Succinic Acid And Its Derivatives Gamma Butyrolactone Separation Technology

Succinic acid and gamma-butyrolactone are important raw materials of organic chemical, they have been widely used in industry, agriculture, medicine and other fields. This paper studied the separation process of succinic acid and gamma-butyrolactone.Through crystallization and anion resin to extraction of succinate, and established mathematical model to analyze adsorption mechanism; then by organic solvent extraction method to separation gamma-butyrolactone; finally through distillation to extraction gamma-butyrolactone. Main contents were:(1) Crystallization experiment of succinate. The results showed that when the initial mass concentration was 8%, the crystallization temperature was -2～-1℃ and the crystallization time is 20 min, the yield could reach 50.4%, if give sufficiently long time the yield could reach 73.2%. The effect of NaCl in solution was studied, the results showed that NaCl in the fermentation broth did not affect the crystallization.(2) By anion resin to extraction succinic acid. Batch experiments showed that the best resin was HZD-9 was selected from six kinds of resins. At room temperature, the concentration was 30 mg/mL, the equilibrium time was 30 min, the adsorption capacity reached 545.8 mg/g. Dynamic experiments showed that pumped into the concentration of 10, 20 and 30 mg/mL succinate, the breakthrough time was shortened from 20 min to 2 min; resin content was 2,6 and 10 g, the breakthrough time increased from 5 min to 39 min. Fitted the experimental data, that the adsorption process obeyed the Langmuir adsorption equation and Weber and Morris second order kinetics equation. Established mathematical models according to the equations, compared experimental data and model fitting data and effect of mass transfer coefficient and pore diffusion coefficient on the adsorption.(3) Extraction of gamma-butyrolactone by organic solvent. The experimental results showed that the most suitable extraction solvent was dichloromethane. At room temperature, O/A is 1:1, extraction time was 20 min, standing time for 30 min in those conditions of single-stage extraction reached 80.4%. By three stage cross flow extraction experiment in 0.5 compared to the same other conditions the extraction rate reached 95.3%. The mass fraction of the bottom of the tower was 99.6%, and the yield reached 80%.