To improve the purity of a crude sample of a chemical, various purification techniques can be employed, such as distillation, chromatography, or crystallization. The choice of the most appropriate method depends on several factors, including the chemical properties of the compound being purified, the nature of the impurities, the desired level of purity, and the scale of the purification process. Here, we will outline a general process to achieve a 95% pure sample of the desired chemical.1. Preliminary analysis: First, analyze the crude sample to determine the nature and concentration of the impurities present. This can be done using techniques such as mass spectrometry, nuclear magnetic resonance NMR , or infrared IR spectroscopy. This information will help in selecting the most appropriate purification method.2. Selection of the purification method: Based on the preliminary analysis, choose the most suitable purification technique. Consider the following factors: a. Distillation: This method is suitable for purifying volatile compounds with significant differences in boiling points compared to the impurities. It is not suitable for thermally unstable compounds or those with very similar boiling points to the impurities. b. Chromatography: This method is suitable for purifying compounds with different affinities for a stationary phase, such as silica gel or alumina. It is a versatile technique that can be used for a wide range of compounds, but may require optimization of the elution conditions. c. Crystallization: This method is suitable for purifying compounds with different solubilities in a solvent or solvent mixture. It is a simple and effective technique, but may require multiple recrystallizations to achieve the desired level of purity.3. Optimization of the purification process: Once the appropriate method has been selected, optimize the process parameters to maximize the purity of the desired compound. This may involve adjusting the temperature, pressure, solvent composition, or other factors, depending on the method used.4. Scale-up: After optimizing the purification process on a small scale, scale up the process to obtain the desired amount of purified compound. This may require additional optimization to ensure that the process remains efficient and effective at a larger scale.5. Final analysis: Analyze the purified sample using the same techniques employed in the preliminary analysis to determine the final purity of the compound. If the desired level of purity 95% in this case has not been achieved, additional purification steps or further optimization of the process may be necessary.6. Storage and handling: Store the purified compound under appropriate conditions to maintain its purity and stability. This may involve protecting it from light, moisture, or oxygen, depending on the specific chemical properties of the compound.By following these steps and carefully considering the factors involved in selecting the most appropriate purification method, it is possible to achieve a 95% pure sample of the desired chemical.