About Safrole

Introduction (top)

Safrole is a natural organic compound found in the roots, bark, and fruits of certain plants. It is widely used in various industries, including food, fragrance, and pharmaceuticals. However, due to its potential health risks and regulatory restrictions, safrole has become a controversial substance in recent years. This ultimate guide provides a comprehensive overview of safrole, its properties, uses, synthesis, extraction methods, and legal status.

Safrole oil

Safrole General Information (top)

Safrole is a natural organic compound that belongs to the class of allylbenzenes. It is found in the roots, bark, and fruits of certain plants, including sassafras, cinnamon, nutmeg, and camphor. Safrole is known for its sweet, spicy, and woody odor, which makes it a popular flavoring agent in food and beverages. It is used in particular as a key ingredient in sassafras root beer, a traditional American drink.

Apart from its use in the food industry, safrole is also widely used in perfumes, soaps, and cosmetics as a fragrance enhancer. It has a strong aromatic profile and can be blended with other natural oils to create unique and complex fragrances. In addition to its use in fragrances, safrole has medicinal properties and is used in traditional Chinese medicine to treat rheumatism, arthritis, and other ailments.

Safrole is also a precursor in the synthesis of MDMA, a popular recreational drug. The process of converting safrole to MDMA involves several chemical reactions and requires specialized knowledge and equipment. Due to its use as a precursor in illicit drug manufacture, safrole is a regulated substance in many countries.

Synthesis way from safrole to MDMA via MDP2P

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Chemical and Physical Properties of Safrole (top)

Safrole is a colorless to yellowish oily liquid with a sweet, spicy, and woody odor. It is a member of the allylbenzene family of compounds, which also includes eugenol, estragole, and anethole. Safrole has a molecular formula of C₁₀H₁₀O₂ and a molecular weight of 162.19 g/mol. It has a boiling point of 232°C and a melting point of 11.2°C. Safrole is a highly reactive compound due to the unsaturation of its allyl chain, and it can easily undergo chemical reactions to form different derivatives, including isosafrole and 3,4-methylenedioxyphenylpropan-2-one.

Safrole formula

Safrole is soluble in alcohol, ether, and chloroform but is insoluble in water. The solubility of safrole in water is less than 0.01 g/100 mL at 25°C. The low solubility of safrole in water is due to the hydrophobic nature of its molecule, which is dominated by the non-polar allyl chain. The polarity of safrole is primarily due to the presence of the oxygen atom in its molecule, which gives it a dipole moment of 2.6 Debye.

Safrole can form hydrogen bonds with water molecules, but the strength of these interactions is weaker than the interactions between water molecules. Therefore, the solubility of safrole in water is limited to only a few parts per million. The solubility of safrole in organic solvents is higher.

Synthesis of Safrole

The most common synthetic method of safrole production is three step synthesis from catechol. This pathway involves a catechol (1) conversion into 1,3-benzodioxole (2), followed by a bromination into 5-bromo-1,3-benzodioxole (3) and alkylation via Grignard reagent into final safrole (4).

Safrole synthesis from catechol

Safrole Extraction Method (top)

The oil of Ocotea cymbarum is extracted from the wood of Ocotea pretiosa, which is found in South America (mainly Brazil, Paraguay, and Columbia). The wood itself is made up of 1% oil by weight which may not seem like a lot until one takes into account the fact that it is easy to cut down a thousand pounds of the tree. Through careful steam distillation of the wood chips, the oil produced contains no less than 90% safrole. This oil may not be labeled as such in health stores, but it is sometimes used as a replacement for sassafras oil as it cannot be distinguished from it without laboratory examination. Large distributors of fragrances and flavoring chemicals might have Ocotea cymbarum oil in their catalog. They can offer it in both pounds and kilograms and their prices are unbeatable. On the other hand, the health food stores usually sell it in small ounce bottles at a much higher rate.

Ocotea Cymbarum

Obtaining sassafras oil from the bark of roots is simple. The difficult element is figuring out how to distinguish the tree and then excavating the roots. The most convenient manner to master distinguishing the tree is to explore a botanical garden. The leaves branch out on the stem and have three distinctive shapes. Usually, a tree might have all three shaped leaves. They are roughly 3" long and 1 1/2-4" wide. When a tree is spotted, unearth the roots. Clean them and remove all of the bark. The oil can now be steam distilled from the scrapings of the root bark. As vapour passes through the roots, it extracts oil via azeotropic distillation and the oil and water condense in the condenser. The oil and water are then collected in suitable sized receptacles. The oil can be witnessed as tiny drops in the condensing water. When no more drops are seen all of the oil has been extracted.

Ocotea Cymbarum leaves

Separate the oil from the water by draining off the extra water and then pouring the rest into a separatory funnel to separate oil from the remaining water. The oil is heavier than water. Dry the oil with calcium chloride or other drying agent and place in a boiling flask for distillation. Collect the fraction boiling from ~228-235°C, this is safrole. The main other part will pass at lower temperatures and is mainly composed of pinene. Utilizing reduced pressure is highly suggested since it is tough to preserve an oil bath at this high a temperature. The yield will also be decreased at higher temperatures due to destruction of the safrole. At 10-11 mmHg safrole boils at 100-101°C. Isolate safrole from commercial oils by similar distillation of the oil.

How To Steam Distill Sassafras Essential Oil

Safrole Storage

Safrole should be stored in tightly sealed, dark containers to shield it from light degradation. Additionally, maintaining a cool and dry environment, preferably at temperatures below 25°C, helps prevent chemical breakdown and prolongs its shelf life. Proper storage practices ensure the integrity of safrole.

Conclusion (top)

Safrole is a versatile compound with a wide range of uses in various industries. It has medicinal properties and is used in traditional Chinese medicine to treat various ailments. However, safrole is also a regulated substance due to its potential health risks and its use as a precursor in the manufacture of MDMA. It is important to follow all legal and safety precautions when handling safrole, and to use it only for authorized purposes.

Bibliography (top)

• Cardoso, João Miguel Pinheiro Pinto Burguete. Extraction of safrole from essential oils with ionic liquids. Diss. 2017. https://run.unl.pt/handle/10362/61276
• Nichols, David. "The chemistry of MDMA." Ecstasy: The complete guide (2001): 39-53. https://books.google.bg/books?hl=ru&lr=&id=CUCcyklcO00C&oi=fnd&pg=PA39&dq=safrole+MDMA&ots=2Ft8YGFxte&sig=uDWC2_R0KM5wNwbEPVyCI45oN1U&redir_esc=y#v=onepage&q=safrole%20mdma&f=false
• Abel, G. "Safrole–Sassafras albidum." Adverse effects of herbal drugs (1997): 123-127. https://link.springer.com/chapter/10.1007/978-3-642-60367-9_11
• Maia, J. G., et al. "New sources of natural safrole." Perfumer and Flavorist 18 (1993): 19-19. https://img.perfumerflavorist.com/files/base/allured/all/document/2016/03/pf.9318.pdf
• https://en.wikipedia.org/wiki/Safrole
• https://bbgate.com/threads/mdp2p-pmk-total-synthesis-via-safrole.884/