{{About|thymolphthalein|other related dyes in the phthalein family|Phthalein dye}}
{{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 470609780 | ImageFile = Thymolphthalein skeletal.svg | ImageClass = skin-invert-image | ImageSize = | PIN = 3,3-Bis[4-hydroxy-2-methyl-5-(propan-2-yl)phenyl]-2-benzofuran-1(3''H'')-one | OtherNames = |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 29054 | InChI = 1/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 | InChIKey = LDKDGDIWEUUXSH-UHFFFAOYAV | ChEMBL_Ref = {{ebicite|correct|EBI}} | ChEMBL = 587849 | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 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 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = LDKDGDIWEUUXSH-UHFFFAOYSA-N | CASNo_Ref = {{cascite|correct|CAS}} | CASNo = 125-20-2 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = YG5I28WSQP | EINECS = 204-729-7 | PubChem = 31316 | SMILES = O=C1OC(c2ccccc12)(c3cc(c(O)cc3C)C(C)C)c4cc(c(O)cc4C)C(C)C }} |Section2={{Chembox Properties | C=28 | H=30 | O=4 | Appearance = White powder | Density = | MeltingPtC = 248 to 252 | MeltingPt_notes = (decomposes) | BoilingPt = | Solubility = }} |Section7={{Chembox Hazards | MainHazards = | NFPA-H = 1 | NFPA-F = 0 | NFPA-R = 0 | NFPA-S = | Hazards_ref=<ref>{{cite web |title=Thymolphthalein |url=https://pubchem.ncbi.nlm.nih.gov/compound/31316#section=Safety-and-Hazards |website=pubchem.ncbi.nlm.nih.gov |language=en}}</ref> | GHSPictograms = {{GHS08}} | GHSSignalWord = Warning | HPhrases = {{H-phrases|341|350|361}} | PPhrases = {{P-phrases|201|202|210|233|240|241|242|243|280|281|303+361+353|308+313|370+378|403+235|405|501}} | FlashPt = | AutoignitionPt = }} }}
'''Thymolphthalein''' is a phthalein dye used as an acid–base (pH) indicator. Its transition range is around pH 9.3–10.5. Below this pH, it is colorless; above, it is blue. The molar extinction coefficient for the blue thymolphthalein dianion is 38,000 M<sup>−1</sup> cm<sup>−1</sup> at 595 nm.<ref>{{cite journal |author=Hahn HH |author2=Cheuk SF |author3=Elfenbein S |author4= Wood WB |title= Studies on the Pathogenesis of Fever: Xix. Localization of Pyrogen in Granulocytes|journal= The Journal of Experimental Medicine|volume=131 |issue=4 |pages=701–9 |date=April 1970 |pmid=5430784 |pmc=2138774 |doi= 10.1084/jem.131.4.701}}</ref>
{{pH_indicator_template|indicator_name=Thymolphthalein |low_pH=9.3 |high_pH=10.5|low_pH_color=white|high_pH_color=blue|high_pH_text=white}}
Thymolphthalein is also known to have use as a laxative<ref>{{cite journal | last1 = Hubacher | first1 = MH | last2 = Doernberg | first2 = S | last3 = Horner | first3 = A | year = 1953 | title = Laxatives: chemical structure and potency of phthaleins and hydroxyanthraquinones | journal = Journal of the American Pharmaceutical Association | volume = 42 | issue = 1| pages = 23–30 | pmid = 13034620 | doi = 10.1002/jps.3030420108 }}</ref> and for disappearing ink.<ref>{{Cite web|url=https://www.chymist.com/Disappearing%20Ink.pdf|title=Disappearing Ink|last=Katz|first=David A.|date=1982|website=www.chymist.com|access-date=August 14, 2017}}</ref>
==Preparation== Thymolphthalein can be synthesized from thymol and phthalic anhydride. :class=skin-invert-image|400px{{clear left}}
==See also== *Phenolphthalein *Thymolphthalexone
==References== {{reflist}}
Category:PH indicators Category:Triarylmethane dyes Category:Phthalides Category:Phenols Category:Isopropyl compounds
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