The aniline point test is a crucial analytical method for determining the compatibility and composition of petroleum products and hydrocarbon solvents. It measures the minimum temperature at which equal volumes of aniline and a sample are completely miscible, providing valuable insights into aromatic content and solvent power.

• Method A: Ideal for transparent samples with an initial boiling point above room temperature and an aniline point between the bubble point and solidification point of the aniline-sample mixture.
• Method B: Recommended for dark or opaque samples using a thin-film approach.
• Method C: Specifically designed for highly volatile samples with a strong tendency to vaporize at the aniline point.
• Method D: Best suited for samples with substantial vaporization at the aniline point, particularly when only small quantities are available.

These standardized test methods ensure accurate, reliable, and repeatable results across different petroleum products, fuels, and hydrocarbon solvents.