The Measurement On Diffusion Coefficients Of O,m,P-xylene And Acetic Acid

The liquid diffusion plays an important role in chemistry as well as in chemical engineering and other related fields, among them the experimental measuration and the theory research of diffusion coefficient is of general practical significance. Besides, the experimental data on liquid diffusion coefficient is very scare.Pure terephthalic acid(PTA) is the main raw material in the manufacturing polyesters.The level of the technology in producing PTA affects development of polyester industry. It is necessary to obtain the basic physical properties and thermodynamics properties for developing new process of PTA or renovating old equipment and process. Owing to technological monopoly, all these basic properties about PTA design can't find in literature. So the diffusion coefficients of the related system in the PTA production process were measured. This project is supported by China Petrochemical Corporation,The work determines the mutual diffusion coefficients of o-xylene, m-xylene, p-xylene with acetic acid by"diaphragm-cell"method. Based on the work studied before, metallic diaphragm-cell to measure mutual diffusion coefficient were prepared. The diaphragm-cell constant were determined by measuring the diffusion coefficient of aqueous solution of aqueous solution of KCl at 298.15K; The reliability of the experimental method was verified by determination for the systems of acetic acid-water solution at 298.15K with which the diffusion coefficients are well know. Metallic diaphragm-cells were employed in measuring the binary integral diffusion coefficients for o-xylene, m-xylene, p-xylene and acetic acid at 298.15-343.15K, Based on the integral diffusion coefficients, their differential diffusion coefficients were calculated and correlated. It is useful and important for engineering and technology design in the PTA production process.Densities and viscosities of the related systems were determined under atmospheric by using Density/Specific Gravity Meter DA-505U vibration tube Ubbelohde suspended-level viscometer. Meanwhile, the calculation to these data were carried on.