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Study On Solid-liquid Phase Equilibria Of Binary Carboxylic Acid

Posted on:2015-09-24Degree:MasterType:Thesis
Country:ChinaCandidate:Z X MaFull Text:PDF
GTID:2181330431993632Subject:Chemical processes
Abstract/Summary:PDF Full Text Request
In the process of industrial production of adipic acid, Succinic acid and glutaricacid can be found in the by-products. After most of adipic acid is separated bycrystallization, there will be a certain amount of succinic acid, glutaric acid and adipicacid in the residual liquid. With the demand of adipic acid increased, the amount ofmixed binary carboxylic acid in the by-products also on the rise. The Separation ofmixed binary carboxylic acid which contains succinic acid, glutaric acid and adipicacid not only can reduce the environmental pollution but also can avoid the waste ofresources. In this paper, the solid-liquid phase equilibria of binary carboxylic acid wasstudied for providing basic data that can be used when we choose or optimize theoperating conditions of separation of mixed binary carboxylic acid.In order to measure the solubility of binary carboxylic acid accurately, a kind ofaccurate and reliable analysis method must be established. We can use a simplereversed-phase high-performance liquid chromatography (HPLC) analysis methodwhich is established in this paper to determine the content of every binary carboxylicacid in the samples, after that, the solubility of each binary carboxylic acid will becalculated. The chromatographic conditions: C-18reverse phase bonded silicacolumn; mobile phase: the concentration of phosphoric acid-potassium dihydrogenphosphate buffer solution is50mmol/L, PH=3.5and the methanol’s volume fractionis18%. After analyzing the precision and recovery rate of this method, it shows thatthe separation effect is good, the speed of analysis is fast and the method has goodaccuracy and high precision. The standard solutions which contain one binarycarboxylic acid, two binary carboxylic acids and three binary carboxylic acids areanalyzed by HPLC, and the standard curves are showed as well.Balance method was used to measure the solubility and the reliability of theexperimental apparatus and experimental methods were verified. Systems includeSuccinic acid–water, glutaric acid–water, adipic acid–water, Succinic acid–cyclohexanol, glutaric acid–cyclohexanol, adipic acid–cyclohexanol, Succinic acid –glutaric acid–water, Succinic acid–adipic acid–water, glutaric acid–adipic acid–water, Succinic acid–glutaric acid–cyclohexanol, Succinic acid–adipic acid–cyclohexanol, glutaric acid–adipic acid–cyclohexanol, Succinic acid–glutaricacid–adipic acid–water, Succinic acid–glutaric acid–adipic acid–cyclohexanol.It can be seen from the solubility data, when the temperature and the solvent are same,the solubility of binary carboxylic acid are different in these systems. It indicates thatwhen two binary carboxylic acids or three binary carboxylic acids are present in asolvent at the same time, they will produce certain interaction which will affect theirdissolution features.Polynomial equation, Apelblat equation, λh equation and Wilson equation wereused to correlate the solubility datas of the binary system, and each model parameterswere given. It showed that in the whole temperature range, the four equations couldcorrelate the experimental data well.
Keywords/Search Tags:solid-liquid phase equilibria, succinic acid, glutaric acid, adipicacid, solubility, HPLC, correlation
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