What is the difference between bromothymol blue and bromothymol blue indicator?
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I saw in a book mentions of bromothymol blue and bromothymol blue indicators; since I have no experience with them, I’m not sure if they are the same indicator. Therefore, I would appreciate it if someone with more knowledge could clarify this for me. This post was last edited by Canghai Yili Sha on 2009-2-14 19:38.]
Bromothymol Blue 【Chinese Name】 Bromothymol Blue 【English Name】 bromothymol blue 【Properties】 Almost colorless or very pale rose-colored crystalline powder. 【Solubility】 Insoluble in water; soluble in ethanol, giving a light brown color; soluble in dilute alkaline solutions, giving a blue color. 【Purpose】 Used as a pH indicator, with a color change range of 6.0–7.6, transitioning from yellow through green to blue. 【Preparation or Source】 It is obtained by the condensation of thymol with o-sulfobenzoic anhydride, followed by bromination. English name: Bromothymol Blue; Other names: Bromothymol sulfonphthalein ； Bromothymol blue Molecular formula: C27H28Br2O5S Molecular weight: 624.39 Product properties: Light rose-colored crystalline powder, with a melting point of 200–202°C; it is soluble in ethanol, ether, methanol, and dilute alkaline hydroxide solutions. Slightly soluble in benzene, toluene, and xylene; slightly soluble in water; practically insoluble in petroleum ether. Purpose: Acid-base indicator ； adsorption indicator ； Chromatographic analysis reagents. Specifications: GB 15352-94. Name: Quality absorption coefficient of indicator; value ≥ 52.0 L/cm·g. Color change range: 6.0 (yellow) to 7.6 (blue). Ethanol solubility test: Pass. Residue after burning (sulfates), %: ≤0.3. You can judge it by yourself; haha. Feel free to visit the analysis technology section often
Thank you for the guidance; it’s very detailed, I’ve learned a lot.
The answer is great, and I really do need it. But the two can still be used in many situations, right?
After checking relevant information, the conventional parameters such as molecular formula and molecular weight are identical; therefore, these two substances are considered to be the same substance, and the more appropriate name is the latter one.
I’ve encountered the same problem as well when analyzing ammonium bifluoride; I used bromothymol blue. HG/T 3586-1999 specifies the use of bromothymol blue, but the results are quite different from those obtained using GB/T 1278-94