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hydroquinone

hydroquinone

hydroquinone Sentence Examples

  • Chromium oxychloride reacts violently on phenol, producing hydroquinone ether, O(C 6 H 4 OH)2; chromic acid gives phenoquinone, and potassium permanganate gives paradiphenol, oxalic acid, and some salicylic acid (R.

  • All four mono-hydroxyxanthones are known, and are prepared by heating salicylic acid with either resorcin, pyrocatechin or hydroquinone; they are yellow crystalline solids, which act as dyestuffs.

  • 7-dihydroxyxanthone, known as euxanthone, is prepared by heating euxanthic acid with hydrochloric acid or by heating hydroquinone carboxylic acid with 3-resorcylic acid and acetic anhydride (S.

  • On fusion with caustic potash it decomposes with formation of tetrahydroxy-benzophenone, which then breaks up into resorcin and hydroquinone.

  • 7-trihydroxyxanthone, is found in the form of its methyl ether (gentisin) in gentian root; it is obtained synthetically by condensing phloroglucin with hydroquinone carboxylic acid.

  • CC13+C02 O?OIi O / O / (4) Cl2HC CO CHCl2+CH302C CCl2C02CH3 (5) Cl2HC CONH2 Cl (z) (2) When phenol is oxidized in acid solution by chlorine, tetrachlorquinone is obtained, a compound also obtainable from hydroquinone.

  • It crystallizes in tables which melt at 140° C. and boil at 267° C. When heated with 10% hydrochloric acid to 180 C. it yields hydroquinone (J.

  • Free hydroxylamine reduces it to hydroquinone.

  • Quinhydrone, C 6 H40 2 -C 6 H 4 (OH) 2, is formed by the direct union of quinone and hydroquinone or by careful oxidation of hydroquinone with ferric chloride solution.

  • On boiling with water it decomposes into quinone and hydroquinone.

  • [3], 27, p. 39 2), crystallizes in colourless prisms which melt at 234° C. When heated in vacuo to 240° C. it yields hydroquinone, quinone and pyrogallol.

  • The percutaneous absorption of hydroquinone (HQ) through rat and human skin in-vitro.

  • Photographic developers often contain hydroquinone and these are also well worth investigating.

  • In the alkaline environment of the urine, arbutin is converted into another chemical, called hydroquinone, which kills bacteria.

  • Metric Sodium sulfite (anhydrous) 2 ozs 70 grams Hydroquinone 176 grains 10 grams sodium carbonate (anhydrous) 1 oz.

  • Chromium oxychloride reacts violently on phenol, producing hydroquinone ether, O(C 6 H 4 OH)2; chromic acid gives phenoquinone, and potassium permanganate gives paradiphenol, oxalic acid, and some salicylic acid (R.

  • All four mono-hydroxyxanthones are known, and are prepared by heating salicylic acid with either resorcin, pyrocatechin or hydroquinone; they are yellow crystalline solids, which act as dyestuffs.

  • 7-dihydroxyxanthone, known as euxanthone, is prepared by heating euxanthic acid with hydrochloric acid or by heating hydroquinone carboxylic acid with 3-resorcylic acid and acetic anhydride (S.

  • On fusion with caustic potash it decomposes with formation of tetrahydroxy-benzophenone, which then breaks up into resorcin and hydroquinone.

  • 7-trihydroxyxanthone, is found in the form of its methyl ether (gentisin) in gentian root; it is obtained synthetically by condensing phloroglucin with hydroquinone carboxylic acid.

  • Of such syntheses we may notice: the condensation of sodium malonic ester to phloroglucin tricarboxylic ester, a substance which gives phloroglucin or trioxybenzene when fused with alkalis, and behaves both as a triketohexamethylene tricarboxylic ester and as a trioxybenzene tricarboxylic ester; the condensation of succinic ester, (CH2 C02C2H5)2, under the influence of sodium to succinosuccinic ester, a diketohexamethylene dicarboxylic ester, which readily yields dioxyterephthalic acid and hydroquinone (F.

  • HO 2 C CCI:CCI CO CC1 3 ' - > H02C CC1:cC1 c02H+CHe13' (to) (xi) Hydroquinone (1.4 or para-dioxybenzene) (1) gives with chlorine, first, a tetrachlorquinone (2), and then hexachlor-p-diketo-R-hexene (3), which alcoholic potash converts into perchloracroylacrylic acid (4).

  • CC13+C02 O?OIi O / O / (4) Cl2HC CO CHCl2+CH302C CCl2C02CH3 (5) Cl2HC CONH2 Cl (z) (2) When phenol is oxidized in acid solution by chlorine, tetrachlorquinone is obtained, a compound also obtainable from hydroquinone.

  • It crystallizes in tables which melt at 140° C. and boil at 267° C. When heated with 10% hydrochloric acid to 180 C. it yields hydroquinone (J.

  • Free hydroxylamine reduces it to hydroquinone.

  • Quinhydrone, C 6 H40 2 -C 6 H 4 (OH) 2, is formed by the direct union of quinone and hydroquinone or by careful oxidation of hydroquinone with ferric chloride solution.

  • On boiling with water it decomposes into quinone and hydroquinone.

  • [3], 27, p. 39 2), crystallizes in colourless prisms which melt at 234° C. When heated in vacuo to 240° C. it yields hydroquinone, quinone and pyrogallol.

  • Metric Sodium sulfite (anhydrous) 2 ozs 70 grams Hydroquinone 176 grains 10 grams Sodium carbonate (anhydrous) 1 oz.

  • These creams contain the chemical Hydroquinone, which is under question with the FDA for potentially causing cancer and other skin ailments.

  • If they bother you, you can cover them with concealing makeup or try a gentle bleaching agent containing hydroquinone.

  • For example, the C-Clarifying Serum contains 10 percent prescription strength vitamin C and four percent prescription strength hydroquinone to promote a brighter, more even skin tone.

  • Hydroquinone is listed as the first ingredient on the label.

  • Hydroquinone, however, has been flagged by Good Guide as a chemical that can cause irritation.

  • The active ingredients in the fading creams are hydroquinone for fading and the sunscreen octinoxate.

  • If you want to hasten the process, use over-the-counter skin creams designed to lighten dark spots; many of these contain hydroquinone, a bleaching ingredient.

  • While scars eventually fade on their own, people with deep complexions may want to speed the process along with products containing hydroquinone.

  • Over-the-counter skin bleaches don't contain as much of the active ingredient hydroquinone as prescription bleaches and may be used in less severe cases.

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