Azelaic Acid: A Bio-Based Building Block for Biodegradable Polymers

The production of fine chemicals, new materials and products from renewable feedstocks represents a continuous challenge. Several procedures have been reported in the literature or patented in the last decade for the main biomass components: carbohydrates (75%), lignins (20%), fats and oils (5%) [1]. Regarding oleochemical developments, the oxidative cleavage of unsaturated fatty acids to produce dicarboxylic acids, hydroxy acids, and amino acids has received great attention in the last decade [2]. Two main oleochemical products obtained by the cleavage of unsaturated fatty acids are sebacic acid and azelaic acid. Azelaic acid (AzA) is a naturally occurring saturated nine carbon atom dicarboxylic acid found in whole grains, wheat, rye and barley [2], first detected in rancid fats. It can be formed endogenously from substrates such as longer-chain dicarboxylic acids and processes like the metabolism of oleic acid, and ψ-oxidation of monocarboxylic acids. The azelaic acid market is predicted to reach USD 160 million by 2023 and the applications include pharmacological ingredients, polymers, plastics, lubricants and materials for electronics [3]. The aim of the present review is to highlight the potential of azelaic acid as powerful building block for the synthesis of bio-based and biodegradable polymers, with a special emphasis on the green synthetic routes, embracing both chemical and enzymatic methods.