Experimental Research On The Reaction-separation Integrated Technology For Mannitol Preparation

Mannitol is an important fine chemical product widely used in medicine, food, chemical industry and other related fields. With the development of the scientific research, the application of mannitol is continuously widening. The application of reaction-separation integrated devices, which is electromechanical integrated high-new technology equipment composed of the coupling of reactors for preparation and chromatographic separation device for extraction, is gradually extensive in chemical production processes such as medicine. Reaction-separation integrated technology is the main process to get high-purity products with high efficiency especially for some mixed products, whose application can reduce the environmental pollution by organic solvent greatly. The efficient continuous production can save energy greatly, and the research closely fit the current important development direction of green chemistry, energy conservation and emission reduction.In order to obtain the high-quality mannitol economically and safely, research on the reaction-separation integrated device for mannitol preparation has been done with both theoretical and experimental methods, and certain results have been achieved.First, in this paper, the basic principles of the preparation of mannitol through electrochemical reaction and the continuous chromatographic separation are described. The principles and difference of several kinds of continuous chromatography is introduced and analyzed. The original concept of the shunt multiple reaction-separation integrated system is proposed and the operation and control process are introduced briefly, which provides a theoretical guidance for the latter experiment.Second, the hardware and software platform for the experiment are installed in accordance with design ideas. The specific experimental study of separation performance between mannitol and glucose is performed. The process control parameters such as best rate of eluate, liquid feed rate and switching time in the separation of glucose and mannitol were found through many single-column experiments, which provide parameters for further multi-column and multi-component separation. On the basis of analysis and discussion of further multi-streaming and multi-column chromatography columns experiments, the flowsheet and effective process conditions are obtained. The experimental study demonstrates the performance of shunt multiple reaction-separation integrated technology and device, and provides the necessary experimental methods and test data for further modeling and simulation of the systems.At last, based on the interphase mass transfer characteristic in reaction-separation process, the partial differential equations for the coupling analysis and calculation are established. Combined with the actual initial and boundary conditions, the adsorption isotherm equations are coupled with partial differential equations to establish the mathematical model of continuous chromatographic separation of glucose and mannitol. Through the simulation of system model, the concentration distribution curves inside the column and the separation curves at the outlet are obtained. And the simulation results are compared with the experimental curves, which shows good agreement and verify the validity and correctness of the mathematical model established in this paper. The simulation results predict characteristics of reaction-separation integrated process of the products, and the method can provide theoretical guidance for design of the new integrated reaction-separation system.