Reactor and its use in polysaccharide ether production

In a process for the production of cellulose ethers from cellulose suspended in organic solvents and alkyl halides and/or lower epoxides by alkalization and etherification with stirring, the improvement of conducting said production in a reactor comprising:

• a vertical cylindrical walled vessel of a diameter D with a convexly curved top and bottom;
• a vertical, rotatable, axial shaft extending through said vessel;
• a plurality of pairs of symetrically opposed stirrer elements radially extending from said shaft a total width d, said pairs spaced an interval A from each other along said shaft, the lowest of said pairs being adjacent to and spaced a distance A' from the bottom of said vessel;
• a plurality of baffles extending vertically along the inner cylindrical wall of said vessel, permitting said stirrer elements to clear, each said baffle having a width B and an inner edge spaced a radial distance a from said inner cylindrical wall;
• inlet means at the top of said vessel and outlet means at the bottom of said vessel;
• the dimensional ratios between D, d, A and a being
• d=0.6 to 0.8 D,
• A=0.15 to 0.20 D, and
• a=0.035 to 0.05 D;
• wherein reactants are charged through said inlet means until they fill said vessel to a height H which is 0.1 to 0.33 D above the uppermost pair of stirrer elements;
• said reactants are continuously stirred by rotation of said shaft and elements at a peripheral speed of 4.5 to 6.7 m.s. during the reaction;
• and the formed reaction product is discharged through said outlet means.