Molekula
Thymolphthalein
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 1999 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
Thymolphthalein is a pH indicator commonly used in acid-base titrations and in the detection of alkaline substances. It appears as a white to pale yellow crystalline powder and turns blue in basic solutions. Available in powder form with a molecular weight of 430.54 g/mol, its CAS number is 125-20-2, and it is stable at ambient storage conditions.
Molekula supplies Thymolphthalein in 25 g and 100 g packs, from £29.64 inc. VAT. It is made or sourced to order. Every batch ships with a certificate of analysis, and safety data sheets are available in 7 languages. Larger quantities, up to multi-tonne, are quoted on request.
Example image for illustration only. Other packaging and pack sizes are available.
Pricing & pack sizes
On backorder — expected to ship by 5 December 2026
These pack sizes aren't a limit. Molekula manufactures, sources and repacks to order — if you need 500 kg and only see 1 kg listed, . We quote from grams to multi-tonne.
Need a different size? Add the nearest pack and change the size in your basket — we price it at the same rate per unit.
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25 g — £24.70 per pack ex VAT · £29.64 inc. VAT
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100 g — £62.00 per pack ex VAT · £74.40 inc. VAT
Need a different quantity or pack?
Tell us how much you need and when — drums, IBCs, sacks or a one-off bulk lot. We'll manufacture or source it and come back with a price.
Prices exclude VAT/sales tax and shipping.
Specifications
| Property | Value |
|---|---|
| Appearance | White powder |
| Melting Point | 251-253°C |
| Loss on Drying | ≤1.0% (100°C) |
| Solubility | Insoluble in water |
| Infrared Spectrum | Conforms |
| Visual Transition Interval | pH 8.8 (colourless) to pH 10.5 (blue) |
| Absorption maxima | 592 - 596 nm |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | Ambient |
| Acidity | Neutral |
Identification
| Property | Value |
|---|---|
| SKU | 40922033 |
| CAS Number | 125-20-2 |
| IUPAC Name | 3,3-bis(4-hydroxy-2-methyl-5-propan-2-ylphenyl)-2-benzofuran-1-one |
| EC Number | 204-729-7 |
| Molecular Formula | C28H30O4 |
| Molecular Weight | 430.54 |
| Exact Mass | 430.2144 |
| SMILES | CC1=CC(=C(C=C1C2(C3=CC=CC=C3C(=O)O2)C4=CC(=C(C=C4C)O)C(C)C)C(C)C)O |
| InChIKey | LDKDGDIWEUUXSH-UHFFFAOYSA-N |
| InChI | InChI=1S/C28H30O4/c1-15(2)20-13-23(17(5)11-25(20)29)28(22-10-8-7-9-19(22)27(31)32-28)24-14-21(16(3)4)26(30)12-18(24)6/h7-16,29-30H,1-6H3 |
| PubChem CID | 31316 |
| REACH Code | Y113 |
| TSCA Listed | Yes |
| HTS Code | 29322050 |
| Tariff Code | 2932209090 |
Safety & GHS
Precautionary statements
- P280 Wear protective gloves/protective clothing/eye protection/face protection
Documents
Safety Data Sheets (SDS)
Available in English, English (US), French, German, Italian, Portuguese, Spanish.
Certificate of Analysis (CoA) by batch
Enter a lot or batch number to retrieve the CoA for that specific batch. We can generate one from spec data if no PDF is on file.
Quality certificates
Molekula Group is certified to ISO 9001:2015 (quality) and ISO 14001:2015 (environmental management), audited by a UKAS-accredited body. Both certificates are valid to 17 May 2028.
Synonyms
- 1(3H)-Isobenzofuranone, 3,3-bis[4-hydroxy-2-methyl-5-(1-methylethyl)phenyl]-
- 3,3-bis(4-hydroxy-2-methyl-5-propan-2-ylphenyl)-2-benzofuran-1-one
- 3,3-bis(4-hydroxy-5-isopropyl-2-methyl-phenyl)isobenzofuran-1-one
- 3,3-bis(4-hydroxy-5-isopropyl-2-methylphenyl)isobenzofuran-1(3H)-one
- 3,3-Bis(4-hydroxy-5-isopropyl-o-tolyl)phthalide
- 3,3-Bis[4-hydroxy-2-methyl-5-(1-methylethyl)phenyl]-1(3H)-isobenzofuranone
- 3,3-bis[4-hydroxy-2-methyl-5-(propan-2-yl)phenyl]-2-benzofuran-1(3H)-one
- 5',5''-Diisopropyl-2',2''-dimethylphenolphthalein
- Phenolphthalein, 5',5''-diisopropyl-2',2''-dimethyl-
- Thymophthalein
Frequently asked questions
What is thymolphthalein used for?
Thymolphthalein is primarily used as a pH indicator in laboratory settings, turning blue in basic solutions (pH 9.3–10.5).
What is the chemical formula and molecular weight of thymolphthalein?
The chemical formula is C28H30O4, and the molecular weight is 430.54 g/mol.
How should thymolphthalein be stored?
Thymolphthalein should be stored at ambient temperature, protected from light and moisture.
What grade of thymolphthalein does Molekula supply?
Molekula supplies thymolphthalein as a white powder conforming to its product specification, which includes a melting point of 251-253°C, loss on drying of ≤1.0% (100°C), a conforming infrared spectrum, a visual transition interval of pH 8.8 (colourless) to pH 10.5 (blue) and absorption maxima of 592-596 nm.
Can Molekula supply thymolphthalein in bulk?
Yes, Molekula can supply thymolphthalein in bulk quantities—please contact sales for details.
What documentation comes with a thymolphthalein order?
Each order includes a Certificate of Analysis (CoA) and safety data sheet (SDS) upon request.
Where can I buy Thymolphthalein?
Directly from Molekula, which lists Thymolphthalein in 25 g and 100 g packs from £29.64 inc. VAT, with a certificate of analysis for every batch. Larger quantities are quoted on request. Molekula's offices: United Kingdom, France, Spain, Germany, Italy, United States and China.
Ready to order or need a custom pack?
Tell us the product, grade, and quantity — Molekula usually responds within one working day with pricing and lead time.