Preparation and Properties of p-phenylenediacrylic Acid Derivatives

@ Preparation of p-phenylenediacrylic acid (p-PDA) derivatives and their properties have been investigated. p-PDA derivatives include a series of p-PDA monoalkyl esters. The new synthetic method which consists of condensation of p-formylcinnamic acid ester with malonic acid, provided novel p-PDA monoesters successfully . p-PDA monoesters having an amide bond were also prepared to know the effect of hydrogen bonding on molecular packing. Thermal and photochemical behaviour of these compounds were evaluated. All of the compounds prepared show liquid crystalline phase. In the crystalline state, several compounds are found to be photoreactive. For example, p-PDA monodecyl esters give oligomers and dimers on irradiation, while p-PDA monoethyl esters with an amide bond undergo photodimerization.