Cyclohexane-1 2 4 5-tetracarboxylic aci&

89-05-4

15383-49-0

The general procedure for the synthesis of cyclohexane-1,2,4,5-tetracarboxylic acid from homophthalic dianhydride was as follows: 34.3 g of commercially available homophthalic dianhydride (GC analytical purity: 98.2%) was added to a 500 mL autoclave, followed by the addition of 250 mL of deionized water and 2.5 g of 5 wt% Pd-C catalyst (as precious metal catalyst). Hydrogen was introduced into the autoclave, and the hydrogen pressure was controlled to be 2 MPa, the reaction temperature was 33 °C ± 1 °C, and the reaction time was 2 hours. After the reaction was completed, the system was cooled to room temperature (15°C~25°C) and the Pd-C catalyst was separated by filtration. The filter cake (Pd-C catalyst) was dried in air overnight and recycled for the next batch of catalytic hydrogenation reaction. The filtrate was distilled to remove the solvent, and a precipitate of hydrogenated homophthalic acid precipitated. The filtrate was filtered again and the filter cake was decolorized and purified with deionized water and activated carbon to give 38.8 g of white solid hydrogenated homophthalic tetracarboxylic acid in 99.1% yield and 99.46% GC purity.