Studies Of Synthesis And Structure Characterization Of Dispersant MF

The dispersant MF is a kind of additives. It is widely used in dye. It is a kind of anionic surfactant that was made by methyl naphthalene after sulfonation, condensation and neutralization with formaldehyde.At present, in order to save costs,some enterprises used wash oil as raw material, after sulfonation, condensation with formaldehyde, liquid alkali neutralization. Wash oil is boiling range in the coal tar fraction of 218℃ to 300℃.The polymerization has a great influence in the dispersion properties and the thermal stability,too low or too high will cause the dispersion,thermal stability and other application performance is not ideal. So how to control the reaction process to get the ideal productioan is urgent.A suitable indicators of wash oil by gas chromatography was found. And we found that the lower of a-methyl naphthalene content and the higher of β-methyl naphthalene content in wash oil, the better application of dispersant MF performance.With wash oil as the raw material,through the orthogonal test,we found the best production process:the temperature of sulfonation reaction is 155℃,n(Wash oil):n(Sulfuric acid)= 1:1.1,this process should be last 4 hours;the temperature of condensation reaction is 110℃,n(Wash oil):n(Formaldehyde)=1:0.6,this process should last 6 hours,the acidity should keep in [16,18).The application performances of the MF are as follows: Dispersion:96%;Salt:0.59%; Heat resistance:155℃;On the polyster:3-4-;On the cotton:3-4+.The molecular weight of the dispersant MF was analyzed by GPC, the relationship between the molecular weight and the heat resistance was found:the greater of the molecular weight the better of the heat resistance. Through comparison of the application performance of MF, we get the best distribution of molecular weight.We have used TLC and HPLC to track the synthesis process of MF.Comparing the two methods,I foundthat TLC is better.Using silica gel G plate as the stationary phase,n-butanol-pyridine-water-ammonia water as the mobile phase,which volume ratio are 4:6:4:l,and 0.2% of tetrabutylammonium bromide is added,the coloring agent is iodine vapor.The results as follows:The sulfonation reaction:Rfl=0.8025、Rf2=0.7037、Rf3=0.5679、Rf4=0.4568、 Rf5=0.3951、Rf6=0.2840、Rf7=0.0494;The condensation reaction:Rfl=0.7529、Rf2=0.6941、 Rf3=0.5196、Rf4=0.4471、Rf5=0.4000、Rf6=0.2824、Rf7=0.1071. It has some significance meaning on the control of production process.Preliminarily, the impact of the dispersant MF to the application performance of disperse dye was explored.