Kinetics of the Cationization of Cotton

Abstract

Cationic cotton has a greater affinity for reactive dyes than untreated cotton, providing economic and environmental advantages for the textile industry. The reaction by which a cationic group is appended to cotton suffers from a competing hydrolysis in the aqueous medium; the inefficiency of the cationization under desired processing conditions currently limits widespread application. A study of the kinetics of the competing processes provided insight into the mechanism of hydrolysis and of the reaction with cotton, enabled by high-throughput parallel reactors. The reaction kinetics and the dependences on temperature and catalytic NaOH are well-defined under a range of industrially useful conditions. The temperature profiles of the competing reactions are similar, and both have the same first-order dependences on [NaOH]. Changing the amount of excess catalytic base and the temperature are therefore not expected to have a significant effect on reaction efficiency but can be used to control the time required for a reaction to go to completion. A rationale for the enhancement of reaction efficiency by organic cosolvents is also described