Difference Between Alpha and Beta Pinene

The key difference between alpha and beta pinene is that alpha-pinene is slightly water-soluble whereas beta-pinene is not soluble in water.

Pinene is an organic compound having the chemical formula C₁₀H₁₆. It is a bicyclic monoterpene compound. It has two structural isomers as alpha and beta-pinene. Both these isomer types are important constituents in pine resin. We can find these isomers in the resins of many other conifers and non-coniferous plants as well. Both these isomers of pinene are useful for many insects for their chemical communication system. Moreover, the major component of turpentine is alpha and beta-pinene.

1. Overview and Key Difference
2. What is Alpha Pinene
3. What is Beta Pinene
4. Side by Side Comparison – Alpha vs Beta Pinene in Tabular Form
5. Summary

What is Alpha Pinene?

Alpha pinene is an organic compound having the chemical formula C₁₀H_16, and it is the alpha structural isomer of pinene. This compound is an alkene containing a reactive 4-membered ring structure. We can find this alpha isomer in the oils of many coniferous tree species such as pine. We can also find it in the essential oil of rosemary plant. There are two enantiomers of alpha pinene as the (+)-alpha pinene and (-)-alpha pinene. Among them, the (-)-alpha pinene is common in European pines while (+)-alpha pinene is common in North American pine trees. Furthermore, we can find the racemic mixture of these enantiomers in some oils like eucalyptus oil and orange peel oil.

Difference Between Alpha and Beta Pinene

Figure 01: Enantiomers of Alpha Pinene

Generally, monoterpenes such as alpha pinene are emitted in large amounts through vegetation. These emissions are affected by temperature and light intensity. The emitted alpha pinene can undergo reactions with ozone and other radicals in the atmosphere. These reactions lead to low-volatility species to produce secondary organic aerosols.

Alpha pinene exists as a clear colourless liquid that is slightly water-soluble and miscible with acetic acid, ethanol, and acetone. This liquid is flammable. It is highly bioavailable (about 60%) in human pulmonary uptake with a rapid metabolism or redistribution. This compound acts as an antimicrobial agent because it is an anti-inflammatory agent. Moreover, this compound exhibits activity similar to an acetylcholinesterase inhibitor, aiding memory.

What is Beta Pinene?

Beta pinene is an organic compound having the chemical formula C₁₀H_16, and it is the beta structural isomer of pinene. It is a type of monoterpene and can be found in plants. This substance occurs as a colourless liquid that is soluble in alcohol but not in water. This substance has a woody-green smell similar to pine.

Figure 02: Chemical Structure of Beta Pinene

Beta pinene is one of the most abundant compounds released by forest trees. When this compound undergoes oxidation in air, it can cause the prevailing of the allylic products of pinocarveol and myrtenol family.

Some examples of the plants that contain this beta isomer include cuminum, cyminum, Humulus lupulus, etc. This substance is not flammable, so it is safe to use.

What is the Difference Between Alpha and Beta Pinene?

Alpha pinene is an organic compound having the chemical formula C₁₀H_16, and it is the alpha structural isomer of pinene. Beta pinene is an organic compound having the chemical formula C₁₀H_16, and it is the beta structural isomer of pinene. The key difference between alpha and beta pinene is that alpha pinene is slightly water-soluble, whereas beta pinene is not soluble in water.

Below infographic lists the differences between alpha and beta pinene in tabular form.

Summary – Alpha vs Beta Pinene

Alpha and beta isomers of pinene have several similarities and differences between them. The key difference between alpha and beta pinene is that alpha pinene is slightly water-soluble, whereas beta pinene is not soluble in water.

Reference:

“Beta-Pinene.” Wikipedia, Wikimedia Foundation, 18 Jan. 2021, Available here.

Image Courtesy:

1. “Alpha-Pinene Isomers” By Inductiveload – Own work (Public Domain) via Commons Wikimedia
2. “Beta-pinen” By Jan Herold – File:Beta-pinen.png (CC BY-SA 3.0) via Commons Wikimedia