What you are looking for is - for all practical needs - impossible. Chemistry is about using available substances to create other substances, but you will almost never start from scratch (ie from elements) - with the exception of very simple substances. So in the real life you will never attempt to make CH3-CH2-O-CH2-CH3 from carbon, hydrogen and oxygen - you will rather start from ethanol, which can be easily bought in any amount.
Purification of reaction products is almost a science in itself. Depending on substance and impurities you may try filtration, crystallization, destillation, extraction or chromatography to name most popular methods.