The Preparation Of Polyoxometalates And Catalytic Oxidative Starch With Hydrogen Peroxide

Green chemistry and green process technology are the approaches of the modernchemical industry, which aims to constantly decrease pollution, unnecessary energy,and raw material consumption. Nowadays, as dwindling reserves and fossil fuelsbecome more expensive, the interest in the production of chemicals and materialsfrom renewable biomass is increasing. Green renewable starch is abundant, widelyavailable, and inexpensive and it is suitable for different applications bybiodegradation or physicalchemical denaturation.The oxidezed starch is one ofmodification starch, also it is an important chemical materials.It can be used infood,paper,texitile,building materials,packaging industry.There are many methods toprepare oxidized strch, such as wet method,semidry method, dry method.sodiumhypochlorite,potassium permanganate,or hydrogen peroxide could be used asoxident.And catalyst could be cobalt chloride,ferrous sulfate,copper sulfate and so on.hydrogen peroxide was appropriately used in wet oxidation process for that itsdecomposition product is water, which would hamless to environment.Therefore, seeking of high active and pollution-free catalyst which was used incatalytic oxidation of starch has important significance. In this paper, the oxidation ofstarch with hydrogen peroxide as the oxidant was explored using polyoxometalatescatalyst and compared with two kinds of polyoxometalate activity. The main results ofthis paper are as follows:1. The catalyst [C₁₆H₃₃N（CH₃）₃]₄[PMo₁₁VO₄₀] was prepared and it wascharacterized by using IR, UV and XRD. In the single factor experiments,the effectsof the varieties of factors on the carboxyl content were studied,including amount of thecatalyst, the content of hydrogen-peroxide and water, time and temperature of thereaction. The results showed that the optimum conditions were:1g of soluble starch,4ml of H₂O₂（30%）,5mg of catalyst,1.5ml of distilled water, reaction temperatur60oC,reaction time9h, the highest amount of carboxyl content could reach0.43molCO₂H/100g production.2. The catalyst [C₁₆H₃₃N（CH₃）₃]₅[PMo₁₀V₂O₄₀] was prepared and it wascharacterized by using IR, UV, XRD and XPS. In the single factor experiments,theeffects of the varieties of factors on the carboxyl content were studied,includingamount of the catalyst, the content of hydrogen-peroxide and water, time and temperature of the reaction. The results showed that the optimum conditions were:1gof soluble starch,4ml of H₂O₂（30%）,3mg of catalyst,1.5ml of distilled water,reaction temperatur70oC, reaction time10h, the highest amount of carboxyl contentcould reach0.58mol CO₂H/100g production.3. The catalyst [（n-C₄H₉）₄N]₄[H₂SiW₁₀O₃₆Cu₂（-1,1-N₃）₂] was prepared and itwas characterized by using IR. In the single factor experiments, the effects of thevarieties of factors on the carboxyl content were studied,including amount of the catalyst,the content of hydgogen-peroxide and water, time and temperature of the reaction.The results showed that the optimum conditions were:1g of soluble starch,4ml ofH₂O₂（30%）,1mg of catalyst,2ml of distilled water, reaction temperature60oC,reaction time9h, the highest amount of carboxyl content could reach0.48molCO₂H/100g production.