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Laccaic Acid
Laccaic acids or laccainic acids are a group of five anthraquinone derivatives, designated A through E, which are components of the red shellac obtained from the insect '' Kerria lacca'', similar to carminic acid and kermesic acid. This article focuses primarily on laccaic acid A (LCA). History Etymology The word varnish goes back to the old Indian Sanskrit word laksha, meaning a hundred thousand lice, and came into German via the Italian “lacca” in the 16th century. The word also exists in Hindi (Lakh) and Sinhala (Lakda). The term Lac Dye comes from English "dye" means paint dye. This pigment is mostly found in South and South-East Asia. Usage Laccaic acids are mainly used to dye natural fabrics (mostly silk, wool, or cotton) and food, including both drinks and solid products. It is one of the most common natural dyes, but it is less used in cosmetics than carmine, the main natural dye used in this industry. The bright red colorant gives a lightfast tint to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthraquinone
Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic organic compound with formula . Isomers include various quinone derivatives. The term anthraquinone however refers to the isomer, 9,10-anthraquinone (IUPAC: 9,10-dioxoanthracene) wherein the keto groups are located on the central ring. It is a building block of many dyes and is used in bleaching pulp for papermaking. It is a yellow, highly crystalline solid, poorly soluble in water but soluble in hot organic solvents. It is almost completely insoluble in ethanol near room temperature but 2.25 g will dissolve in 100 g of boiling ethanol. It is found in nature as the rare mineral hoelite. Synthesis There are several current industrial methods to produce 9,10-anthraquinone: # The oxidation of anthracene. Chromium(VI) is the typical oxidant. # The Friedel-Crafts reaction of benzene and phthalic anhydride in presence of AlCl3. o-Benzoylbenzoic acid is an intermediate. This reaction is useful for produc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
