| Identification | More | [Name]
2-Hydroxy-1,4-naphoquinone | [CAS]
83-72-7 | [Synonyms]
2-Hydroxy-1,4-naphoquinone
2-HYDROXY-1,4-NAPHTHAQUINONE
2-HYDROXY-1,4-NAPHTHOQUINONE
2-HYDROXY-P-NAPHTHOQUINONE
CI 75480
JAROCOL LAWSONE
LAWSONE
NATURAL ORANGE 6
1,4-Naphthalenedione,2-hydroxy-
1,4-Naphthoquinone, 2-hydroxy-
2-Hydroxy-1,4-naphthalenedione
2-hydroxy-4-naphthalenedione
2-hydroxy-4-naphthoquinone
2-Hydroxynaphthoquinone
4-Naphthalenedione,2-hydroxy-1
C.I. Natural Orange 6
c.i.naturalorange6
Flower Of Paradise
flowerofparadise
Hana | [EINECS(EC#)]
201-496-3 | [Molecular Formula]
C10H6O3 | [MDL Number]
MFCD00001678 | [Molecular Weight]
174.15 | [MOL File]
83-72-7.mol |
| Chemical Properties | Back Directory | [Definition]
A coloring principle obtained from dried leaves of certain tropical plants (North Africa, India). | [Appearance]
Yellow crystal powder | [Melting point ]
192-195 °C (dec.)(lit.)
| [Boiling point ]
265.11°C (rough estimate) | [density ]
1.2346 (rough estimate) | [refractive index ]
1.5036 (estimate) | [storage temp. ]
Sealed in dry,Room Temperature | [solubility ]
Acetonitrile (Slightly), Chloroform (Slightly), Methanol (Slightly) | [Colour Index ]
75480 | [form ]
Crystalline Powder | [pka]
4.31±0.10(Predicted) | [color ]
Yellow | [Stability:]
Stable. Combustible. Incompatible with strong oxidizing agents. | [Water Solubility ]
2 g/L (20 ºC) | [Merck ]
14,5393 | [BRN ]
1565260 | [Contact allergens]
Henna, prepared by powdering the dried leaves of henna plant (Lawsonia inermis L.), is used for coloring and conditioning hair and nails, particularly by Muslims or Hindus. It contains Lawsone, which very rarely induces contact allergy. Most dermatitis caused by “black henna” is due to PPD and derivatives | [InChIKey]
CSFWPUWCSPOLJW-UHFFFAOYSA-N | [LogP]
1.380 | [CAS DataBase Reference]
83-72-7(CAS DataBase Reference) | [NIST Chemistry Reference]
1,4-Naphthalenedione, 2-hydroxy-(83-72-7) | [EPA Substance Registry System]
83-72-7(EPA Substance) |
| Hazard Information | Back Directory | [Chemical Properties]
Yellow crystal powder | [Uses]
An antimicrobial antioxidant dye isolated from Henna. | [Uses]
antifungal, sunscreen, antibacterial, antineoplastic | [General Description]
Yellow prisms or yellow powder. | [Reactivity Profile]
Phenols, such as 2-HYDROXY-1,4-NAPHTHOQUINONE(83-72-7), do not behave as organic alcohols, as one might guess from the presence of a hydroxyl (-OH) group in their structure. Instead, they react as weak organic acids. Phenols and cresols are much weaker as acids than common carboxylic acids (phenol has Ka = 1.3 x 10^[-10]). These materials are incompatible with strong reducing substances such as hydrides, nitrides, alkali metals, and sulfides. Flammable gas (H2) is often generated, and the heat of the reaction may ignite the gas. Heat is also generated by the acid-base reaction between phenols and bases. Such heating may initiate polymerization of the organic compound. Phenols are sulfonated very readily (for example, by concentrated sulfuric acid at room temperature). The reactions generate heat. Phenols are also nitrated very rapidly, even by dilute nitric acid. Nitrated phenols often explode when heated. Many of them form metal salts that tend toward detonation by rather mild shock. | [Air & Water Reactions]
Insoluble in water. | [Health Hazard]
ACUTE/CHRONIC HAZARDS: This compound may be absorbed through the skin and can cause skin irritation. | [Fire Hazard]
Flash point data for this chemical are not available but 2-HYDROXY-1,4-NAPHTHOQUINONE is probably combustible. | [History]
Lawsone (CI Natural Orange 6; CI 75420), also known as henna and isojuglone, occurs in the shrub henna (Lawsone alba). In England, the plant is known as Egyptian privet. The dye was extracted from the leaves of the plant, using sodium bicarbonate, and the extracts used to dye protein fibers an orange shade. Henna is probably the oldest cosmetic known. The ancient Egyptians used it as a hair dye and for staining fingernails. It is said that Mohammed dyed his beard with henna. Lawsone has been identified as 2-hydroxy-1,4-naphthoquinone. It has been synthesized by the Thiele acetylation of 1,4-naphthoquinone followed by hydrolysis and oxidation. | [Synthesis Reference(s)]
The Journal of Organic Chemistry, 53, p. 808, 1988 DOI: 10.1021/jo00239a023
Tetrahedron Letters, 25, p. 533, 1984 DOI: 10.1016/S0040-4039(00)99930-1 | [storage]
Store at -20°C | [Purification Methods]
Crystallise Lawsone B from *C6H6 or AcOH (m 192.5o, 195-196o). It sublimes in a vacuum (m 194o). It has UV with max at 455nm (aqueous NaOH). [Beilstein 8 H 300, 8 I 635, 8 II 344, 8 III 2543, 8 IV 2360.] |
| Safety Data | Back Directory | [Hazard Codes ]
Xi,Xn | [Risk Statements ]
R36/37/38:Irritating to eyes, respiratory system and skin .
R68:Possible risk of irreversible effects.
R36:Irritating to the eyes.
R22:Harmful if swallowed. | [Safety Statements ]
S26:In case of contact with eyes, rinse immediately with plenty of water and seek medical advice .
S37/39:Wear suitable gloves and eye/face protection .
S36/37/39:Wear suitable protective clothing, gloves and eye/face protection .
S36:Wear suitable protective clothing . | [WGK Germany ]
3
| [RTECS ]
QL8200000
| [TSCA ]
Yes | [HS Code ]
29146990 |
| Raw materials And Preparation Products | Back Directory | [Raw materials]
Ammonium sulfamate-->1,4-Naphthoquinone-->1,2-NAPHTHOQUINONE-->naphthalene-1,2,4-triyl triacetate-->naphthalene-1,2,4-triol-->2-Naphthalenol, 1,4-dimethoxy--->1,3-DIHYDROXYNAPHTHALENE-->2-METHOXY-1,4-NAPHTHOQUINONE-->4-methoxynaphthalene-1,2-dione-->1,2-DIHYDROXYNAPHTHALENE-->2-Chloro-3-hydroxy-1,4-naphthoquinone-->2-hydroxy-3-iodonaphthalene-1,4-dione-->1,4-Dihydroxynaphthalene-->2-Naphthol-->1-Tetralone-->2-Methoxynaphthalene-->2-NITROTHIOPHENOL | [Preparation Products]
Nile Red-->2-Chloro-1,4-naphthoquinone |
| Questions And Answer | Back Directory | [Description]
Lawsone [CAS: 83-72-7] (CI Natural Orange 6; CI 75420), also known as henna and isojuglone, occurs in the shrub henna (Lawsone alba). In England, the plant is known as Egyptian privet. The dye was extracted from the leaves of the plant, using sodium bicarbonate, and the extracts used to dye protein fibers an orange shade. Henna is probably the oldest cosmetic known. The ancient Egyptians used it as a hair dye and for staining fingernails. It is said that Mohammed dyed his beard with henna. Lawsone has been identified as 2-hydroxy-1,4-naphthoquinone. It has been synthesized by the Thiele acetylation of 1,4-naphthoquinone followed by hydrolysis and oxidation. | [Chemical Propterties]
2-Hydroxy-1,4-naphthoquinone (HNQ, C10H6O3) is also called Lawsone, which is a white cubic crystal. Its melting point is 192-195 oC, and flash point is 192 oC. The solubility of HNQ is 2 g/L in water at 20 oC. It is stable, but it is combustible and incompatible with strong oxidizing agents.
| [Application]
2-Hydroxy-1,4-naphthoquinone(HNQ) is the principal natural dye ingredient contained at 1.0-1.4% in the leaves of Henna (Lawsonia inermis). It is an ancient red-orange dye. Henna has been used for more than 4000 years not only as a hair dye, but also as a body paint and tattoo dye. Today, semi-permanent hair dyes containing Henna as well as its pure dye ingredient HNQ are widely used and have become increasingly popular due to their natural origin.
| [Biological Toxicity]
2-Hydroxy-1,4-naphoquinone(HNQ) was reported to be a weak bacterial mutagen for Salmonella typhimurium strain TA98 or was more clearly mutagenic for strain TA 2637, both in the presence of metabolic activation. HNQ was unable to induce sex-linked recessive lethal mutations in Drosophila melanogaster. The available data suggest that the use of Henna or 2-Hydroxy-1,4-naphoquinone(HNQ) for hair dyeing presents no or negligible risk of genotoxicity to the consumer.
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