| 摘要 |
PURPOSE: A method for preparing 5-acetamido-N,N'-bis(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamide is provided to enable a continuous process for acetylation and the subsequent removal of the excess acetic anhydride. CONSTITUTION: A process for industrial preparation of 5-acetamido-N,N'-bis(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamide ("Compound A") comprises the following sequential and continuous steps: (i) acetylating 5-amino-N,N'-bis(2,3-dihydroxypropyl)-2,4,6-triiodoisophthalamide ("Compound B") in a first continuous stirred tank reactor at a temperature between about 40 deg.C and about 70 deg.C; (ii) acetylating Compound B in a second continuous stirred tank reactor at a temperature between about 70 deg.C and 125 deg.C; (iii) removing acetic anhydride and acetic acid under a pressure of between about 50 mbar and about 150 mbar and at a temperature of between about 70 deg.C and about 100 deg.C; and (iv) adding methanol and simultaneously distilling off a mixture of methanol and methyl acetate at atmospheric pressure.
|
