Examples of suitable methods of encapsulation include encapsulation by liposomes, wax, paraffin or any material or combination of materials which protect the retinoid from exposure to oxygen and inhibit oxidation of the retinoid from oxidation. According to the polar paradox theory, this should lead to a dissolution of . Chem. A preferred embodiment utilizes encapsulation. Forms of retinoids have been developed wherein the retinoid is protected by a protective system. 109. 322, 4855 (2012), K. Tamura, T. Kasuga, T. Nakagawa, Fluid Phase Equilib. There are various other uses associated with its reducing power. [23] This conclusion was reached based on the extent of absorption in humans and the incidence of neoplasms in rats in several studies where adult rats were found to have increased rates of tumours, including thyroid follicular cell hyperplasias, anisokaryosis (variation in nuclei sizes), mononuclear cell leukemia, hepatocellular adenomas and renal tubule cell adenomas. 15, 188196 (1996), U. Domaska, Fluid Phase Equilib. This complex dissolves in hot water, where the two molecules dissociate in solution. At 40C, 4% hydroquinone compositions have the same color stability with slightly more sodium metabisulfite, at least about 0.01% at about 3.5 to about 4.0 pH; at least about 0.05% sodium metabisulfite at about 4.5 to about 6.0 pH; and at pH; at least about 0.05% sodium metabisulfite at about 4.5 to about 6.0 pH; and at least about 0.10% sodium metabisulfite at about 6.5 to about 7.0 pH. N')].uJr 2005 Wiley-VCH, Weinheim. C6H4O2) is formed. The obtained results show that the solubility of benzoic acid in water is greater than that of salicylic acid, but in the case of the two isomers of dihydroxybenzene, the solubility of resorcinol is approximately 100 times that of hydroquinone. Dietland Muller-Schwarze, 2003, page 43 (, National Institute for Occupational Safety and Health, Additive manufacturing of ceramics from preceramic polymers, http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31976L0768:EN:HTML, "Clear N Smooth Skin Toning Cream recalled", Skin Bleaching Drug Products for Over-the-Counter Product Use; Proposed Rule, "About the Center for Drug Evaluation and Research - Hydroquinone Studies Under The National Toxicology Program (NTP)", Campaign For Safe Cosmetics - Hydroquinone, "Skin lightening preparations and the hydroquinone controversy", https://en.wikipedia.org/w/index.php?title=Hydroquinone&oldid=1136453324, Wikipedia articles needing page number citations from October 2016, Pages using collapsible list with both background and text-align in titlestyle, Articles containing unverified chemical infoboxes, Creative Commons Attribution-ShareAlike License 3.0, The most widely used route is similar to the, A potentially significant synthesis of hydroquinone from, Hydroquinone was first obtained in 1820 by the French chemists, Pelletier and Caventou (1820) "Recherches chimiques sur les quinquinas" (Chemical investigations of quinquinas [i.e., the bark of various, This page was last edited on 30 January 2023, at 11:09. Have an order or account question? 0000005089 00000 n
Thank you for your inquiry and interest in ChemPoint. Privacy Policy. Appearance: Free-flowing white crystalsOdor: OdorlessMolecular weight: 110.11Empirical formula: C6H6O2Assay (Anhydrous basis): 99.0-100.5 %Melting point: 172-174CWater: 0.5 wt % max.Residue on ignition: 0.5 % maxSolubility: Moderately soluble in water, glycerin, propylene glycol, and highly soluble in ethanol, Can work in conjunction with glycolic acid to help reduce pigment in melasma Non-GMOExtremely low vapor pressureUSP GradeEuropean Pharma GradeDrug master file available upon request. The reservoir opens through a muscle-controlled valve onto a thick-walled reaction chamber. 0000002585 00000 n
The solubility was increased by addition of ethanol, reached a maximum . 76/768/EEC:1976 Council Directive 76/768/EEC of 27 July 1976 on the approximation of the laws of the Member States relating to cosmetic products: Organic Chemistry, Solomon and Fryhle, 10th edition, Wiley Publishing, 2010. These reactions release free oxygen and generate enough heat to bring the mixture to the boiling point and vaporize about a fifth of it, producing a hot spray from the beetle's abdomen. isosorbide, Ascorbic acid, i.e. Keywords: D-170D; D-170; D170D; D170 Created Date Find answers in our support articles. For more information, please see our 49, 313321 (2015). 58 / Monday, March 26, 2012 / Rules and Regulations 10/31/2017 EN (English US) 6/8 12.3. Using a laser-monitoring observation technique, the solubility of hydroquinone in water, methanol, ethanol, 2-propanol, ethyl acetate, butyl acetate, and acetic acid were measured at temperatures ranging from 276.65 K to 345.10 K under the atmospheric pressure. It is understood that while the invention has been described in conjunction with the detailed description thereof, that the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. ~lgM~Gc{1S_1Q/_/v">S 9
Water Solubility 73000 mg/L at 25C 2.6B pH pKa 4.0 - 4.7 pK1 = 9.9 2.12 Oxidation:Reduction Potential +286 mV at 25C and pH 7 ENVIRONMENTAL FATE/BIODEGRADATION Preferably, the protected retinoid, in particular retinoic acid, retinal, and their derivatives, isomers and analogs (such as adapalene, tazarotene and isotretoin), is in the form of small beads or spheres suitable for incorporation into a topical composition. Eng. 0.5% magnesium ascorbyl phosphate protected at pH 6.0-7.0, 1.0-1.5% at pH 5.5-7.0, and 2.0-3.0% at pH 3.5-7.0. This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions. Solubility: Moderately soluble in water, glycerin, propylene glycol, and highly soluble in ethanol Features & Benefits Can work in conjunction with glycolic acid to help reduce pigment in melasma Non-GMO Extremely low vapor pressure USP Grade European Pharma Grade Drug master file available upon request Applications Phillip M. Hudnall "Hydroquinone" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. 1401417, Country of ref document: 0000005757 00000 n
[34], It is also one of the chemical compounds found in castoreum. trailer
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65, 5786 (1998), Y.-H. Zhang, Trends Analyt. In 1-octanol, the decreasing order of the solubility of these compounds is as follows: resorcinol>benzoic acid>salicylic acid>hydroquinone. Using a laser-monitoring observation technique, the solubility of hydroquinone in water, methanol, ethanol, 2-propanol, ethyl acetate, butyl acetate, and acetic acid were measured at temperatures ranging from 276.65 K to 345.10 K under the atmospheric pressure. One embodiment of the invention is a composition which comprises hydroquinone (about 1% to about 12%, preferably about 2% to about 10%, more preferably about 2% to about 8%, more preferably with about 2% to about 4%, and most preferably about 3% to about 4%) and has a neutral pH of from about 5.5 to about 8.0, more preferably a pH of from about 5.5 to about 7.5, and most preferably at a pH of from about 6.0 to about 7.5. We have discovered that a hydroquinone composition (with about 1 to about 12% hydroquinone, preferably with about 2% to about 10%, more preferably with about 2% to about 8%, more preferably with about 2% to about 4%, most preferably with about 3% to about 4% hydroquinone) with preferably a pH of from about 5.5 to about 8.0, more preferably a pH of from about 5.5 to about 7.5, and most preferably at a pH of from about 6.0 to about 7.5, can include cationic salts of acidic ascorbyl esters, preferably sodium ascorbyl phosphate, more preferably aminopropyl ascorbyl phosphate, most preferably magnesium ascorbyl phosphate as an antioxidant and the color destabilization problems are appreciably less as compared to hydroquinone compositions without such a cationic salt of acidic ascorbyl esters in the neutral pH range: preferably a pH of from about 5.5 to about 8.0, more preferably a pH of from about 5.5 to about 7.5, and most preferably at a pH of from about 6.0 to about 7.5. Skin Contact Wash off immediately with plenty of water for at least 15 minutes. %PDF-1.4
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[21][25][23] NTP evaluation showed some evidence of long-term carcinogenic and genotoxic effects[26], While hydroquinone remains widely prescribed for treatment of hyperpigmentation, questions raised about its safety profile by regulatory agencies in the EU, Japan, and USA encourage the search for other agents with comparable efficacy. 0 7 r @ &. With an account you can check out faster, view your online order history and access your shopping bag or saved items from any device. However, hydroquinone discolors at the pH range of 7.0 to 8.5. Protected retinoid may be added to these compositions for additional skin benefit effects. 2017-02-16T10:10:56+01:00 Editor's Rating: The present invention combats this problem, with hydroquinone compositions in the neutral pH range, preferably a pH of from about 5.5 to about 8.0, more preferably a pH of from about 5.5 to about 7.5, and most preferably at a pH of from about 6.0 to about 7.5. The Density of hydroquinone is . This is a prescription-only ingredient in some countries, including the member states of the European Union under Directives 76/768/EEC:1976. HyTSwoc
[5laQIBHADED2mtFOE.c}088GNg9w '0 Jb I did that by using 1 cup of cream, 4tbsp of hydroquinone and 4tbsp of water or solvent. The color stability of the hydroquinone composition is promoted by one or more antioxidants in the hydroquinone phase, preferably sulfite, including but not limited to sulfites, bisulfites, metabisulfites, their salts and their derivatives, most preferably sodium metabisulfite, and a cationic salt of acidic ascorbyl esters, most preferably magnesium ascorbyl phosphate. This saturated dicarboxylic acid exists as a white powder. hydroquinone, 1,4-benzenediol, quinol, 1,4-dihydroxybenzene, p-benzenediol, 4-hydroxyphenol, p-hydroquinone, p-hydroxyphenol, p-dihydroxybenzene, benzoquinol, Electrophoresis, Western Blotting and ELISA, Chromatography and Mass Spectrometry Reagents, Laboratory Syringe Needles and Accessories, Lab Coats, Aprons, and Other Safety Apparel, Sharps Disposal Containers and Accessories, Classroom Laboratory Supplies and Consumables, Applied Biosystems TaqMan Assay and Arrays Search Tool, Applied Biosystems TaqMan Custom Assay Design Tools, Applied Biosystems Custom qPCR Primers and TaqMan Probes Tool, Chemical Storage and Management Resource Center, Solubility in water: 70g/L in water (20C). GHS P Statement: Wear protective gloves/protective clothing/eye protection/face protection.Call a POISON CENTER or doctor/physician if you feel unwell.IF ON SKIN: Gently wash with plenty of soap and water.IF IN EYES: Rinse cautiously with water for several minutes. The FDA had classified hydroquinone in 1982 as a safe product - generally recognized as safe and effective (GRASE), however additional studies under the National Toxicology Program (NTP) were suggested in order to determine whether there is a risk to humans from the use of hydroquinone. . Eng. 0000008435 00000 n
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Approved only for prescription use in the U.S. market.Ideal for creams, lotions, and gels for personal care ingredients, pharmaceutical chemical, pharmaceutical excipients, and skin care ingredients. A specific embodiment of the invention is listed in the following table. Learn more about Institutional subscriptions, C. M. S. de Mendona, I. P. de Barros Lima, C. F. S. Arago, A. P. B. Gomes, J. Therm. :hS-g"s2Sj Ij=x'V]gPV8tt~qkAVXi|u}5;#.pl-/4JFQ.EP3&F.qa2hI{N qBmG(z#n [GN.}aazN(~8kux9#tnYwIHFuxW v9UNj&ffNW_\\Tc""8=_"7wC>svwQy\^4gF H][QzmlOI(B@ U4[Xb0,|m0*D"/#$\u(QI)RYg\;8 Yjh The solubility of sodium phenytoin in binary mixtures of ethanol +water at 298.2, 303.2, 308.2 and 313.2 K was measured. HVoLg~Z+ Except where otherwise noted, data are given for materials in their, Hydroquinone oxidation with V2O5/NaClO3/H2SO4, http://www.sciencemadness.org/smwiki/index.php?title=Hydroquinone&oldid=11523, Articles containing unverified chemical infoboxes, GNU Free Documentation License 1.3 or later. Hydroquinone Revision Date 24-Dec-2021 General Advice If symptoms persist, call a physician. It does not have the same predisposition to cause dermatitis as metol does. However, the oil-soluble TBHQ is more hydrophobic with a distinctly increased log P value compared to HQ. Variations in pH have proven to result in excessive discoloration ranging from brownish to black. However, a problem with a formulation containing both retinoids and hydroquinone has been their incompatible pH ranges. Belhachemi, B., Makhlouf, H. & Belhachemi, M.H. NR
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20, 14331442 (1986), G. Wienke, J. Gmehling, Toxicol. 4. SAS Anti-ox booster 1% 0.3g. G(DC:!c?5w
[QDP, f\01j&8ea]Ke~z d _5H^j0M.|Y^bYb[Rm~-[ImSv. ;4kNNw?r yn^EOwCDyd>_?TU^vyss*|g9A1 avr
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CKRu)(5O_^6|Qta', uG70]'vt|n3Xh[vMTc.{o0Y#(O5\/mGfI+L0~1E1~hi:ZY_W6n*EaSn*R+I)Pw|y\^/te;yO. The present invention addresses the problem of excessive discoloration in hydroquinone compositions of a neutral pH. Hydroquinone is 1,4-benzenediol. V)gB0iW8#8w8_QQj@&A)/g>'K t;\
$FZUn(4T%)0C&Zi8bxEB;PAom?W= 2008-2023 ChemPoint. Read our Privacy Notice. They may also include ingredients with other therapeutic actions, such as anti-inflammatories, antibiotics, exfoliants and peels. The amount of crosslinking was controlled by the reaction conditions, including temperature, reaction time, and . 0000000731 00000 n
Reddit and its partners use cookies and similar technologies to provide you with a better experience. The natural pH for conventional hydroquinone compositions is acidic, generally less than about 4 even though this is harsh to the skin and to other components of the product. The solubilities of benzoic acid, salicylic acid, resorcinol and hydroquinone in water and in 1-octanol were measured by the dynamic method which is also called the synthetic method from 297.25 K to 334.45 K. Using differential scanning calorimetry (DSC Q2000 and SDT Q600), the melting temperature and the enthalpy of fusion of these solutes were determined. Chemically, hydroquinone is designated as p-dihydroxybenzene; the empirical formula is C 6 H 6 O 2; molecular weight is 110.0. Protected retinoid, with its skin benefit capabilities, may also be included with the hydroquinone composition. Color stability improvement is evident at all levels. [17], An important reaction is the conversion of hydroquinone to the mono- and diamine derivatives. International Journal of Thermophysics 0000002221 00000 n
While patients suffer from pigmentation disorders, they may also suffer from other skin disorders and signs of aging, including but not limited to rough skin texture, mottled pigmentation, sallow complexion, lines and wrinkles. The solubility in water is 6.72g/L. Diamines, useful in the rubber industry as antiozone agents, are similarly produced from aniline: Hydroquinone has a variety of uses principally associated with its action as a reducing agent that is soluble in water. One skilled in the art is familiar with the known protective system technologies, such as encapsulation and entrapment methodologies. This range of pH has been preferred for hydroquinone compositions, because it has been believed that the hydroquinone is less likely to excessively discolor under acid conditions. nQt}MA0alSx k&^>0|>_',G! &"oq YcbX.=a*t
R@ For use herein, the encapsulation forms a protective system to prohibit or inhibit the oxidation of the retinoid. ORIGINAL CODE: 0009012, Free format text: This page was last modified on 19 June 2019, at 20:05. Thermodyn. I made my own hydroquinone 4% and added it to my cream. Chim. In another embodiment of the invention, hydroquinone and a protected retinoid are both combined in the composition. 0000002198 00000 n
Gravimetric method is used to measured hydroquinone solubility in water, ethanol and in water+ethanol binary mixtures at temperatures (293.15, 295.15, 298.15, 300.15, 303.15, 305.15, 308.15, 310.15 and 313.15)K. Mole fractions solubility of hydroquinone are correlated with temperature by using the Apelblat equation. The drug is freely soluble in water and in alcohol. [27] Several such agents are already available or under research,[28] including azelaic acid,[29] kojic acid, retinoids, cysteamine,[30] topical steroids, glycolic acid, and other substances. It is a reducing agent that is reversibly oxidized to semiquinone and quinone. By accepting all cookies, you agree to our use of cookies to deliver and maintain our services and site, improve the quality of Reddit, personalize Reddit content and advertising, and measure the effectiveness of advertising. 29(3): 283-330, 1999. Hydroquinone is used as a topical application in skin whitening to reduce the color of skin. Thanks to the added vitamin E, it leaves your skin feeling smooth and soft, too. Classical photo shops also sell hydroquinone. [24], Numerous studies have revealed that hydroquinone, if taken orally, can cause exogenous ochronosis, a disfiguring disease in which blue-black pigments are deposited onto the skin; however, skin preparations containing the ingredient are administered topically. Toughness of the polymer increases due to the presence of flexible units in the backbone such as long chain diols (e.g., diethylene glycol, dipropylene glycol, triethylene glycol) or long chain saturated acids (e.g., adipic . Bioaccumulative potential Hydroquinone (123 -31 -9) Bioaccumulative potential Not established. These phases (described below) are combined in a mixing tank with an in-line homogenizer as follows. 388, 7381 (2010), H. Li, G. Hu, F. Guo, L. Zhao, J. Zhu, Y. Zhang, Can. Stir until uniform. Environ. By clicking Accept, you consent to the use of cookies. Have an order or account question, find answers in our Online Support articles. 2017-02-16T10:10:56+01:00 Human exposure to hydroquinone can occur by dietary, occupational, and environmental sources. The information given is designed only as a guide for safe handling and use. 38, 40814091 (1999), J. Qingzhu, M. Peisheng, Y. Shouzhi, W. Qiang, W. Chang, L. Guiju, J. Chem. You take the cream, put it in a container, take the powder measurement and add it. Van Haelst, P. Heesen, F. Van Der Wielen, H. Govers, Chemosphere 29, 16511660 (1994), Article HlRMo0WB:NnVCnE4(i0 (1* )@NzHR!>i;8XaXnsO0LNT0l$B%"NAb0I9V
*6/-\vn0W"fKF:AAgl:psRZ?k`&eB IUQ0ET;W#vL=@XwRG{-LHlTz]^s%OB(GF 11'I On this Wikipedia the language links are at the top of the page across from the article title. Chem. In hydroquinone and sodium metabisulfite compositions, it is believed that the sodium metabisulfite oxidizes first and delays the start of any oxidation of the hydroquinone, so that excessive discoloration is delayed or totally avoided. HMkA+"c>jZ^ho=81NW;]Ib;+i#iFArHpz). `9F6~qg3]0,#!V9Q> p=|h| ChemPoint will not under any circumstances release personal user information to individuals or companies. Gerhard Franz, Roger A. Sheldon "Oxidation" in. Google Scholar, A.-C. Huang, Y.-K. Chuang, C.-F. Huang, C.-M. Shu, J. Therm. When the contents of the reservoir are forced into the reaction chamber, the catalases and peroxidases rapidly break down the hydrogen peroxide and catalyze the oxidation of the hydroquinones into p-quinones. stearic, palmitic, arachidic acids, Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. uuid:3780f5dc-b322-4e29-9b1d-4c4d10b1e282 Data 53, 12781282 (2008), A. AzA inhibits tyrosinase. This compound is gathered from the beaver's castor sacs.[35]. 43, 13111316 (2007), J. Qing-Zhu, M. Pei-Sheng, Z. Huan, X. Shu-Qian, W. Qiang, Q. Yan, Fluid Phase Equilib. All information collection is solely used to support ChemPoint customers service communications. Rev. Hydroquinone is soluble in alcohol solvents such as ethanol and methanol [17]. Production of Hydroquinone Industrial production of hydroquinone usually happens in two ways. I can't use water because I cannot dissolve enough Hydroquinone into it to reach the desired concentration. Chem. Hydroquinone (C 6 H 4 (OH) 2), also known as benzene-1,4-diol or quinol, is an aromatic organic compound, with a variety of uses in chemistry. How to dissolve Hydroquinone to make 4 oz. Such carriers are widely known in the art and deliver the composition's ingredients to the skin without excessive degradation, inactivation or other unwanted interaction. You take the cream, put it in a container, take the powder measurement and add it. and solubility in water. Hydroquinone is a white crystalline solid, poorly soluble in water, but more soluble in organic solvents. Antioxidants, preferably sulfites, including but not limited to sulfites, bisulfites, metabisulfites, their salts, and their derivatives, most preferably sodium metabisulfite, have been used to stabilize certain compositions, which have included hydroquinone. It is not to be considered as either a warranty or quality specification. 115, 22772285 (2014), Article The Beaver: Its Life and Impact. It is found in wheat, rye, and barley.It is a precursor to diverse industrial products including polymers and plasticizers, as well as being a component of a number of hair and skin conditioners. 0000004433 00000 n
Eng. Int J Thermophys 42, 1 (2021). The obtained results show that the . HYdroquinone can be found in various skin care products. Mobility in soil No additional information available 12.5. The method of item 1 07 wherein the hydroquinone is present in about 4%. Cite this article. With respect to organic solvents, the solubility varies from 57% in ethanol to less than 0.1% in benzene. How do I dissolve hydroquinone powder to make a 20% and 10% concentration? "F$H:R!zFQd?r9\A&GrQhE]a4zBgE#H *B=0HIpp0MxJ$D1D, VKYdE"EI2EBGt4MzNr!YK ?%_&#(0J:EAiQ(()WT6U@P+!~mDe!hh/']B/?a0nhF!X8kc&5S6lIa2cKMA!E#dV(kel
}}Cq9 Found. Airborne hydroquinone may be oxidized to quinone at ordinary . The solubility in water is 6.72g/L. The disodium diphenolate salt of hydroquinone is used as an alternating comonomer unit in the production of the polymer PEEK. The preferred protected retinoid is in the form of small beads or vesicles which are of a form that can be adjusted to be incorporated into varied topical compositions. 20grams ofhydroquinonein 20oz is liquid is 10%. The protective system can be an entrapment system, a single or multi- laminar system, such as by the formation of vesicles such as a liposome or by utilizing wax, paraffin, silicone, polyethylene, or any material or system which protects the retinoid from oxidation. Eastman Hydroquinone, USP Grade is for skin-lightening products to address hyperpigmentation. 2017-02-16T09:38:58+01:00 The composition is preferably formulated in separate phases as designated below. uv curable cellulose estersuv curable cellulose esters . . I did that by using 1 cup of cream, 4tbsp of hydroquinone and 4tbsp of water or solvent. Conversion factors (at 25C and normal atmospheric pressure) 1 ppm = 4.5 mg/m 3 1 mg/m 3 = 0.222 ppm Table 1. J. Cookie Notice English, J.C. and Deisinger, P.J. I'd like the consistency to be thin like a gel so that it absorbs quicker. vz >I
d50dwp?i4,H3. The solubilities of benzoic acid, salicylic acid, resorcinol and hydroquinone in water and in 1-octanol were measured by the dynamic method which is also called the synthetic method from 297.25K to 334.45K. Using differential scanning calorimetry (DSC Q2000 and SDT Q600), the melting temperature and the enthalpy of fusion of these solutes were determined. Anal. S.C. Gad, T. Pham, in Encyclopedia of Toxicology (Third Edition), 2014 Environmental Fate and Behavior. 0000005306 00000 n
Cationic salts of acidic ascorbyl esters, including inorganic salts, preferably magnesium ascorbyl phosphate, and amino acyl derivatives, preferably aminopropyl ascorbyl phosphate, are preferred in this invention. Eastman Hydroquinone, USP, meets or exceeds the requirements of the United States Pharmacopoeia and is produced under conditions of current good manufacturing practices (cGMP). Compositions according to this invention may include dermatologically acceptable carriers. Correspondence to 4]DYR@'c HYdroquinone can be found in various skin care products. The preferred form of protected retinol is manufactured by SunSmart (also known as Particle Sciences, Inc. of Bethlehem, PA) under the brand name of SunCaps A-1283. In the environment, hydroquinone showed increased toxicity for aquatic organisms, being less harmful for bacteria and fungi. Polysorbate 20 0.5% 0.15g. Add the hydroquinone to the water. STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN. For a shipping quote, check the box and the bottom and provide us your shipping information. You can expect to hear back from a ChemPoint product specialist within 1 business hour. Hydroquinone is combustible when preheated. Adobe Acrobat 10.1.6 Paper Capture Plug-in 132, 165172 (2018), X. Li, Q. Yin, W. Chen, J. Wang, J. Chem. [Na+].OC(=O)CC(O)(CC([O-])=O)C(O)=O.OC(=O)CC(O)(CC([O-])=O)C(O)=O, SPECIFIC USE OF COSMETICS OR SIMILAR TOILET PREPARATIONS, Preparations for care of the skin for chemically bleaching or whitening the skin, PREPARATIONS FOR MEDICAL, DENTAL, OR TOILET PURPOSES, Medicinal preparations containing organic active ingredients, Acids; Anhydrides, halides or salts thereof, e.g. Hydroquinone (C6H4(OH)2), also known as benzene-1,4-diol or quinol, is an aromatic organic compound, with a variety of uses in chemistry. 2023 Springer Nature Switzerland AG. 420, 2429 (2016), W. E. Acree Jr, Thermochim Acta 189, 3756 (1991), F. L. Nordstrm, . C. Rasmuson, J. Chem. The solubilities in binary and ternary systems of hydroquinone (1,4-dihydroxybenzene) and p-quinone (1,4-benzoquinone) in supercritical carbon dioxide were measured in the pressure range 10.0 to 35.0 MPa at temperatures of 333, 348 and 363 K.In binary systems, the solubility of hydroquinone was three orders of magnitude lower than that of p-quinone.