The photochemical isomerization of maleic to fumaric acid: an undergraduate organic chemistry experiment

Castro, Albert J.; Ellenberger, Suzanne R.; Sluka, James P.

doi:10.1021/ed060p521

Cited by 10 publications

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“…The isomerization also occurs by heating an aqueous solution of maleic acid in a sealed tube above 130° C, by catalyzing with various acids and salts at ≈ 100° C and as a result of bromine atoms. [1][2][3][4][5][6][7][8][9] The first investigation on the temperature dependence of the isomerization kinetics for the maleic acid in the liquid state was performed by Hojendal. 10 He found an activation energy of 15.8 kcal mol -1 .…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of the Isomerization of Maleic Acid Into Fumaric Acid

Ugarte

Bustos

Moreno‐Villoslada

2011

J. Chil. Chem. Soc.

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The isomerization reaction of 2-butenedioic acid in gas phase has been studied using Hartree-Fock (HF), Møller-Plesset to 2 nd order (MP2) and BLYP, B3LYP Density Functional Theory (DFT) levels of approximation. Potential energy surfaces (PES) of the singlet and triplet states of the molecule are constructed in order to corroborate the hypothesis that the reaction proceeds by a non-adiabatic path. A total of ten stationary points (eight singlet and two triplet) were characterized as energy minima or saddle points. Thermochemical analysis of the triplet conformers and singlet most stable structures yields a value of the ΔH° of activation for isomerization that is in good agreement with the expected results.

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Section: Introductionmentioning

confidence: 99%

Theoretical Study of the Isomerization of Maleic Acid Into Fumaric Acid

Ugarte

Bustos

Moreno‐Villoslada

2011

J. Chil. Chem. Soc.

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“…Thus, researchers have tried to develop isomerization methods to improve the synthesis efficiency. Several noteworthy catalysts have been reported to enhance the reaction conditions and increase the productivity of fumaric acid, including bromate ion, , vanadium pentoxide, hydrochloric acid, and poly(4-vinyl pyridine) . In a further study, researchers have introduced microwaves to reduce the reaction time of maleic acid and malic acid for assisted synthesis .…”

Section: Introductionmentioning

confidence: 99%

Kinetic Study on the Preparation of Fumaric Acid from Maleic Acid by Batch Noncatalytic Isomerization

2019

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In recent years, the increase in demand for fumaric acid from industry has resulted in an increased need for a high-selectivity process for the conversion of maleic acid to fumaric acid. A highly selective conversion of fumaric acid was achieved without a catalyst by a simple one-step hydrothermal reaction. In addition, the competitive conversion of maleic acid, fumaric acid, and malic acid was first systematically investigated in detail without using a catalyst. The products were characterized by X-ray diffraction and Fourier transform infrared, which demonstrated that the product was fumaric acid. The highly selective conversion of fumaric acid was achieved, and the yield of fumaric acid could reach 92%. Furthermore, a reaction kinetic model was put forward to study the competitive transformation process. The kinetic model predictions were found to agree well with the experimental data. The kinetic parameters were used to explain the changes in the content of every substance at different reaction temperatures and reaction times. In addition, the initial maleic acid concentration in the reaction was also considered as an influencing factor. These results can facilitate the conditional control and product control of industrial processes for the production of fumaric acid or malic acid using latter without a catalyst.

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“…Se encuentra, por ejemplo, en plantas del género fumaria (Fumaria officinalis), en el liquén Cetraria islandica y en hongos de las especies Boletus y Agaricus. 1 La forma ionizada del ácido fumárico (fumarato) es un intermediario clave en el ciclo de Krebs. El ácido maleico es un producto de síntesis obtenido a partir de la hidrólisis del anhídrido maleico; este último, se produce a partir de la oxidación catalítica (V 2 O 5 , aire, 400-500 ºC) del benceno.…”

Section: Introductionunclassified

“…1 En las reacciones de isomerización en disolución acuosa, el ácido fumárico cristaliza a medida que va siendo formado, desplazando el equilibrio de reacción y dando como resultado un alto rendimiento en producto. Por otro lado, la luz ultravioleta provoca que en una disolución de ácido fumárico se establezca un equilibrio entre los dos isómeros.…”

Section: Introductionunclassified

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Estudio teórico de la isomerización del ácido maleico en ácido fumárico: un enfoque basado en el concepto de superficie de energía potencial

Ugarte¹,

Salgado²,

Martínez³

et al. 2010

Quím. Nova

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POTENTIAL ENERGY SURFACE. A comparative study based on potential energy surfaces (PES) of 2-butanedioic and hypothetic 2-butanedioic/HCl acids is useful for understanding the maleic acid isomerization. The PES enables locating conformers of minimum energy, intermediates of reactions and transition states. From contour diagrams, a set of possible reaction paths are depicted interconnecting the proposed structures. The study was carried out in absentia and in the presence of the catalyst (HCl), using an solvatation model provided by the Gaussian software package. Clearly, the effect of HCl is given by new reaction paths with lower energetic barriers in relation to the reaction without catalyzing.Keywords: potencial energy surface; isomerization; maleic acid. INTRODUCCIÓNUna clase particular de isómeros geométricos (cis-trans) son aquellos compuestos que difieren en el ordenamiento espacial de los grupos ligados a un enlace doble. En estos isómeros, los dos grupos unidos al átomo de carbono de un enlace doble son diferentes entre sí; lo mismo es válido para el otro átomo de carbono; sin esta condición, los dos isómeros serían indistinguibles. Normalmente, existirá una rotación libre y una restringida alrededor de un enlace simple y uno doble, respectivamente. Así, los grupos que se unen a átomos de carbono de un enlace doble permanecerán fijos a uno u otro lado del enlace. Al presentar propiedades diferentes, los isómeros cis-trans pueden ser distinguidos uno del otro.La proporción en que coexisten en equilibrio, a una determinada temperatura, las diferentes poblaciones de isómeros depende de sus diferencias en energías libres, ΔGº. No obstante, el equilibrio de interconversión se producirá siempre y cuando la barrera rotacional, representada por la energía libre de activación (ΔG ‡ ), no sea demasiado alta. Un ejemplo clásico de isomería cis-trans es la representada por el ácido 2-butenodioico, que en condiciones normales es un sólido. En este compuesto el isómero cis-2-butenodioico recibe el nombre de ácido maleico, mientras que el trans-2-butenodioico se denomina ácido fumárico.El ácido fumárico se distribuye ampliamente en la naturaleza. Se encuentra, por ejemplo, en plantas del género fumaria (Fumaria officinalis), en el liquén Cetraria islandica y en hongos de las especies Boletus y Agaricus.1 La forma ionizada del ácido fumárico (fumarato) es un intermediario clave en el ciclo de Krebs. El ácido maleico es un producto de síntesis obtenido a partir de la hidrólisis del anhídrido maleico; este último, se produce a partir de la oxidación catalítica (V 2 O 5 , aire, 400-500 ºC) del benceno.De acuerdo a los valores del calor de formación de ambos isóme-ros en fase sólida ( Tabla 1) 2 se deduce que el isómero cis es ≈ 4.9 kcal mol -1 menos estable que el isómero trans. Esta diferencia se explica sí consideramos los posibles puentes de hidrógeno intermoleculares en ambos isómeros (dos para la forma trans y uno para la forma cis) y la proximidad de los dos grupos carbóxilo en el isómero cis; si bien la repulsión est...

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The photochemical isomerization of maleic to fumaric acid: an undergraduate organic chemistry experiment

Cited by 10 publications

References 0 publications

Theoretical Study of the Isomerization of Maleic Acid Into Fumaric Acid

Theoretical Study of the Isomerization of Maleic Acid Into Fumaric Acid

Kinetic Study on the Preparation of Fumaric Acid from Maleic Acid by Batch Noncatalytic Isomerization

Estudio teórico de la isomerización del ácido maleico en ácido fumárico: un enfoque basado en el concepto de superficie de energía potencial

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