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Study On The Phase Equilibrium Of The Quaternary System Sodium Sulfate + Sodium Chloride + Hydrogen Peroxide + Water And Thermal Decomposition Kinetics Of The Adduct Formed Among The System

Posted on:2004-09-13Degree:DoctorType:Dissertation
Country:ChinaCandidate:H K ZhaoFull Text:PDF
GTID:1101360125957308Subject:Chemical processes
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Hydrogen peroxide adducts of inorganic compounds generally include sodium percarbonate, sodium perborate and sodium phosphate-hydrogen peroxide adducts. These adducts are mainly used for bleaching, sterilization, and the like. The fields of application of these hydrogen peroxide adducts are frequently limited by the properties of the starting inorganic compounds, and because most of the above-mentioned hydrogen peroxide adducts have a very high alkalinity in aqueous solutions, various limitations are imposed on the uses of these adducts. In view of the fact that sodium sulfate is neutral and nontoxic and is a substance that is available at a low cost and is now used in large quantities as a builder for synthetic detergents, it is considered that if it is possible to prepare a stable sodium sulfate-hydrogen peroxide adduct on an industrial scale, significant advantages will be attained. However, because the stability of sodium sulfate-hydrogen peroxide adducts, which are represented by the general formula Na2SO4 mH2O2 H2O, is very poor. Processes for preparing same and processes of using this hydrogen peroxide adduct have scarcely been reported in the art.The stable sodium sulfate-hydrogen peroxide-sodium chloride adduct with formula 4Na2SO4 2H2O2 NaCl, which is also named PSC was firstly synthesized by the Kao Soap Lo. Ltd and Nippon peroxide Co. Ltd. The PSC adduct is a new-type of neutral assistant for synthetic detergents with pH 6~8 in aqueous solutions. There are abundant resources of sodium sulfate in China, so studying the new technology to produce sodium sulfate-hydrogen peroxide-sodium chloride adduct can explore a new route to utilize the resource of sodium sulfate effectively and produce fine chemicals with high added value. No three wastes are discharged in the process of producing the PSC adduct, it can meet the demand of environmental protection. There are marked economic benefits and social benefits to produce and spread utility of the PSC adduct.The synthetic process of PSC has been reported in literature. It is well known that the preparing process of the PSC adduct is based on the phase diagram of the quaternary system: Na2SO4+ NaCl + H2O2+ H2O. Although the ternary diagrams of the subsystems Na2SO4 + NaCl + H2O, Na2SO4 + H2O2 + H2O have been investigated, no research was reported on the phase diagram of quaternary system. In this paper, the subsystems sodium chloride + hydrogen peroxide + water, sodium sulfate + hydrogen peroxide + water, and sodium sulfate + sodium chloride + water were studied at a temperature of 283 K, 288 K, and 293 K usingthe moist method. Based on the ternary phase diagrams, phase diagrams of the quaternary system sodium sulfate + sodium chloride + hydrogen peroxide + water were studied at a temperature of 283 K and 288 K. Besides, the solubility data, the densities and refractive index of liquid phase of the quaternary system and its subsystems were measured. The phase diagrams of ternary and quaternary systems were constructed. For the quaternary phase diagrams, there are four solid phases formed at constant temperature. It includes two co-satured points, five univariant curves and four crystallization regions corresponding to NaCl, Na2SO410H2O, Na2SO40.5H2O2H2O, and 4Na2SO4-2H2O2NaCl. It is important to investigate the phase diagrams for designing and optimizing the preparing process of the PSC adduct.The system sodium sulfate + sodium chloride + hydrogen peroxide + water is a representative electrolyte-nonelectrolyte system, especially which includes unstable hydrogen peroxide. No research was reported on the calculation and correlation of such system. The empirical equation put forward by Beutier and Renon was applied to hydrogen-peroxide system, which is described asThe parameters value of AA and uaaa are obtained via regression using saturated vapor pressure of the hydrogen peroxide aqueous solution. Based on the results, the solubility data of the system sodium sulfate + sodium chloride + hydrogen peroxide + water and its subsystems sodium chloride + h...
Keywords/Search Tags:4Na2SO4·2H2O2·NaCl, Na2SO4·0.5H2O2·H2O, Sodium sulfate, sodium chloride, Hydrogen peroxide, Phase diagram, Phase equilibrium, Thermal decomposition, Decomposition kinetics
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