A solvent, derived from the Latin, Solvo meaning to loosen, unite, or solve, is a substance used to dissolve another, creating a homogenous solution. Solvents are omnipresent in our daily life, water often being referred to as the universal solvent that acts as a medium in which we exist. In nature, solvents are used as carriers for vital nutrients across all organisms. Imagine the sugar dissolved in water being pulled up the phloem through capillary action created by the evaporation occurring along the pores of lemon grass leaves. Clever as we are, we humans have discovered that the uses of these marvelous materials are many.
It is important to note that when two substances form a solution, there is no chemical reaction occurring. One substance dissolving into another is in fact a physical change in which the particles of the solute have oriented themselves in the intermolecular, “gaps” of the solvent due to their electronegative attraction known as dipole moments for polar solvents, and London forces in the case of non-polar molecules. The availability of these gaps directly correlates to the amount of energy within a system. This is to say that as more heat is introduced into a solvent, the more quantity and variety of solutes will be able to dissolve into a solution. The opposite is true when removing heat from a solution.The solvency of a substance can be measured and classed by the level of intermolecular interactions capable between the solvent and the solute. Simply put, molecules of like properties tend to be soluble. Polar molecules dissolve other polar substances, and the same is true for molecules that share a non-polar nature. The introduction of a polar substance into a non-polar one, for instance, will result in a layering effect with the more dense one orienting itself on the top.This unique physical property offers several versatile applications, and refinement through the use of a solvent as a carrier and means of separations is a mainstay in the industry of purification. In Cannabis extraction, all of the above discussed properties of solvents are used in the selective removal of the different components of the cannabis plant, and as a medium for their purification. When considering the properties of the different components within Cannabis, it is clear why the simplest and most pure extracts are done with non-polar hydrocarbons. Their London interactions in combination with the pressure needed to keep them in a liquid state provide just enough solvency to dissolve the desired non-polar cannabinoids and terpenes before the hydrocarbons are purged off. However, the intentions of some are to extract a true representation of the plant as a whole, or perhaps to ensure the optimal capture of all those desired cannabinoids. This can only be accomplished using a solvent with the capacity to dissolve polar compounds as well. The highly electronegative Hydroxyl group of an alcohol provides the perfect dipole interaction to easily capture any desired compounds on a sample of biomass, polar or otherwise. In addition, the solubility of an alcohol can be greatly inhibited by reducing it’s operating temperature, costly as the process may be. Other Cannabis purification processes in which solvency is vital include winterization, acid/base extraction, and elution. All of these seemingly complex procedures owe their discovery to the simple properties of solubility. It becomes clear that the administration of simple physical properties can yield increasingly astounding results in the right creative hands. The greatest minds of our past have shown that there are evermore novel applications of these physical characteristics to be discovered for the benefit and amusement of us all.