摘要
在298.15 K下,用滴定式微量热法对α-、β-环糊精(α-/β-CD)与两个新型同系列表面活性剂3-烷氧基-2-羟丙基三甲基氯化铵(CnNC l,n=8,12)的包合作用进行了研究。结果表明,C8NC l与α-/β-CD均形成摩尔比为1∶1的稳定包合物,实验稳定常数分别为1.41×103dm3.mol-1和6.50×102dm3.mol-1;而C12NC l与α-/β-CD分别形成摩尔比为1∶2和1∶1的包合物,实验稳定常数分别为1.05×106dm6.mol-2和8.83×103dm3.mol-1。具有较长疏水链的C12NC l与两类环糊精包合过程的标准焓变(ΔHθ)和标准熵变(ΔSθ)较小。α-CD包合物的形成过程是焓驱动熵阻滞,而β-CD包合物的形成过程则是熵焓共同驱动。
Interactions of α -/β - CD with 3 - alkoxyl -2 - hydroxypropyltrimethylammonium chlorides （CnNCl） in aqueous solutions were investigated with titration microcalorimetry at temperature 298.15 K. Results showed that both the reactions between C8NCl and α - CD as well as between C8NCl and β - CD can form stable clathrates of same mole ratio of 1 ： 1 with the apparent experimental stability constants of 1.41 × 10^3 dm^3 · mol^-1 and 6.50 × 10^2 dm^3·mol^-1 respectively; while C12NCl will react with α - CD and β - CD forming clathrates of mole ratio of 1 ： 2 and 1 ： 1 respectively with apparent experimental stability constants of 1.05 × 10^6 dm^6 ·mol^-2 and 8.83 ×10^3 dm^3 ·mol^-1 respectively. The standard enthalpy change （ΔH^θ） and standard entropy change （ΔS^θ） of the clathration between C12NCl that has the longer carbon chain and α - /β- CD are smaller than that of C8NCl that has the shorter carbon chain. It has been proved that the formation process of clathrates of α- CD is driven by enthalpy and hindered by entropy; while the formation process of clathrates of β- CD is commonly driven by both enthalpy and entropy.
出处
《日用化学工业》
CAS
CSCD
北大核心
2008年第3期137-141,共5页
China Surfactant Detergent & Cosmetics
