| Customization: | Available |
|---|---|
| CAS No.: | 77-09-8 |
| Formula: | C20h14o4 |
|
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Product Name:
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Phenolphthalein
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CAS:
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77-09-8
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MF:
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C20H14O4
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|
MW:
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318.32
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EINECS:
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201-004-7
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Melting point
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261-263 °C (lit.)
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Boiling point
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417.49°C (rough estimate)
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bulk density
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350-450kg/m3
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form
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Solid
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Colour Index
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764
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color
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White to yellow-white
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| TEST ITEM: | SPECIFICATION: | RESULTS: |
| Characteristics: | A white or almost white powder, practically insoluble in water, soluble in alcohol. | A white powder, practically insoluble in water, soluble in alcohol. |
| Melting Point | It melts at about 260°C-262°C | 261°C ~262°C |
| Identification | A:Positive B:Positive |
A:Positive B:Positive |
| Appearance of solution | The solution is clear and not more intensely coloured than reference solution Y7 | Complies |
| Related substances | Less than 0.01% | <0.01% |
| Heavy metals | Not more than0.001% | <0.0009% |
| Acidity or alkalinity | Complies | Complies |
| Chlorides | Not more than 0.01% | <0.01% |
| Sulphates | Not more than 0.02% | <0.02% |
| Loss on drying | Not more than 0.5% | 0.12% |
| Sulphated ash | Not more than 0.1% | 0.01% |
| Assay | 98.0%-101.0%(C20H14O4) | 99.6% |
Phenolphthalein is a weak organic acid. It is a colorless lactone structure in a solution with a pH value of less than 8.2, and a red quinone structure when the pH value is greater than 8.2.
The color change range of phenolphthalein is 8.2~10.0, so phenolphthalein can only test alkalis but not acids.
The quinone form or quinone acid salt of phenolphthalein is very unstable in alkaline media. It will slowly transform into a colorless carboxylate form; when it encounters a concentrated alkali solution, it will immediately transform into a colorless carboxylate form. Therefore, when the phenolphthalein reagent is dripped into a concentrated alkali solution, the phenolphthalein begins to turn red, and soon the red color fades and becomes colorless.
Phenolphthalein is a white or slightly yellowish fine crystal that is insoluble in water but easily soluble in alcohol. Therefore, phenolphthalein is usually prepared into an alcohol solution for use. When the phenolphthalein reagent is dripped into water or a neutral or acidic aqueous solution, a white turbid substance will appear. This is because alcohol can be miscible with water in any proportion, causing the insoluble phenolphthalein in the reagent to precipitate.
The main uses of phenolphthalein are:
(1) Used in organic synthesis: mainly used for synthetic plastics, especially for the synthesis of diazonium phthalide polyaryletherketone polyaryletherketone polymers. Due to their excellent heat resistance, water resistance, chemical corrosion resistance, heat aging resistance and good processing and molding properties, the fibers, coatings and composite materials made from them are widely used in electronic appliances, mechanical equipment, transportation, aerospace, atomic energy engineering fields;
(2) Used as alkali indicators, indicators for non-aqueous solution titration, and reagents for chromatography.
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