Please let me know which is more soluble in water 1-Octanol or 1,3-Propanediol, and please what is the reasons and explain. ?? Thank you

2 Answers
Aug 31, 2015

the more soluble is propandiol, moreovere the solubility of propandiol in water is full while the solubility of octanol is poor

Explanation:

the solubility of organic compounds in water is caused by hydrophilic groups like OH alcoholic, and it is more soluble when the hydrocarbon is small

Aug 31, 2015

The long chain octan-1-ol would have limited or no solubility in water. 1,3-propanediol should have substantial solubility in water.

Explanation:

Octanol has a functional group that water is likely to solvate, the hydroxyl group. On the other hand, octanol has a long hydrophobic tail that is 8 carbons long ( hydrophobic = frightened of water; hydrophilic = loves water).

The organic chain is unlikely to be solvated effectively by water, and octanol would have very limited or no solubility in water. Short chain alcohols, ethanol, and methanol, have unlimited miscibility with water; they are water-like solvents. (In effect, they are 1/2 a water molecule). 1,3-propanediol should also have substantial solubility, as there are there polar functional groups on both ends of the carbon chain. However, as physical scientists, we should seek quantitative information. http://www.solubilityofthings.com/water/alcohols.

This bears out what we are saying: alcoholic solubility in water decreases as the chain length increases. So your job is to find the solubility of 1-propanol in water (this will be somewhere) and contrast this solubility with that of the diol.

As a further example, ethanol is miscible with hexanes, whereas methanol is not. Can you explain why?