Effect of water on the kinetics of the catalytic reaction between benzoic acid and aniline

Shteinberg, L. Ya.; Kondratov, S. A.; Shein, S. M.; Marshalova, V. V.

doi:10.1134/s0023158407050059

Cited by 8 publications

(5 citation statements)

References 3 publications

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“…96 The reaction progress of the amidation was also found to be highly dependent on a high mass transfer rate of water. 97 The N-formylation of amines using neat formic acid and zinc(II) chloride as catalyst was investigated by Shekhar et al 98,99 Electron rich aniline derivatives were reported to be highly reactive, furnishing the formamide products in 80-98% yield after 10-90 min at 70 1C using 10 mol% of ZnCl 2 (Scheme 26). Electron-poor aryl amines and secondary amines, however, required longer reaction times (4-15 h) in order to obtain useful yields.…”

Section: Homogeneous Metal-catalysed Protocolsmentioning

confidence: 99%

Catalytic amide formation from non-activated carboxylic acids and amines

et al. 2014

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The amide functionality is found in a wide variety of biological and synthetic structures such as proteins, polymers, pesticides and pharmaceuticals. Due to the fact that synthetic amides are still mainly produced by the aid of coupling reagents with poor atom-economy, the direct catalytic formation of amides from carboxylic acids and amines has become a field of emerging importance. A general, efficient and selective catalytic method for this transformation would meet well with the increasing criterias for green 10 chemistry. This review covers catalytic and synthetically relevant methods for direct condensation of carboxylic acids and amines. A comprehensive overview of homogeneous and heterogeneous catalytic methods is presented, covering biocatalysis, Lewis acid catalysts based on boron and metals as well an assortment of other types of catalysts.

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Section: Homogeneous Metal-catalysed Protocolsmentioning

confidence: 99%

Catalytic amide formation from non-activated carboxylic acids and amines

et al. 2014

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“…The mechanism by which the boron species promotes the formation of amides from carboxylic acids and amines is yet to be fully determined. , However, even under catalytic conditions, water removal is usually needed and the importance of removing water to ensure high conversion levels is regularly reported. , Water removal is generally achieved using a combination of molecular sieves, Soxhlet extraction, and calcium hydride or using azeotropic distillation with toluene or xylenes as entrainers together with a Dean–Stark apparatus (or phase-splitter on plant) to effect separation of the biphasic mixture . The latter is a form of reactive distillation .…”

Section: Introductionmentioning

confidence: 99%

Intensified Azeotropic Distillation: A Strategy for Optimizing Direct Amidation

Grosjean

Parker

Thirsk

et al. 2012

Org. Process Res. Dev.

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The direct synthesis of amides from the corresponding carboxylic acids and amines is shown to operate under varying degrees of mixed kinetic and mass transfer rate control when water is removed by azeotropic distillation. Unless the volumetric heat input rate is reported, it is not possible to make a valid comparison between different catalysts, as the difference in Q boil alone can be responsible for the apparent difference in observed rate. A systematic approach is developed to quantify the contribution of boil-up rate to conversion rate and so decouple the physical rates from the chemistry. Intensive boiling is used to improve the removal of water during azeotropic distillation and considerably enhance conversion. The results show that some acylations previously thought to be difficult or impossible can be achieved in the absence of coupling agents under green conditions. The use of a cascade of CSTR flow reactors operating under intensified conditions is assessed for scale up of direct amidation reactions and compared to a production scale batch reactor. The findings and conclusions of this work have general applicability to all condensation reactions.

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“…It is also known that titanium alcoholates and titanium hydroxide are prone to form oligomers. [39][40][41] So a number of species could act as a catalyst, but the most likely under our conditions (elevated temperature, vacuum distillation) is titanium dioxide in the form of nanoparticles with porous structure (Fig. 2, right).…”

Section: Lactamisation Reactionsmentioning

confidence: 99%

“…There was no reaction in the IL sample remaining aer ltration. So the possible catalyst could be (a) the freshly precipitated Ti(OH) 4 , its dimers or trimers [39][40][41] or freshly obtained TiO 2 (further written as TiO 2 *), (b) the mentioned Ti species complexed with amino acid. For clarication, the lactamisation of 4-aminobutanoic acid was carried out in the presence of a TiO 2 */amino acid complex, which had been prepared separately from Ti(OiPr) 4 and 4-aminobutanoic acid in isopropanol at reux for 3 h with subsequent ltration of the catalyst.…”

Section: Lactamisation Reactionsmentioning

confidence: 99%