The Study On The Purification Of 2-methyl Quinoline

2-methylquinoline has an extensive application value,which is used as the intermediates for organic synthesis of pharmaceuticals and antioxidants of lubricating oil.At present domestic country mainly adopts phosphate salt method to refine 2-methylquinoline,making larger equipment corrosion and producing a large amount of waste water,which causes environment pollution.From the aspect of high efficiency,energy saving and environmental protection,papers use 70% 2-methylquinoline extracted from wash oil as raw material,then make a research on purifying 2-methylquinoline by applying methods of phenol adducts,o-cresol adducts,and SH-1 adducts respectively,and discuss its detail process and technology conditions.(1)In the experiment of using phenol to refine 2-methylquinoline,paper studies on the amount of the phenol,crystallization temperature,the amount of toluene in the recrystallization and the other factors effect on the purifying of 2-methylquinoline.The results show that: phenol can effectively improve the purity of the product;in a certain temperature range,with the reducing of the crystallization temperature,the purity of 2-methylquinoline gradually reduced,and the yield is increased.If the temperature is too low,not only it consumes a great deal of energy,but also crystal separation is more difficult;After 3 times crystallization in the purity of 2-methylquinoline,it can reach to higher than 99%;The amount of toluene in the process of recrystallization and three times crystallization has little effects on the mass fraction of the product;Aspen Plus simulation of 2-methylquinoline with phenol has no azeotropic point,which 2-methylquinoline can be easily obtained through simple distillation.(2)O-cresol forms an adduct with 2-methylquinoline and other impurities of quinolines with different melting point.Paper discusses the amount of o-cresol,the amount of toluene for the first time crystallization effect on the purification of 2-methylquinoline.The results show that: O-cresol can form an adduct with 2-methylquinoline whose melting point is higher than the phenol-2-methylquinoline adduct.It more easily forms a crystal separated out from other impurities adducts.With the increase of the amount of o-cresol,the product yield decline and it is difficult to crystallize;When first crystallization added toluene mixture with raw materials and o-cresol,it can significantly improve the product yield and purity;After 3 times crystallization,the purity is higher than 99%,yield is higher than the yield of using phenol to purify 2-methylquinoline.Aspen Plus simulation of 2-methylquinoline and o-cresol distillation process needs both column plate number(19).It shows that reflux ratio(0.37)are little,and has less energy consumption.They can be simply distillation separated.(3)In the experiment of using SH-1 to purify 2-methylquinoline,paper discusses the selection and the amount of inert solvent,the concentration of SH-1,crystallization temperature,inert solvent washing crystal and the amount of inert solvent in the crystallization effect on the purification of the product.Results show that: the system needs higher crystallization temperature,with o-xylene as inert solvent;the first time crystallization without inert solvent,it is difficult to separate the crystal with the mother liquor;with the increase of the SH-1,the purity of the product decrease;Adding a certain amount of o-xylene can significantly improve the purity and yield of the product.(4)Using SH-1 to purify 2-methylquinoline,the first crystallization mother liquor contains large amounts of quinolines impurities is measured.Using extraction method to deal with the mother liquor,the solvent ratio,extraction temperature,the times of extraction effect on the mother liquor extraction is discussed.The results show that: with the increase of the extraction temperature,organic solubility increases,the extraction effect becomes poor;with the increase of extraction solvent,it has little effects on the extraction effect.Mother liquor after extracting can be used in the crystallization solvent for the first time.