Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

REACTOR DESIGN OF THE DIISOBUTYLPHTHALATEMANUFACTUREI.A. Kozlovskiy, A.V. Kustov, V.N. SapunovPP-III-21D.I. Mendeleev University of Chemical Technology of Russia,Chair of Petrochemical Synthesis, 9 Miusskaya Square, Moscow, 125047, Russia,tel/fax: +7(499)978-95-54, e-mail: iakozlovsky@rambler.ruPhthalate esters are used as plasticisers, solvents and perfumery compounds. Acontinuous synthesis of diisobutylphthalate from phthalic anhydride and isobuthanol is carriedout. The first reaction step, alcoholysis of phthalic anhydride with the monoester formation, israpid and goes to completion. The reaction starts at moderate temperature and proceedsexothermically.OOO+ HOOOHOOSecond step is the conversion of the monoester to a diester with the formation of water.OOOOHO+HO+ H 2 OOOOThis is a reversible reaction and proceeds much more slowly than the first. To shift theequilibrium towards the diester the reaction water is removed by azeotrope formation with thealcohol. The azeotrope can be removed from reaction vessel by rectification of water- alcoholmixing and, after purification steps, the alcohol can be recycled. Reaction rate is acceleratedby usage of ion exchange resin Amberlyst A-70 as a catalyst in the temperature range of 120– 140 °C. Both reaction and rectification processes are performed in a closed system consistedof a tube reactor filled with the ion exchange resin and the vessel with a rectificated column.The reaction mixture via a circulation pump is passed through both apparatus. Two anotherpumps feed and pump out the end-reaction mixture.343