Abstract:

On the basis of a single-factor experiment, the affecting factors of the amount of NaOH, reaction temperature and molar ratio of raw material for the reaction are chosen. Synthesized for complex of methionine manganese by the raw materials of methionine and manganese sulfate monohydrate, through the response surface center methodology to optimize the reaction conditions: n (methionine)∶n (MnSO₄ ·H₂O) = 2.006∶1 and n (MnSO₄· H₂O)∶n (NaOH) = 1∶2, reaction temperature at 80 ℃, the yield can reach 85.37%, and a quadratic regression equation is established. The composition of the complex is characterized by content analysis, infrared spectra, thermogravimetric and XRD powder diffraction analysis. It is observed that the complex does not contain water of crystallization, and that content analysis of the complex by EDTA complexometric titration and kjeldahl determination obtains the formula of manganese methionine as Mn (C₅H₁₁O₂NS)₂.

Key words: methionine manganese; synthesis; response surface methodology; characterization