4814-93-1Relevant articles and documents
The mechanisms of the formation of by-products in the catalytic synthesis of C-alkylimidazoles from diamines and carboxylic acids
Gitis, K. M.,Raevskaya, N. I.,Isagulyants, G. V.
, p. 895 - 898 (2007/10/02)
The formation of 1-ethyl-2-methylimidazole (1-Et-2-MI) and 1-ethyl-2-methylimidazoline (1-Et-2-MIN), intermediates in the synthesis of 2-methylimidazole (2-MI) from ethylenediamine (EDA) and AcOH in the presence of a platinum-on-alumina catalyst, was studied.Using CH3(14)COOH the incorporation of two acetate units into 1-Et-2-MI and 1-Et-2-MIN molecules was demonstrated.The same products were also obtained on dehydrogenation of 2-methylimidazoline (2-MIN) under mild conditions (220-230 deg C).A part of the latter is transformed to N-ethyl ethylendiamine (EEDA) and EDA.These facts indicate that both 1-Et-2-MI and 1-Et-2-MIN result from hydrogenolysis of the imidazoline ring with subsequent ethylation.A reverse reaction, the C5-cyclization of EEDA, was also observed.The formation of 2-MI is favored by increasing temperature.
THE STAGED SYNTHESIS OF 2-METHYLIMIDAZOLE FROM ETHYLENEDIAMINE AND ACETIC ACID IN THE PRESENCE OF A BIFUNCTIONAL ALUMINOPLATINUM CATALYST
Gitis, K. M.,Raevskaya, N. I.,Isagulyants, G. V.
, p. 1551 - 1554 (2007/10/02)
An investigation has been conducted into the staged synthesis of 2-methylimidazole from ethylenediamine and acetic acid in the presence of a bifunctional aluminoplatinum catalyst.It has been shown that the formation stage of 2-methylimidazoline occurs more quickly on γ-Al2O3 than its dehydrogenation on the Pt centers.From a comparison of the processes of dehydrogenation of 2-methylimidazoline in the molten phase and in aqueous solution it follows that the water eliminated in the imidazoline formation stage could cause the decrease in activity during the dehydrogenation on the Pt centers.The structures of the secondary and intermediate products have been established for each stage of the process and their formation routes are discussed. Keywords: aluminoplatinum catalysts, bifunctional catalysis, alkylimidazoles, 2-methylimidazole.
