Simeonov E.Chilev C.2024-07-162024-07-162024-07-162024-07-162015-01-011314-79781314-7471SCOPUS_ID:84944329073https://rlib.uctm.edu/handle/123456789/1122Experimental kinetics has been obtained by extraction from leaves of Nicotiana tabacum L. at periodical conditions in a stirred vessel. The influence of the liquid-solid ratio and the kind of the solvent have been determined. A four parameters model for calculating the values of Deffhas been found using non-linear regression of the experimental results. The diffusion model have been solved using variable Deff. There is a very good coincidence between the numerical and experimental data.enArticle