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ITEM
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INDEX
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Top grade
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Result
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Appearance
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white scaly or crystalline powder
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|
Molten Chroma(Chroma no. )≤
|
20
|
15
|
|
thermostable Chroma(Chroma no. )≤
|
50
|
11
|
|
Chroma of vitriol(Chroma no. )≤
|
60
|
10
|
|
crystallization point°C≥
|
130.5
|
130.3
|
|
Purity(mass fraction)%≥
|
99.8
|
99.9
|
|
Free acid(mass fraction)≤ %
|
0.2
|
0.01
|
Phthalic anhydride is the organic compound with the formula C6H4(CO)2O. It is the anhydride of phthalic acid. This colourless solid is an important industrial chemical, especially for the large-scale production of plasticizers for plastics. Phthalic anhydride is an important chemical intermediate in the plastics industry from which are derived numerous phthalate esters that function as plasticizers in synthetic resins. Phthalic anhydride itself is used as a monomer for synthetic resins such as glyptal, the alkyd resins, and the polyester resins. Phthalic anhydride is also used as a precursor of anthraquinone, phthalein, rhodamine, phthalocyanine, fluorescein, and xanthene dyes. Phthalic anhydride is used in the synthesis of primary amines, the agricultural fungicide phaltan, and thalidomide. Other reactions with phthalic anhydride yield phenolphthalein, benzoic acid, phthalylsulfathiazole (an intestinal antimicrobial agent), and orthophthalic acid.
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