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Phthalic anhydride is the organic compound with the formula C 6 H 4 (CO) 2 O. It is the anhydride of phthalic acid. Phthalic anhydride is a principal commercial form of phthalic acid. It was the first anhydride of a dicarboxylic acid to be used commercially. This white solid is an important industrial chemical, especially for the large-scale ...
Examples are the synthesis of thymolphthalein (a pH indicator) from two equivalents of thymol and phthalic anhydride: A reaction of phthalic anhydride with resorcinol in the presence of zinc chloride gives the fluorophore fluorescein. Replacing resorcinol by N,N-diethylaminophenol in this reaction gives rhodamine B:
In organic chemistry, phthalic acid is an aromatic dicarboxylic acid, with formula C6H4(CO2H)2 and structure HO (O)C− C 6 H 4− C (O)OH. Although phthalic acid is of modest commercial importance, the closely related derivative phthalic anhydride is a commodity chemical produced on a large scale. [4] Phthalic acid is one of three isomers of ...
Infobox references. Diethyl phthalate (DEP) is a phthalate ester. It occurs as a colourless liquid without significant odour but has a bitter, disagreeable taste. It is more dense than water and insoluble in water; hence, it sinks in water.
Phthalates are produced industrially by the acid catalysed reaction of phthalic anhydride with excess alcohol.The synthesis of diethyl phthalate is illustrative of this: . The properties of the phthalate can be varied by changing the alcohol, [12] allowing for an almost limitless range of products, although only around 30 are, or have been, commercially important.
The phthalic anhydride/urea process, developed in Great Britain and in the USA. Both approaches can be carried out either without (baking process) or with a solvent (solvent process). Higher yields may be achieved with the solvent process (> 95%) than with the baking process (70 to 80%), so that the solvent process has initially simulated more ...
Dimethyl phthalate is manufactured commercially via the esterification of phthalic anhydride with methanol. The reaction can be catalysed by a strong acid, such as sulfuric acid; various lewis acids may be used as an alterative, including complexes of titanium, zirconium or tin. Excess methanol is used to ensure complete conversion, with the ...
Phthalein dye. Chemical structure of phenolphthalein, a common phthalein dye. Phthalein dyes are a class of dyes mainly used as pH indicators, due to their ability to change colors depending on pH. [1] They are formed by the reaction of phthalic anhydride with various phenols. They are a subclass of triarylmethane dyes.