色谱法筛选C_9芳烃萃取精馏溶剂

Selection of Solvents of C 9 Aromatic Hydrocarbons Extractive Distillation by Gas Liquid Chromatography

将萃取精馏溶剂作为气相色谱固定液，利用气－液色谱法对Ｃ９芳烃所用溶剂进行了选择。共测试环丁砜、邻苯二甲酸二甲酯等７种溶剂。其中邻苯二甲酸二甲酯对Ｃ９芳烃异构体的分离效果较好。方法省时省力，消耗少，结果可靠。

The extractive distillation is a very important method for the separation of chemicals with nearly the same boiling points. Selectivity (S) was used as a parameter for separation. The more the S is apart from 1, the better the solvent for separation is. S can be obtained from the ratio of the adjusted retention times in GC easily. Seven solvents for extractive distillation with regard to C 9 aromatic hydrocarbons were tested as stationary phases in gas liquid chromatography at different temperatures. The solvents are solfolane, DEG, N methyl 2 pyrrolidone and 4 phthalates. From the experiments we can conclude: (1) The selectivities of these solvents decreased to different extent with temperature rising. Hence low temperature is better for separation of C 9 aromatic hydrocarbons. (2) These solvents have different effects on selectivities, because there are different forces between the solvents and C 9 aromatic hydrocarbons. It is obvious that polarities of solvents have certain effects on selectivities. But it is not absolutely right that the stronger the polarity is, the better the effects are. (3) Among these seven solvents dimethyl phthalate is better for separation of C 9 aromatic hydrocarbons. Dioctyl phthalate and N methyl 2 pyrrolidone are also good choices for extracting 1,3,5 trimethylbenzene from C 9 aromatic hydrocarbons.