By acting as a free radical scavenger, hydroquinone serves to prolong the shelflife of light-sensitive resins such as preceramic polymers. Hydroquinone can lose a hydrogen cation from both hydroxyl groups to form a diphenolate ion.
People may use hydroquinone as a form of treatment for hyperpigmentation skin conditions, wherein some areas of skin grow darker than surrounding areas. Some conditions that people may use hydroquinone for include: People with melasma have brown or gray-brown patches on their skin.
The term hydroquinone was coined by Friedrich Wöhler in 1843. Hydroqiunone is most often produced by the cumene process in a reaction mechanism and entails the dialkylation of benzene with propene to give out 1,4-diisopropylbenzene.
The compound reacts with air to produce the bis (hydroperoxide), that is structurally associated with cumene hydroperoxide and reorders in acid to let out acetone and hydroquinone. Hydroquinone is widely used as an inhibitor, an antioxidant, and as an intermediate chemical in the synthesis of dyes, motor fuels, and oils.
The reactivity of hydroquinone's hydroxyl groups resembles that of other phenols, being weakly acidic. The resulting conjugate base undergoes easy O -alkylation to give mono- and diethers. Similarly, hydroquinone is highly susceptible to ring substitution by Friedel–Crafts reactions such as alkylation.
Hydroquinone has a variety of uses principally associated with its action as a reducing agent that is soluble in water. It is a major component in most black and white photographic developers for film and paper where, with the compound metol, it reduces silver halides to elemental silver .
Hydroquinones are one of the two primary reagents in the defensive glands of bombardier beetles, along with hydrogen peroxide (and perhaps other compounds, depending on the species), which collect in a reservoir. The reservoir opens through a muscle-controlled valve onto a thick-walled reaction chamber.
Trusted Source. . Several years later, concerns about safety prompted retailers to pull hydroquinone from the market. The FDA went on to discover that many of the products in question contained contaminants like mercury. They established that these contaminants were behind reports of adverse effects.
Hydroquinone bleaches your skin by decreasing the number of melanocytes present. Melanocytes make melanin, which is what produces your skin tone. In cases of hyperpigmentation, more melanin is present due to an increase in melanocyte production. By controlling these melanocytes, your skin will become more evenly toned over time.
AMBI Fade Cream. This 2 percent hydroquinone product comes in both normal and oily skin versions. It also contains vitamin E and alpha hydroxy acids for smoother, more toned skin compared to using hydroquinone alone. Higher concentrations and pure forms of hydroquinone are only available with a prescription.
Although hydroquinone can help fade red or brown spots that have lingered, it won’t help with active inflammation. For example, the ingredient can help minimize acne scarring, but it won’t have an effect on redness from active breakouts.
If you don’t see any improvement after three months, discontinue use. If you do see improvement, you can use the product for up to four months, and then begin to taper off use.
If you have dry or sensitive skin, you may find that hydroquinone causes further dryness or irritation. This usually tapers off as your skin adjusts to the ingredient. People who have normal or oily skin are less likely to experience these side effects. The ingredient tends to work best on fair skin tones.
Historically, there’s been some back-and-forth on the safety of hydroquinone. In 1982, the U.S. Food and Drug Administration recognized the ingredient as safe and effective.
They can do this by applying a small amount of the product to the affected area of skin. Check for signs of irritation, such as itching or redness.
Hydroquinone is a chemical that bleaches the skin. It can come as a cream, emulsion, gel, or lotion. A person can apply these products directly to the skin. Creams that contain 2% hydroquinone are available to buy over the counter in most drugstores. Stronger creams are available with a prescription from a doctor.
First, make sure that the area is clean and dry. Apply a thin layer of product to the affected skin and rub it in well. Lastly, wash the hands thoroughly. This will stop the hydroquinone from lightening the skin on the fingers.
Those with acne scars may also use hydroquinone-based skin-lightening creams. Products containing 2% hydroquinone are available over the counter at most drugstores. Stronger concentrations are available with a prescription. These products are generally safe, but long-term use can cause issues, such as ochronosis.
Hydroquinone is not the only skin-lightening product available over the counter. The American Academy of Dermatology urge people to choose skin-lightening products carefully. For example, some contain steroids that can cause pimples and rashes. Long-term use can even make the skin thin and fragile.
Stronger creams are available with a prescription from a doctor. People may use hydroquinone as a form of treatment for hyperpigmentation skin conditions, wherein some areas of skin grow darker than surrounding areas. Some conditions that people may use hydroquinone for include:
Hydroquinone is used as a developing agent in black-and-white photography, lithography, and x-ray films. It is also used as an intermediate to produce antioxidants for rubber and food. It is added to a number of industrial monomers to inhibit polymerization during shipping, storage, and processing.
Hydroquinone's production and use as a chemical intermediate, glue and hair dye ingredient, and administration as a skin depigmentor may result in its release to the environment through various waste streams. Hydroquinone occurs naturally in several arthropods and assorted species of plants. If released to air, a vapor pressure of 2.4X10-5 mm Hg at 25 °C indicates hydroquinone will exist in both the vapor and particulate phases in the atmosphere. Vapor-phase hydroquinone will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 17 hrs. Particulate-phase hydroquinone will be removed from the atmosphere by wet and dry deposition. Hydroquinone contains chromophores that absorb at wavelengths >290 nm and, therefore, may be susceptible to direct photolysis by sunlight. If released to soil, hydroquinone is expected to have moderate mobility based upon an estimated Koc of 240. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 4.7X10-11 atm-cu m/mole. Hydroquinone is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Hydroquinone was found to biodegrade in the coupled units test, the Zahn-Wellens test, the MITI test, the Sturm test, the AFNOR test, the OECD screening test and the closed bottle test, indicating that biodegradation may be an important environmental fate process in soil and water, although its biodegradation is likely to be strongly concentration-dependent. It may be inhibitory at high concentration. If released into water, hydroquinone is expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions (pH 5 to 9). Aqueous hydroquinone showed 75% decomposition after 44 hours of UV photooxidation. Occupational exposure to hydroquinone may occur through inhalation and dermal contact with this compound at workplaces where hydroquinone is produced or used. Monitoring/use data indicate that the general population may be exposed to hydroquinone via inhalation of wood or cigarette smoke, ingestion of certain foods and dermal contact with consumer products containing hydroquinone. (SRC)
Compound-related clinical signs in rats included tremors lasting up to 30 minutes after each dosing at 500 and 1,000 mg/kg. In the 14-day gavage studies with mice, 4/5 male mice and 5/5 female mice receiving 500 mg/kg and 3/5 males receiving 250 mg/kg died before the end of the studies. Tremors followed by convulsions were seen at 250 and 500 mg/kg.
Hydroquinone reduces melanin pigment production through inhibition of the tyrosinase enzyme, which is involved in the initial step of the melanin pigment biosynthesis pathway. Hydroquinone takes several months to take effect.
According to a classification scheme (2), this estimated Koc value suggests that hydroquinone is expected to have moderate mobility in soil. Hydroquinone can exhibit chemisorption to transition metal-containing particulate matter via reaction with the copper oxide /silca surfaces present (3).
The Henry's Law constant for hydroquinone is estimated as 4.7X10-11 atm-cu m/mole (SRC) derived from its vapor pressure, 2.4X10-5 mm Hg (1) , and water solubility, 7.2X10+4 mg/L (2). This Henry's Law constant indicates that hydroquinone is expected to be essentially nonvolatile from water and moist soil surfaces (3). Hydroquinone is not expected to volatilize from dry soil surfaces (SRC) based upon its vapor pressure (1).
HYDROQUINONE is a slight explosion hazard when exposed to heat. Incompatible with strong oxidizing agents. Also incompatible with bases. It reacts with oxygen and sodium hydroxide. Reacts with ferric salts (NTP, 1992). Hot and/or concentrated NaOH can cause hydroquinone to decompose exothermically at elevated temperature. (NFPA Pub. 491M, 1975, 385)
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Human contact to hydroquinone can take place by dietary, occupational, and environmental sources. In the environment, hydroquinone shows increase toxicity for aquatic organisms. Latest pieces of evidence showed that hydroquinone is able to augment carcinogenic risk by causing DNA damage.
Production Method of Hydroquinone. Hydroqiunone is most often produced by the cumene process in a reaction mechanism and entails the dialkylation of benzene with propene to give out 1,4-diisopropylbenzene.
Hydroquinone is an aromatic organic compound which is a melanin synthesis inhibitor. It has a chemical formula of C6H4 (OH)2. It is a type of phenol which is a derivative of benzene. It consists of two hydroxyl groups bonded in a benzene ring similar to a para position. Hydroquinone is a white granular solid. Other derivatives of this compound are also denoted to as 1, 4-Benzenediol, Quinol, Benzene-1 and Hydrochinone. The term hydroquinone was coined by Friedrich Wöhler in 1843.
Skin sensitivity of hydroquinone may be ascertained beforehand of the treatment by applying a small amount of cream to the hyperpigmented area. To have the desired effect, hydroquinone should be used along with a strong sunscreen.
Hydroquinone is a white granular solid. Other derivatives of this compound are also denoted to as 1, 4-Benzenediol, Quinol, Benzene-1 and Hydrochinone. The term hydroquinone was coined by Friedrich Wöhler in 1843.