The Research Of Decolorization And Purification For Industrial Pentaerythritol

According to the problems of yellow color, low purity of industrial production pentaerythritol of purity 91.88% and whiteness 91.88%, analysis of impurity components and research of decolorization technology were conducted, in order to provide effective technical parameters for decolorizing and controlling production quality in industrial production.The main impurities of the products were identified by IR,1HNMR, Raman, TG, DSC, LC-MS etc. Results showed that impurities consisted of some dipentaerythritol, a little multi dipentaerythritol, methyl ether of pentaerythritol, trace amounts of acetal and ester compounds. Moreover, the yellow impurities might be the acetal and ester compounds. In addition, it was confirmed by researching the synthesis process conditions of pentaerythritol.After recrystallizing the pentaerythritol products through adding the seed crystals and freezing at 0? by 8h, the purity and whiteness could be improved to be 95.76% and 98.4% respectively. Also, the purity and whiteness could be improved to be 97.12% and 98.4% by recrystallizing twice. The purity and whiteness respectively were 93.35% and 98.1%, when the crystallization temperature was about 0-30?. Moreover, the purity of pentareythritol was 98.02% and the whiteness was 98.6%, when the crystallization mother solution temperature was 70?.The purity and whiteness could be improved to be 94.46% and 98.2% after disposing by hydrophilic fiber composite resin microporous membrane.The pentaerythritol products were disposed by activated carbon fibers, ion exchange resins and macroporous adsorption resins. And results implied that the best adsorption conditions of the active carbon fibers were 35?,2g/L and 75min, and the purity and whiteness could be enhanced to be 94.78% and 98.1% respectively.6 kinds of ion exchange resins and 6 kinds of macroporous adsorption resins were used to treat the pentaerythritol products. And the separation effects of ion exchange resins were better than that of macroporous adsorption resins, and strongly basic anion macroporous adsorption resin D201 was regarded as the optimum resin, also its static and dynamic adsorption process conditions were investigated. Results implied that the best static adsorption conditions of D201 resin were 25?,0.67 g/L and 60min, under this condition, the purity and whiteness of the products could be elevated to be 94.34% and 99% respectively. The best dynamic adsorption conditions of D201 resin were 25?, 3:1 in adsorbent bed height-diameter ratio and 4 min in residence time, and the purity and whiteness would be increased to be 95.06% and 98.9% respectively.