vol. oils 2011l
TRANSCRIPT
Volatile oils Definition
• It is a distilled oils obtained from plant tissue or animal sources.
• They are widely used in perfumes, flavoring and medicines.
• Their chemical composition differs, for
example, terpenes, aldehydes, ketons or phenols, oxygen, sulfur, nitrogen.
Volatile OilsVolatile OilsFixed OilsFixed Oils
VolatileVolatile Non-volatileNon-volatile
HydrocarbonsHydrocarbons
not leave permanent stain
on filter paper
TriglyceridesTriglycerides
leave permanent stain on
filter paper
Non-greasyNon-greasyGreasyGreasy
On storage Not rancid Not rancid but but
rather rather resinifyresinify
On storage rancidrancid upon upon
exposure to Oexposure to O22
Kinds of Essential Oils
The principal components of essential oils are terpenes and aromatic compounds.
Why do plants produce essential oils?
• Attraction effectTo insects, birds and other animals for pollination and seed dispersal.
• Repellant effectPlants produce offensive odors or bitter substances to repel pests or predators, or inhibit the growth of molds or harmful bacteria. (Protection against insects and fungi).
• Waste products of metabolism.
Characters of volatile oils
1.Physical characters: • Colorless volatile liquid• Have high refractive index and optically
active• Immiscible with water• Soluble in organic solvent• Resinification when storage due to darken in
color when exposed to light
2. Chemical characters:
• It is a mixture of hydrocarbons and oxygenated compounds (such as alcohol, ketons, aldehydes, phenol, esters).
• Some oils consists of one main component as oil of clove (eugenol). oil of menthe (menthol).
• The properties of the volatile oils are determined by the number of isoprene units.
• Terpenes and terpenoides are the primary constituents of the essential oils of many types of plants and floweres.
What are terpenes ?• Terpenes are defined as natural products
whose structures may be divided into isoprene units.
• Hemiterpenes: consists of a single isoprene units have the molecular formula C5H8
• Monoterpenes: consists of a two isoprene units have the molecular formula C10H16
• Sesquiterpenes: consists of a three isoprene units have the molecular formula C15H24
• Diterpene: consists of a four isoprene units have the molecular formula C20H32
• Sesterterpenes: consists of a five isoprene units have the molecular formula C25H40
• Triterpenes: consists of a six isoprene units have the molecular formula C30H48
Classes of Terpenes present in V.O.:A.Monoterpenes1. Acyclic.2. Monocyclic.3. Bicyclic.4. Aromatic.B. Sesquiterpenes1. Monocyclic.2. Bicyclic.C. Oxygenated hydrocarbons: (oxygenated
terpenes) e.g. alcohols, esters, phenols, oxides, peroxides, aldehydes and ketones.
Chemical constituents and odour of volatile oils
According to the major constituents, volatile oils acquired different odour as:
• Fruity odors of ester and lactones• Pleasant odor of ketones• Bitter almond odor of nitrile
Chemical constituents and action• Sesquterpene hepatic and glandular
stimulant, anti-inflammatory, antiallergic and nasal decongestant.
• Monoterpene hydrocarbon antiviral, stimulant, irritant and immuno-stimulant.
• Esters spasmolytic, fungicidal, soothing to the skin, anti-inflammatory.
• ketones cell regenerative, mucolytic and neurotoxic.
• Aldehyde sedative, anti-inflammatory, antiviral and relaxing.
• Oxides expectorant and antiviral.• Esters soothing.
Pharmacological importance of volatile oils:
1.Antiseptic and preservative as Lavender, thyme, clove
2.Antispasmodic as Anise, fennel, menthe, chamomile
3.Sedative as clove4.Irritating agent , externally increase in
capillary blood flow as eucalyptus. Internally
5.Stimulates mucus cell , so used as expectorant
Medicinal uses • As infusion or separated volatile oils and their isolates by inhalation or
orally as gargles • Local stimulants• Carminatives• Mild antiseptic • Bacteriostatics• Local irritants• Anthelmentics• Local analgesic• In powder form used as spices and condiments in food to impart aroma
and flavor and act as preservative • In perfume industries , cosmetic preparation • Insecticides
Preparation of volatile oils:
Methods
DistillationWater dist.
Water and steam dist.
Steam dist.
ExpressionSponge methodScarificationRasping processMachines
ExtractionVolatile solventNon-volatile solvent
Methods for preparation of Volatile Oils:
1.Distillation.2.Scarification and expression.3.Solvent extraction.4.Enzymatic hydrolysis of glycosides.
1. Distillation Methods Principle: When two immiscible liquid are heated they
will boil at a temperature below the boiling point of either one.
Types of distillation:A.Simple steam distillation (water-
distillation).B.Saturated stem distillation (water and
steam).
A. Simple steam distillation (water distillation):
1.Immersing the plant directly in a container filled with water, then boiled.
2.Heterogeneous vapors are condensed on a cold surface and collected in a special receiver.
3.Oil separates from water on the bases of difference in density and immiscibility.
Cohobation: is the return of the aromatic water to still to be
redistilled in order to improve the yield of oil.
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B. Saturated stem distillation:
1.Saturated stem.2.The plant not contact with water.3.Stem pressure and temperature could be
modified according to the composition of the oil.Thermolabile as esters – need lower pressure and
temperature.High boiling point as sesquiterpenoids – need
higher pressure and temperature.
B. Scarification and expression:
• It based on puncturing and/or squeezing of the plant material to liberate the oil.
• It is used for heat sensitive oils which are present in large amounts in outer peels of fruits as citrus fruits.
Preparation and purification of oil The peel consist of two parts Outer part: colored, rich in waxes and pigments
and oil glands. Inner part: white, formed of pectin and cellulose.
The method includes:
I. Squeezing Methods.II.Scarification (Ecuelle - a - piquer method).III.Expression Method.
I. Squeezing Methods
a) Squeezing with water:
1. Squeezing of the peel under stream of water, yield emulsion of oil, water, pectin, cellulose, pigment and wax.
2. Removal of water, pectin and cellulose by centrifugation.
3. Removal of wax by strong cooling, followed by filtration or decantation.
b) Sponge Method:
1. Fruits are washed, cut into halves and fleshy part removed.
2. Peels are soaked in water and pressed between a convex projection and a sponge.
3. Saturated sponge is squeezed in vessel and emulsion centrifuged and cooled.
II. Scarification (Ecuelle - a - piquer method)
Based on puncturing (scarifying ) the surface of whole fruits
Instrument used is funnel-shaped, consisting of a shallow bowl with a tubular projection at the center.
The bowl-like part bears internally numerous pins long enough to scarify the oil glands and release the oil.
III.Expression Method
1. Removing the outer layer of the peel, collecting in special bags followed by strong pressing.
2. Oil obtained is collected, left to stand, decant, and filtered.
Machine processesIt based on whole fruits are charged into
machines in which the peels are removed, sprayed with water, squeezed or pressed and oil collected through wool filters
C. Extraction methods
It is used for preparation of delicate flower oils such as Jasmine, which contain either
Small amounts of oils. Oils which decompose by heat. According to the solvent used they classified into:
• Non- volatile solvent extraction• Volatile solvent extraction• Extraction with supercritical gas
Volatile oils
Hydrocarbon
Alcohol
Phenols and
phenolic ethers
Monohhydric e.g.
Thymol, Carvacro
l ,Anisol
Aldehyd and
ketones
Aldehydes
AliphaticAcyclic
e.g Citronellol, Citral
Alicyclice.g.
Perillaldehyde
Aromatice.g
Benzaldehyde,Va
nillin
Ketonesc
Acyclice.g
aceton
Alicyclic
Aromatic
Bicyclice.g.
Camphor,Fenchon
e
EstersOxide & Peroxide
s
�ُEster of
aliphaticE,geranyl acetate
Aromatice.g
Benzyl benzoate
Containing
nitrogene.g.
Anthranilate
Oxide Peroxide
Monoterpene
e.g 1,8-cineole
Sesquiterpenee.g.
Bisabolol
Aliphatic AlicyclicAcyclic Alicyclic Aromatic
Monoe.g
Myrecene
Ocimene
Sesquiterpene
.e.g Farnecen
e
Bicyclic
Monoterpene
Tricyclice.g
Santalene
Monoe.g.
Limonene
Sesquiterpenee.g
Cadinenes
3,6 membere
d ringe.g
Thajone, Carvone
AromaticBenzyl alcohol
Bicyclicl
MonocMenthol
Dihydrice.g.
Eugenolisoeugen
ol
TrihydricMyristinisomyrist
in
Tetrahydric
Parsely camphor
TricyclicSantalol
Monoterpene
Borneol
SesquiterCarotol
Volatile Oils
Hydrocarbon AlcohoslPhenols&
Phenolicethers
Aldehyde& Ketones
EstersOxides &
Preoxides
HydrocarbonV.O.
Acyclic
Monoterpinee.g. Myrecene
Ocimene
Sesquiterpenee.g. Farnesene
Alicyclic Aromatic
MonoLimonene
BicyclicTricyclic
e,.g. Santtalene
Monoterpene
Sesquiterpenee.g. naphthalene derivative
cadinene
3,6 membered ringe.g. Thajane
carane
4,6 membered ring e.G pinane
AlcoholV.O.
Aliphatic Alicyclic Aromatic
Benzyl alcohol
Monocyclice.g. Menthol
BicycliclTricyclic
SesquterpenoidSantalol
MonoterpeneBorneol
SesquiterpeneCarotol
Saturatedd Unsaturated
Phenols and phenoliccomponds
Monohhydric e.g .
ThymolCarvacrol
AnisolAnathole9 Anise camphor0
Dihydrice.g. EugenolIsoeugenol
TrihydricMyristin
TetrahydricParsely apiole
Parsley camphor
Aldehyd and ketones
Aldehydes Ketonesc
AliphaticAcyclic
e.G citronellolcitral
Alicyclice.g .
Perill aldehyde
Aromatice.g benzaldehydeSalicylaldehyde
Vanillin
Alicyclic Aromatic
Monocyclice.g.carvoneMenthone
Acyclice.g. Acetone
Bicyclice.G Fenchone
Camphore
Esters
�ُEster of aliphatice.g. geranyl acetate
Benzyl acetate
Aromatice.g
Benzyl salicylateMethyl salicylate
Containing nitrogene.g methyl anthranilate
Oxide & Peroxi
Oxide Peroxide
Monoterpenee.g 1,8 -
Sesquiterpenee.g .
Hydrocarbon V. O.
Acyclic, Monoterpene
Myrcene and OcimeneOccurrence: in Lemon grass, Cympobogon Isolation: By fractional distillation, Purification by H2O soluble
phenate with NaOH non- phenolic fraction (insoluble part) fractional distillation.
Detection of Myrecene in the presence of Ocimene:
Myrecene with Potassium permanganate in acetone Succinic acid + Lead
1. Myrecene (Lead succinate) needle crystals.
2. Ocimene (Lead succinate) rhomboidal crystals.
Sesquiterpene
Farnesene Occurrence: Humulous lupulusPreparation: by fractional distillation.Uses: flavoring agent
Monocyclic, Alicyclic Hydrocarbon
Limonene Occurrence: in OrangePreparation: by fractional distillation.Uses: Flavoring agent.
Alicyclic, bicyclic monoterpene hydrocarbon
α-Pinene
Occurrence: coniferous oil, lemon, corianderIsolation: 1. By fractional distillation. 2. By precipitation as nitroso chloride crystal then aniline
α-pinene.Uses: • Manufacture of borneol and camphor.• Mucolytic in cough mixture.
Alicyclic, monocyclic, sesquiterpene hydrocarbon
Zingiberene
Occurrence: GingerIsolation: 1. By fractional distillation under vacuum. Test: • Zingiberene + Hydrochloric acid crystal of
dihydrochloride .
Alicyclic bicyclic sesquiterpene hydrocarbon
Azulene (coloured H.C.) e.g. Chamazulene
Test: Azulene + mineral acid ( H2SO4)
Crystalline derivatives, then decompose by water.
Uses Anti-inflammatory - Cosmetic preparation
Aromatic hydrocarbon P-cymeneOccurrence: lemon, lavanderIsolation: by fractional distillation.• Purification from terpenoid by oxidation with
cold dil. KMnO4.
• From limonene or pinene by dehydration, heating with sulphur p-cymene
Test: With Potassium permanganate crystal of P – hydroxyisopropyl benzoic acid.
Uses: Perfuming soaps.
AlcoholsPreparation1. By additive products: using Cacl2 solid,
regeneration by water, ext. with ether or benzene.2. Chromatography.3. Derivatization: depending upon the presence of functional
alc. gp., addition reaction as oxidation, halogenation, hydration for unsaturated as borneol & geraniol
4. Estrification using either:1- Phthalic anhydride.2- Boric acid –1ry are more react than 2ry, 3ry not react3- Succenic anhydride.5. Dehydration: 3ry more react then 2ry, 1ry resistant except
geraniol using ZnCl2.
•Acyclic terpene alcohol
Citronellol
Occurrence: Oil of rose and citronella.
Preparation:1.By fractional distillation of the hydro distilled oil.2.Semi synthetically from geraniol or nerol by hydrogenation.
Uses: In Cosmetic preparation.
Geraniol and Nerol
Occurrence:Geraniol In oils of palme rosa, rose, geranium.Nerol In oils of Neroli, bergamot.Preparation: Nerol is difficult to be obtained in a pure form. Geraniol formed a solid derivatives with calcium chloride , while nerol does not form a complex. Geraniol heated with dehydrating agent, diterpenUses:•In perfume, cosmetic preparation.
LinaloolOccurrence: In oil of Lavander , Lemon, Rose, Preparation: Fractional distillation Heating with glacial acitic acid -------mixture of geraniol, nerol and terpeniolWith chromic acid -------------- citralWith halogen acids ---------- Linalyl derivative (linalyl chloride) Uses:In perfume, cosmetic preparation
Alicyclic terpene alcoholAlicyclic Monocyclic Monoterpene alcohol Menthol Occurrence: In oil of peppermint Preparation:Naturally: From oils by cooling and deposited crystals by centrifuge. Synthesis: Catalytic reduction of thymol using cupper chromate. Test of identityCrystals + conc. Sulphuric acid + vanillin sulphuric reagent ----orange yellow color + water -------violet Crystals + glacial acetic acid + three drops of conc. Sulphuric acid + one drop of conc. Nitric acid ----no green or bluish color (thymol gives green color) Uses : Antiseptic, Counter irritant, Carminative, gastric sedative, Flavoring agents in mouthwashes & toothpastes
• Alicyclic bicyclic monoterpene alcohol Borneol, Isoborneol Source: Nutmeg, lavender, coriander Preparation: By fractional dist, Purification by acidphethalate Synthesis: 1. From α-pinene + HCL gas at -10 o α-pinene HCL,
Isomerization bornyl chloride + KOH borneol
2. From camphor using Na amalgam in alc. borneol
Separation of Borneol and Camphor:Phethalic anhydride with NaOH Sod. Salt which
soluble in water, extract with org. solvent camphor in org. solvent and Sodium Salt of borneol in aq.
Separation of Mixture Of α-pinene, borneol and camphor: 1. α-Pinene by fractional distillation.2. Camphor by oxime.3. Borneol by acid phthalate ester. Uses Sedative, Antiseptic, Counter irritant and room sprays.
Aromatic alcohol-Benzyl alcohol (low volatility) Source: Jasmin, balsamPreparation By fractional dist -Bad storage bitter almond odor + crystal
of benzoic acid• Test Oxidation with chromic acid + H2SO4
benzoic acid • Uses Perfume and Cosmetic
Phenols and phenolic esters: Uses: Antiseptic, germicidal, Properties: acidic, unstable, sol. In alkali. With FeCl3 blue, violet color With Br bromo derivativePreparation: By cooling. By shaking the oil with dil. KOH aq.
Layer ext. by ether or steam distillation.
Monohydric phenols
1-Thymol 2- Anethol ( Anise camphor)Source: F. Labiatae Anise, FennelPreparation: Cooling if in large amounts. Fractional distillation.Uses: Flavoring, cosmetic, mouth wash gargleTests:
• FeCl3+ H2SO4---blue + KMnO4 -----P-anisald.
• Na OH ---pale red color dark when left.
• Synthesis of Thymol 1- Menthone + Bromin/quinolin
Thymol 2- Piperitone Thymol • Synthesis of Anethol Alc. anisole + propionald/ Hcl, H2SO4/ pyridine Anethol
Dihydric phenol Eugenol (pale yellow oily liquid)Source: Clove, Cinnamon, NutmegPreparation: Oil + aq. NaOH , ext. with ether, Phenolic
insol. Salt, acidify, then stem distillation or ext. with ether
Test: • with alc. Fecl3 blue• with aq. FeCl3 grayish yellow• with KOH needle crystal
Uses: – Local anesthetic in toothache (inhibit nerve conducting),
Anti-inflamatory , Bactericidal, Preparation of vanillin.
Ald. and KetonsPreparation:1. By fractional dist.2. By cooling if solid & in large amounts Assay 1- Condensation Reaction with hydroxylamine oxime Exss. Hydroxylamine HCL is added to known
weight of oil, release HCL is titrated against standared. alc. KOH using methyl red for ald & dimethyl yellow for ketons
Acyclic monoterpene ald.
Citronellal Citral Source: Lemone oil CitrusPreparation: Fractional distillation.
Uses: Perfumes Not used in perfume Insect repellent but in Cosmetic preparation.Separation of citral a from citral b by sodium bisulfate,
citral a is sparingly soluble but citral b is readily soluble.
Aromatic ald.
Benzald. Vanillin Source Oil of bitter almond Vanilla podPrep. Enzymatic hyd. Fermentation of vanilla podsStem dist., pur. By calc. hyd. Ext. with ether ,cryst. From alc /ferric sulphate , redistillation Uses Manuifacture of dye flavoring, perfumes Perfumes Synthesis of vanillin• from lignin ( biproduct of paper)• from Eugenol
Alicyclic bicyclic monoterpeneFenchone Camphor Fennel lavender, rosmary
Preparation:By fractional dist. Steam dist, solidify on the wall (cooling)Uses:Counter irritant preservative Flavoring agents antisepticPerfumes• Synthesis of camphor 1- from pinene 2- borneolReaction Camphor + sod. Metal in alc borneol & isoborneol
Ketons• Acyclic (acetone)• Alicyclic monoterpene Menthone Carvone Diosphenol (Buchu camphor)• Mentha, mentha buchu caraway Buchu• By oxime by NaHSO3 cooling
• Regene. By acid recover by NaOH• Carminatives, antiseptic.
• Alicyclic bicyclic monoterpeneFenchone Camphor Fennel lavender, rosmaryBy fractional dist. Steam dist, solidify on the wall(cooling) Counter irritant preservative Flavoring agents antisepticPerfumes• Syntesis of camphor 1- from pinenen 2- borneolReaction Camphor + sod. Metal in alc. borneol & isoborneol
Test to differ. Bet. Natural & synthetic camphor• + vanillin / HCL yellow /green /blue
colour in natural Yellow only in synthetic• Test for chloride negative with natural Positive with syntheticSeparation of camphor & borneol• + hydroxylamine oxime formation
of camphor• Then add dil acid, oxime dissolved & borneol
removed by ext with solvent
Oxide & peroxide
Monoterpene oxide Cineol ( eucalyptol)Source EucalyptusPrep. Fractional distillation, then coolingTest + hydroquinone colorless prism
or rhomboid crystalUses Local anesthetic, Antiseptic, anti-inflammatory,expectorant
Monoterpenoid peroxideAscaridoleSources oil of chenopodiumPrep. Fractional dist under vacuum ( avoid high temp. to prevent explosion)
Uses Anthelementic
Organosulpher compounds Allyl isothiocyanate Source black mustered Prep. Enzymatic hydrolysis. ,then distillation
( heaver than water)Uses Local rubefacient in plasters Flavoring agents