Preparation Of Cellulose Acetoacetate Alkanoate

Cellulose esters are some of the most commercially important functional cellulose productions. The annual world production of cellulose esters can reach as high as9x105ton. Among these cellulose esters, Cellulose Acetoacetate (CAA) which has Ketone and Methylene two groups are interesting targets for synthesis, because of the unusual properties imparted by the acetoacetate ester group (for example, the methylene group can occur condensation with aldehydes). In order to find cellulose derivatives which shows notable characteristics and used easier, based on modification of cellulose many works has done. The specific work are as follows:1.The Cellulose Acetoacetate (CAA) was prepared by reacting Microcrystalline Cellulose with tert-butyl acetoacetate (t-BAA) under LiCl/DMAc homogeneous reaction conditions. Furhtermore, effects of dosage of t-BAA, reaction time, reaction temperature and catalyst on yield and DS of cellulose were also investigated. The optimal preparation conditions of CAA were as follows:the ratio of both t-BAA(mol) and anhydroglucose unit (mol)2:1, reaction temperature110℃, reaction time3h, concentration of cellulose in DMAc/LiCl5%, under the catalysis of p-toluenesulfonic acid or4-dimethylamio-pyridine. The DS and yield of CAA was reached1.60and71%respectively.2. In order to develop efficient technology process, we arranged the scaleup reaction of Synthesis of Cellulose Acetoacetate by a same method. 3. Firstly, Cellulose Acetoacetate Alkanoate were prepared using CAA (DS<3) as the raw material, anhydride (acetic anhydride, propionic anhydride, n-butyric anhydride) as acylation reagents. Secondly, a series DS of Cellulose Acetoacetate Alkanoate were prepared by reacting cellulose with differ ratio of diketene and anhydride (acetic anhydride, propionic anhydride, n-butyric anhydride) in LiCl/DMAc solution of cellulose. Finaly, Acetoacetate-Functional of Cellulose Acetate Tow were prepared by reacting Cellulose Acetate with-BAA or diketene under homogeneous and heterogeneous conditions. 4. The solubility of Cellulose esters which synthesized above were investigated. Sample8soluble in water, the solubility around12%. Sample12soluble in acetone/water(v:v=1:1), the solubility around1.5%. Sample18soluble in acetone, the solubility around6%. Sample19soluble in acetone, the solubility around11%. Sample22soluble in acetone, the solubility around15%.