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CWL - M efficient extraction separation equipment acetonitrile, ethyl acetate and water mixture

by:Deyuan      2020-09-02
CWL - M efficient extraction separation equipment acetonitrile, ethyl acetate and water mixture research
abstract:. cwl - M high efficiency extraction equipment separate mixtures of acetonitrile, ethyl acetate and water research, in order to from pharmaceutical waste recycling in acetonitrile and ethyl acetate, the extractive distillation separation method is studied in the separation of the application of acetonitrile acetic ester, identified the first preprocessing, and then for extractive distillation process and process conditions. Using the above technical recovery of ethyl acetate from waste liquid, the content of the ethyl acetate reached 98. More than 5%.
a pharmaceutical factory in the production process, some with acetonitrile, ethyl acetate and water waste, direct emissions not only caused the waste of resources, but also caused serious environmental pollution, and their separation recycling, has important economic and environmental benefits.
as the boiling point of acetonitrile and ethyl acetate was close to ( Ethyl ester, 77 ℃, acetonitrile, 81 ℃) , at the same time, acetonitrile and ethyl acetate in azeotropic distillation process of phenomenon for the boiling point of 74. 8 ℃ of azeotrope: 23% acetonitrile, ethyl acetate and ethyl ester 77% fall and water for the boiling point of 70. 38 ℃, of azeotrope: water 8. Ethyl 47%, 91. 5%) , acetonitrile and water also exists azeotropic phenomena ( Boiling point 76 ℃, azeotrope composition: 85% acetonitrile and water (15%) , therefore, it is difficult to use the method of ordinary distillation separation of the mixture waste.
azeotropic distillation and extraction distillation, salt distillation, etc all can be used for separation of azeotropic distillation, but they all have their own disadvantages, such as high energy consumption of the azeotropic distillation; The extractive distillation solvent circulation quantity is big, cause the plate efficiency is low, production capacity of the tower; Salt distillation the intensity of labor is higher. Tianjin university batch azeotropic distillation separation was proposed, using this method to separate ethyl ester and acetonitrile, but content can't meet the production requirements. Therefore, we use the extractive distillation separation. Acetonitrile and ethyl acetate in water solubility, acetonitrile arbitrary than miscibility with water and ethyl and slightly soluble in water, so the suitable water extractive distillation. We are in the process of distillation, the guarantee of reflux ratio, and add a certain amount of water, straight from the top of the tower are keeping the top temperature of ethyl acetate and water azeotropic point, to ensure that the top products for ethyl acetate and water azeotrope, acetonitrile are all hydraulic tower kettle back, to the top to the azeotropic point of acetonitrile and water temperature, stop the spray water, producing acetonitrile and ethyl acetate azeotrope can, in the next batch of waste liquid treatment.

1 experimental section 1 material and instrument
the acetonitrile acetic ester liquid waste a pharmaceutical factory, the ethyl acetate content is about 92%, about 5% acetonitrile content, water content about 3%
rectification tower, 20 m diameter within 20 mm 2 mmX2mm theta stainless steel net ring packing, column reactor volume of 2 000 ml electric heating jacket heating; Agilent6890 gas chromatograph with a 70 - bit empty.
1。
1 2 experimental method. 2 1 waste liquid waste liquor pretreatment
the first detection of acetonitrile and ethyl acetate content ( Chromatographic purity results ethyl ester 90%, 10% acetonitrile. According to the volume of water and waste liquid 1:1 mixture, let stand, split phase, after the processing of waste liquid, ethyl containing 93% ~ 95%, and acetonitrile down to 3% ~ 5%

will after pretreatment of waste liquid ( 1500 mI concentrate processing the remaining 1, 400 mI) Join tower kettle heating power supply is connected, to be the top temperature rise to 70 ~ 71 ℃, 30 min from the top of the tower by peristaltic pump total reflux joined extraction with water, control the flow rate to keep the tower temperature at 71 ~ 73 ℃, the reflux ratio control for 2:1 sampling gas chromatograph to determine the content of ethyl acetate in the distillate tower top in 98. 8% ~ 99. If 23%, less than 98. 5%, then the appropriate increase the flow of water.
1。 After 2, 3, distilled water pretreatment of wastewater of heavy phase wastewater, using ordinary distillation can be concentrated waste flow back to the first step for processing. 2 the results and discussion

2. 1 water pretreatment of
wastewater pretreatment process of the amount of water in the influence on the treatment effect is bigger, use volume ratio of 1:1 water pretreatment of waste liquid, waste liquid can obviously change in the relative content of ethyl acetate and acetonitrile, lay a foundation for the subsequent distillation.
2。 2 extraction plus the amount of water in the process of distillation and recycling
in the process of distillation extraction of water quantity and the size of the recycling at the top of the column can influence the content of content, to join the volume ratio of 0. 2:1 ~ 0. 3:1 water extractive distillation, control the reflux ratio 2:1 or so, the effect is best, the content of ethyl acetate is 99% conclusion

3 acetonitrile and ethyl acetate are easy and any other form azeotropic solvent content, and the boiling point of both types of difference is not big, it is difficult to use the method of azeotropic distillation separation, we use the method of extraction distillation separation of ethyl ester and a mixture of acetonitrile, achieved good effect, not only has a certain economic benefits, and waste, protect the environment.


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