Investigation was carried out to clarify the relation between the degree of Chlorination and the properties of chlorinated product.
The reaction of lignosulfonic acid with chlorine comprises chlorination (substitution), oxidation and hydrolysis. An amount of total Cl consumption, consumption by substitution and by oxidation was determined at various Chlorination time.
Following results were obtained :
Reaction proceeded in three stages ([A] [B] [C]). In (A) stage 1st oxidation occured, at the beginning of the reaction. Substitution proceeded from the beginning and in [B] stage only the substitution reaction take place for a while then at the end of this stage again 2nd oxidation occured with the substitution. In [C] stage 3rd oxidation proceeded without acompanying substitution.
Chlorine consumption at 1st oxidation was 40% to red pine LSCa and 25% to LSCa from deciduous wood. To complete the substitution reaction, about 100% chlorine was required to LSCa from red pine and 90% chlorine to LSCa from deciduous wood.
From reaction and ionization difference spectra, the structural changes which occured in the chlorination were estimated. Thus, for red pine LSCa, at the beginning of the reaction, substitution of Cl into the 6-position of the aromatic nucleous, then formation of di- or tri-chloro substituted compound, demethylation at methoxyl group and formation of quinon structure were assumed.
It was assumed that the structural changes of LSCa from deciduous wood differed from that of red pine LSCa.

View full abstract

The price of wood adequate for pulping has increased significantly of late years, and a natural consequence, the aim in pulp research has been directed towards wood unsuitable for digestion.
Our chief attention was focused upon the utilization of Japanese larch as pulpwood with a view to further utilizing wood not fit for sulfite cooking.
In part I, it was found that the modified two-stage sulfite pulping of larch resulted in pulps with higher yields and better strength properties and that pulps free from yellowing were obtainable only with this method.
In this report, pine heartwood and cedar waste both with high resin contents were cooked by the same method and pulps prepared from these woods had the same excellent properties as from Japanese larch.
Mixtures of larchwood and cedar waste were also pulped with the above mentioned process and pulps with good properties were obtained at lower chemical ratios.
In comparison with the other new one or multi-stage sulfite pulping methods, the modified two-stage sulfite pulping process was found to be one of the best digestion processes for mixtures of pulpwood mainly consisting of pine and fir.

View full abstract