Synthesis of 2,6-dihydroxytoluene
|School||Nanjing University of Technology and Engineering|
|Keywords||2,6 - diaminotoluene 2,6 - bis hydroxy toluene Hydrolysis Extraction Crafts|
The 2,6 - dihydroxytoluene is one of the very important fine chemical intermediates , widely used in various fields of pharmaceuticals, pesticides, paints , hair dye . 2,6 - diamino toluene as raw material , 2,6 - dihydroxy toluene , prepared under high temperature and high pressure direct hydrolysis in acidic system focuses on the extraction process of the synthesis conditions and post-processing of the 2,6 - dihydroxy toluene conditions , with IR , GC / MS and 1 H -NMR of the target product and intermediates were characterized and reaction mechanism was discussed . System by comparing the sulfuric acid , ammonium bisulfate system , organic acids system and phosphoric acid system , high-temperature and high-pressure step hydrolysis of 2,6 - diaminotoluene direct preparation of 2,6 - dihydroxy toluene synthesis conditions , the results show that the effect of the phosphoric acid system best. Key research to synthesis 2,6 - dihydroxytoluene , phosphoric acid system by single factor and orthogonal experiments analysis , optimal process conditions : feed ratio n (phosphoric acid ) : n ( 2,6 - diamino toluene ) : n ( water) = 7:1:60 , and the reaction time was 6 h , the reaction temperature was 220 ° C , complete conversion under this condition , 2,6 - diaminotoluene , 2,6 - bis hydroxy toluene yield reached 96.3% , 98.5 % purity , purity of 99.3% after recrystallization . Study the the mother liquor successive apply reaction , apply at least six . Focus on the extraction process in the experiment after processing system of the extraction process of the reaction solution by solvent extraction method to get the optimum extraction conditions : extraction temperature is 25 ℃, extraction time of 30min , The the extraction finished standing time is 1h, extraction compared to 1.2 , the extraction rate of 95% if three times better extraction , the extraction rate can reach 98% . 2,6 - dihydroxy toluene - water - ethyl acetate three-component system liquid phase balance , draw a triangle phase diagram , distribution graph and selectivity curves and Hand formula of phase equilibrium data associated phase equilibrium data for the property is relational .