Unveiling the Power of Alpha-Pinene: Nature’s Gift Transforms Industries and Health Landscapes!

Alpha-Pinene CAS 2437-95-8

Pinene is a series of unsaturated bicyclic monoterpenes. Two geometric isomers of pinene exist in nature: α-pinene and β-pinene. Both isomers are chiral. As the name implies, pinene is found in pine trees. Specifically, pinene is the main component of the liquid extract of conifers. Pinene is also found in many non-coniferous plants, such as camphor pine (Heterotheca) and big sagebrush (Artemisia tridentata).

α-Pinene is a terpene organic compound. It is one of two isomers of pinene, the other being β-pinene. It is an olefin containing a reactive four-membered ring. It is found in the oils of many species of coniferous trees, especially pine and fir. It is also found in the essential oils of rosemary (Rosmarinus officinalis) and Satureja myrtifolia (also known as Zoufa in some areas). Two enantiomers are known in nature; (1S,5S)- or (-)-α-pinene is more common in European pines, while the (1R,5R)- or (+)-α isomer is more common in North America. Racemic mixtures of the enantiomers are found in certain oils, such as eucalyptus oil and orange peel oil.

1. ALPHA-PINENE Chemical Properties

Chemical formula: C10H16

Molar mass: 136.238 g-mol-1

Appearance: Colourless transparent liquid

Density: 0.858 g/ml (liquid at 20 °C)

Melting point: -62.80 °C; -81.04 °F; 210.35 K[1].

Boiling Point: 156.85 ± 4.00 °C; 314.33 ± 7.20 °F; 430.00 ± 4.00 K[1] .

Water solubility: Very low

Solubility in acetic acid: miscible

Solubility in ethanol: miscible

Solubility in acetone: miscible

Chiral rotation ([α]D): -50.7° (1S,5S-pinene)

Melting point：-55 °C

Boiling point：155-156 °C(lit.)

density：0.858 g/mL at 25 °C(lit.)

refractive index：n20/D 1.465(lit.)

Fp：90 °F

Dielectric constant：2.6（25℃）

α-Pinene is a colourless transparent liquid at room temperature, volatile, insoluble in water, containing a special bicyclic double bond structure, with good biological activity and unique reaction diversity. It is one of the important raw materials for the synthesis of camphor, icicle, rosinol, spice, resin and other chemical products in the fields of chemical and atmospheric chemistry.

2. Reactivity

Important commercially available derivatives of α-pinene are linalool, geraniol, nerol, a-pinene and camphene.

α-Pinene 1 is active due to the presence of a four-membered ring adjacent to the alkene. This compound is susceptible to skeletal rearrangements such as the Wagner-Melwein rearrangement. Acids usually lead to rearrangement products. Concentrated sulphuric acid and ethanol yield the major products, pinacol 2 and its ether 3, while glacial acetic acid yields the corresponding acetate 4. When dilute acids are used, terpene hydrate 5 becomes the major product.

At low temperatures in the presence of diethyl ether, a simple addition product 6a can be produced with one molar equivalent of anhydrous HCl, but it is very unstable. At room temperature, or in the absence of ether, the main products are benzyl chloride 6b, and to a lesser extent turnip chloride 6c. For many years 6b (also known as “artificial camphor”) was referred to as “pinene hydrochloride” until it was shown to be identical with chloroborane derived from camphene. If more hydrochloric acid is used, nonchiral 7 (dipentene hydrochloride) and some 6b become the main products. Nitrosyl chloride, in the presence of a base, produces oxime 8, which reduces to “pinamine”.9 Both 8 and 9 are stable compounds containing intact four-membered rings, and these compounds have been of great assistance in determining this important component of the pinene skeleton.

Under aerobic oxidation conditions, the major oxidation products are pinene oxide, veratrole peroxide, veratrol, and verbenone.

3. Role in the atmosphere

Monoterpenes, of which α-pinene is one of the main species, are released in large quantities from vegetation, and these releases are affected by temperature and light intensity. In the atmosphere, α-pinene reacts with ozone, hydroxyl radicals or NO3 radicals,[full citation needed] to produce low volatility substances that partially condense on existing aerosols, thus creating secondary organic aerosols. This has been demonstrated in many laboratory experiments with monoterpenes and sesquiterpenes. The clearly identified products of α-pinene are pinaldehyde, n-pinaldehyde, pinenoic acid, pinenoic acid and pinoleic acid.

4. β-Pinene Uses and Synthesis Methods

A. Anti-tumour effect

Zhang Z et al. In the study of α-pinene’s effect on non-small cell lung cancer, α-pinene synergistically treated A549 cells with paclitaxel, which could increase the efficacy of paclitaxel in suppressing tumours through the method of combined medication. The results showed that α-pinene was able to significantly promote tumour cell apoptosis. This was mainly due to the synergistic effect when co-administered with paclitaxel. Further study of the mechanism showed that α-pinene, when used in combination with paclitaxel, was able to cause a significant increase in the proportion of cells in the G0/G1 phase, and there were alterations in cellular morphological characteristics, such as changes in chromatin sequestration and nuclear fragmentation, in order to lead to the generation of apoptosis in tumour cells.

B. Anti-fungal effect

The cell wall of Candida albicans is mainly composed of chitin, glucose and mannan, the chemical composition of the cell membrane is mainly ergosterol, and the nucleic acid is mainly DNA and a small amount of RNA. the synthesis of these components can lead to the death of the bacterial cells. Xia Zhongdi et al. in the study found that α-pinene on Candida albicans cell wall in the butyl, polysaccharide synthesis, the synthesis of ergosterol in the cell membrane and the synthesis of nucleic acids DNA and RNA have obvious inhibitory effect, including inhibition of ergosterol synthesis is more obvious.Pichette A and other studies have also found that α-pinene has an anti-inflammatory, antibacterial, antioxidant effect.

C. Anti-allergic and improve the role of ulcers

In Nam SY et al. study on the inhibitory effect of α-pinene on allergic rhinitis in mice, found that splenic lymphocyte IL-4 expression decreased, nasal mucosa in the IgE, α-TNF, ICAM-1 and macrophage inflammatory protein-2 decreased. Eosinophils and mast cells, which were increased in mice in vivo, were also significantly reduced after α-pinene treatment. In addition, in a study of α-pinene’s action on the human mast cell line HMC-1, α-pinene inhibited the activities of phosphorylated RIP2, IKK-β, NF-κB and caspase-1 after sensitisation. Therefore, α-pinene is considered an anti-allergic agent.

In the study of improvement of ulcers, Pinheiro Mde A et al. oil extracted α-pinene treated gastric ulcers in mice and found that show α-pinene has significant anti-ulcer activity.

5. Properties and Uses

α-Pinene is highly bioavailable, with a 60% lung uptake and rapid metabolism or redistribution. α-Pinene has anti-inflammatory and possibly antimicrobial effects via PGE1. It has acetylcholinesterase inhibitory activity and may be useful for memory. It is also used as an antimicrobial agent. It has acetylcholinesterase inhibitor activity and aids in memory. Like camphenol, veratrol and pinenol, (-)-α-pinene is a positive modulator of GABAA receptors. It acts at the binding site of benzodiazepines.

α-Pinene is the basis for the biosynthesis of CB2 ligands such as HU-308.

α-Pinene is one of the many terpenes and terpenoids found in the cannabis plant. These compounds are also found in high levels in the finished dried cannabis flower preparations commonly known as marijuana. It is widely believed by scientists and cannabis experts that these terpenes and terpenoids have a strong influence on the unique “character” or “personality” of each cannabis plant. alpha-pinene in particular is believed to reduce memory deficits, which are often one of the side effects of THC. [citation needed] It is likely that alpha-pinene has this activity because it is an acetylcholinesterase inhibitor, which is a class of compounds known to aid memory and increase alertness.

Alpha-pinene also contributes significantly to the many different, distinctive odour characteristics of a wide range of cannabis species, varieties and cultivars.

Pinene (especially α) is the main component of turpentine, a solvent and fuel derived from nature.

The use of pinene as a biofuel in spark ignition engines has been explored. Studies have shown that the calorific value of pinene dimer is comparable to that of the jet fuel JP-10.

6. Biosynthesis

Both α-pinene and β-pinene are produced by cyclisation of geranyl pyrophosphate through linalyl pyrophosphate, followed by the loss of a proton from the carbocation equivalent. Researchers at Georgia Tech and the Joint Bioenergy Institute synthesised pinene using a bacterium.

7. Overview

β-Pinene is a bicyclic monoterpene. It is an isomer of α-pinene, one of the main components in turpentine. The content varies depending on the species, 28% to 35% in the turpentine oil of wetland pine (Ji’an, Jiangxi, China). Relative molecular mass 136, molecular formula C10H16. molecule with a cyclobutane, an isopropyl and extracyclic double bond. It has similar chemical properties with α-pinene. Colourless liquid, density (20 ℃) 0.8712, boiling point 162 ~ 163 ℃. Refractive index (20 ℃) 1.4787, spin (20 ℃) (in ethanol) -22.44 ℃. It can be used for the synthesis of linalool, nerol, geraniol, lauryl alcohol and its esters, nopf alcohol, nopf acetate, citral, violet ketone, citronellol and aldehydes, hydroxycitronellal and its esters, neo-belladonna aldehyde, neo-belladonna nitrile, dragon birthstone, terpene resins and so on. It is also an important raw material for the synthesis of spices and flavours.

Preparation

a. The preparation method of high purity β-pinene includes the following steps:

a) Add turpentine into the reaction kettle, heat and melt, and vacuum;

b) heating to 75 ℃, distillation for 1.5 hours, and then the distillate was repeatedly distilled 3 times according to the aforementioned temperature and time; the distillate was collected and set aside;

c) continue to raise the temperature to 160°C, distill for 1.2 hours, and then distill the distillate repeatedly for 3 times to obtain β-pinene crude product;

d) collect said β-pinene crude product, transfer to the reactor, pass into the concentrated sulfuric acid, stir evenly, and react for 1 hour to obtain a part of high purity β-pinene; wherein the mass ratio of concentrated sulfuric acid to β-pinene crude product is 1:1;

e) Transferring the distillate of step B into a reactor, adding a palladium catalyst with diatomaceous earth as a carrier, adjusting the temperature to 180°C, and reacting isomerically for 30 minutes to obtain another part of high-purity β-pinene;

f) Combining step D high-purity β-pinene with step E high-purity β-pinene.

b. Second, add turpentine into the reaction kettle, heating and melting, vacuum; heating to 75 ℃, distillation 1.5 hours, and then in accordance with the foregoing temperature and time of the distillate repeated distillation 3 times; continue to raise the temperature to 160 ℃, distillation 1.2 hours, and repeated distillation for 2 times, to get the β-pinene crude product; collect the said β-pinene crude product, transferred to the reaction kettle, through the concentrated sulfuric acid, stirring uniformly, the reaction for 40 minutes The reaction was carried out for 40 minutes to obtain high purity β-pinene; the mass ratio of concentrated sulfuric acid to β-pinene crude product was 1:3.

8. Applications

β-Pinene can be used for the synthesis of linalool, nerol, geraniol, lauryl alcohol and its esters, nopf alcohol, nopf acetate, citral, violet ketone, citronella alcohol and aldehyde, hydroxy citronella aldehyde and its esters, neo-belladonna aldehyde, neo-belladonna nitrile, dragon birthstone, terpene resins and so on. It is an important raw material for the synthesis of spices and flavours.v

With the deepening of China’s research on the use of turpentine to extract synthetic flavours, the downstream user demand for lauric acid is increasing, and the demand is also growing. β-Pinene cleavage to generate lauric acid:

According to the following steps: 110 grams of β-pinene content of 95.1% of β-pinene mixture into the carburetor, the beginning of the vacuum, heating; vacuum control in the -0.075Mpa ~ -0.085MPa, the heating temperature to 110 ℃, control of 30 minutes to evaporate the carburetor of the material, the formation of β-pinene gas, β-pinene gas into the mixer with 5 times the β-pinene gas volume of nitrogen for β-pinene cracking. β-pinene gas into the mixer and 5 times the volume of β-pinene gas nitrogen for mixing, mixing temperature control at 90 ° C; after entering the preheater for preheating, preheater gas mixture to 240 ° C, and then the mixed gas in a vacuum into the cracking tube with a catalyst layer of catalyst layer into the mixture of gases; the catalyst layer here for the zeolite molecular sieve catalyst; the temperature of the cracking tube along the axial direction of the tube body in turn into three The temperature of the cracking tube is divided into three axial sections along the tube, and the temperatures at the three points are 365℃, 460℃ and 475℃, and the vacuum degree of the cracking tube is -0.085Mpa. The cracking product coming out of the cracking tube is cooled down to less than 50℃ by two-stage cooling to form a liquid to obtain 100g lauric alkene. The analysis of laurilene showed that the content of β-pinene was 1.8%, the content of laurilene was 78.62%, the conversion rate was 98.1%, and the selectivity was 84.26%.