Isakova, K. A.

Tuguldurova, Vera P.

Russian

Tomsk State University Repository

THE MINISTRY OF EDUCATION AND SCIENCE OF THE RUSSIAN FEDERATIONNATIONAL RESEARCH TOMSK STATE UNIVERSITYCATALYSIS: FROM SCIENCE TO INDUSTRYProceedings ofVII International scientific school-conference for young scientistsOctober 11-15, 2022Tomsk 2022CATALYSIS: from Science to Industry 2022 Section 3: PosterpresentationsThe methodology for the kinetic study of the reaction of the 2-methylimidazole formation by NMR-spectroscopy in situK.A. Isakova, V.P. TuguldurovaTomsk State University, Tomsk, Russia isakovakristina280@gmail.comImidazole and its derivatives are commonly used in every aspect of life. Of particular interest from imidazole derivatives is 2-methylimidazole [1]. This compound is used as a raw material in the synthesis of medicines, polymers, insecticides and dyes, and is an accelerator for curing epoxy resins.The main method of obtaining 2-methylimidazole is the condensation of glyoxal, acetaldehyde and ammonia (Debu method), occurring in an aqueous solution [2]. Despite the large studies in the chemistry of imidazoles, a systematic study of the kinetics of their formation from the point of view of the nature of the reagents used and factors affecting the rate of formation and composition of the final mixture has not been carried out to date, and the kinetic parameters of this reaction have not been established.The development of methodological approaches for experimental investigation of the kinetics of the interaction of acetaldehyde and glyoxal with ammonia is an important area of modem physical organic chemistry and chemical industry.Thereby, this work was focused on the development of a methodology for determining the kinetic parameters of the reaction of the formation of 2-methylimidazole during condensation of acetaldehyde, glyoxal and ammonia in an aqueous solution. The acetaldehyde and ammonia adduct (acetaldehyde- ammonia trimer) [3] as the synthetic equivalent of acetaldehyde and ammonia in reaction with glyoxal and NMR spectroscopy in situ [4] were used. The developed method for determining kinetic parameters allows us to establish the reaction order, rate constants, initial rates of product formation and reagent consumption.The three-necked flask containing a reflux condenser and a thermometer was used for the experiment. Glyoxal and an acetaldehyde-ammonia trimer with a molar concentration of 0.6 mol/1 were introduced into the flask, (in ratio 1:1). The time of addition of glyoxal was noted as the reaction start time. Further, a sample from the reaction flask was taken and transferred to an ampoule with D2O and an internal standard -  DMSO. After that, the ampoule was placed in an NMR spectrometer and the spectra were monitored in progress of the reaction.For the first time to establish the main kinetic parameters (rate constant was 0.810'^ s' ,̂ initial product formation rate was 0.83 10'^mol l'  ̂ s' ,̂ reagent flow rate was 1.1410'^ mol l'  ̂ s'̂  and order of a reaction 1). The developed in situ NMR technique for monitoring the concentrations of reagents and reaction products in real time has been applied for the first time for this class of reactions. The developed in situ NMR method was used for the first time in this class of reactions to monitor concentrations of reactants and reaction products. The proposed method can also be used to establish the kinetic parameters of similar organic reactions occurring in solution.References1. Kumari, S.; Pramod, K. S.; NitinK. Der Chemica Sinica 2010, i(3), 36-47.2. Elderfield, R. Heterocyclic compounds. John Wiley & Sons, inc.: New York, 1961.3. Lewis D. T. J. Chem. Soc. 1939, 968-972.4. Clegg, Codina A. Bruker BioSpin, 2017.155

The methodology for the kinetic study of the reaction of the 2-methylimidazole formation by NMR-spectroscopy in situ

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The methodology for the kinetic study of the reaction of the 2-methylimidazole formation by NMR-spectroscopy in situ

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