Estimation of Pulp Lignin Content in The High Yield Pulping of Prosopis

Abstract

Investigations carried out on the chlorination reaction of lignin with prosopis pulp by high yield pulping process indicated optimum reaction time to be 0.5 h for the estimation of chlorine number (CN). The chlorine number value determined with 0.5 h chlorination time is found to be correlated with the unbleached pulp lignin contents as % lignin 0.8992 chlorine number 0.4899 with 95 % confidence limit for the slope 0.8872 ± 0.052 I and for the intercept = -0.4688 ± 1.1300. 22 to 32 % of the total lignin content was observed to be acid soluble and therefore in the regression equation of lignin on the chlorine number value when total lignin value (soluble + insoluble) is fed to the equation the correlation ship gives more accurate data for pulp lignin content. This linear correlation ship between the total lignin content and the chlorine number is recommended for analytical simplification in the high yield range of pulping investigation.