Quick Search
CAS NUMBER: 77-09-8
EC NUMBER: 201-004-7
MOLECULAR FORMULA: C20H14O4
MOLECULAR WEIGHT: 318.3
IUPAC NAME: 3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-one
Phenolphthalein is a chemical compound with the formula C20H14O4 and is often written as "HIn" or "phph" in shorthand notation.
Phenolphthalein is often used as an indicator in acid–base titrations.
For this application, it turns colorless in acidic solutions and pink in basic solutions.
Phenolphthalein belongs to the class of dyes known as phthalein dyes.
Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols for use in experiments.
Phenolphthalein is a weak acid, which can lose H+ ions in solution.
The nonionized phenolphthalein molecule is colorless, the protonated phenolphthalein ion is an orange, and the deprotonated phenolphthalein ion is fuchsia.
When a base is added to a solution containing phenolphthalein, the equilibrium between the nonionized and the deprotonated states shifts in favor of the deprotonated state as H+ ions are removed from solution.
Uses:
pH indicator Phenolphthalein's common use is as an indicator in acid-base titrations.
Phenolphthalein also serves as a component of universal indicator, together with methyl red, bromothymol blue, and thymol blue.
Phenolphthalein adopts at least four different states in aqueous solution as a result of pH changes.
Under strongly acidic conditions, it exists in protonated form (HIn+), providing an orange coloration.
Between strongly acidic and slightly basic conditions, the lactone form (HIn) is colorless.
The doubly deprotonated (In2-) phenolate form (the anion form of phenol) gives the familiar pink color.
In strongly basic solutions, phenolphthalein is converted to its In(OH)3− form, and its pink color undergoes a rather slow fading reaction and becomes completely colorless above 13.0 pH.
-Phenolphthalein is used in acid base titrations as an indicator
-Phenolphthalein is used in Kastle-Meyer test
-Phenolphthalein was before used as a laxative
Concrete Carbonation:
Phenolphthalein's pH sensitivity is exploited in other applications: concrete has naturally high pH due to the calcium hydroxide formed when Portland cement reacts with water.
As the concrete reacts with carbon dioxide in the atmosphere, pH decreases to 8.5-9. When a 1% phenolphthalein solution is applied to normal concrete, it turns bright pink. However, if it remains colorless, it shows that the concrete has undergone carbonation.
In a similar application, some spackling used to repair holes in drywall contains phenolphthalein.
When applied, the basic spackling material retains a pink color; when the spackling has cured by reaction with atmospheric carbon dioxide, the pink color fades
In a highly basic solution, phenolphthalein's slow change from pink to colorless as it is converted to its In(OH)3− form is used in chemistry classes for the study of reaction kinetics.
Entertainment:
Phenolphthalein is used in toys, for example as a component of disappearing inks, or disappearing dye on the "Hollywood Hair" Barbie hair.
In the ink, it is mixed with sodium hydroxide, which reacts with carbon dioxide in the air.
This reaction leads to the pH falling below the color change threshold as hydrogen ions are released by the reaction:
OH−(aq) + CO2(g) → CO2−3(aq) + H+(aq).
To develop the hair and "magic" graphical patterns, the ink is sprayed with a solution of hydroxide, which leads to the appearance of the hidden graphics by the same mechanism described above for color change in alkaline solution.
The pattern will eventually disappear again because of the reaction with carbon dioxide.
Thymolphthalein is used for the same purpose and in the same way, when a blue color is desired.
Medical Uses:
See also: Phenol red
Phenolphthalein has been used for over a century as a laxative, but is now being removed from over-the-counter laxatives because of concerns over carcinogenicity.
Laxative products formerly containing phenolphalein have often been reformulated to have alternate active ingredients: Feen-a-Mint switched to bisacodyl and Ex-Lax was switched to a senna extract.
Thymolphthalein is a related laxative made from thymol.
Despite concerns regarding its carcinogenicity, the use of phenolphthalein as a laxative is unlikely to cause ovarian cancer.
Phenolphthalein has been found to inhibit human cellular calcium influx via store-operated calcium entry (SOCE, see Calcium release activated channel § Structure).
This is effected by its inhibiting thrombin and thapsigargin, two activators of SOCE that increase intracellular free calcium.
Phenolphthalein has been added to the European Chemicals Agency's candidate list for Substances of Very High Concern (SVHC).[14]
A reduced form of phenolphthalein, phenolphthalin, which is colorless, is used in a test to identify substances thought to contain blood, commonly known as the Kastle–Meyer test.
A dry sample is collected with a swab or filter paper.
A few drops of alcohol, then a few drops of phenolphthalin, and finally a few drops of hydrogen peroxide are dripped onto the sample.
If the sample contains hemoglobin, it will turn pink immediately upon addition of the peroxide, because of the generation of phenolphthalein.
A positive test indicates the sample contains hemoglobin and, therefore, is likely blood. A false positive can result from the presence of substances with catalytic activity similar to hemoglobin.
This test is not destructive to the sample; it can be kept and used in further tests. This test has the same reaction with blood from any animal whose blood contains hemoglobin, including almost all vertebrates; further testing would be required to determine whether it originated from a human.
Phenolphthalein is an organic compound of the phthalein family that is widely employed as an acid-base indicator.
As an indicator of a solution’s pH, phenolphthalein is colourless below pH 8.5 and attains a pink to deep red hue above pH 9.0.
Phenolphthalein is a potent laxative, which acts within 6–8 hours; its effects may last 3–4 days.
Such adverse reactions as kidney irritation or skin rash may occur.
Phenolphthalein was used widely in over-the-counter laxatives, but in 1999 the U.S. Food and Drug Administration banned its use in such medicines because animal studies indicated that it may cause cancer in humans.
Phenolphthalein, which is closely related to the triphenylmethane dyes, was discovered in 1871 by the German chemist Adolf von Baeyer, who prepared it by fusing phenol and phthalic anhydride in the presence of sulfuric acid or zinc chloride, the procedure still employed.
Phenolphthalein appears as white or yellowish-white to pale orange fine crystalline powder.
Phenolphthalein is Odorless.
Aqueous solution is acidic.
Colorless to pH 8.5; pink to deep-red above pH 9.
Colorless in presence of large amounts of alkali.
Phenolphthalein is an organic compound used as a laboratory reagent and pH indicator.
Phenolphthalein exerts laxative effects by stimulating the intestinal mucosa and constricting smooth muscles.
However, phenolphthalein is no longer used as a laxative due to the suspected carcinogenicity of this compound.
Phenolphthalein is a member of phenols.
Phenolphthalein derives from a 2-benzofuran-1(3H)-one.
Phenolphthalein is an organic compound which is used medicinally as a cathartic.
Phenolphthalein has a chemical formula C20H14O4. It is written as “phph” or HIn”.
Phenolphthalein is used in acid base titration as an indicator.
As an indicator it turns pink to red in alkaline and is colourless in acid solutions.
Phenolphthalein is dissolved with alcohol for experiment purpose and it is slightly soluble in water.
Phenolphthalein is either yellowish-white to pale orange or white fine crystalline powder and in its liquid form it appears as a colourless till PH 8.5 and above that it appears as pink to deep red.
Phenolphthalein does not have taste and smell. This chemical compound is widely used as PH indicator and laboratory agent.
Under acidic conditions when phthalic anhydride is condensed with two equivalents of pheno, Phenolphthalein is synthesized.
Phenolphthalein is a weak acid and belong to class of dyes called Pthalein dyes
What are the uses of Phenolphthalein?
One popular application of phenolphthalein is as an indicator in acid-base titrations.
Phenolphthalein is somewhat water-soluble, and is typically dissolved in alcohols for experimental use.
Phenolphthalein is a weak acid which, in solutions, can lose H+ ions.
The molecule of phenolphthalein is colourless, and the ion of phenolphthalein is purple.
Is Phenolphthalein acidic or basic?
Phenolphthalein, an organic compound with the chemical formula C20H14O4, is a weak acid which can be used as an indicator for acid-base titrations.
In acidic solutions, the compound is colourless.
Phenolphthalein is pinkish in simple solutions (with the transition occurring around pH 9).
How does phenolphthalein function as an indicator?
Phenolphthalein is a colourless, weak acid that is widely used as an indicator in titration experiments to indicate the endpoint of the titration.
The endpoint is indicated by the formation of a pink colour since this compound dissociates to form pink anions when dissolved in water.
Phenolphthalein is a white or yellowish-white crystalline compound C20H14O4 used in analysis as an indicator because its solution is brilliant red in alkalies
Phenolphthalein is decolorized by acids and in medicine as a laxative
Phenolphthalein is a slightly acidic compound, hence considered a weak acid.
Phenolphthalein has the chemical formula of C20H14O4and is a large organic molecule.
In crystalline form, phenolphthalein appears to be white to yellow in colour.
In short, it can be written as "HIn" or "phph"
Phenolphthalein is readily soluble in alcohol and mildly soluble in water.
So, Phenolphthalein is dissolved in alcohol to be used in experiments.
Phenolphthalein acts as an indicator in acid-base titrations.
There are three hexagonal structures and one pentagonal structure, two alcoholic groups, and one ketone group in the structure of Phenolphthalein.
Also, the carbon, hydrogen, and oxygen chains form the Phenolphthalein structure.
Phenolphthalein can be synthesized by phthalic anhydride condensation with two phenol equivalents under acidic conditions.
Phenolphthalein Uses:
1) In acid-base titrations, the popular use of phenolphthalein is as an indicator (phenolphthalein titration).
-To determine the concentration, titration is an experiment where a volume of a solution of known concentration is applied to a volume of another solution.
Most titrations are acid-base neutralization reactions.
-Non-ionized forms of phenolphthalein are colourless.
The protonated form of phenolphthalein in acidic solution is orange in colour.
The deprotonated form of phenolphthalein in the basic solution is pink in colour.
-Phenolphthalein, although its ion is pink, is a weak acid and is colourless in solution.
The equilibrium would shift if hydrogen ions (H+, as found in an acid) were applied to the pink solution, and the solution would be colourless.
The phenolphthalein will be converted into its ion by adding hydroxide ions (OH-, as found in bases) and the solution will turn pink.
-As a result of pH modifications, Phenolphthalein adopts at least four distinct stages in an aqueous solution.
Phenolphthalein occurs in the protonated form (HIn+) under highly acidic conditions, producing an orange colouration.
The lactone type (HIn) is colourless in both highly acidic and slightly simple conditions.
The familiar pink colour is given by the doubly deprotonated (In2-) phenolate form (the anion form of phenol).
Phenolphthalein is converted to its In(OH)3 form in highly simple solutions, and its pink colour undergoes a very slow fading reaction and becomes completely colourless above 13.0 pH.
2) Cement Carbonation:
-Cement naturally has a high pH as it forms calcium hydroxide when it reacts with water.
In the atmosphere, concrete reacts with carbon dioxide and its pH is reduced to 8.5-9 pH.
If phenolphthalein is applied to the cement undergoing carbonation, it remains colourless.
Phenolphthalein turns pink when it's applied to normal cement.3.
3) Phenolphthalein has been used as a laxative before.
4) Medical Uses:Kastle–Meyer test
-In a test to classify substances believed to contain blood, widely known as the Kastle-Meyer test, a reduced form of phenolphthalein, phenolphthalin, which is colourless, is used.
Through a swab or filter paper, a dry sample is obtained.
A few drops of alcohol are dripped onto the sample, then a few drops of phenolphthalein, and finally a few drops of hydrogen peroxide.
If the sample contains haemoglobin, and phenolphthalein is applied, it will turn pink immediately upon the peroxide addition.A positive test means that the sample contains haemoglobin and is thus likely to contain blood.
The presence of substances with catalytic activity similar to haemoglobin will result in a false positive.
This test is not harmful to the specimen; it can be preserved and used in further experiments.
Every species whose blood contains haemoglobin, including almost all vertebrates, has the same reaction to blood in this test; further research will be appropriate to determine if it came from a human being.
The phenolphthalein indicator allows chemists to visually identify whether a substance is an acid or a base.
The color change in phenolphthalein is a result of ionization, and this alters the shape of the phenolphthalein molecules.
Phenolphthalein (pronounced fee-nawl-thal-een), often abbreviated to phph, is a weak acid. This mildly acidic compound is a white to yellow crystalline solid.
Phenolphthalein easily dissolves in alcohols and is slightly soluble in water.
Phenolphthalein is a large organic molecule with the chemical formula of C20H14O4.
Ionization occurs when a molecule gains or loses electrons, and this gives the molecule a negative or positive electric charge.
Ionized molecules attract other molecules with the opposite charge and repel those with the same charge.
Phenolphthalein is a weak acid and is colorless in solution although its ion is pink.
If hydrogen ions (H+, as found in an acid) were added to the pink solution, the equilibrium would switch, and the solution would be colorless.
Adding hydroxide ions (OH-, as found in bases) will change the phenolphthalein into its ion and turn the solution pink.
Structure of Phenolphthalein:
The phenolphthalein indicator has two different structures based on whether it is in an alkali (pink) or acid (colorless) solution.
Both structures absorb light in the ultra-violet region, a region not accessible for the human eye. However, the pink form also absorbs in the visible light spectrum.
The reason for the visible light absorption is the structure of the pink form of the phenolphthalein indicator.
Due to ionization, the electrons in the molecule are more delocalized than in the colorless form.
Briefly, delocalization is when electrons in a molecule are not associated with a single atom, and instead are spread over more than one atom.
An increase in delocalization shifts the energy gap between molecular orbitals.
Less energy is needed for an electron to make the jump into a higher orbital.
The absorption of energy is in in the green region, 553 nanometers, of the light spectrum.
The human eye perceives a pink hue in the solution.
The stronger the alkaline solution is, the more the phenolphthalein indicator changes and the darker the pink hue will be.
Chemical Properties:
Phenolphthalein is a weak organic acid, at room temperature, appearing as white or microstrip yellow small crystals, being odorless, tasteless, insoluble in water and soluble in alcohol (ethanol) and ether.
When dissolved in alcohol solution, it can be made of acid and alkali indicator.
Phenolphthalein is colorless in acid solution while exhibiting red color in the carbonate solution of alkali metal.
However, if placed in the concentrated alkali solution, it will produce colorless tri-metal Salt so that the red color will fade.
In view of this feature, laboratory commonly uses it as a kind of acid and alkali titration indicator with the discoloration range of PH being around 8.2 to 10.0, turning from colorless to red.
When the phenolphthalein reagent is dropped into water or neutral, acidic aqueous solution, there will be white turbidity.
This is due to that the alcohol is easily soluble in water, so that the reagent water-insoluble phenolphthalein is precipitated out.
The other major applications are as follows:
-the pharmaceutical raw materials in pharmaceutical industry: it is suitable for habitual stubborn constipation, including tablets, suppositories and other formulations.
-Phenolphthalein can be used for organic synthesis: mainly used in synthesizing plastics, especially in synthesizing the phthalazinone poly aryl ether ketone poly aryl ether ketone polymers.
This kind of polymers, because of its excellent heat resistance, water resistance, corrosion resistance, heat aging resistance and good processability, fibers, coatings and composites made of it are widely used in
*the fields of electrical and electronic equipment
*transportation and aerospace
*atomic energy engineering
*military.
-Phenolphthalein is used as acid and alkali indicator, non-aqueous solution titration indicator and chromatography analysis reagents.
General Description:
Phenolphthalein mainly acts on the large intestine, which produces semi-liquid excreta in 4 to 8 hours with little or no colic.
The claim that yellow phenolphthalein is three times stronger than white remains unproven.
As a result of enterohepatic circulation, the effect of a single dose is sustainable for 3 to 4 days.
The drug is an active member of many laxatives that can be sold legally without prescription.
Serious adverse effects are rare but can occur when used in excess.
Phenolphthalein should be avoided on the elderly, because its long-term role can cause severe depletion of water and electrolytes.
Dermatitis (fixed rash, itching, burning sensation, blistering, and residual pigmentation) can occur in allergic patients.
There were reports of a fatal anaphylaxis but no definite causative relationship with phenolphthalein.
There are occasional reports of non-thrombocytopenic purpura.
Long-lasting administration can occasionally caused dehydration and electrolyte imbalance due to excessive diarrhea.
Phenolphthalein causes alkaline urine or faeces pink.
Phenolphthalein's Molecular Structure:
This product can be obtained by mixing phthalic anhydride with phenol, followed by co-heating with sulfuric acid.
Phenolphthalein has its chemical name be 2- [bis- (4-hydroxyphenyl) methyl] benzoic acid.
Molecular formula: C20H16O4
relative molecular mass: 318.33
Phenolphthalein appears as triclinic white to yellowish crystalline powder with the melting point of 237 ~ 259 ℃ and the relative density of 1.277 (20/4 ℃).
Phenolphthalein is easily soluble in ethanol, ether and other organic solvents, slightly soluble in water.
Phenolphthalein has a weak acidity and is almost completely presented in the molecule state even in very dilute solution.
Phenolphthalein is soluble in alkaline solution, exhibiting red color in alkaline solution, but is colorless in acidic solution.
The three benzene rings in the phenolphthalein molecule are linked to the carbon atoms of a sp3 hybrid center, and there is no conjugate relationship between the benzene rings, being colorless.
After coming across alkali, the lactone ring open and generate disodium salt, the central carbon atoms are transferred into the sp2 hybrid state, containing benzoquinone structure.
Phenolphthalein Indicator:
Phenolphthalein indicator is a commonly used acid/alkali titration indicator in analytic chemistry.
Phenolphthalein, in alkaline solution, has its colorless lactone ring open to form quinone structure with the color exhibiting red.
Upon coming across strong alkali, phenolphthalein can be converted into colorless carboxylate.
Phenolphthalein's color range is pH 7.0 (colorless) ~ 10.0 (red).
The test solution was prepared by dissolving 1 g of 90% ethanol per liter of ethanol.
Phenolphthalein is colorless in the solution of pH below 8.5, become red at pH higher than 9. Upon excess amount of alkali and no color.
PHYSICAL PROPERTIES OF PHENOLPHTHALEIN:
-Molecular Weight: 318.3
-XLogP3: 3.6
-Exact Mass: 318.08920892
-Monoisotopic Mass: 318.08920892
-Topological Polar Surface Area: 66.8 Ų
-Physical Description: Phenolphthalein appears as white or yellowish-white to pale orange fine crystalline powder
-Color: yellowish-white
-Form: Pale yellow powder
-Odor: Odorless
-Melting Point: 262.5 °C
-Solubility: 400 mg/L
-Density: 1.277
-Vapor Pressure: 2.41
-Henrys Law Constant: 9.0X10-16 atm
-Stability/Shelf Life: Stable in air
-pKa: 9.7
-Collision Cross Section: 172.1 Ų
This product is a commonly used acid indicator with the range of color change between pH 8.2 (colorless) to 10.0 (red).
Phenolphthalein is also a drug, can be used as a laxative, acting on the colon for the treatment of constipation.
Phenolphthalein is Used as an acid-base indicator; as irritant laxative for the treatment of constipation
Phenolphthalein is derived from the condensation of phthalic anhydride and phenol.
Phenolphthalein can be used as an inhibitor and pH indicator.
Phenolphthalein also induces centrosome amplification and tubulin depolymerization in vitro.
Phenolphthalein is a dye used as anacid-base indicator.
Phenolphthalein is colourlessbelow pH 8 and red above pH 9.6.
Phenolphthalein is used in titrations involving weakacids and strong bases.
Phenolphthalein is also usedas a laxative.
CHEMICAL PROPERTIES OF PHENOLPHTHALEIN:
-Hydrogen Bond Donor Count: 2
-Hydrogen Bond Acceptor Count: 4
-Rotatable Bond Count: 2
-Heavy Atom Count: 24
-Formal Charge: 0
-Complexity: 438
-Isotope Atom Count: 0
-Defined Atom Stereocenter Count: 0
-Undefined Atom Stereocenter Count: 0
-Defined Bond Stereocenter Count: 0
-Undefined Bond Stereocenter Count: 0
-Covalently-Bonded Unit Count: 1
-Compound Is Canonicalized: Yes
STORAGE OF PHENOLPHTHALEIN:
-Phenolphthalein Should be stored separately from strong bases.
-Phenolphthalein should be kept away from immediate reagents.
-Phenolphthalein should be stored in a moisture-free environment.
-Phenolphthalein should be kept in ventilated environments.
-Phenolphthalein should be in dry and clean containers.
-Phenolphthalein should be stored under constant temperature.
-Phenolphthalein must be under constant pressure.
SYNONYMS:
Phthalimetten
Euchessina
Phthalin
Espotabs
Phenolax
Koprol
Laxogen
Trilax
Purga
Spulmako-lax
Feen-A-Mint Gum
Purgen
3,3-Bis(4-hydroxyphenyl)phthalide
3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone
Alophen
Doxidan
Dihydroxyphthalophenone
Phillips Gelcaps
1(3H)-Isobenzofuranone, 3,3-bis(4-hydroxyphenyl)-
Fenolftalein
Phenolphtaleine
Phenophthalein
3,3-Bis(p-hydroxyphenyl)phthalide
3,3-Bis(4-hydroxyphenyl)isobenzofuran-1(3H)-one
3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-one
Feen-A-Mint Laxative Mints
3,3-Bis(4-hydroxyphenyl)-2-benzofuran-1(3H)-one
component of Agoral
3,3-bis(4-hydroxyphenyl)-1,3-dihydro-2-benzofuran-1-one
Phthalide 3,3,-bis(p-hydroxyphenyl)-
Phenolphthalein, ACS reagent
Colax
Laxin
FemiLax
3,3-bis(4-hydroxyphenyl)-3-hydroisobenzofuran-1-one
Fenolftaleina [INN-Spanish]
Phenolphthaleinum [INN-Latin]
Fenolftaleina
Phenolphthaleinum
Phthalide 3,-bis(p-hydroxyphenyl)-
alpha-Di(p-hydroxyphenyl)phthalide
Phenolphthalein Solution, Alcoholic 1.0%
1(3H)-Isobenzofuranone,3-bis(4-hydroxyphenyl)-
Phenolphthalein, 98.5%, pure, Indicator grade
3, 3-Bis(p-hydroxyphenyl)-1(3H)-isobenzofuranone
phenolphtalein
Phenolphthalein [USP:INN:BAN]
Doxan (Salt/Mix)
Phenolphthalein,white
Agoral (Salt/Mix)
Modane (TN)
Phenolphthalein,(S)
Laxcaps (Salt/Mix)
Phenolphthalein,yellow
Yellow phenolphthalein
3,3-bis(4-hydroxyphenyl)isobenzofuran-1-one
Phenolphthalein ACS reagent
alpha-(p-Hydroxyphenyl)-alpha-(4-oxo-2,5-cyclohexadien-1-ylidene)-o-toluic acid
Phenolphthalein, pH indicator
5-18-04-00188 (Beilstein Handbook Reference)
Phenolphthalein Paper, DAB 6
Phenolphthalein solution, 0.1 N
Pharmakon1600-01500480
Phenolphthalein, p.a., ACS reagent
Phenolphthalein pH indicator solution
Phenolphthalein, 0.5% w/v in alcohol
component of Feen-A-Mint Pills (Salt/Mix)
3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-on
Phenolphthalein, 2% solution in 95% ethanol
Phenolphthalein, SAJ first grade, >=97.0%
alpha.-Di(p-hydroxyphenyl)phthalide
3,3-bis (4-hydroxyphenyl)-2-benzofuran-1-on
Phenolphthalein, JIS special grade, >=98.0%
3,3-Bis(4-hydroxyphenyl)-2-benzofuran-1(3H)-one #
3,3-Bis-(4-hydroxy-phenyl)-3H-isobenzofuran-1-one
Phenolphthalein solution, 1 % (w/v), pH 7.8-10.0
Phenolphthalein solution, 0.04 % (w/v), pH 7.8-10.0
Phenolphthalein solution, 0.1 % (w/v), pH 7.8-10.0
Phenolphthalein solution, 0.5 wt. % in ethanol: water (1:1)
