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Investigation Of New Synthetic Process Of DSD Acid And Solubility Characteristics Of4,4'-dinitrostilbene-2,2'-disulfonate Disodium Salt

Posted on:2013-09-29Degree:MasterType:Thesis
Country:ChinaCandidate:M X DuFull Text:PDF
GTID:2311330452469713Subject:Chemical Engineering
Abstract/Summary:PDF Full Text Request
4,4'-diamino-2,2'-disulfonic acid (DSD) is an important intermediate for thesynthesis of the stilbene fluorescent brighteners and reactive dyes. The existingprocess of DSD production is composed of three steps (sulfonation, oxidation, andreduction). The oxidation process is usually carried out in the alkaline aqueous mediawith a low yield and a large quantity of wastewater generated. It is of greatsignificance to study new processes of DSD acid.A new synthesis process of DSD acid was studied in this paper, the processincluded two steps: the condensation process of p-nitro-toluene-o-sulfonic acid (NTS)in the alkaline media and the reduction process of the condensation products.Comparing with the traditional process, the new process consumes less water andgenerates less wastewater. The analysis method of the new process was explored inthis paper, and the acetonitrile-0.01M ammonium acetate solution can be used as themobile phase in the HPLC analysis of the intermediates existed in the new processand the gradient program may be a better choice. Basis on the developed analysismethod, the new process of DSD acid was studied. The HPLC was used to track theend of the reduction process and determine the concentration of DSD in the solution.The results showed that the yield of the new process was about30~38%, which islower than the yield reported in the literatures and the traditional process. It isnecessary to study further in the condensation process.Using the aqueous organic solution to replace the aqueous solution as the reactionsolvent is an important improvement of the oxidation process. The solubility of4,4'-dinitrostilbene-2,2'-disulfonate disodium salt (DNSNa) in the mixed aqueousorganic solutions (ethanol+water and diethylene glycol+water) was determined inthe latter part of this study. The E-NRTL mode equation was used to correlate themeasured data, from which the model parameters were obtained. The result showedthat the experimental data and the calculated data of solubility of DNSNa in thediethylene glycol+water using the E-NRTL equation fitted well, theroot-mean-square deviations was0.70K, while the root-mean-square deviations ofDNSNa+ethanol+water was1.23K.
Keywords/Search Tags:DSD, Condensation process, Solid-liquid equilibrium, E-NRTLmodel
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