EFFECTS OF TEMPERATURE AND DISPERSANT ON PHOTOIRRADIATION OF p-FORMYLCINNAMIC ACID CRYSTAL

Article abstract of DOI:10.1246/cl.1981.1799

p-Formylcinnamic acid (p-FCA) crystal dimerizes quantitatively via the crystal lattice controlled photochemical process to form 4,4'-diformyl-β-truxinic acid (p-FCA dimer).The crystalline dimer was obtained quantitatively on photoirradiation of p-FCA crystal below 35 deg C in aqueous dispersant and included one mole of crystal water (p-FCA dimer*H2O).In non-aqueous dispersant, the dimer was produced quantitatively below about 55 deg C: the amorphous dimer was produced in the range of about 55 deg C to 0 deg C, and the crystalline dimer below 0 deg C, the degree of crystallinity increasing with decreasing the reaction temperature.Maximal reaction rates were observed at 15 deg C in water and at 35 deg C in non-aqueous dispersants.Three kinds of dimers (crystalline p-FCA dimer*H2O, and crystalline and amorphous p-FCA dimers) were interconvertible by appropriate treatments.