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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.

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The motive of the work was to prepare selective ion-exchangers based on technical lignins. Thus, three spent liquor lignins, namely spruce organosolv (OSL), commercial pine kraft (CKL) and industrial spruce-pine kraft (IKL) lignins, were modified by 1) O-carboxymethylation (CM-lignins), 2) Mannich reaction with glycine (Gly-lignins), 3) Mannich reaction with iminodiacetic acid (IDA-lignins), and 4) carboxymethylation of Gly-lignins (Gly-CM-lignins). The course and conditions of the Mannich reaction modifications were examined on dihydroeugenol s a model compound. The modified lignins were characterized by elemental analyses. The ability of modified lignins to bind metal ions was quantified in batchwise conditions using 5 mM unbufferred Solutions of Cu 2+ , Cd 2+ and Zn 2+ ions, separately. The decrease in concentration after the lignin treatment was measured by the flame atomic absorption spectrometry. The starting lignins were found almost inactive, whereas the modified lignins exhibited ion-exchanging properties with highest values of binding capacity for Gly-CM-and IDA-lignins (up to 0.6 mmol/g). The O-carboxymethyl groups were found to be centres of a non-specific binding and of lower affinity toward the three ions, whereas N-carboxymethyl groups showed a preferential Sorption in the order Cu < Zn < Cd.