Abstract:
The present invention provides a method for production of cellulose ethers in a high solids process substantially without use of organic solvents as reaction and/or washing medium. In the method of the invention the first alkalization step is carried out by using high solids content cellulose pulp and solid sodium hydroxide. This is followed by an etherification step where the solids content is preferably further increased and the use of solid etherification reactant is preferred. As no organic solvents are used as reaction media the invented method enables production of cellulose ethers directly from never dried pulp with significant savings in energy and investment costs. The method is especially suitable for the production of carboxymethyl cellulose sodium salt (CMC) with low degree of substitution (DS
Abstract:
Un método para la preparación de éteres de celulosa a partir de pulpa húmeda, nunca secada, con un alto contenido de sólidos con un proceso que comprende un tratamiento alcalino y una etapa de eterificación, llevando a cabo el tratamiento alcalino con hidróxido de sodio (NaOH) sólido (80-99,5% p/p) granulado o molido, sustancialmente sin uso de disolventes orgánicos, y trabajando mecánicamente el material de forma continua o en intervalos de tiempo durante el tratamiento alcalino, en donde el contenido de la pulpa en la etapa de tratamiento alcalino es superior al 20% p/p pero menor al 75% p/p.