4-甲基-2-(α-甲基苄基)酚铷钾萃取反应机理及热力学研究
|
摘要
为使卤水中的铷钾得到有效分离,文中研究了4-甲基-2-(α-甲基苄基)酚/脱芳溶剂油在碱性溶液中萃取铷、钾中的反应机理。通过考查分配比与p H值以及萃取剂浓度的关系,采用斜率法与饱和容量法测得了萃合物的组成为MOR·2ROH(M为K~+或Rb~+),确定了萃取反应方程式,证明了该萃取反应为阳离子交换机理,求得表观平衡常数K(Rb)=30.20,K(K)=14.79。通过考查分配比与温度的关系,求得萃取熵ΔS(Rb)=-128.94 J/(K·mol),ΔS(K)=-85.83 J/(K·mol);萃取焓ΔH(Rb)=-29.49 kJ/mol,ΔH(K)=-18.59 kJ/mol;吉布斯自由能ΔG(Rb)=-8.31 kJ/mol,ΔG(K)=-6.57 kJ/mol,证明萃取反应为放热反应,铷的萃取能力大于钾。
In order to separate Rb~+ from K~+ effectively in brine,the extraction mechanism and thermodynamic function of Rb~+ and K~+ by 4-methyl-2( α-methyl benzyl) Phenol were studied in alkali solution. The extraction balance reaction was determined by slope method and saturation method. By investigating the relation between coefficient of distribution and pH,as well as concentration of the extractant,the extracted compound was MOR·2 ROH( M for K~+ and Rb~+ ),the extraction mechanism was determined as cation exchange mechanism,the extraction formula was determined as M+( a)+ OH-( a)+ 3 ROH( o)= MOR · 2 ROH( O)+ H_2O( a). The extraction apparent equilibrium constants of Rb,K is 30. 20,14. 79 respectively. Meanwhile,the thermodynamic functions of Rb and K is: ΔS( Rb) =-128. 94 J/( K·mol),ΔS( K) =-85. 83 J/( K·mol); ΔH( Rb) =-29. 49 kJ/mol,ΔH( K) =-18. 59 kJ/mol; ΔG( Rb) =-8. 31 kJ/mol,ΔG( K) =-6. 57 kJ/mol by investigating the relation between coefficient of distribution rate and temperature. This indicates that extraction reaction is exothermic reaction and the extraction ability of Rb is better than K.
In order to separate Rb~+ from K~+ effectively in brine,the extraction mechanism and thermodynamic function of Rb~+ and K~+ by 4-methyl-2( α-methyl benzyl) Phenol were studied in alkali solution. The extraction balance reaction was determined by slope method and saturation method. By investigating the relation between coefficient of distribution and pH,as well as concentration of the extractant,the extracted compound was MOR·2 ROH( M for K~+ and Rb~+ ),the extraction mechanism was determined as cation exchange mechanism,the extraction formula was determined as M+( a)+ OH-( a)+ 3 ROH( o)= MOR · 2 ROH( O)+ H_2O( a). The extraction apparent equilibrium constants of Rb,K is 30. 20,14. 79 respectively. Meanwhile,the thermodynamic functions of Rb and K is: ΔS( Rb) =-128. 94 J/( K·mol),ΔS( K) =-85. 83 J/( K·mol); ΔH( Rb) =-29. 49 kJ/mol,ΔH( K) =-18. 59 kJ/mol; ΔG( Rb) =-8. 31 kJ/mol,ΔG( K) =-6. 57 kJ/mol by investigating the relation between coefficient of distribution rate and temperature. This indicates that extraction reaction is exothermic reaction and the extraction ability of Rb is better than K.
引文
[1]BUTTERMAN W C,REESE R G.Mineral commodity profiles rubidium[R].Open-File Report,2003.
[2]OSTASZYNSKI A,WIELGAT J,URBA'N SKI T.Michael addition reaction in the presence of potassium and rubidium fluorides as catalysts[J].Tetrahedron,1969,25(9):1929-1938.
[3]陈振兴,方忠和,黄彩娟,等.铯-铷-钒系低温硫酸催化剂的研制[J].催化学报,2000,21(4):384-386.
[4]盛丁杰,张明森.碱金属铷对邻二甲苯制苯酐催化剂性能的影响[J].石油学报(石油加工),2001,17(5):36-41.
[5]林耀庭,唐庆.四川盆地卤水分布及开发前景展望[J].化工矿产地质,1999,21(4):209-214.
[6]WAGNER F S.Kirk-Othmer encyclopedia of chemical technology[M].New York:Wiley&Sons,2004:591-600.
[7]闫明,钟辉,张艳.卤水中分离提取铷、铯的研究进展[J].盐湖研究,2006,14(3):67-72.
[8]刘雪颖,杨锦瑜,陈晓伟,等.t-BAMBP分离铷钾萃取机理及热力学函数研究[J].核化学与放射化学,2007,29(3):151-155.
[9]邓琴,安莲英,黄正根.4-甲基-2-(α-甲苄基)酚铷钾萃取分离工艺研究[J].化学工程,2017,45(2):17-20.
[10]赵琳.t-BAMBP萃取铷的热力学、动力学及连续萃取放大试验[D].成都:成都理工大学,2016.
[11]张卓勇,陈杭亭.电感耦合等离子体发射光谱法测定东北大豆中微量元素[J].光谱学与光谱分析,2002,22(4):673-675.
[12]梁逸曾,俞汝勤.化学计量学[M].北京:高等教育出版社,2003.
[13]汪家鼎,陈家镛.溶剂萃取手册[M].北京:化学工业出版社,2001.
[2]OSTASZYNSKI A,WIELGAT J,URBA'N SKI T.Michael addition reaction in the presence of potassium and rubidium fluorides as catalysts[J].Tetrahedron,1969,25(9):1929-1938.
[3]陈振兴,方忠和,黄彩娟,等.铯-铷-钒系低温硫酸催化剂的研制[J].催化学报,2000,21(4):384-386.
[4]盛丁杰,张明森.碱金属铷对邻二甲苯制苯酐催化剂性能的影响[J].石油学报(石油加工),2001,17(5):36-41.
[5]林耀庭,唐庆.四川盆地卤水分布及开发前景展望[J].化工矿产地质,1999,21(4):209-214.
[6]WAGNER F S.Kirk-Othmer encyclopedia of chemical technology[M].New York:Wiley&Sons,2004:591-600.
[7]闫明,钟辉,张艳.卤水中分离提取铷、铯的研究进展[J].盐湖研究,2006,14(3):67-72.
[8]刘雪颖,杨锦瑜,陈晓伟,等.t-BAMBP分离铷钾萃取机理及热力学函数研究[J].核化学与放射化学,2007,29(3):151-155.
[9]邓琴,安莲英,黄正根.4-甲基-2-(α-甲苄基)酚铷钾萃取分离工艺研究[J].化学工程,2017,45(2):17-20.
[10]赵琳.t-BAMBP萃取铷的热力学、动力学及连续萃取放大试验[D].成都:成都理工大学,2016.
[11]张卓勇,陈杭亭.电感耦合等离子体发射光谱法测定东北大豆中微量元素[J].光谱学与光谱分析,2002,22(4):673-675.
[12]梁逸曾,俞汝勤.化学计量学[M].北京:高等教育出版社,2003.
[13]汪家鼎,陈家镛.溶剂萃取手册[M].北京:化学工业出版社,2001.