Solubility Of CDMB,CDMA And DMAn In 12 Organic Solvents And Its Application

4-chloro-2,5-dimethoxyaniline(CDMA,CAS No.6358-64-1)is an important intermediate for the preparation of yellow and red azo organic pigments.The remaining4-chloro-2,5-dimethoxynitrobenzene(CDMB CAS No.6940-53-0)which does not react and the dehalogenation production 2,5-dimethoxyaniline(DMAn CAS No.102-56-7)contained in the system would lower the quality of AS-IRL and AS-LC.We found suitable organic solvents which can purify CDMA by recrystallization respectively according to different conditions,and then optimized the production process of AS-LC and AS-IRG.We chose to study the solubility in 12 organic solvents(2-methoxyethanol,2-ethoxyethanol,1-methoxy-2-propanol,diethylene glycol,2-(2-methoxyethoxy)ethanol,diethylene glycol dimethyl ether,diethylene glycol monoethyl ether,anisole,2-ethoxyethyl ether,ethylene glycol monopropyl ether,benzyl alcohol and acetophenone)based on the principle of the dissolution in the similar material structure.In this work,the solubility data had been measured by a dynamic method over the temperature range from 275 to 340 K at atmosphere pressure.The experimental data were correlated with the Wilson,the NRTL,the modified Apelblat and the ?h models,which have been successfully used to describe the solid-liquid equilibrium(SLE).The interaction parameters of the models and the root-mean-square-devation(RMSD)were obtained using the Nelder Mead Simplex Method through Matlab.The Wilson and the NRTL models have higher accuracy for the RMSD of them are 0-1.35 K and 0-1.83 K respectively.Experimental results show that in all the systems,the solubility of CDMB,CDMA and DMAn increase with temperature.The solubility of DMAn is strongly dependent on temperature,whereas CDMB is weakly dependent.As for the molecular structure of the solvent,in general,increasing the length of the carbon chain can reduce the solubility while adding the ether group or the carbonyl can increase the solubility of three solutes.To produce AS-LC,acetophenone was suggested to be used as recrystallization solvent.From 295 K to 340 K in acetophenone,CDMA is twice as soluble as CDMB,and the solubility both vary linearly as the temperature increase.As for AS-IRG,diethylene glycol was preferred.When the temperature is lower than 305 K,DMAn is almost insoluble,but when the temperature is higher than 305 K,the solubility of DMAn increase rapidly.It is easier to remain DMAn in the solvent and to carry out the following process.