Nitrification of hydroxyalkyl cellulose in organic solvent

Two kinds of hydroxyalkyl cellulose, hydroxyethyl cellulose (HEC) and dihydroxypropyl cellulose (DHPC) were nitrified in HNO₃/CH2Cl ₂ system. The esterfication processes of HEC and DHPC in HNO ₃/CH₂C1₂ system were studied. Crystallization properties of NHEC and NDHPC were analyzed by XRD and Jade5. 0 analysis software. The morphology of gel particles formed in the nitrification were observed by microscope. The results show that the nitrification process of HEC and DHPC is proved to contain two stages divided by the separation-gel transition point, The first nitrification stage (before gel forming) is similar to cellulose, the nitro content reach its maxmium when the gel begin forming and declined rapidly as gel continued forming in the second stage. The larger the molar substitution (MS) is, the lower the nitro content is, and the easier the gel forming. HEC was easier to form gel in the nitrification process than DHPC with the same MS of hydroxyalkyl cellulos due to its lower degree of crystallization.