Conversion Of Maleic Anhydride And Properties Of The Products

Maleic anhydride is a very useful intermediate for the synthesis of many chemical products. In this work, two green chemicals, iminodisuccinic acid (IDS) and N-methylaspartic acid (NMA), were synthesized from MA and the formation mechanism and the properties of IDS were studied.The thermodynamic properties of IDS were calculated. The results showed that the standard molar formation enthalpies for IDS is -1736 kJ·mol^-1, the standard molar entropy is 541.8 J·mol^-1·K^-1, and the molar formation enthalpies for IDS at any temperature can be calculated by Under 0.1 MPa and 298-423K, the reaction for the synthesis of IDS from maleic aicd and ammonia is exothermic and thermodynamically favorable.In the synthesis of IDS, the optimal condictions were found as follows: MA: NaOH: NH₃: H₂O (mol) = 2:3:2:16, 160°C, 10.0h. Under these conditions, up to 80.0% yield of IDS was obtained. The mechanism study results indicated that IDS might be formed through the formation of aspartic acid as the intermediate.In the synthesis of NMA, under the conditions of MA:CH₃NH₂:H₂O (mol) = 1:2:6, 100°C, 1.0h, up to 52.7% yield of NMA was obtained. The extraction of heavy metals from soil by IDS was studied. The results showed that IDS could extract heavy metals from soil as effectively as EDTA.