a.What advantages does ligroin have over n-pentane as a recrystallization solvent?

b. What advantages foes ethanol have over n-octanol as a recrystallization solvent?

Doesn't it make a difference as to what we are recrystallizing?

"Like dissolves like"...ligroin and n-pentane are nonpolar solvents (saturated hydrocarbons), and therefore have no significant advangtage over each other in terms of ability to dissolve various materials, although one might be stronger. The same is the case for ethanol and n-octanol, although those are alcohols rather than saturated hydrocarbons, yet the same argument applies. DON'T take my words as absolute though, I am an undergrad in my first semester of O-Chem and this is to the extent of my knowledge. It is sound however from what I've read, because again disregarding their relative strengths in the two questions, both solvents being compared are limited to the same range of solutes that they are able to dissolve with respect to one another.

Common sense dictates that crystallization of a compound can only occur if the compound that you're trying to crystallize is a crystalline solid. Crystalline solids are generally polar molecules that can freely interact with neighboring molecules to form a lattice (a uniform, geometric distribution of like molecules). Keep this in mind while I answer your question.

1) ethanol vs octanol - Ethanol is a better crystallization solvent because of two main factors. First, octanol is much more lipophilic than ethanol. This means that octanol likes lipids more than ethanol. And since lipids are not crystalline solids but, rather, waxy solids at best, octanol is the poorer solvent of the two to use for crystallization. Ethanol, on the other hand, is the better alcohol to use in crystallization because it is better at dissolving polar compounds that are less lipophilic and more crystalline in nature. Reason #2: 1-octanol, with a bp of 195 degrees C, is much more difficult to remove than ethanol when drying a cyrstalline solid... By David M

To compare the advantages of different solvents for recrystallization, we can consider factors such as solubility, boiling point, toxicity, availability, and cost. Let's analyze both scenarios:

a. Advantages of ligroin over n-pentane as a recrystallization solvent:
- Solubility: Ligroin generally has higher solubility for a variety of compounds compared to n-pentane, which means it can dissolve a wider range of substances during the recrystallization process.
- Boiling Point: Ligroin has a higher boiling point than n-pentane. This higher boiling point allows for better control over the recrystallization conditions, as it reduces the risk of rapid evaporation and potential loss of the desired product.
- Availability: Ligroin is often more readily available in laboratory settings compared to n-pentane, making it easier to obtain for recrystallization experiments.
- Cost: The cost of ligroin is generally lower compared to n-pentane, which can be advantageous when working with limited budget constraints.

b. Advantages of ethanol over n-octanol as a recrystallization solvent:
- Solubility: Ethanol tends to have higher solubility than n-octanol for many organic compounds. This can be beneficial when trying to dissolve a wider variety of substances during the recrystallization process.
- Toxicity: Ethanol is less toxic than n-octanol. It is important to prioritize safety when working with solvents, and ethanol's lower toxicity makes it a safer choice.
- Availability: Ethanol is commonly available in various concentrations, including high purity options, making it easily accessible for recrystallization experiments. On the other hand, n-octanol might be less commonly found in some laboratory settings.
- Cost: Ethanol is generally more affordable than n-octanol, which can make it a more cost-effective choice, especially when larger quantities of solvent are required for recrystallization.

It is important to note that the advantages listed above may vary depending on the specific compounds being crystallized and the desired outcome of the recrystallization process. Therefore, it is always recommended to perform preliminary solubility tests and consider the specific requirements of the experiment to choose the most appropriate solvent for recrystallization.