99.5% Thymolphthalein PH indicator cas 125-20-2

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Products Description

Name: Thymolphthalein

Cas: 125-20-2

Purity: 99.5%min


Basic Info:

CAS No.:






Stock Availability

In stock

Brand Name

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Product Introduction:

The scientific name of thymolphthalein is “3,3-bis(4-hydroxy-5-isopropyl-2-methylphenyl)-phthalide”, which is an organic reagent. The chemical formula is C28H30O4 and the molecular weight is 430.54. White crystalline powder. Easily soluble in ether, acetone, sulfuric acid and alkali solutions, but insoluble in water.

Thymolphthalein is often used as an acid-base indicator. Its pH range is 9.4-10.6, and its color changes from colorless to blue. When used, it is often made into a 0.1% 90% ethanol solution. It is also often combined with other indicators to form a gentle and soft indicator to make the discoloration range narrower and the observation clearer.

Product Nature:

  • Melting point: 251-253 °C(lit.)
  • Density: 0.92 g/mL at 25 °C
  • Flash point: 74 °F
  • Storage conditions: no restrictions.
  • Solubility: ethanol: clarity passes test
  • PH value: 8.6~10.5


Product NameThymolphthalein
CAS No.125-20-2
Appearance White crystalline powder
Content99.5% min
Shelf Life2 years
Packing1kg/bag,25kg/bag or as your requirements

Product function:

  • Thymolphthalein, used as a pH indicator, the color range is from 9.4 to 10.6, from colorless to blue.
  • Thymolphthalein is also used as a reagent for testing blood and chromatographic analysis.

What is the difference between thymolphthalein and phenolphthalein:

  • [Structural formula]
    • Basically the same as phenolphthalein, except that the phenol group is replaced with 5-methyl-2-isopropylphenol group.
  • Phenolphthalein has a wide range of uses:
    • Pharmaceutical raw materials for the pharmaceutical industry: suitable for habitual stubborn constipation, with various dosage forms such as tablets and suppositories.
    • For organic synthesis: mainly used for the synthesis of plastics, especially for the synthesis of phthalazinone polyaryl ether ketone polyaryl ether ketone polymers, which have excellent heat resistance, water resistance and resistance Chemical corrosion, heat aging resistance and good processing and formability, fibers, coatings and composite materials made from them are soon widely used in electronic appliances, mechanical equipment, transportation, aerospace, atomic energy engineering, military and other fields .
    • Used for acid-base indicator, indicator for non-aqueous titration, reagent for chromatography.



  1.  Hahn HH; Cheuk SF; Elfenbein S; Wood WB (April 1970). “Studies on the Pathogenesis of Fever: Xix. Localization of Pyrogen in Granulocytes”J. Exp. Med131 (4): 701–9. doi:10.1084/jem.131.4.701PMC 2138774PMID 5430784.
  2. ^ Hubacher, MH; Doernberg, S; Horner, A (1953). “Laxatives: chemical structure and potency of phthaleins and hydroxyanthraquinones”. J Am Pharm Assoc Am Pharm Assoc42 (1): 23–30. doi:10.1002/jps.3030420108PMID 13034620.
  3. ^ Katz, David A. (1982). “Disappearing Ink” (PDF)www.chymist.com. Retrieved August 14, 2017.
  4. Wikipedia


Pre-Sales Service

* Prompt reply and 24 hours online, professional team to provide best price and high quality product.

* Sample testing support.

* Every batch of products will be tested to ensureits quality.

*The packing also can be according the customers` requirment.

*Any inquiries will be replied within 24 hours.

*we provide Commerical Invoice, Packing List, Bill of loading, COA , Health certificate and Origin certificate. If your markets have any special requirements, let us know.


After-Sales Service

*The fact of logistics information monitoring.

* Any questions about the product can be consulted at any time.

*Product has any problem can return.


1. ≤50kg, Express delivery recommended, usually called as DDU service;

2. ≤500kg, Air shipping recommended, usually called as FOB, CFR, or CIF service;

3. >500kg, sea shipping recommended, usually called as FOB, CFR, or CIF service;

4. For high value products, please select air shipping and express delivery for safe.


Do you accept sample order?

We will make samples before mass production, and after sample approved, we’ll begin mass production. Doing 100% inspection during production, then do random inspection before packing.



You can get free samples for some products,you only need to pay the shipping cost or arrange a courier to us and take the samples. You can send us your product specifications and requests,we will manufacture the products according to your requests.

What’s your MOQ?

Our MOQ is 1kg. But usually we accept less quantity such as 100g on the condition that sample charge is 100% paid.

Do you supply product report?

Yes. We’ll give you product analysis report before shipping.

  Is there a discount?

Different quantity has different discount.

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