Synthesis And Application Of Catalysts Applied To Hydrogen Peroxide Bleaching At Low Temperature

Due to the rise of energy conservation and environmental protection,as well as the implementation of the strategy of sustainable development in the country,low temperature bleaching technology has been developed by domestic colleges and enterprise.Thanks to its high catalytic activity,Schiff alkali metal complex has a broad prospect in the washing,sterilization and enzymatic simulation with hyperoxide.Furthermore,there are also many researches related to the low temperature bleaching.However,as the poor water solubility of most of the Schiff alkali metal complexes,it has become a big problem when they are applied to the bleaching systems which are regarding water as the medium.Besides,Schiff alkali metal complexes would have different functions if the structures of ligands are slightly changed.Hence,it can be predicted that not every Schiff alkali metal complex is suitable for low temperature bleaching.In order to overcome the problems that the existing Schiff alkali metal complexes have,the main target of this research is to design,synthesize and confirm several different types of Schiff alkali metal manganese complexes,and one of the most effective Schiff alkali metal manganese complex was selected and applied to hydrogen peroxide bleaching with cotton fabric at low temperature.Additionally,the bleaching process was discussed.Specific research contents and results are as follows:?1?Firstly,the sodium salicylaldehyde-sulfonic was synthesized by salicylaldehyde,concentrated sulfuric acid and sodium carbonate.Secondly,the ligand was obtained via a condensationpolymerizationbetweensodiumsalicylaldehyde-sulfonicand1,3-diamino-2-propanol.Finally,the obtained ligand reacted with manganese acetates,and the water soluble and high catalytic activity Schiff alkali metal manganese complexes were achieved.Moreover,the synthetic process was optimized and the results are as follows:Concentrated sulfuric acid was added in the condition of ice bath,and the yield of sodium salicylaldehyde-sulfonic could be more than 55.4%when the reaction temperature was at35?and reaction time was ranging at 18h.Then,when the molar ratio between sodium salicylaldehyde-sulfonic and 1,3-diamino-2-propanol was at 3.0:1,reaction temperature and time were at 60?and 2³h respectively,the yield of double sodium salicylaldehyde-sulfonic sulfonate 1.3-two amino 2-alcoho could reach 91.1%.The synthesized complexes were applied to bleaching of cotton knitted fabric at low temperature,and the temperature,complexes concentration and pH value were investigated.The optimized conditions are recommended as:30%H₂O₂ of 8g/L,complexes concentration of 8?mol/L,pH value of 10.5,bath ratio of 1:20,bleaching at 60?for50min,and washing with water at the temperature of 70?for 10min.Afterwards,the whiteness of the treated fabric was 77.7%,and the capillary effect was 1.2cm·?30 min?^-1.?2?Sulfo salicylic aldehyde condensation amino acetonitrile Schiff alkali metal manganese complex MnS6 has a perfect effect on bleaching of cotton knitted fabric.The optimized conditions are recommended as:MnS6 of 6?mol/L,30%H₂O₂ of 8g/L,pH value of 10.5,stable auxiliary of 0.5g/L,HM-JFC 1g/L,bath ratio of 1:20,bleaching at70?for 50min,and washing with water at the temperature of 70?for 10min.Afterwards,the whiteness of the treated fabric was 84.4%,and the capillary effect was 4.6cm·?30min?^-1.Sulfo salicylic aldehyde condensation amino acetonitrile Schiff alkali metal manganese complex MnS6 has little impact on cotton's capillary effect after bleaching.In order to realize low temperature scouring and bleaching in one bath,MnS6 should be utilized with surfactant of good quality at the same time.The optimized conditions are recommended as:MnS6 of 6?mol/L,30%H₂O₂ of 8g/L,NaOH of 2g/L,stable auxiliary of 0.5g/L,bath ratio of 1:20,bleaching at 80?for 50min,and washing with water at the temperature of 70?for 10min.Additionally,the concentration of 3#scouring agent which is formulated with FMEE,HM-JFC and 6501 is 1 g/L.Afterwards,the whiteness of the cotton knitted fabric was 83.2%,and the capillary effect was 9.7cm·?30 min?^-1.The performances of hydrogen peroxide bleaching which is catalyzed by Schiff alkali metal manganese complex can be improved by an addition of acetonitrile.It not only can improve the whiteness and capillary effect of the cotton fabric,but also can reduce the pressure of employment of deoxidize enzymes in the subsequent process after bleaching.The optimized conditions are recommended as:MnS6 of 6?mol/L,30%H₂O₂ of 8g/L,NaOH of 2g/L,stable auxiliary of 0.5g/L,3#scouring agent of 1g/L,acetonitrile of 7.8 g/L,bath ratio of 1:20,bleaching at 80?for 50min,and washing with water at the temperature of 70?for 10min.Afterwards,the whiteness of the treated fabric was 85.6%,the capillary effect was 11.5cm·?30 min?^-1 and the strength retention rate was of 91.7%.In addition,the content of hydrogen peroxide on the surface of the cloth was low.