六氟磷酸锂的纯化

以PCl5和LiF为原料制备的LiPF6中Cl?含量较高，为了降低产品中Cl?含量以及提高产品纯度，本文采用乙醚和苯对其进行了纯化研究。在乙醚、乙二醇二甲醚、乙腈、丙酮几种溶剂中，确定了用乙醚来纯化LiPF6后，首先考察了LiPF6、LiCl、PCl5在乙醚中的溶解度，结果表明：乙醚能有效地分离LiCl和LiF，但是不能很好地分离PCl5，使得纯化后的Cl?较高。继续研究PCl5在苯、甲苯、二甲苯、氯苯、环己烷中的溶解度，结果表明：氯离子在苯和甲苯中有较好的溶解性能。继而，用苯和甲苯分别进行纯化研究，结果表明：用苯纯化后的LiPF6产品中的Cl?含量在2 mg/L以下，苯的残留量为0.0004%。认为乙醚和苯是纯化LiPF6产品的最佳溶剂选择。

Purification of lithium hexafluorophosphate

Lithium hexafluorophosphate with high chloride content was prepared from PCl5 and LiF. In order to reduce chloride content and improve product purity，purifying lithium hexafluorophosphate with ethyl ether and benzene was studied. The solubilities of LiPF6，LiCl and PCl5 in ether were investigated firstly after choosing ethyl ether from ethyl ether，glycol dimethyl ether，acetonitrile and acetone. Ethyl ether could separate LiCl and LiF from the product well but not PCl5，so chloride content in LiPF6 was still too high. Another solvent must be selected to remove chloride ion. So the solubilities of PCl5 in benzene，toluene，dimethylbenzene，chlorobenzene，cyclohexane were studied. Benzene and toluene did better than others. Then benzene and toluene were used separately to purify LiPF6. The chloride content in LiPF6 was reduced to 2 mg/L by using benzene. Residue of benzene in the product after recrystallization was 0.0004%. Ethyl ether and benzene were the best solvents to purify LiPF6.