877-24-7

Basic information

• Product Name: Potassium hydrogen phthalate
• Synonyms: BUFFER;BUFFER CONCENTRATE, PH 6.00;BUFFER CONCENTRATE, PH 7.00;BUFFER MIXTURE, PH 6.8;BUFFER O;BUFFER, PH 1.0;BUFFER, PH 1.00;BUFFER, PH 11.00
• CAS NO: 877-24-7
• Molecular Formula: C₈H₅O₄*K
• Molecular Weight: 204.22
• EINECS: 212-889-4
• Product Categories: INORGANIC & ORGANIC CHEMICALS;Classes of Metal Compounds;K (Potassium) Compounds (excluding simple potassium salts);Typical Metal Compounds;Analytical reagent
• Mol File: 877-24-7.mol
• Article Data: 4

Chemical Properties

• Melting Point: 295-300 °C (dec.)(lit.)
• Boiling Point: 98.5-99.5 ;°C/740 ;mmHg(lit .)
• Flash Point: 196.7 °C
• Appearance: White/Solid
• Density: 1.006 g/mL at 20 °C
• Vapor Pressure: 2.14E-06mmHg at 25°C
• Storage Temp.: Store at RT.
• Solubility: H2O: 100 mg/mL, clear, colorless
• Water Solubility: 80 G/L (20 ºC)
• Stability: Stable. Incompatible with strong oxidizing agents.
• Merck: 14,7612
• BRN: 3637128
• CAS DataBase Reference: Potassium hydrogen phthalate(CAS DataBase Reference)
• NIST Chemistry Reference: Potassium hydrogen phthalate(877-24-7)
• EPA Substance Registry System: Potassium hydrogen phthalate(877-24-7)

Safety Data

• Hazard Codes: Xi,C,T
• Statements: 36/38-36/37/38-34-61-60
• Safety Statements: 26-36-24/25-22-45-36/37/39-53
• RIDADR: UN 1789 8/PG 3
• WGK Germany: 1
• RTECS: CZ4326000
• F: 34
• TSCA: Yes
• Hazardous Substances Data: 877-24-7(Hazardous Substances Data)

Usage

Chemical Properties

white crystalline powder

Uses

Different sources of media describe the Uses of 877-24-7 differently. You can refer to the following data:
1. As primary standard for preparing volumetric alkali solutions, also as a buffer in pH determinations.
2. As a primary standard for preparing volumetric alkali solutions and as a buffer in pH determinations. Potassium hydrogen phthalate is used as a primary standard for acid- base titrations as well as for calibrating pH meters. It acts as a buffer in pH determination. It finds application as a useful standard for total organic carbon testing.
3. Potassium hydrogen phthalate [KHP; pH(S) = 4.005 (25 °C)] is a certified secondary standard reference material used as a calibration buffer standard for pH instruments or pH electrodes.

General Description

SRM 2185_cert SRM 2185 _SDS

Flammability and Explosibility

Notclassified

Purification Methods

Crystallise it first from a dilute aqueous solution of K2CO3, then H2O (3mL/g) between 100o and 0o. Before being used as a standard in volumetric analysis, analytical grade potassium hydrogen phthalate should be dried at 120o for 2hours, then allowed to cool in a desiccator. [Beilstein 9 IV 3169.]

InChI:InChI=1/C8H6O4.K/c9-7(10)5-3-1-2-4-6(5)8(11)12;/h1-4H,(H,9,10)(H,11,12);/q;+1/p-1

Synthetic route

C8H4(2)HO4(1-)*K(1+) → potassium hydrogen phthalate (877-24-7)

Conditions	Yield
With water-d2 In water at 34.9℃; Equilibrium constant;

benzene-1,2-dicarboxylic acid (88-99-3) + potassium hydroxide → potassium hydrogen phthalate (877-24-7)

Conditions	Yield
In water mixed at 1:1 ratio, evapd.; recrystn.;

benzene-1,2-dicarboxylic acid (88-99-3) → potassium hydrogen phthalate (877-24-7)

Conditions	Yield
With potassium hydroxide In water
With potassium hydroxide In water at 20℃; for 0.5h;

N-phthaloylglycine (4702-13-0) → potassium hydrogen phthalate (877-24-7)

Conditions	Yield
With potassium hydroxide In ethanol at 20℃; for 4h;

phthalic anhydride (85-44-9) → potassium hydrogen phthalate (877-24-7)

Conditions	Yield
Multi-step reaction with 2 steps 1: 180 °C 2: potassium hydroxide / ethanol / 4 h / 20 °C View Scheme

15-crown-5 (33100-27-5) + potassium hydrogen phthalate (877-24-7) → C8H5O4(1-)*C12H24KO6

Conditions	Yield
In water at 20℃; for 12h;	100%

hexammine cobalt(III) chloride + water (7732-18-5) + potassium hydrogen phthalate (877-24-7) → hexaamminecobalt(III) chloride hydrogen phthalate trihydrate

Conditions	Yield
In water byproducts: KCl; dissolving of (Co(NH3)6)Cl3 (1 equiv.) in hot water, addn. of potassium hydrogen phthalate (3 equiv.); slow cooling; crystn. for a few hours; filtration, crystn. from supernatant soln., combining of cryst.; drying in air; elem. anal.;	99%

potassium hydrogen phthalate (877-24-7) + benzene-1,2-dicarboxylic acid (88-99-3) → phthalic anhydride (85-44-9)

Conditions	Yield
Stage #1: benzene-1,2-dicarboxylic acid With trichloroisocyanuric acid; triphenylphosphine In dichloromethane at 0 - 20℃; Stage #2: potassium hydrogen phthalate In dichloromethane at 20℃; for 1h;	95%

potassium hydrogen phthalate (877-24-7) + Methanesulfonic acid 2-[2-(2-prop-2-ynyloxy-ethoxy)-ethoxy]-ethyl ester → 2-(2-(2-(2-(prop-2-yn-1-yloxy)ethoxy)ethoxy)ethyl)isoindoline-1,3-dione (1408059-52-8)

Conditions	Yield
With sodium iodide In N,N-dimethyl-formamide at 80℃;	94%
With sodium iodide In N,N-dimethyl-formamide at 80℃;	5.7 g

potassium hydrogen phthalate (877-24-7) + nickel(II) acetate tetrahydrate (6018-89-9) + 4-Methylimidazole (822-36-6) → [Ni(4-methylimidazole)2(phthalate)(H2O)]

Conditions	Yield
In ethanol; water aq. soln. of Ni salt was added to warm soln. of K salt and 4-methylimidazole in EtOH; stirred under reflux for 1 h; filtered; washed (H2O, EtOH); dried in air; elem. anal.;	90%

potassium hydrogen phthalate (877-24-7) + pentakis(thiourea)dicopper(I) sulfate trihydrate + thiourea (17356-08-0) → tris(thiourea)copper(I) monohydrogenphthalate

Conditions	Yield
In water hot aq. soln. potassium monohydrogenphthalate was added rapidly to hot soln. Cu complex and thiourea in water; ppt. was collected and washed with water; elem. anal.;	84%

1-chloro-4-pentyne (14267-92-6) + potassium hydrogen phthalate (877-24-7) → N-(pent-4-ynyl)phthalimide (6097-07-0)

Conditions	Yield
With sodium iodide In N,N-dimethyl-formamide at 100℃; for 12h;	78%

[2,2]bipyridinyl (366-18-7) + potassium hydrogen phthalate (877-24-7) + cobalt(II) diacetate tetrahydrate (6147-53-1) → [(2,2'-bipyridine)(o-phthalate)aquacobalt(II)] (872975-43-4)

Conditions	Yield
In methanol a soln. of K salt added to a soln. of Co salt and bipy, heated for 1 h; crysts. filtered, washed (methanol), dried (air); elem. anal.;	75.6%

potassium hydrogen phthalate (877-24-7) + silver nitrate → Ag2(C6H4(CO2)2)(NH3)2 (172043-90-2)

Conditions	Yield
With NH3 In ammonia aq. ammonia=NH3; molar ratio Ag:phthalate=2:1, in 10% NH3; crystn. on evapn. (room temp., in dark, several weeks); elem. anal.;	75%

potassium hydrogen phthalate (877-24-7) + p-toluenesulfonic acid 2-[2-[2-(2-hydroxyethoxy)ethoxy]ethoxy]ethyl ester (77544-60-6) → C16H23NO7

Conditions	Yield
In N,N-dimethyl-formamide at 120℃; Inert atmosphere;	73%

potassium hydrogen phthalate (877-24-7) + (R)-4-chloromethyl-2,2-dimethyl-1,3-dioxolane (57044-24-3) → (R)-isopropylidene glycerol hemiphthalate

Conditions	Yield
With pyridine In dimethylsulfoxide-d6 for 24h; Solvent; Reflux;	72%

4-methyl-1H-imidazole (822-36-6) + potassium hydrogen phthalate (877-24-7) + cobalt(II) diacetate tetrahydrate (6147-53-1) → [Co(o-phthalate)(4-methylimidazole)2(H2O)]n

Conditions	Yield
In water a soln. of Co-contg. compd. (5 mmol) in water was added to a hot soln. of KHPht (5 mmol) and 4-MeIm (10 mmol) in water; the mixt. was stirred and heated for 30 min and left to stand overnight at room temp.; the crystals were filtered off, washed with water and ethanol and dried in air; elem. anal.;	70%

potassium hydrogen phthalate (877-24-7) + (S)-4-(chloromethyl)-2,2-dimethyl-1,3-dioxolane → (S)-isopropylidene glycerol 2-carboxybenzoate

Conditions	Yield
With pyridine In dimethylsulfoxide-d6 for 24h; Solvent; Reflux;	69%

4,4'-bipyridine (553-26-4) + potassium hydrogen phthalate (877-24-7) + zinc(II) acetate dihydrate (5970-45-6) → Zn(2+)*C6H4(COO)2(2-)*C10H8N2*4H2O=Zn[C6H4(COO)2(C10H8N2)(H2O)2]*2H2O

Conditions	Yield
In water soln. of 4,4'-bipyridine (10 mmol) and potassium hydrogen phthalate (10 mmol) in H2O (25 ml) added to soln. of Zn acetate (10 mmol) in H2O (10 ml), refluxed for 1 h, cooled; ppt. filtered off, washed (H2O), air-dried; elem. anal.;	68.18%

picoline (108-89-4) + potassium hydrogen phthalate (877-24-7) + copper dichloride → copper ortho-phthalic acid γ-picoline complex (251968-40-8)

Conditions	Yield
In water CuCl2 and picoline addn. to hot soln. of phthalate, heating and stirring(30 min), cooling; ppt. filtration off, washing (water, ethanol, ether); elem. anal.;	53%

2-methylimidazole (693-98-1) + nickel(II) nitrate hexahydrate + potassium hydrogen phthalate (877-24-7) → [Ni(2-methylimidazole)2(phthalate)(H2O)3]*H2O (1219807-45-0)

Conditions	Yield
In water aq. soln. of Ni salt was added to warm aq. soln. of K salt and 2-methylimidazole; stirred under reflux for 1 h; filtered; washed (H2O, EtOH); dried in air; elem. anal.;	48%

4,4'-dipyridylamine (1915-42-0) + copper(II) choride dihydrate + potassium hydrogen phthalate (877-24-7) → ([Cu2(phthalate(2-))2(4,4'-dipyridylamine))]*H2O)n

Conditions	Yield
In water High Pressure; mixt. salt CuCl2*2H2O and K-phthalic acid, ligand was suspended in waterand heated at 120°C for 24 h; ppt. was filtered off, washed with H2O, EtOH, acetone, dried in air; elem. anal.;	45%

nickel(II) nitrate hexahydrate + potassium hydrogen phthalate (877-24-7) → [Ni(H2O)6(μ-H2O)2K2(hydrogenphthalate)4(H2O)]

Conditions	Yield
With aq. KOH In ethanol; water EtOH/H2O soln. of potassium hydrogen phthalate added to aq. Ni(NO3)2; pHset to 8 by aq. KOH; heated to 425 K for 96 h; crystd. by cooling to room temp.;	42.23%

(NnBu4)[Mn4O2(O2CPh)9(H2O)] + potassium hydrogen phthalate (877-24-7) → K4[Mn18O16(O2CPh)22(phthalate)2(H2O)4]

Conditions	Yield
In acetonitrile equimolar amts., stirring for 5 d; filtration, crystn. on slow evapn. (room temp., 10 d), collection (filtration), washing (hexanes), drying (vac.); further crop on concn. of filtrate; elem. anal.;	40%

cadmium(II) nitrate tetrhydrate + potassium hydrogen phthalate (877-24-7) → [Cd(phthalate)(H2O)] (25932-09-6)

Conditions	Yield
With KOH; oxalic acid In water High Pressure; neutralization of aq. mixt. of KH(phthalate), Cd(NO3)2*4H2O and oxalic acid with aq. soln. of KOH under continuous stirring, seling in stainlesssteel vessel, heating to 160°C for 120 h; slowly cooling to ambient temp., crystn., sepn., washing with water; elem. anal.;	40%

[2,2]bipyridinyl (366-18-7) + cobalt basic carbonate hydrate + water (7732-18-5) + potassium hydrogen phthalate (877-24-7) + potassium carbonate (584-08-7) → [bis(2,2'-bipyridine)carbonatocobalt(III)] o-phthalate hydrate (1/8)

Conditions	Yield
With air In water a warm soln. of acid and bipy added to a suspn. of metal salts, stirred at 60°C for 30 min; hot filtered, alowed to cool to room temp., after 2 wk. crysts. filtered, washed (water, ethanol), dried (air); elem. anal.;	30.4%

3-Methylpyridine (108-99-6) + potassium hydrogen phthalate (877-24-7) + nickel(II) acetate tetrahydrate (6018-89-9) → [Ni(o-phthalato)(3-methylpyridine)2(H2O)3]*H2O + [Ni(o-phthalato)(3-methylpyridine)(H2O)]

Conditions	Yield
In water a soln. of Ni salt added to a hot soln. of ligands, refluxed for 1.5 h; filtered, the filtrate left to stand at room temp. in an open flask, filtered, washed (H2O, EtOH), dried (air); elem. anal.;	A 27.86% B n/a

1H-imidazole (288-32-4) + nickel(II) carbonate (719261-06-0) + potassium hydrogen phthalate (877-24-7) → [Ni(imidazole)3(phthalate)(H2O)2]*H2O (1219807-44-9) + [Ni(imidazole)6](phthalate)*H2O (1219807-43-8)

Conditions	Yield
In methanol; water Ni salt (1 equiv.) and K salt (1 equiv.) were added to soln. of imidazole (2 equiv.) in H2O/MeOH (1/1); refluxed for 2 h; filtered; slowly evapd. for several d; filtered; washed (MeOH, ether); dried in air; septd. by hand; elem. anal.;	A 20% B 11%

cobalt(II) nitrate hexahydrate + potassium hydrogen phthalate (877-24-7) → dihydroxydiphthalatotricobalt(II)

Conditions	Yield
In water High Pressure; soln. of Co(NO3)2*6H2O (0.6 mmol) and KOOCC6COOH (1.8 mmol) heated to 473K for 60 h; cooled to room temp.; elem. anal.; detd. by XRD;	10%

potassium hydrogen phthalate (877-24-7) + dimethyltin dichloride (753-73-1) → dimethyl tin (2+); dimethyl tin (2+)

ethanol (64-17-5) + potassium hydrogen phthalate (877-24-7) + chloroformic acid ethyl ester (541-41-3) → monoethyl phthalate (2306-33-4)

Conditions	Yield
Zersetzen des Produktes mit Wasser;

potassium hydrogen phthalate (877-24-7) → C8H4(2)HO4(1-)*K(1+)

Conditions	Yield
With water-d2 In water at 34.9℃; Equilibrium constant;

BARBITURIC ACID (67-52-7) + nitrostyrene (5153-67-3) + potassium hydrogen phthalate (877-24-7) + benzene-1,2-dicarboxylic acid (88-99-3) + aqueous dioxane → 5-(2-nitro-1-phenyl-ethyl)-pyrimidine-2,4,6-trione (5909-47-7)

Conditions	Yield
at 0℃; Kinetics;
at 70℃; Kinetics;

Upstream product

• 88-99-3 benzene-1,2-dicarboxylic acid 
• 85-44-9 phthalic anhydride 
• 4702-13-0 N-phthaloylglycine 

Downstream Products

• 2306-33-4 monoethyl phthalate 
• 34557-54-5 methane 
• 2305-32-0 trans-1,2-cyclohexanedicarboxylic acid 
• 65-85-0 benzoic acid 
• 251968-40-8 copper ortho-phthalic acid γ-picoline complex 
• 1219807-44-9 [Ni(imidazole)3(phthalate)(H₂O)2]*H₂O 
• 1219807-43-8 [Ni(imidazole)6](phthalate)*H₂O 
• 1228236-84-7 bis(μ2-1-carboxybenzene-2-carboxylato)diaqua(monohydrogen phthalato)(1,10-phenanthroline)samarium(III) 

Relevant articles and documents

Effect of metallic dopants on potassium acid phthalate (KAP) single crystals

Optically transparent single crystals of Cu2+ and Zn2+ doped potassium acid phthalate (KAP) were grown in aqueous solution by slow evaporation technique at room temperature. Single crystal X-ray diffraction analysis confirmed the changes in the lattice parameters of the doped crystals. The presence of functional groups in the crystal lattice has been determined qualitatively by Fourier transform infrared (FTIR) analysis. Optical absorption studies revealed that the doped crystals possess very low absorption in the entire visible region. The dielectric constant has been studied as a function of frequency for the doped crystals at temperatures viz., 328, 348, 368 K. Further the influence of metal dopants on the dielectric behaviour has been studied which clearly exhibited the ferroelectric properties of the crystal.

Facile and direct synthesis of symmetrical acid anhydrides using a newly prepared powerful and efficient mixed reagent

An efficient mixed reagent for direct synthesis of symmetrical carboxylic anhydrides from carboxylic acids has been prepared. Carboxylic acids are converted to anhydrides using triphenylphosphine/ trichloroisocyanuric acid under mild reaction conditions at room temperature. Short reaction time, excellent yields of products, low cost, availability of reagents, simple experimental procedure, and easy work-up of the products are the main advantages of the presented method.