Anionic effect in high concentration alcohol organosolv pulping

Abstract

Anionic effects are demonstrated with Mg-salts and free acids in high alcohol content organosolv pulping. Not all catalysts examined could effectively liberate the fibers from the wood matrix. The best result was obtained with the 0.025 M MgCl₂ catalysis system, at which nearly 60% screened pulp, with viscosity of 19.9 cPs., can be produced. Mg(NO₃)₂ was found capable of liberating fibers, however, under the conditions set for the experiment, complete fiber liberation was not achieved. In contrast, MgSO₄ and Mg(CH₃COO)₂ were incapable of fiber liberation in themselves. On the other hand, in acid form, HCl and H₂SO₄ were capable of liberating the fibers, whereas HNO₃ and CH₃COOH catalysts were found ineffective. Especially with H₂SO₄, it should be noted that this catalysis system created a very strong hydrolyzing effect that unselectively destroyed both lignin and carbohydrates, resulting in severely damaged pulp which is useless for papermaking purposes. Therefore, choosing a suitable catalyst is the key factor for producing an organosolv pulp at high yield and with good fiber quality.