Selective N-alkylation of aniline with methanol over γ-alumina

Ko, An-Nan; Yang, Ching-Liang; Zhu, Wei-de; Lin, Hung-en

doi:10.1016/0926-860x(95)00209-x

Cited by 52 publications

(22 citation statements)

References 23 publications

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“…The mechanism of the aniline alkylation reaction was well established by Nan Ko et al [31], according to which Lewis acid sites of the metal oxide systems interact with the methoxy species, and the hydrogen atoms of the undissociated hydoxyl groups interact with the Lewis basic sites (Fig. 9).…”

Section: Resultsmentioning

confidence: 99%

Selective N-monomethylation of aniline over Zn1−xNixFe2O4 (x=0, 0.2, 0.5, 0.8 and 1) type systems

Sreekumar

Raja

Kiran

et al. 1999

Applied Catalysis A: General

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The reaction of aniline with methanol was carried out over Zn 1Àx Ni x Fe 2 O 4 (x0, 0.2, 0.5, 0.8 and 1) type systems in a ®xed-bed down-¯ow reactor. It was observed that systems possessing low``x'' values are highly selective and active for mono N-alkylation of aniline leading to N-methyl aniline. Selectivity for N-methyl aniline over ZnFe 2 O 4 was more than 99% under the optimized reaction conditions. Even at methanol to aniline molar ratio of 2, the yield of N-methyl aniline was nearly 55.5%, whereas its yield exceeded 67% at the molar ratio of 7. The Lewis acid sites of the catalysts are mainly responsible for the good catalytic performance. Cation distribution in the spinel lattice in¯uences their acido-basic properties, and hence, these factors have been considered as helpful to evaluate the activity and stability of the systems. #

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Section: Resultsmentioning

confidence: 99%

Selective N-monomethylation of aniline over Zn1−xNixFe2O4 (x=0, 0.2, 0.5, 0.8 and 1) type systems

Sreekumar

Raja

Kiran

et al. 1999

Applied Catalysis A: General

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“…Heterogenous solid-gas catalysis is a clean, environmentally safe method and the catalysts are easier to handle than those in previous processes using mineral acids. A literature survey on aniline alkylation indicated that considerable attention has been focused on the synthesis of new catalysts such as metal oxides [2][3][4][5], mixed oxides of the spinel type [6][7][8], phosphates [2,9,10], clays [4,11] and zeolites [4,12,13]. Most of them show high activity for aniline alkylation and even a high selectivity to N-alkylanilines against toluidines.…”

Section: Introductionmentioning

confidence: 99%

N-alkylation of aniline with ethanol over an industrial niobic acid catalyst ? influence of water formation on kinetics and selectivity

2005

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The reaction of aniline with ethanol was carried out over an industrial niobic acid catalyst in a fixed bed reactor at atmospheric pressure and 220-260°C. The main products, N-ethylaniline and N,N-diethylaniline were formed consecutively. A kinetic study including a model discrimination between several Hougen/Watson type rate equations led to an Eley/Rideal mechanism, where the reaction of gas phase aniline with adsorbed ethanol is the rate determining step. As second adsorbing agent, water inhibits the reaction in higher partial pressures. N-alkylation was the main reaction observed but the addition of water decreased the selectivity and up to 15% C-alkylated products were found. The apparent activation energies for the first and second N-ethylation are 85.6 and 70.7 kJ/mol, respectively. The high equilibrium constants indicate a nearly irreversible reaction.

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“…Conventional liquid acids such as sulfuric, hydrochloric, hydrobromic, and hydroiodic acids have been reported to catalyze the methylation of amines [102]. On the other hand, solid acids such as alumina [103][104][105][106], silica-alumina [107], faujasite [108], beta zeolite, EMT zeolites [109], AlPO 4 -5 [110,111], and niobic acid [112] have been used as catalysts in the gas-phase flow system, which requires no solvent, circumvents tedious separation procedures, and recycles the catalyst. These catalysts are chiefly used for the alkylation of aniline, because this reaction proceeds smoothly.…”

Section: Methylation Of Toluene (Equationmentioning

confidence: 99%

Catalytic Reactions over Halide Cluster Complexes of Group 5–7 Metals

Nagashima

Kamiguchi

Chihara

2014

Metals

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Halide clusters of Group 5-7 metals develop catalytic activity above 150-250 °C, and the activity is retained up to 350-450 °C by taking advantage of their thermal stability, low vapor pressure, and high melting point. Two types of active site function: the solid Brønsted acid site and a coordinatively unsaturated site that catalyzes like the platinum metals do. Various types of catalytic reactions including new reactions and concerted catalyses have been observed over the clusters: hydrogenation, dehydrogenation, hydrogenolysis, isomerization of alkene and alkyne, and alkylation of toluene, amine, phenol, and thiol. Ring-closure reactions to afford quinoline, benzofuran, indene, and heterocyclic common rings are also catalyzed. Beckmann rearrangement, S-acylation of thiol, and dehydrohalogenation are also catalyzed. Although the majority of the reactions proceed over conventional catalysts, closer inspection shows some conspicuous features, particularly in terms of selectivity. Halide cluster catalysts are characterized by some aspects: cluster counter anion is too large to abstract counter cation from the protonated reactants, cluster catalyst is not poisoned by halogen and sulfur atoms. Among others, cluster catalysts are stable at high temperatures up to 350-450 °C. At high temperatures, apparent activation energy decreases, and hence weak acid can be a catalyst without decomposing reactants. OPEN ACCESSMetals 2014, 4 236

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Selective N-alkylation of aniline with methanol over γ-alumina

Cited by 52 publications

References 23 publications

Selective N-monomethylation of aniline over Zn1−xNixFe2O4 (x=0, 0.2, 0.5, 0.8 and 1) type systems

Selective N-monomethylation of aniline over Zn1−xNixFe2O4 (x=0, 0.2, 0.5, 0.8 and 1) type systems

N-alkylation of aniline with ethanol over an industrial niobic acid catalyst ? influence of water formation on kinetics and selectivity

Catalytic Reactions over Halide Cluster Complexes of Group 5–7 Metals

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