We reported experimental measurements of the diffusion coefficient of methane at effectively infinite dilution in methylbenzene and in heptane at temperatures ranging from (323 to 398) K and at pressures up to 65 MPa. The Taylor dispersion method was used and the overall combined standard relative uncertainty was 2.3%. The experimental diffusion coefficients were correlated with a simple empirical model as well as the Stokes–Einstein model with the effective hydrodynamic radius of methane depending linearly upon the solvent density. The new data address key gaps in the literature and may facilitate the development of an improved predictive model for the diffusion coefficients of dilute gaseous solutes in hydrocarbon liquids.

中文翻译：

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温度介于 323 K 和 398 K 之间，压力高达 65 MPa 时，甲烷在甲苯和庚烷中的扩散系数

我们报告了甲烷在甲苯和庚烷中有效无限稀释、温度范围为 (323 到 398) K 和压力高达 65 MPa 的实验测量值。使用泰勒色散法，总体组合标准相对不确定度为 2.3%。实验扩散系数与简单的经验模型以及 Stokes-Einstein 模型相关，甲烷的有效流体动力学半径与溶剂密度呈线性关系。新数据解决了文献中的关键空白，可能有助于开发改进的烃类液体中稀气态溶质扩散系数的预测模型。