Distillation and distillation are actually exactly the same! Why, actually, it's because Americans are notoriously lazy ... originally there was only one word, that is, distill, but because of the phonetic symbol of the word itself, the two "L" actually have only one L pronunciation, and even if the basic structure of an L is missing, it is reasonable and will not be affected, so lazy Americans simply remove an L, so this word only exists in the United States. But if it is a more formal written document such as a report or a thesis, then Americans will use "distinct" instead of "distinct", otherwise it will be less rigorous.