Conversion of SrSO4 to acidic strontium oxalate hydrate(H[Sr(C2O4)1.5(H2O)]) in aqueous H2C2O4 solutions proceeds as a consecutive reaction. In the first step of the consecutive reaction, SrSO4 reacts with H2C2O4 and ...Conversion of SrSO4 to acidic strontium oxalate hydrate(H[Sr(C2O4)1.5(H2O)]) in aqueous H2C2O4 solutions proceeds as a consecutive reaction. In the first step of the consecutive reaction, SrSO4 reacts with H2C2O4 and pseudomorphic conversion to SrC2 O4·H2O occurs. In the second step, SrC2 O4·H2O reacts with H2C2O4 to form H[Sr(C2 O4)1.5(H2O)]. Sr(HC2 O4)(C2 O4)0.5·H2 O crystallizes during cooling of the reaction mixture to room temperature if the solution reaches the saturation concentration of (H[Sr(C2O4)1.5(H2O)]. The aims of this study are the derivation of reaction rate equations and the determination of the kinetic parameters such as pre-exponential factor, apparent activation energy and order of H2C2O4 concentration for each reaction step.Fractional conversions of SrSO4 were calculated using the quantitative amounts of dissolved S and Sr. It was determined that the reaction rate increased at the initial time of reaction by increasing the temperature using solutions with approximately same H2C2O4 concentrations. The reaction extends very slowly after a certain time in solutions with low H2C2O4 concentration and ends by the formation of a protective layer of SrC2O4-H2O around the surfaces of solid particles. Fractional conversion of SrSO4 is increased by increasing concentration of H2C2O4 at constant temperature. Kinetic model equations were derived using shrinking core model for each step.展开更多
以毛发中的角蛋白为复合氨基酸的来源,对复合氨基酸钙的合成工艺进行了初步探讨。在单因素试验的基础上,通过正交试验研究了p H、螯合温度、螯合时间以及氨基酸与钙的配位比对螯合反应的影响,确立了最佳的反应条件:反应液p H 9,反应温...以毛发中的角蛋白为复合氨基酸的来源,对复合氨基酸钙的合成工艺进行了初步探讨。在单因素试验的基础上,通过正交试验研究了p H、螯合温度、螯合时间以及氨基酸与钙的配位比对螯合反应的影响,确立了最佳的反应条件:反应液p H 9,反应温度40℃,反应时间60 min,复合氨基酸与钙的配位比2∶1。并用紫外光谱、红外光谱和差示热量扫描仪(DSC)鉴定了产品。展开更多
基金the financial support of the Scientific Research Projects Coordination Unit of Istanbul University (Project number: 17344 and 31088)
文摘Conversion of SrSO4 to acidic strontium oxalate hydrate(H[Sr(C2O4)1.5(H2O)]) in aqueous H2C2O4 solutions proceeds as a consecutive reaction. In the first step of the consecutive reaction, SrSO4 reacts with H2C2O4 and pseudomorphic conversion to SrC2 O4·H2O occurs. In the second step, SrC2 O4·H2O reacts with H2C2O4 to form H[Sr(C2 O4)1.5(H2O)]. Sr(HC2 O4)(C2 O4)0.5·H2 O crystallizes during cooling of the reaction mixture to room temperature if the solution reaches the saturation concentration of (H[Sr(C2O4)1.5(H2O)]. The aims of this study are the derivation of reaction rate equations and the determination of the kinetic parameters such as pre-exponential factor, apparent activation energy and order of H2C2O4 concentration for each reaction step.Fractional conversions of SrSO4 were calculated using the quantitative amounts of dissolved S and Sr. It was determined that the reaction rate increased at the initial time of reaction by increasing the temperature using solutions with approximately same H2C2O4 concentrations. The reaction extends very slowly after a certain time in solutions with low H2C2O4 concentration and ends by the formation of a protective layer of SrC2O4-H2O around the surfaces of solid particles. Fractional conversion of SrSO4 is increased by increasing concentration of H2C2O4 at constant temperature. Kinetic model equations were derived using shrinking core model for each step.
文摘以毛发中的角蛋白为复合氨基酸的来源,对复合氨基酸钙的合成工艺进行了初步探讨。在单因素试验的基础上,通过正交试验研究了p H、螯合温度、螯合时间以及氨基酸与钙的配位比对螯合反应的影响,确立了最佳的反应条件:反应液p H 9,反应温度40℃,反应时间60 min,复合氨基酸与钙的配位比2∶1。并用紫外光谱、红外光谱和差示热量扫描仪(DSC)鉴定了产品。
