| Various bleaching agents have been incorporated into household detergents so as to attain a bleaching or sterilizing effect as well as washing effect during clothes washing. As such bleaching agents, there have been employed sodium perborate and sodium percarbonate. However, each of these two bleaching agents is highly alkaline and added to heavy-duty detergents in order to obtain long-time storage stability. Use of heavey-duty detergents is prefereeed for washing clothes composed of such fibers as cotton fibers and polyester fibers, but when fine clothes made of wool, silk or nylon are washed with these heavy-duty detergents, yellowing of such clothes occurs or a rough and hard touch is imparted to the washed clothes. However, because sodium perborate and sodium percarbonate are unstable in neutral light-duty detergents.further, known neutral bleaching agents such as peroxyurea and sodium sulfate-hydrogen peroxide adduct are similarly unstable.Sodium sulfate- hydrogen peroxide- sodium chloride adduct is a new-type bleaching agent which can incorporate in a neutral detergent composition and overcome the disadvantage above. This adduct with the formula: 4Na2SO4 2H2O2 NaCl, which is also named SPS, has good properties as a whitener, dissolves quickly and its solubility in cold water is high. In addition, it is preparaed from non-toxic salts that are abundant, cheap and used regularly in washing power formulations. This adduct has the properties of both sodium sulfate and hydrogen peroxide, when it satured in water, oxygen atoms can be released for bleaching and sterilizing with the decomposition of hydrogen peroxide. At the same time, 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. As a neutral assistant for synthetic detergents with pH 6-8 in aqueous solutions, in a simple, economical and ecological fashion, because it does not generate any residue, this adduct is fully compatiable with the most rigorous present or future enciroment legislation.Using the phase diagram of the quaternary system of Na2SO4 NaCl H2O2 H2O and the theory of phase diagram, the preparation of this adduct is studied in this paper. The equation of the adduct's crystallization area at 288K is attained by non-linear regression, also the optimum mol ratio of the raw materials, H2O2:NaCl:Na2SO4:H2O, is lying among 1:0.83:1.62:4.41.Based on the pre-experiment and the calculation of quaternary system phase diagram, the preparation process of two steps has been obtained. The result of the first step is as below: the raw materials ratio:4g NaCl, 32g Na2SO4, 25ml H2O2 by mass percent of 30%, the temperature of reaction: 283K-293K, the time of reaction: 30~40 minutes, the time and temperation of drying: 40-60 minutes and 323K-333K, the products of the first step is29.56?.1g with the content of H2O2 9.46 + 0. 1%.The mass of NaCl 6.99g and Na2SO4 21.34g added to the first step filtrate are calculated besed on the results of the first step and the phase diagram. The art of the preparation is same to the first step. The results of the experiments compared with the the the results of the calculation were no less than 5%, while the standards are the content of hydrogen peroxide and the yield of the adduct. The experiment is magnified 10 times using industried raw material, the content of hydrogen peroxide of the adduct is more than 9.4% and the yield is consistent with the result of the calculation.The storage stability of hydrogen peroxide adducts is a key problem area, particularly under conditions involving alkaline agent composition, high humidity and high temperature. The type and the qualitity of the stabilizers are studied in this paper, for the H2O2 in the adduct is liable to decomposition. The results of monofactor experiment indicate that the stability of the adduct mounted to 97.84% by adding 0.08g EDTA. The result of the comparing test and magnifying test indicate that the average ratio of H2O2 decomposition is less tha... |
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