Modification And Application Of Lignosulfonate

Lignin sulfonate is an important byproduct in papermaking industry, so scientists all over the world pay attention to its recycling value.As same as the lignin, the chemical and physical properties of lignin sulfonate is relatively complicated, it is about the size of molecular weight, reactivity properties such as pulp raw material, the influence of factors such as pulping process. An important issue is how to find a way to study lignin sulfonate with the current technology.In the research, the lignin sulfonate which is from acid slurry can be separated by alkali analysis precipitation. And by means of heating temperature to 85℃, the supernatant layer will continue to precipitate the sediment under the acidic conditions. Lignin sulfonate can’t be completely separated by alkali precipitation method. In acidic environment, when heated, sulfonic acid base turned into sulfonic acid ester base, and acid ester base has stronger complexing ability, so as to continue removing magnesium base. Therefore, in the study of this research, control experiment of alkali precipitation and fluid is needed, and records of physical and chemical properties should be wrote down. This subject is mainly to study the phenol chemical modification of lignin sulfonic acid magnesium, by changing the experiment conditions, including alkaline solution of acid, reaction temperature and reaction time, the amount of sulfuric acid concentration, the amount of sulfuric acid and phenol. The author needs to observe the experiment phenomenon, then measure properties of phenolic products, including solubility, FTIR and thermal weightlessness, molecular weight and Zeta potential.With the literature data we can know that the sulfonic group of lignosulfonate had a characteristic absorption peak at 1210 cm^-1、1170 cm^-1and 1040 cm^-1. Sulfonic acid ester base absorption peak at 1400 cm^-1 and 1200 cm^-1 S = O stretching vibration peak and 990 cm^-1, 800 cm^-1 C-（O-S） stretching vibration peak to 830 cm^-1, 600 cm^-1 with the absorption of benzene ring substituent matchups. Experimental study shows that by heating the solution and precipitation of acid solution, alkali did produce sulfonic acid ester base. Found in the thermogravimetric analysis, thermal weightlessness in 450℃ sulfonic acid group, sulfonic acid ester based thermal weightlessness in 350℃, and the red liquid alkali sediment contains a small amount of sulfonate base. Under different conditions, to phenol modified lignin sulfonate, different reaction phenomena, the nature of the phenolic products is different also, is mainly due to the small molecules formed the oligomer, the oligomer in 250℃ has an obvious weight loss process. Results showed that the phenol products of gel chromatogram, the peak time from 5 min to 25 min, namely the t1（5-21min） and t2（21-25min） segment is small molecules of the oligomer, t1 section of high polymerization degree, t2 section of the low degree of polymerization, The peak time from 25 min to 33 min is the peak lignin sulfonic acid ester, and low molecular weight.This study by controlling the lignin sulfonate phenol reaction conditions, a preliminary complete control of the phenolic products of molecular weight. It provides a reliable guarantee for further purification and application.