Sulfonation and sulfur treatment
At present, the source of most sulfonated modified lignosulphonate products which at home and abroad is main abtracted from modified sulphite paper pulping waste liquor and alkaline papermaking pulping black liquor. Compared with alkaline papermaking pulping black liquor lignosulphonate product,sulfite method Paper pulping waste liquor of the modified products have the better Water-soluble, dispersion, surface active. the sulphite paper pulping waste liquor sulfonation modified is a kind of practical method . the sulphite paper pulping waste liquor sulfonation modified, is generally used in high temperature sulfonation method.make the lignosulphonate reaction with Na2SO3 under 150 ℃～200 ℃.,Introduction of sulfonic group on lignosulphonate side chain, to obtain the better water-soluble products.
Ma Tao etc.put forward the sulfonated test conditions: dosage of Na2SO3 is 110 mmol/g～610 mmol/g,the mass ratio of NaOH and Na2SO3 is1:9, the reaction high temperature is 165 ℃, holding time of 5h. Sokalova etc. put forward that under the action of oxidant, Lignosulphonate free radicals sulfonation reaction can be in relatively low temperature degrees,Zhou Yong etc.put forward that In the reaction according to the mole ratio1:15 join Na2SO3, Oxidant FeCl3, adjust pH 9 ~ 12, reaction 2 h under 95 ℃ ~ 98 ℃,to be obtained the lignosulphonate.
In the process of synthesis of lignosulphonate phenol resin reaction, the methoxyl of Lignosulphonate aromatic nucleus obstruct the Hydroxymethyl polycondensation in the chain of adjacent C9. Under certain conditions, to take advantage of sulfur to methylation modification of lignosulphonate, in the original position of methoxyl group introduced phenolic base, In order to increase the reaction activity of lignosulphonate. Use of sulfide modified lignosulphonate instead of the 60% phenol can be synthesized the better performance Lignosulphonate phenol hydroxyl resin. the appropriate conditions of Sulphate lignosulphonate sulfur Chemical modification is sulfur mass fraction at 5%, Alkali mass fraction at 4%, reaction 15 min under 260 ℃, The modified lignosulphonate methoxyl matrix Volume fraction reduced from 18.81% to11.84%.