A comparative study on aniline alkylation activity using methanol and dimethyl carbonate as the alkylating agents over Zn–Co–Fe ternary spinel systems

Abstract

The catalyst compositions of the Zn 1−x Co x Fe 2 O 4 (x= 0, 0.2, 0.5, 0.8 and 1.0) spiel series possessing 'x' values, x≤0.5, are unique for selective N-monomethylation of aniline using methanol as the alkylating agent. Since dimethyl carbonate (DMC) is another potential non-toxic alkylating agent, alkylation of aniline was investigated over various Zn-Co ferrites using DMC as the alkylating agent. The merits and demerits of the two alkylating agents are compared. Catalytic activity followed a similar trend with respect to the composition of the ferrospinel systems. DMC is active at comparatively low temperature, where methanol shows only mild activity. However, on the selectivity basis, DMC as an alkylating agent could not compete with methanol, since the former gave appreciable amounts of N,N-dimethylaniline (NNDMA) even at low temperature where methanol gave nearly 99% N-methylaniline (NMA) selectivity. As in the case of methanol, DMC also did not give any C-alkylated products.

A comparative esterification of benzyl alcohol with acetic acid over zeolites Hβ, HY and HZSM5

“…where k s is the rate constant k s if adsorption of benzyl alcohol is the controlling step, and k s = k s C B if the chemi- cal reaction is the rate limiting step [23,24]. K A and K B are equilibrium adsorption constants for acetic acid and benzyl alcohol, respectively; and C A and C B are the initial concentrations of acetic acid and benzyl alcohol, respectively.…”

Study of cyclohexanol decomposition reaction over the ferrospinels, A1−xCuxFe2O4 (A=Ni or Co and x=0, 0.3, 0.5, 0.7 and 1), prepared by ‘soft’ chemical methods

“…The Mossbauer spectra of the mixed ferrites showed that the isomer shift (IS) values were in the range 0.3-0.4 mm/s with respect to natural iron, a value typical of Fe 3+ with a total spin value of 5 2 . The quadrupolar splitting constant value ( E Q ) is a measure of the magnitude of electric field gradient (EFG) about the Mossbauer nucleus.…”

Solvothermal Synthesis and Catalytic Properties of Nanocrystalline ZnFe2−xAlxO4 (x = 0, 1, 2) Spinels in Aniline Methylation

“…Several studies on vapour phase methylation of aniline on mixed metal oxides with spinel structure as catalysts have been reported [26][27][28][29][30][31]. Mixed oxides with spinel structure are very interesting materials for alkylation reactions because their catalytic effectiveness for this type of reactions can be easy modified by introducing of the third metal into the spinel structure leading to the change of their acid-base nature.…”