmed the mechanism of phthalic anhydride formation by Diels-Alder reaction between maleic anhydride and C4 unsaturated hydrocarbons. The process is limited by low stationary concentration of C4 unsaturated hydrocarbons in reaction mixture which is connected with high rate of their oxidation to maleic anhydride. It was shown that n-butane oxidation leads to formation of maleic anhydride only but the introduction of unsaturated C4-hydrocarbons on inlet of the second catalytic reactor accompanied by phthalic anhydride appearance on outlet of these two consecutive reactors system. It was established that in case of 1,3-butene introduction in the second reactor the quantity of phthalic anhydride formed is more than in case of 2-butene addition. It was predicted that a decrease of the temperature in the second reactor can leads to an increase the phthalic anhydride selectivity and its yield as result of Diels-Alder reaction effectiveness. This assumption was confirmed by experimental results. In results the method of phthalic anhydride production by the use of two consecutive reactors was proposed. The summary yield of this product on this new process can reach up to 35 mol. %. In the case of n-pentane oxidation the formation of maleic and phthalic anhydrides was observed with excess of first product but the introduction of unsaturated C4-hydrocarbons in the inlet of second reactor leads to an increase of the phthalic anhydride concentration and its selectivity and yield. In result the yield of phthalic anhydride equal to 35 mol. % can be obtained. So, the proposed by us mechanism of phthalic anhydride was confirmed by new experimental results and other pathways for the selectivity and yield of this product can be predicted.

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Formation of Phthalic Anhydride by Diels–Alder Reaction During n-Pentane Oxidation on VPO Catalysts and Control of the Process Selectivity

Cited by 4 publications

References 10 publications

Phthalic anhydride (PA): a valuable substrate in organic transformations

Phthalic anhydride (PA): a valuable substrate in organic transformations

Activation of C–H bonds of normal alkanes in sulfuric acid solutions of Mn(III)/Mn(II)

The pathways of the phthalic anhydride selectivity and yield increase at C4-C5-hydrocarbons oxidation

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