Preparation of High Molecular Weight Polysuccinimides

L-Aspartic acid solubilized with hydrochloric was polymerized with 30% polypho-sphoric acid at 180°C to prepare linear polysuccinimides having a Mw of 180,000 dal tons. When the polysuccinimide was hydrolyzed with dilute sodium hydroxide an a,p-polysodium aspartate hydrogel was generated. 

Eleven 50-ml beakers was charged with L-aspartic acid (0.01 mol) and solubilized with 13.3 ml of IM hydrochloric acid (0.013 mol) at ambient temperature. The first three beakers were treated with 0.066 ml of polyphosphoric acid (specific gravity 2.0) and then warmed to 80°C acid. The second three beakers was treated with 0.266 ml polyphosphoric acid the last four beakers were treated with 0.399 g of polyphosphoric acid. Each solution was dried at 120°C, resulting in clear glassy pucks of intimate mixtures of aspartic acid and the polyphosphoric acid catalyst. The dried materials 

The Step 1 product was ring-opened by mild alkaline hydrolysis using 1 equivalent of 

IM of NaOH per equivalent of succinimide. The alkaline conditions were held at pH 10 by auto-titration at 80°C in water bath. Under these mild conditions polysuccinimides were converted to polyaspartates within 1 hour. 

TABLE 1. Summary of weight average molecular weights from the preparation of polysuccinimides using L-aspartic acid using polyphosphoric acid. 

---

Title Preparation of High Molecular Weight Polysuccinimides... 

---