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Key Documents

179922

Sigma-Aldrich

Potassium phthalate monobasic

ACS reagent, acidimetric standard

Synonym(s):

KHP, Phthalic acid monopotassium salt, Potassium biphthalate, Potassium hydrogen phthalate

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About This Item

Linear Formula:
HOOCC6H4COOK
CAS Number:
Molecular Weight:
204.22
Beilstein:
3637128
EC Number:
MDL number:
UNSPSC Code:
12352100
PubChem Substance ID:
NACRES:
NA.21
grade:
ACS reagent
form:
crystals

grade

ACS reagent

Quality Level

Assay

99.95-100.05% dry basis

form

crystals

quality

acidimetric standard

impurities

≤0.002% S compounds
≤0.003% Cl compounds
≤0.005% insolubles

pH

4.00-4.02 (25.0 °C±0.2 °C, 0.05 M)

mp

295-300 °C (dec.) (lit.)

cation traces

Fe: ≤5 ppm
Na: ≤0.005%
heavy metals: ≤5 ppm (by ICP)

functional group

carboxylic acid

SMILES string

[K+].OC(=O)c1ccccc1C([O-])=O

InChI

1S/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

InChI key

IWZKICVEHNUQTL-UHFFFAOYSA-M

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Application

Potassium phthalate monobasic may be used as a primary standard in acidimetric titration and also to prepare potassium phthalate buffer solution for pH calibration.

Storage Class Code

13 - Non Combustible Solids

WGK

WGK 1

Flash Point(F)

387.1 °F - Pensky-Martens closed cup

Flash Point(C)

197.3 °C - Pensky-Martens closed cup

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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