Homogeneous modification of sugarcane bagasse cellulose with succinic anhydride using a ionic liquid as reaction medium

The homogeneous chemical modification of sugarcane bagasse cellulose with succinic anhydride using 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid as a reaction medium was studied. Parameters investigated included the molar ratio of succinic anhydride/anhydroglucose units in cellulose in a range from 2:1 to 14:1, reaction time (from 30 to 160min), and reaction temperature (between 60 and 110 degrees C). The succinylated cellulosic derivatives were prepared with a low degree of substitution (DS) ranging from 0.071 to 0.22. The results showed that the increase of reaction temperature, molar ratio of SA/AGU in cellulose, and reaction time led to an increase in DS of cellulose samples. The products were characterized by FT-IR and solid-state CP/MAS (13)C NMR spectroscopy, and thermal analysis. It was found that the crystallinity of the cellulose was completely disrupted in the ionic liquid system under the conditions given. The data also demonstrated that homogeneous modification of cellulose with succinic anhydride in AmimCl resulted in the production of cellulosic monoester. The thermal stability of the succinylated cellulose decreased upon chemical modification.

Choledochoscopy in management of retained biliary stones and recurrent lesions

Postoperative choledochofiberscopy was performed in 188 patients with retained biliary stones and recurrent lesions. The following entrances to the biliary tract for choledochoscopy were used: the T-tube tract (129 patients), an afferent jejunal limb of a choledochojejunostomy (43), the jejunostomy tube tract of an efferent limb (12), an U-tube tract (2), and a ductal fistula after segmental liver resection (2). 380 choledochoscopic sessions were carried out, 2 sessions on the average for each patient. The overall success rate of stone removal was 90.5%. No mortality was related to this procedure. Eleven patients developed fever and chills after manipulations but all responded to antibiotics. Two patients had perforation of the T-tube tract during the removal of stones and were reoperated on for abdominal drainage. They recovered eventually. Stone extraction with a flexible choledochoscope is a proven procedure. For residual intrahepatic stones, however, a satisfactory entrance into the biliary tree should be provided for subsequent stone removals. We believe that the jejunostomy tube tract of an efferent limb of an afferent jejunal limb of a choledochojejunostomy is a useful entrance for choledochoscopy because it is permanent in meeting therapeutic demands.