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Research On Technology For Extraction And Separation Of Dicarboxylic Acid From DBA Wasteliquor

Posted on:2016-04-30Degree:MasterType:Thesis
Country:ChinaCandidate:J J GuoFull Text:PDF
GTID:2191330479491462Subject:Chemical Engineering
Abstract/Summary:PDF Full Text Request
Separation of succinic acid, glutaric acid and adipic acid from mixed dibasic acid( DBA waste liquor) has great value for improving the added value of dicarboxylic acids. The thesis uses the method of solvent extraction to separate dicarboxylic acid from DBA waste liquor and the acid-base titration and HPLC as the analytical methods of content of each acid. The extraction process, the extraction thermodynamics, the theory of countercurrent extraction and the interaction between solvent and solute were studied.The three dicarboxylic acids of single systems and the DBA waste liquor were as raw materials. G302 was chosen as the extraction agent. The raw materials were extracted at 308.15 K for 5 min with the rotation rate of 600 r/min, and the O/W of greater than 1.5 by the single factor test and saturation capacity test. The single factor test of back extraction was carried out, and the optimum back extraction conditions were obtained as follows: water was chosen as the back extraction agent at 308.15 K. The research of extraction thermodynamic showed the extraction process was an exothermic reaction, therefore, the increase of temperature would be disadvantageous to the reaction. The reaction enthalpy was respectively: succinic acid 1-3.91 SH k J mol?? ? ?, glutaric acid 1-2.40 GH k J mol?? ? ?, adipic acid 1-3.24 AH k J mol?? ? ?. On the same conditions, neither the extraction nor back extraction process had the synergistic and the competition effect by comparing the extraction rate and the back extraction ratio of same dibasic acid with the different systems.The conclusion was drawn by studying the fractionation extraction process that the extraction stages were four, the O/W of extraction process was 3.5:1, the washing stages was 7, the O/W of washing process was 7:1, then the extraction rate of C4~C6 dicarboxylic acids was all above 99%. In order to increase the concentration of nitric acid in the outlet and improve the purity of dibasic acids with the needs of extraction rate of three dibasic acids, the lowest O/W of extraction process could be adjusted to 2:1. By cascade process design and consideration to side reactions, ultimately on the conditions of the flow ratio of : : 1: 3 : 3F S WV V V ?, the washing stages of 12, the O/W of washing process of 1:1, the extraction stages of 7, the O/W of extraction process of 3:1, then the highest purity of succinic acid reached to 100% and glutaric acid reached to 73%.The effect of the standing time of the loaded organic phase on the back extraction ratio showed that the back extraction ratio of the loaded systems containing nitric acid after placing a long period decreased, but had no effect on the loaded systems without nitric acid. The peaks of the loaded systems containing nitric acid before and after standing a long period moved to lower wavenumber named red shift by FTIR and Raman spectrophotometry, while the peaks of the loaded systems without nitric acid had no change. By the UV-Vis spectrophotometry The measurement results of the loaded systems containing nitric acid was compared with the loaded systems without nitric acid after a long period placement, the peaks of the former moved to longer wavelength which was called red shift, however, no displacement change of the peaks between the free nitric acid loaded systems. In this process, comparing the solution of succinic acid, glutaric acid, adipic acid with the corresponding loaded systems, the displacement of the peaks had changed because of the solvation. The blank extraction agent of G302 and loaded systems containing dibasic acids were measured by infrared spectroscopy, and the conclusion was drawn that G302 was associated with each dicarboxylic acid by hydrogen bond.
Keywords/Search Tags:DBA waste liquor, solvent extraction, separation, succinic acid, glutaric acid, adipic acid
PDF Full Text Request
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