CAS: 138-86-3
EC Number: 205-341-0
Chemical formula: C 10 H 16
Molecular mass: 136.23gmol- 1
Limonene is a chemical found in the peels of citrus fruits and in other plants.
Limonene is used to make medicine.
Limonene is used to promote weight loss, prevent cancer, treat cancer, and treat bronchitis.
In foods, beverages, and chewing gum, limonene is used as a flavoring.
In pharmaceuticals, limonene is added to help medicinal ointments and creams penetrate the skin.
In manufacturing, limonene is used as a fragrance, cleaner (solvent), and as an ingredient in water-free hand cleansers.
Chemical constituent of many natural fragrant ingredients, notably citrus oils such as lemon (d-limonene) and pine trees or species of the mint family (l-limonene).
Topically, limonene can cause sensitivity and is best avoided.
Also, because of its penetration-enhancing effects on skin, it’s particularly important to avoid products that contain limonene plus other skin sensitizers like denatured alcohol.
Like most volatile fragrance components, limonene also has strong antioxidant benefits and has also been shown to calm skin; however, when exposed to air these highly volatile antioxidant compounds oxidize and become capable of sensitizing skin.
Limonene comes from citrus fruits and is used in many cleaning products:
So you’ve heard about limonene being used in cleaning products, and you want to know what this stuff is and whether it’s safe.
Well, here’s our lemon-scented guide to this often maligned chemical.
You know that delicious, fresh smell you get when you slice open an orange, lemon or lime? Well, it’s mostly limonene, and it doesn’t just smell nice; it’s also useful and safe.
That’s why it is used in products designed to clean your home.
Limonene is a naturally occurring compound found mainly in the skin of certain plants and fruits, including lemons and oranges.
Limonene is used in cleaning products for two reasons: it has a pleasant, lemon-orange smell, and it acts as a solvent to help clean.
Limonene is from a large family of natural substances called terpenes, and it has no colour and its toxicity is low.
However, you might have heard about it recently because, when it reacts with ozone in the air, it undergoes change which releases tiny amounts of other compounds, including formaldehyde.
Peeling an orange releases orange oil into the air.
As orange oil is 90% limonene you can get more exposure by peeling an orange than from using cleaning products.
Belongs to the class of organic compounds known as menthane monoterpenoids.
These are monoterpenoids with a structure based on the o-, m-, or p-menthane backbone.
P-menthane consists of the cyclohexane ring with a methyl group and a (2-methyl)-propyl group at the 1 and 4 ring position, respectively.
The o- and m- menthanes are much rarer, and presumably arise by alkyl migration of p-menthanes.
Limonene is a hydrocarbon, classed as a terpene.
Limonene is a colourless liquid at room temperatures with an extremely strong smell of oranges.
Limonene takes its name from the lemon, as the rind of the lemon, like other citrus fruits, contains considerable amounts of this chemical compound, which is responsible for much of their smell.
Limonene is a chiral molecule, and as is common with such forms, biological sources produce one specific enantiomer: the principal industrial source, citrus fruit, contains D-limonene ((+)-limonene), which is the (R)-enantiomer (CAS number 5989-27-5, EINECS number 227-813-5).
Racemic limonene is known as dipentene
Limonene is a scent ingredient and solvent naturally ocurring in the rind of citrus fruit.
Upon storage and exposure to sunlight and air, limonene degrades to various oxidation products which act as skin and respiratory irritants and sensitizers.
Limonene is one of the most common compounds found in the essential oils of aromatic plants.
The occurrence of this monoterpene hydrocarbon in various plant genera could be attributed to its precursory role in the biosynthesis of other monoterpenes and its defensive role against herbivores.
Due to the medicinal potential and application in the flavor and fragrance industries, limonene has been extensively investigated.
In this paper the biosynthetic, ecological and pharmacological importance of limonene is presented in an attempt to coherently summarize some of the most salient aspects from various studies in a form of a concise review.
Biotechnological production of limonene in microorganisms
This mini review describes novel, biotechnology-based, ways of producing the monoterpene limonene.
Limonene is applied in relatively highly priced products, such as fragrances, and also has applications with lower value but large production volume, such as biomaterials.
Limonene is currently produced as a side product from the citrus juice industry, but the availability and quality are fluctuating and may be insufficient for novel bulk applications.
Therefore, complementary microbial production of limonene would be interesting.
Since limonene can be derivatized to high-value compounds, microbial platforms also have a great potential beyond just producing limonene.
In this review, we discuss the ins and outs of microbial limonene production in comparison with plant-based and chemical production.
Achievements and specific challenges for microbial production of limonene are discussed, especially in the light of bulk applications such as biomaterials.
Limonene is a well-known cyclic monoterpene.
Limonene is an olefin hydrocarbon (C10H16), which can occur in two optical forms.
Limonene is one of the most important and widespread terpenes in the flavor and fragrance industry.
Limonene (in both optical forms) has been found in more than 300 plant essential oils (DNP 2015) from very diverse species including orange, lemon, mint, and fir.
Limonenes biosynthesis has been well described in the plant kingdom.
Limonene has been detected naturally in trace amounts in the headspace of microbes (Effmert et al. 2012; Heddergott et al. 2014; Hung et al. 2013); however, to our knowledge, no corresponding biosynthetic mechanism has been identified.
By transformation with plant limonene synthases, microorganisms such as yeast and bacteria have been engineered to produce limonene.
In this work, biotechnological production of limonene for application as commodity chemical is reviewed.
Others have reviewed general aspects of production of terpenes in microbes and plants (Aharoni et al. 2006; Duetz et al. 2003; Kirby and Keasling 2009; Vickers et al. 2014; Wang et al. 2015).
Recently, Lange (2015) reviewed the biosynthesis and biotechnology of limonene for flavor and fragrance applications.
New applications of limonene for fuel and biomaterials ask for large and stable production volumes.
Metabolic engineering strategies, like overexpressing precursor pathway enzymes, have been applied for the purpose of increasing limonene titers, which are at the moment still far from the maximal theoretical yield.
Crucial in such strategies is the overproduction of geranyl diphosphate (GPP), the direct precursor of limonene.
New opportunities to increase yield will be discussed, including novel strategies for capturing the product from the microbial cultures and possibilities for relieving limonene toxicity.
When successful, these optimization strategies could result in a role for limonene-based products in the bio-based economy
Limonene, a naturally occurring hydrocarbon, is a cyclic monoterpene with the molecular formula C10H16.
Limonene is commonly found in the rinds of citrus fruits such as grapefruit, lemon, lime and, in particular, oranges.
Indeed, limonene constitutes 98% (by weight) of the essential oil obtained from orange peel.
Limonene is also present in the seeds of caraway and dill.
The IUPAC name for limonene is 1-methyl-4-prop-1-en-2-ylcyclohexene.
Limonene is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene and is the main component of the oil in the fruit peels of citrus fruits.
D - isomer is a sweetener used in food production, which occurs in nature mostly as an orange scent.
Limonene is also used as a precursor to carvone in chemical synthesis and as a renewable-based solvent in cleaning products.
Limonene is a chemical found in the peels of citrus fruits and in other plants.
Limonene is used to make medicine.
Limonene is used for obesity, cancer, and bronchitis, but there is no good scientific evidence to support these uses.
In foods, beverages, and chewing gum, limonene is used as a flavoring.
In pharmaceuticals, limonene is added to help medicinal ointments and creams penetrate the skin.
In manufacturing, limonene is used as a fragrance, cleaner (solvent), and as an ingredient in household cleaning products, cosmetics, and personal hygiene products.
Less common L - The isomer is found in peppermint oils and has a pine , turpentine -like odor.
The compound is one of the main volatile monoterpenes found in the resin of conifers , especially Pinaceae , and orange oil . Limonene gets its name from the French lemon (" lime ").
Limonene is a chiral molecule, and biological sources produce an enantiomer: main industrial source is citrus ( R ) - enantiomer DContains -limonene((+)- limonene).
D -Limonene is obtained commercially from citrus fruits by two main methods: centrifugal separation or steam distillation.
Limonene is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the oil of citrus fruit peels.
The d-isomer, occurring more commonly in nature as the fragrance of oranges, is a flavoring agent in food manufacturing.
Limonene is also used in chemical synthesis as a precursor to carvone and as a renewables-based solvent in cleaning products.
The less common l-isomer has a piny, turpentine-like odor, and is found in the edible parts of such plants as caraway, dill, and bergamot orange plants.
Limonene takes its name from Italian limone ("lemon").
Limonene is a chiral molecule, and biological sources produce one enantiomer: the principal industrial source, citrus fruit, contains d-limonene ((+)-limonene), which is the (R)-enantiomer.
Racemic limonene is known as dipentene.
d-Limonene is obtained commercially from citrus fruits through two primary methods: centrifugal separation or steam distillation.
Limonene is a mild skin and eye irritant.
Ingestion of 20 g of d-limonene caused diarrhea and a temporary increase in protein in the urine (proteinurea) in five male volunteers.
These data, in addition to the low acute toxicity in animal tests, suggest that d-limonene is not very toxic by ingestion.
Air levels of d-limonene may irritate the eyes and airways of some people, especially when the levels build up indoors (see above for discussion about gas phase reactions between ozone and terpenes which can be a significant source of secondary organic aerosols).
d-Limonene has been used successfully for the postoperative dissolution of retained cholesterol gallstones.
limonene, a colourless liquid abundant in the essential oils of pine and citrus trees and used as a lemonlike odorant in industrial and household products and as a chemical intermediate.
Limonene exists in two isomeric forms (compounds with the same molecular formula—in this case, C10H16—but with different structures), namely l-limonene, the isomer that rotates the plane of polarized light counterclockwise, and d-limonene, the isomer that causes rotation in the opposite direction.
In the extraction of citrus juices d-limonene is obtained as a by-product, and it also occurs in caraway oil; l-limonene is present in pine needles and cones; dl-limonene, or dipentene, the mixture of equal amounts of the l- and d-isomers, is a component of turpentine.
Dipentene may be sulfurized to produce additives that improve the performance of lubricating oils under heavy loads; d-limonene is commercially converted to l-carvone, which has a caraway-seed flavour.
Limonene: a versatile chemical of the bioeconomy
Limonene is a renewable chemical with numerous and growing applications. Its traditional uses such as flavor, fragrance and green solvent are rapidly expanding to include its utilization as a platform chemical, extraction solvent for natural products and an active agent for functionalized products.
We anticipate that the expansion in uses for limonene will translate into increasing production and use of this relevant natural product, especially for advanced applications.
Summary of Limonene:
Limonene is a useful compound and pleasant to smell.
Limonene is a renewable resource and is considered to have very low toxicity, and is even being studied as a possible dietary supplement to prevent cancer.
Although it can react with ozone in the air to produce tiny amounts of formaldehyde for a short period of time, those amounts are considered by the WHO to present negligible risk.
Isomerism of Limonene:
Carbon number four (labelled with an asterisk) of the cyclohexene ring is chiral.
Limonene therefore has two optical isomers.
The optical isomers are non-superimposable mirror images of each other and their three-dimensional structures can be compared here.
Chiral centres are labelled as R or S using IUPAC nomenclature. Thus the two isomers of limonene can be named 4(R)-limonene and 4(S)-limonene.
Alternative prefixes to label optical isomers include d and l and more commonly the symbols + and - are used.
The two enantiomers have identical chemical properties but different odours.
Limonene is the isomer that is found in oranges.
And unsurprisingly it smells of oranges!
The smell of (-)-limonene is similar to turpentine, although some people suggest it has a lemon like aroma.
An usual compound of Limonene:
Most naturally occurring chiral compounds are found as a single optical isomer only.
However, limonene is an exception and both enantiomers are produced in nature.
Limonene is an important precursor in the biosynthesis of (-)-menthol the major component of mint and the molecule responsible for the herb's refreshing taste.
Details of the reaction pathway can be found in Simon Cotton’s menthol page.
As mentioned previously (+)-limonene is the isomer found in orange peel.
Limonene is thought that its high abundance in this part of the fruit is connected with the fact that it is an insecticide.
As well as its smell limonene also contributes to the flavour of the fruit and as such has been used as a food additive for many years.
Aside from the food industry limonene has a variety of uses.
Limonene is an ingredient of Orange Guard, a home friendly pest control product that exploits the insecticide properties of limonene.
At room temperature limonene is a liquid and has proven to be a good solvent.
The non-polar nature of limonene means that it has an affinity for petroleum based greases and it has been used as an industrial cleaner for more than thirty years.
One advantage is that limonene is not toxic and is replacing the use of solvents like methyl ethyl ketone (MEK), xylene (dimethylbenzene) and chlorofluorocarbons (CFCs), the use of which has been banned.
Limonene also has the advantage of being biodegradable and can rapidly break down into carbon dioxide and water. Another benefit of limonene is that it is obtained from a renewable resource.
A by-product of the citrus juicing process is the oil found in the peel of the fruit.
Limonene can be distilled from this oil for both technical and food based uses.
The popularity of limonene based cleaners is growing and it can now be found in many domestic products such as the Mr Muscle Orange Action range of cleaners.
An Australian company, Orange Power, seek to make all of their products from natural, and locally produced, sources.
Their aim is to reduce reliance on fossil fuels and dangerous chemicals which have a cumulative harmful effect on both the population and the environment.
Alternative Parents of Limonene:
Monocyclic monoterpenoids
Branched unsaturated hydrocarbons
Cycloalkenes
Unsaturated aliphatic hydrocarbons
Substituents of Limonene:
P-menthane monoterpenoid
Monocyclic monoterpenoid
Branched unsaturated hydrocarbon
Cycloalkene
Cyclic olefin
Unsaturated aliphatic hydrocarbon
Unsaturated hydrocarbon
Olefin
Hydrocarbon
Aliphatic homomonocyclic compound
Biochem/physiol Actions of Limonene:
Limonene is a cyclie terpene from Chinese medicinal herb essential oils used in the synthesis of carvone.
Limonene may be used as a shrinking agent to dissolve polystyrene.
Limonene may be used in various insecticidal and insect repellant applications.
Limonene may block cancer-forming chemicals and kill cancer cells in the laboratory.
But more research is needed to know if this occurs in humans.
Organs and systems of Limonene:
Respiratory
Limonene, and possibly linoleic and oleic acids, can have irritative and bronchconstrictive airway effects and can cause reduced vital capacity.
Patients with significant inhalational exposure should be removed from the environment and undergo appropriate decontamination.
Inhaled β2-adrenoceptor agonists can be used for bronchoconstriction.
Urinary tract
Limonene ingested in sufficient quantity can cause proteinuria.
However, nephropathy and renal tumors are not expected in humans.
Skin
Contact dermatitis has been attributed to limonene, and a purpuric rash has been attributed to topical exposure to d-limonene.
Autoxidation of d-limonene readily occurs, yielding a variety of oxygenated monocyclic terpenes that are strong contact allergens.
The prevalence of contact allergy after exposure to d-limonene among patients with dermatitis has been studied.
The proportion of positive patch tests to oxidized d-limonene was comparable to that seen with several allergens in the standard series, and patients who reacted to d-limonene often reacted to fragrance mix, balsam of Peru, and colophony.
In a study of patch tests with 3% oxidized R-(+)-limonene in 2273 patients at four dermatology clinics in Europe, there were positive reactions 0.3%, 3.8%, 3.9%, and 6.5%, a total of 63 patients, of whom 57% did not react to fragrance mix or balsam of Peru.
Metabolism/Metabolites of Limonene:
After oral administration, major metabolite in urine was perillic acid 8,9-diol in rats and rabbits, perillyl-beta-d-glucopyranosiduronic acid in hamsters, p-menth-1-ene-8,9-diol in dogs, and 8-hydroxy-p-menth-1-en-9-yl-beta-d-glucopyranosiduronic acid in guinea pigs and man.
Limonene given orally to humans yields the following major plasma metabolites: perillic acid, limonene-1,2-diol, limonene-8,9-diol, and dihydroperillic acid, probably derived from perillic acid.
Limonene (unchanged) and perillic acid artifacts (methyl ester) were also detected as minor plasma metabolites.
Peak plasma levels for all metabolites were achieved 4-6 hours after administration, with the exception of limonene-8,9-diol which reached its peak level one hour after administration.
Phase II glucuronic acid conjugates have been identified in the urine of human volunteers for all major and minor metabolites.
They include the glucuronic acid conjugates of perillic acid, dihydroperillic acid, limonene-8,9-diol, limonene-10- ol, limonene-6-ol, and limonene-7-ol (perillyl alcohol).
Mechanism of Action of Limonene:
The anticarcinogenic effects of monocyclic monoterpenes such as limonene were demonstrated when given during the initiation phase of 7,12-dimethylbenz[a]anthracene induced mammary cancer in Wistar-Furth rats.
The possible mechanisms for this chemoprevention activity including limonene's effects on 7,12-dimethylbenz(a)anthracene-DNA adduct formation and hepatic metabolism of 7,12-dimethylbenz[a]anthracene were investigated.
Twenty four hours after carcinogen administration, there were approx 50% decreases in 7,12-dimethylbenz(a)anthracene-DNA adducts found in control animals formed in the liver, spleen, kidney and lung of limonene fed animals.
While circulating levels of 7,12-dimethylbenz(a)anthracene and/or its metabolites were not different in control and limonene fed rats, there was a 2.3 fold increase in 7,12-dimethylbenz(a)anthracene and/or 7,12-dimethylbenz(a)anthracene derived metabolites in the urine of the limonene fed animals.
Limonene and sobrerol, a hydroxylated monocyclic monoterpenoid with increased chemoprevention activity, modulated cytochrome p450 and epoxide hydrolyase activity.
The 5% limonene diet increased total cytochrome p450 to the same extent as phenobarbital treatment, while 1% sobrerol (isoeffective in chemoprevention to 5% limonene) did not.
However, both 5% limonene and 1% sobrerol diets greatly increased the levels of microsomal epoxide hydrolyase protein and associated hydrating activities towards benzo[a]pyrene 4,5-oxide when compared to control and phenobarbital treatment.
These changes also modified the rate and regioselectivity of in vitro microsomal 7,12-dimethylbenz(a)anthracene metabolism when compared to phenobarbital treatment or control.
Identification of the specific isoforms of cytochrome p450 induced by these terpenoids was performed with antibodies to cytochrome p450 isozymes in Western blot analysis and inhibition studies of microsomal 7,12-dimethylbenz(a)anthracene metabolism.
Five percent limonene was more effective than 1% sobrerol at increasing the levels of members of the cytochrome p450 2B and 2C families but was equally effective at increasing epoxide hydrolyase.
Furthermore, both terpenoid diets caused increased formation of the proximate carcinogen, 7,12-dimethylbenz(a)anthracene 3,4-dihydrodiol.
Limonene is the oil extracted from the peels of oranges and other citrus fruits.
People have been extracting essential oils like limonene from citrus fruits for centuries.
Today, limonene is often used as a natural treatment for a variety of health issues and is a popular ingredient in household items.
However, not all of limonene’s benefits and uses are supported by science.
This article examines limonene’s uses, potential benefits, side effects, and dosage.
Limonene is a chemical found in the rind of citrus fruits, such as lemons, limes, and oranges.
Limonene is especially concentrated in orange peels, comprising around 97% of this rind’s essential oils.
Limonene’s often referred to as d-limonene, which is its main chemical form.
Limonene belongs to a group of compounds known as terpenes, whose strong aromas protect plants by deterring predators.
Limonene is one of the most common terpenes found in nature and may offer several health benefits.
Limonene has been shown to possess anti-inflammatory, antioxidant, anti-stress, and possibly disease-preventing properties.
Linked to several health benefits of Limonene:
Limonene has been studied for its potential anti-inflammatory, antioxidant, anticancer, and heart-disease-fighting properties.
However, most research has been conducted in test tubes or on animals, making it difficult to fully understand the role of limonene in human health and disease prevention.
Anti-inflammatory and antioxidant benefits
Limonene has been shown to reduce inflammation in some studies.
While short-term inflammation is your body’s natural response to stress and is beneficial, chronic inflammation can harm your body and is a major cause of illness.
Limonene’s important to prevent or reduce this type of inflammation as much as possible.
Limonene has been shown to reduce inflammatory markers that relate to osteoarthritis, a condition characterized by chronic inflammation.
A test-tube study in human cartilage cells noted that limonene reduced nitric oxide production.
Nitric oxide is a signaling molecule that plays a key role in inflammatory pathways.
In a study in rats with ulcerative colitis — another disease characterized by inflammation — treatment with limonene significantly decreased inflammation and colon damage, as well as common inflammatory markers.
Limonene has demonstrated antioxidant effects as well.
Antioxidants help reduce cell damage caused by unstable molecules called free radicals.
Free radical accumulation can lead to oxidative stress, which may trigger inflammation and disease.
One test-tube study revealed that limonene may inhibit free radicals in leukemia cells, suggesting a decrease in inflammation and cellular damage that would normally contribute to disease.
Although promising, these effects need to be confirmed by human studies.
May boost heart health of Limonene:
Heart disease remains the leading cause of death in the United States, accounting for nearly one in four deaths.
Limonene may lower your risk of heart disease by reducing certain risk factors, such as elevated cholesterol, blood sugar, and triglyceride levels.
In one study, mice given 0.27 grams of limonene per pound of body weight (0.6 grams/kg) showed reduced triglycerides, LDL (bad) cholesterol, fasting blood sugar, and fat accumulation in the liver, compared to a control group.
In another study, stroke-prone rats given 0.04 grams of limonene per pound of body weight (20 mg/kg) exhibited significant reductions in blood pressure compared to rats of similar health status that did not receive the supplement.
Keep in mind that human studies are needed before strong conclusions can be drawn.
Safety and research of Limonene:
Limonene and its oxidation products are skin irritants, and limonene-1,2-oxide (formed by aerial oxidation) is a known skin sensitizer.
Most reported cases of irritation have involved long-term industrial exposure to the pure compound, e.g. during degreasing or the preparation of paints.
However a study of patients presenting dermatitis showed that 3% were sensitized to limonene.
Limonene causes renal cancer in male rats, but not in female rats or in mice of either sex, due to binding of the metabolite limonene-1,2-oxide to α2u-globulin, a protein produced only by male rats.
There is no evidence for carcinogenicity or genotoxicity in humans. The IARC classifies d-limonene under Class 3: not classifiable as to its carcinogenicity to humans.
Limonene applied to skin may cause irritation from contact dermatitis, but otherwise appears to be safe for human uses.
Limonene is flammable as a liquid or vapor and it is toxic to aquatic life.
Other benefits of Limonene:
Aside from the benefits listed above, limonene may:
Reduce appetite.
The scent of limonene has been shown to significantly reduce appetite in blowflies.
However, this effect has not been studied in humans.
Decrease stress and anxiety.
Rodent studies suggest that limonene could be used in aromatherapy as an anti-stress and anti-anxiety agent.
Support healthy digestion.
Limonene may protect against stomach ulcers.
In a study in rats, citrus aurantium oil, which is 97% limonene, protected nearly all of the rodents against ulcers caused by medication use.
Potentially effective dosages
Because few limonene studies exist in humans, it’s difficult to provide a dosage recommendation.
Nonetheless, dosages of up to 2 grams daily have been safely used in studies.
Capsule supplements that can be purchased online contain dosages of 250–1,000 mg.
Limonene is also available in liquid form with typical dosages of 0.05 ml per serving.
However, supplements aren’t always necessary.
You can easily obtain this compound by eating citrus fruits and peels.
For example, fresh orange, lime, or lemon zest can be used to add limonene to baked goods, drinks, and other items.
What’s more, pulpy citrus juices, such as lemon or orange juice, boast limonene, too.
Common uses of limonene:
Limonene is a popular additive in foods, cosmetics, cleaning products, and natural insect repellants.
For example, it’s used in foods like sodas, desserts, and candies to provide a lemony flavor.
Limonene is extracted through hydrodistillation, a process in which fruit peels are soaked in water and heated until the volatile molecules are released via steam, condensed, and separated.
Due to its strong aroma, limonene is utilized as a botanical insecticide. It’s an active ingredient in multiple pesticide products, such as eco-friendly insect repellents.
Other household products containing this compound include soaps, shampoos, lotions, perfumes, laundry detergents, and air fresheners.
Additionally, limonene is available in concentrated supplements in capsule and liquid form.
These are often marketed for their supposed health benefits.
This citrus compound is also used as an aromatic oil for its calming and therapeutic properties.
Industrial of Limonene:
There have been some reported cases of skin sensitisation, but these have usually developed in those involved regularly with pure limonene in an industrial setting for paint preparation or degreasing machinery.
Use and Manufacturing of Limonene:
Limonene is a naturally occurring chemical which is used in many food products, soaps and perfumes for its lemon-like flavor and odor.
Limonene also is a registered active ingredient in 15 pesticide products used as insecticides, insect repellents, and dog and cat repellents.
Pesticide products containing limonene are used for flea and tick control on pets, as an insecticide spray, an outdoor dog and cat repellent, a fly repellent tablecloth, a mosquito larvicide, and an insect repellent for use on humans.
Formulations include ready-to-use solutions, emulsifiable concentrates, granulars and impregnated material.
Limonene is applied by hand as needed, both indoors and outdoors. Use practice limitations include a label prohibition against use on weanling kittens and a caution against use of undiluted product.
As the main odour constituent of citrus (plant family Rutaceae), d-limonene is used in food manufacturing and some medicines, e.g., bitter alkaloids, as a flavoring, and added to cleaning products such as hand cleansers to give a lemon-orange fragrance.
See: orange oil.
Limonene is increasingly being used as a solvent for cleaning purposes, such as the removal of oil from machine parts, as it is produced from a renewable source (citrus oil, as a byproduct of orange juice manufacture.)
Limonene works as paint stripper when applied to painted wood. The (R)-enantiomer is also used as botanical insecticide.
The (S)-enantiomer, also known as l-limonene (CAS number 5989-54-8, EINECS number 227-815-6), is used as a fragrance in some cleaning products.
In contrast to the citrus (orange-lemon) scent (see above) of d-limonene, the enantiomer l-limonene has a piney, turpentine-like odor.
Limonene is very common in cosmetic products.
Due to its combustible nature, d-limonene has also seen limited use as an experimental biofuel.
Found in a vast array of cleaning products, cosmetics, food flavourings and even aromatherapy, it comes in two forms: d-limonene and l-limonene.
These are like “different handed” versions of the same molecule, with only subtle difference
