Amidated pectin derivatives with n-propyl-, 3-aminopropyl-, 3-propanol- or 7-aminoheptyl-substituents

Highly methylated (HM) pectin (DM = 90%) was amidated with four amines under anhydrous conditions. The goal was to prepare modified pectins that could be useful components of composites with new properties. The yields and degree of amidation (DA) of the products were, respectively, 67–92% and 67.3–72.0%. Maximal values were obtained for pectin propylamide (1) and minimal for pectin 7-aminoheptylamide (4). While products 1 and pectin 3-propanolamide (2) showed 95 g/100 g solubility in water, pectin 3-aminopropylamide (3) was 46 g/100 g and 4 only 3 g/100 g water-soluble. The TG/DTA data indicate that the thermal properties were not dramatically altered under inert environment and improved as far as thermooxidation resistance. From the overall prospective product 3 seems to be the most valuable component for further composite preparation.