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'''Thymolphthalein''' is an [[acid]]-[[base (chemistry)|base]] ([[pH]]) [[PH indicator|indicator]]. Its transition range is at approximately [[pH]] 9.3-10.5. Below this pH, it is colorless; above this pH, it is [[blue]]. The [[Molar absorptivity|molar extinction coefficient]] for the blue thymolphthalein [[Anion#Ions|dianion]] is 38000 M<sup>-1</sup>cm<sup>-1</sup> at 595 nm.<ref>{{cite journal |author=Hahn HH, Cheuk SF, Elfenbein S, Wood WB |title=STUDIES ON THE PATHOGENESIS OF FEVER : XIX. LOCALIZATION OF PYROGEN IN GRANULOCYTES |journal=J. Exp. Med. |volume=131 |issue=4 |pages=701–9 |year=1970 |month=April |pmid=5430784 |pmc=2138774 |doi= 10.1084/jem.131.4.701|url= http://www.jem.org/cgi/reprint/131/4/701.pdf}}</ref>
'''Thymolphthalein''' is an [[acid]]-[[base (chemistry)|base]] ([[pH]]) [[PH indicator|indicator]]. Its transition range is at approximately [[pH]] 9.3-10.5. Below this pH, it is colorless; above this pH, it is [[blue]]. The [[Molar absorptivity|molar extinction coefficient]] for the blue thymolphthalein [[Anion#Ions|dianion]] is 38000 M<sup>-1</sup>cm<sup>-1</sup> at 595 nm.<ref>{{cite journal |author=Hahn HH, Cheuk SF, Elfenbein S, Wood WB |title= |journal=J. Exp. Med. |volume=131 |issue=4 |pages=701–9 |year=1970 |month=April |pmid=5430784 |pmc=2138774 |doi= 10.1084/jem.131.4.701|url= http://www.jem.org/cgi/reprint/131/4/701.pdf}}</ref>


{{pH_indicator_template|indicator_name=Thymolphthalein |low_pH=9.3 |high_pH=10.5|low_pH_color=|high_pH_color=blue}}
{{pH_indicator_template|indicator_name=Thymolphthalein |low_pH=9.3 |high_pH=10.5|low_pH_color=|high_pH_color=blue}}

Revision as of 18:23, 12 December 2013

Thymolphthalein
Names
IUPAC name
3,3-bis(4-hydroxy-2-methyl-5-propan-2-ylphenyl)-2-benzofuran-1-one
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.004.300 Edit this at Wikidata
EC Number
  • 204-729-7
  • 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 checkY
    Key: LDKDGDIWEUUXSH-UHFFFAOYSA-N checkY
  • 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
    Key: LDKDGDIWEUUXSH-UHFFFAOYAV
  • O=C1OC(c2ccccc12)(c3cc(c(O)cc3C)C(C)C)c4cc(c(O)cc4C)C(C)C
Properties
C28H30O4
Molar mass 430.544 g·mol−1
Appearance White powder
Melting point 248 - 252 °C (decomp.)
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
0
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Thymolphthalein is an acid-base (pH) indicator. Its transition range is at approximately pH 9.3-10.5. Below this pH, it is colorless; above this pH, it is blue. The molar extinction coefficient for the blue thymolphthalein dianion is 38000 M-1cm-1 at 595 nm.[1]

Thymolphthalein (pH indicator)
below pH 9.3 above pH 10.5
9.3 ⇌ 10.5

Preparation

Thymolphthalein can be synthesized from thymol and phthalic anhydride via Friedel-Crafts alkylation:

References

  1. ^ Hahn HH, Cheuk SF, Elfenbein S, Wood WB (1970). J. Exp. Med. 131 (4): 701–9. doi:10.1084/jem.131.4.701. PMC 2138774. PMID 5430784 http://www.jem.org/cgi/reprint/131/4/701.pdf. {{cite journal}}: Missing or empty |title= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
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