Length of Methylene Bridges in Cellulose Formals Made by Reacting Soda Cellulose With Dihalomethanes and With Bis(halomethyl) Ethers

Methylene bridges having an average length n ranging from 1.04 to 1.21 were introduced into cellulose by reaction with dibromomethane or with dichloromethane under strongly alkaline conditions. Similarly, bis(bromomethyl)ether or bis(chloromethyl)ether gave n values ranging from 2.25 to 2.72. Repeated treatments with dibromomethane gave formaldehyde contents leveling off at 17 to 18%, or a D.S. of about 2.