Study On The Synthesis And Catalytic Oxidation Property Of Water-soluble Binuclear Cobalt Phthalocyanines

According to the unique photoelectric and catalytic oxidation properties, etc., the planar binuclear metal phthalocyanines recently receive research focuses on the materials, chemistry, physics and other areas. The vast application of nonsub-stituted metal- phthalocyanines have been limited, since they are difficult to dissolve in water or organic solvents. Nowdays, the catalysts of sweetening used in the refining industry are mainly CoPPc and CoSPc, but due to their poor water-soluble and alkali soluble properties, their catalytic activity were severely affected.To solve the problems mentioned, the water-soluble binuclear cobalt phthalocyanines were synthesized, and their catalytic oxidation properties of sweetening were studied. The major contents are as follows:Using trimellitic anhydride, pyromellitic dianhydride（PDMA）, urea, CoCl₂·6H₂O as reactants, ammonium molybdate as catalyst, Hexa-amide binuclear cobalt phthalocyanines （CoBPcN₆） was synthesized respectively through solid-phase method and liquid-phase method（BPBF₄ as solvent）. The main factors which affect the yield of CoBPcN₆ were investigated by orthogonal test. The results indicated that the optimal conditions are as follows: the best conditions of solid-phase method were: n（urea）: n（PMDA） = 60, n （CoCl₂·6H₂O）: n （PMDA） = 2.5, T = 200℃, t =4h; the best conditions of liquid-phase method were: V （BPBF4） = 60mL, n （PMDA）: n （urea） = 50, T = 200℃, t = 2h.The CoBPcN₆ were hydrolyzed to hexacarboxy binuclear cobalt phthalocyanines （CoBPcC₆） under alkaline conditions. By examining the hydrolysis temperature, hydrolysis time and the mass fraction of alkali, the optimal hydrolysis conditions are as follows: T = 100℃, t = 12h, w （KOH） = 40%. The separation method of mononuclear and binuclear carboxyl metal phthalocyanines was established. The products were separated by column chromatography. The structures of the products were confirmed by characterization methods including UV-Vis absorption spectra, IR spectra, ¹H-NMR, elemental analysis, combined with metal content, carboxyl content, et al..The catalytic oxidation properties of water-soluble binuclear cobalt phthalocyanines in sweetening were investigated by the liquid-liquid method and fixed-bed method. Compared with the industrial catalysts of sweetening, the best sweetening catalyst was filtered out.