Menthol-based deep eutectic liquid has been used for the reactive liquid-liquid extraction of the carbamazepine from its aqueous solution after it was synthesized by heating and mixing. Diethyl succinate was used as diluent, while deep eutectic liquid was the extractant. Several deep eutectic liquids containing menthol and carboxylic acids (acetic acid and formic acid) with different molar ratios (1/1 and 1/2) were composed. pH, density, viscosity, and refractive index values of the designed deep eutectic liquids were measured. Furthermore, Fourier transform infrared spectroscopy method was also applied into the deep eutectic liquids for characterization. Deep eutectic liquid increased the extraction performance of the diluent from 11 to 36% comparing to the untreated one. The proposed system (menthol/acetic acid with 1/1 of molar ratio) has extracted more than 90% of the target pharmaceutical compound from its aqueous solution in 30 min. The concentration of extractant in the diluent, initial carbamazepine content in aqueous media, and ionic intensity have influenced the reactive liquid-liquid extraction. Depending on the thermodynamics outcome, the transfer process of carbamazepine from aqueous phase into hydrophobic phase is an endothermic and spontaneous in nature. It has been also observed to be a separation process with a structure that tends to be irregular.

Graphical abstract

在加热和混合合成卡马西平之后，以薄荷醇为基础的深共晶液体已用于从卡马西平的水溶液中进行反应性液-液萃取。琥珀酸二乙酯用作稀释剂，而深共晶液体则用作萃取剂。组成了几种含有薄荷醇和不同摩尔比（1/1和1/2）的羧酸（乙酸和甲酸）的深共晶液体。测量了所设计的深共晶液体的pH，密度，粘度和折射率值。此外，傅里叶变换红外光谱法也被用于深共晶液体中进行表征。与未处理的溶液相比，深的低共熔液体将稀释剂的提取性能从11％提高到36％。拟议的系统（摩尔比为1/1的薄荷醇/乙酸）在30分钟内从其水溶液中提取了90％以上的目标药物化合物。稀释剂中萃取剂的浓度，水性介质中卡马西平的初始含量以及离子强度影响了反应性液-液萃取。根据热力学结果，卡马西平从水相到疏水相的转移过程本质上是吸热的和自发的。还已经观察到是具有趋于不规则的结构的分离过程。离子强度和离子强度影响了反应性液-液萃取。根据热力学结果，卡马西平从水相到疏水相的转移过程本质上是吸热的和自发的。还已经观察到是具有趋于不规则的结构的分离过程。离子强度和离子强度影响了反应性液-液萃取。根据热力学结果，卡马西平从水相到疏水相的转移过程本质上是吸热的和自发的。还已经观察到是具有趋于不规则的结构的分离过程。

图形概要