Experimental study of ethylene molecular diffusion coefficient in NMP

In this paper, the molecular diffusion coefficient is calculated by obtaining experimental data of gas diffusion in stagnant solvent and using mathematical models based on Fick's second law. The purpose of this paper is to calculate the ethylene diffusion coefficients in n-methyl pyrrolidone (NMP) solvent at initial pressures of 600, 800 and 1100 kPa and temperatures of 278.1, 298.1 and 328.1 K using two available models. Although similar to previous researches, the experimental results from both models showed that the diffusion coefficients increase with increasing temperature, the type of dependence on temperature as DAB = A.Tn has been different from the researchers' point of view. To examine, the experimental results were compared with the predictions of Wilke-Chang model, in which n = 5.65, and Diaz model, in which n =8.5. The dependence of the molecular diffusion coefficient on temperature in the two experimental models is different, and the prediction of the Diaz model had better agreement to the experimental data of this study.