CO<sub>2</sub>-Protected Amine Formation from Nitrile and Imine Hydrogenation in Gas-Expanded Liquids

Xie, Xianmei; Liotta, and Charles L.; Eckert, Charles A.

doi:10.1021/ie0498201

Cited by 88 publications

(71 citation statements)

References 35 publications

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“…The distance between O and H is 1.906 Å in the absence of CO2 (Figure 10a) and it is extended to 1.945 and 1.952 Å when the CO2-coordinated clusters are formed ( Figure 10b, 10c), which clearly indicates that the intra-hydrogen bonding between 2-nitro group and amino group in 1 is weakened by the coordination of CO2 around 1. It is well known that an amine species has strong affinity with CO2 32,33 and it may cause the suppression of intra-hydrogen bonding, resulting in the increase of the reactivity of 2-nitro group in 1 as above-mentioned in Figure 2. The structures of CO2-coordinated clusters of 2NA and 4NA with three and four CO2 molecules were also calculated using DFT simulations (Figure 11).…”

Section: Molecular Simulationsmentioning

confidence: 97%

Molecular interactions with CO₂ for controlling the regioselectivity of liquid phase hydrogenation of 2,4-dinitroaniline

Yoshida

Tomizawa

Tachikawa

et al. 2014

Phys. Chem. Chem. Phys.

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Abstract:The catalytic hydrogenation of 2,4-dinitroaniline with a 0.5 wt% Pt/TiO2 was investigated in a multiphase medium of tetrahydrofuran (THF) pressurized by CO2 at different pressures and at 323 K. When CO2 pressure was raised, the overall rate of hydrogenation simply decreased but the selectivity to the desired product of 4-nitro-1,2-phenylenediamine increased. The noticeable enhancement of the selectivity to 4-nitro-1,2-phenylenediamine can be explained by chemical actions of CO2 molecules.In situ high-pressure FTIR and molecular simulations demonstrate that the dissolved CO2 molecules may interact with amino group of the substrate and weaken the intra-hydrogen bonding between the amino and 2-nitro groups, which results in the change of the relative reactivity of the two nitro groups, yielding the desired product in a higher selectivity. The change of the intra-and inter-molecular interactions between the substrate and CO2 molecules was theoretically examined by DFT calculation.2

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Section: Molecular Simulationsmentioning

confidence: 97%

Molecular interactions with CO₂ for controlling the regioselectivity of liquid phase hydrogenation of 2,4-dinitroaniline

Yoshida

Tomizawa

Tachikawa

et al. 2014

Phys. Chem. Chem. Phys.

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“…That is, CO 2 can function as a reaction promoter for liquid-phase reactions as well as gas-liquid reactions such as oxidation [20][21][22][23], hydrogenation [24][25][26][27][28][29][30], and hydroformylation [31][32][33]. For the substrates of iodobenzene and methyl acrylate, however, no positive effect of CO 2 pressurization on the rate of Heck reaction was observed [16].…”

Section: Methodsmentioning

confidence: 99%

Carbon dioxide pressure induced heterogeneous and homogeneous Heck and Sonogashira coupling reactions using fluorinated palladium complex catalysts

Akiyama

Meng

Fujita

et al. 2009

The Journal of Supercritical Fluids

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The Heck reaction of iodobenzene and methyl acrylate was investigated with CO 2 -philic Pd complex catalysts having fluorous ponytails and the organic base triethylamine (Et 3 N) in the presence of CO 2 under solventless conditions at 80 C. The catalysts are not soluble in the organic phase in the absence of CO 2 and the reaction occurs in a solid-liquid biphasic system. When the organic liquid mixture is pressurized by CO 2 , CO 2 is dissolved into the organic phase and this promotes the dissolution of the Pd complex catalysts. As a result, the Heck reaction occurs homogeneously in the organic phase, which enhances the rate of reaction. This positive effect of CO 2 pressurization competes with the negative effect that the reacting species are diluted by an increasing amount of CO 2 molecules dissolved. Thus, the maximum conversion appears at a CO 2 pressure of around 4 MPa under the present reaction conditions. The catalysts are separated in the solid granules by depressurization and are recyclable without loss of activity after washing with n-hexane and/or water. When the washing is made with hexane alone, the catalytic activity tends to increase on the repeated Heck reactions, probably due to the accumulation of such a base adduct as Et 3 NHI on the catalysts. When the washing is further made with water, however, the base adduct is taken off from the catalysts and they show similar activity levels in the repeated runs. The potential of CO 2 pressure tunable heterogeneous/homogeneous reaction system has also been investigated for Sonogashira reactions of iodobenzene and phenylacetylene under similar conditions.

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“…Xie et al have reported the use CO2-expanded liquids (GXLs) as solvents for this reduction process. [10] In this report, advantage is taken of the fact that CO2 readily dissolves in a wide variety of polar organic solvent. This systems are termed "CO2-expanded liquids" and are simply mixtures of polar organic solvent and CO2.…”

Section: Reversible Protecting Strategiesmentioning

confidence: 99%

Sustainable Chemistry: Reversible reaction of CO2 with amines

Pollet

Liotta

2016

Fr. Ukr. J. Chem.

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The reaction of primary and secondary amines with CO2 has been successfully leveraged to develop sustainable processes. In this article, we review specific examples that use the reversible reaction of CO2 with amines to synergistically enhance reaction and recovery of the products. The three cases of interest highlighted herein are: (i) reversible protection of amines, (ii) reversible ionic liquids for CO2 capture and chemical transformations, and (iii) reversible gels of ethylene diamine. These examples demonstrate that the reversible reaction of amines with CO2 is one of the tools in the sustainable technology's toolbox. ________________________________________________________________________________

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CO₂-Protected Amine Formation from Nitrile and Imine Hydrogenation in Gas-Expanded Liquids

Cited by 88 publications

References 35 publications

Molecular interactions with CO₂ for controlling the regioselectivity of liquid phase hydrogenation of 2,4-dinitroaniline

Molecular interactions with CO₂ for controlling the regioselectivity of liquid phase hydrogenation of 2,4-dinitroaniline

Carbon dioxide pressure induced heterogeneous and homogeneous Heck and Sonogashira coupling reactions using fluorinated palladium complex catalysts

Sustainable Chemistry: Reversible reaction of CO2 with amines

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CO2-Protected Amine Formation from Nitrile and Imine Hydrogenation in Gas-Expanded Liquids

Cited by 88 publications

References 35 publications

Molecular interactions with CO2 for controlling the regioselectivity of liquid phase hydrogenation of 2,4-dinitroaniline

Molecular interactions with CO2 for controlling the regioselectivity of liquid phase hydrogenation of 2,4-dinitroaniline

Carbon dioxide pressure induced heterogeneous and homogeneous Heck and Sonogashira coupling reactions using fluorinated palladium complex catalysts

Sustainable Chemistry: Reversible reaction of CO2 with amines

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Product

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About

CO₂-Protected Amine Formation from Nitrile and Imine Hydrogenation in Gas-Expanded Liquids

Molecular interactions with CO₂ for controlling the regioselectivity of liquid phase hydrogenation of 2,4-dinitroaniline

Molecular interactions with CO₂ for controlling the regioselectivity of liquid phase hydrogenation of 2,4-dinitroaniline