Patent ID: 6504055
Filing Date: 2003-01-07
Classification: C07C,C07D

Abstract:
A process for the preparation of formaldehyde, citraconic acid and succinic acid which comprises:(a) reacting a molar excess of formaldehyde with dimethyl succinate in vapor phase with a catalyst, the catalyst consisting of a porous material having a surface area between about 30 m2/g and 700 m2/g, surface acid site density from about 66 to 2350 micromole/g, surface base site density from about 0 to 500 micromole/g and acid strength (pKa) of about +3 to âˆ’3 until reaction is substantially complete and recovering from the reaction products the citraconic anhydride thereby produced at a temperature of 320Â° to 440Â° C. at a pressure of about 20 to 400 psi; (b) hydrolyzing the citraconic anhydride to citraconic acid and the dimethyl succinate to succinic acid and methanol at elevated temperatures in water so that the methanol is distilled from the reaction mixture; (c) oxidizing the methanol from step (b) to produce formaldehyde; and (d) separating the citraconic acid and succinic acid from the reaction mixture.