Industrial Chemistry

Perfumes 

Dr. Ramy Y. MorjanFaculty of Science

The Islamic University-Gaza

2011

Perfume is a mixture of fragrant essential oil and aroma compounds, fixatives, and solvents used to give the human body, objects, and living spaces a pleasant smell.

PerfumePerfume comes from the Latin "per" meaning "through" and "fumum," or "smoke.

BackgroundSince the beginning of recorded history, humans have attempted to mask or enhance their own odor by using perfume, which emulates nature's pleasant smells. Many natural and man-made materials have been used to make perfume to apply to the skin and clothing, to put in cleaners and cosmetics, or to scent the air. Because of differences in body chemistry, temperature, and body odors, no perfume will smell exactly the same on any two people.

Many ancient perfumes were made by extracting natural oils from plants through pressing and steaming. The oil was then burned to scent the air.

Today, most perfume is used to scent bar soaps. Some products are even perfumed with industrial odorants to mask unpleasant smells or to appear "unscented."

While fragrant liquids used for the body are often considered perfume, true perfumes are defined as extracts or essences and contain a percentage of oil distilled in alcohol. Water is also used.

It was not until the late 1800s, when synthetic chemicals were used. The first synthetic perfume was nitrobenzene, made from nitric acid and benzene. This synthetic mixture gave off an almond smell and was often used to scent soaps. In 1868, Englishman William Perkin synthesized coumarin from the South American tonka bean to create a fragrance that smelled like freshly sown hay.

What Can Perfume Be Made From?

Any perfume you buy or make yourself is a chemical compound made from fragrant oils, aroma blends, fixatives and solvents, which when mix together produce a pleasant or attractive smell.

What are Essential Oils?

E.O. are highly concentrated natural plant extracts.

Essential oils come from various parts of plants - the seeds, bark, leaves, stems, roots, flowers, and fruit. The oils can be distilled from the plant material or extracted however the majority are distilled.

Essential oils are highly complex substances. They are consisting of hundreds - even thousands – of different natural chemicals.

The average essential oil may contain anywhere from 80 to 400 known chemical constituents. Many oils contain even more, occurring in minute quantities - but all contributing to the oil's therapeutic effects.

It requires years of study to understand these constituents, their activity and functions.

BASIC CHEMICAL STRUCTURE

Essential oils molecules are made up primarily of carbon, hydrogen, and oxygen.

The aromatic constituents of essential oils are built from hydrocarbon chains (carbon and hydrogen atoms). They are normally joined together in ring-like chemical structures.

The chains are held together by carbon atoms linked together. Oxygen, hydrogen, nitrogen, sulphur, and other carbon atoms attach at various points of the chain to make up the different oils.

Essential oils are made up of many chemical constituents. No two oils are alike in their structure or their effects.

BASIC CHEMICAL STRUCTURE

Example of the main constituents found in essential oils: Alcohols , Aldehydes, Esters, Ethers, Ketones, Phenols and Terpenes.

linalool

HO

3,7-dimethylocta-1,6-dien-3-ol

eugenol

O

HO

4-allyl-2-methoxyphenol

thymol

OH

2-isopropyl-5-methylphenol

The aromatic-ring structure of essential oils is much more complex than the simpler, linear carbon-hydrogen structure of fatty oils. Essential oils also contain sulphur and nitrogen atoms that fatty oils do not have.

The basic building block of many essential oils is a five-carbon molecule called an isoprene. Most essential oils are built from isoprene. This is the building block that makes up the terpenoids.

isoprene

When two isoprene units link together, they create a monoterpene; when three join, they create a sesquiterpene; and so forth. Triterpenoids are some of the largest molecules found in essential oils. They consist of 30 carbon atoms -- or six isoprene units linked together.

Each of these can be broken down into numerous smaller units

OH

Oily liquids, which are entirely or almost entirely

volatile without decompositionPlant products, giving the odors and tastes

characteristic of the particular plant, thus possessing the

essence.Ether like in their volatility.

Volatile Oils, Essential oils, Ethereal oils Terpenoids

Comparison between fixed oils and essential oils

Their volatilityWhen smeared on paperOxidation (resinified, fixed oil rancid). Chemical structureSaponification by KOH (NOT saponify)

Which part of the plant usedGrowing seasonAltitudeSoil ConditionsFertilizer (chemical or organic)Geographical LocationHarvesting MethodsDistillation process (low heat vs high heat)

Factors that affect on the quality of essential oil are:

Properties of Essential Oils

Antibacterial, antiviral, antifungal, anti-parasitic

Hormone regulatorStimulates the immune systemAntispasmodic, Anti-inflammatoryAnti-emeticAnti-anxiety, antidepressant, relaxingAstringent, skin toner and moisturizerWound healingDecreases sinus/respiratory congestion

Essential oil vs. fragrance oil

Fragrance oils (or perfume oils) are manufactured fragrances that are either fully synthetic or a combination of synthetic and natural oils that imitate scents. Although these scents do exist, we have no way to extract their essences from their sources Therefore, we make them.

Essential oils are the fragrant oils found naturally in flowers, herbs, spices and leaves. The oil is extracted directly from the plant source, thus capturing the essence and any possible healing benefits.

Essential oils are highly concentrated and some must be diluted in a carrier oil.

Perfume oil is necessarily diluted with a solvent because undiluted oils (natural or synthetic) contain high concentrations of volatile components that will likely result in allergic reactions and possibly injury when applied directly to skin or clothing

Please Note

Undiluted these have unpleasant smells but in alcoholic solution they act as preserving agents)

Essential oils have medicinal or mood altering effects that make them useful in aromatherapy.

Essential oils are volatile so to increase the staying power of an essential oil they use a fixative.

Synthetic fragrance oils have no healing benefits

Fragrance Oils have a greater staying power and do not require the use of a fixative.

Aroma CompoundsAn aroma compound, also known as odorant, aroma, fragrance or flavor, is a chemical compound that has a smell or odor.

A chemical compound has a smell or odor when two conditions are met:

1)the compound needs to be volatile, so it can be transported to the olfactory system in the upper part of the nose.2) and it needs to be in a sufficiently high concentration to be able to interact with one or more of the olfactory receptors.

- Volatile (or semi-volatile) Compound

They have some water solubility, high vapor pressure, low polarity, dissolve in fat (lipophilicity), molecular weight 294.

Aroma compounds are found throughout the plant kingdom.

A large number of chemical compounds are characterized by particular fruit and flower fragrances

Concentration levelsPerfume oil is necessarily diluted with a solvent because undiluted oils (natural or synthetic) contain high concentrations of volatile components that will likely result in allergic reactions and possibly injury when applied directly to skin or clothing. By far the most common solvent for perfume oil dilution is ethanol or a mixture of ethanol and water. Dilutions of the perfume oil can also be done using solvents such as jojoba, fractionated coconut oil or wax. The concentration by percent/volume of perfume oil is as follows:

Perfume extract: 20%-40% aromatic compounds Eau de parfum: 10-30% aromatic compounds Eau de toilette: 5-20% aromatic compounds Eau de cologne: 2-5% aromatic compounds

Eau de Toilette, Eau de Parfum and Eau de Cologne are the most famous versions of scented luxury and are most commonly know as EDT, EDP and EDC

Perfumes, Colognes and scents are usually complex combinations of natural materials, such as essential oils from plants and synthetic products that increase the lasting power and heighten the smell. Alcohol is used as a liquid base for perfume, and basically this ratio of alcohol to scented perfume concentrates determine what the final concoction is labeled.

From highest concentration to least, the different forms of perfume are:

Perfume also called extract or extrait perfume, can include 15-40% perfume concentrates. This is the purest form of scented product and is the most expensive.

Eau de parfum: contains about 7-15% perfume concentrates. This is the most popular and common form of perfume. It provides a long-lasting fragrance and generally doesn't cost as much as extract perfume.

Eau de toilette has around 1-6% perfume concentrates. This makes for a light scent that doesn't linger as long as the more intense versions.

Notes in perfumery are descriptors of scents that can be sensed upon the application of a perfume. Notes are separated into three classes:

Perfume Notes

Perfume Notes denote groups of smells that can be sensed with respect to the time after the application of a perfume.These notes are created carefully with knowledge of the evaporation process and intended use of the perfume.

1) Top Notes

2) Middle/Heart Notes

3) Base Notes

Top notes:

The scents that are perceived immediately on application of a perfume. Top notes form a person's initial impression of a perfume and thus, they are very important in the selling of a perfume. The scents of this note class are usually described as "fresh," "assertive" or "sharp." The compounds that contribute to top notes are strong in scent, very volatile, and evaporate quickly. Citrus and ginger scents are common

top notes. Also called the head notes

Middle notes:

The scent of a perfume that emerges after the top notes dissipate. The middle note compounds form the "heart" or main body of a perfume and act to mask the often unpleasant initial impression of base notes, which become more pleasant with time. Not surprisingly, the scent of middle note compounds is usually more mellow. Scents from this note class appear anywhere from 2 minutes to 1 hour after the application of a perfume. Lavender and rose scents are typical middle notes. Also called the heart notes

Base notes: The scent of a perfume that appears after the departure of the top notes. The base and middle notes together are the main theme of a perfume. Base notes bring depth and solidness to a perfume. Compounds of this class are often the fixatives used to hold and boost the strength of the lighter top and middle notes. The compounds of this class of scents are typically rich and "deep" and are usually not perceived until 30 minutes after the application of the perfume or during the period of perfume dry-down. Musk, and scents of plant resins are commonly used as base notes.

Fixative is a natural or synthetic substance used to reduce the evaporation rate and improve stability when added to more volatile components. This allows the final product to last longer while keeping its original fragrance. Fixatives are indispensable commodities to the perfume industry. Some examples of fixatives are ambergris, sandalwood, musk, vetiver, orris rot, and bergamot orange. In some instances, such as soapmaking,castor oil, may be used. Natural fixatives usually have a fragrance considered a base note in perfumery terms, reflecting their low volatility