877-24-7 potassium biphthalate

For standardizing a base solution, primary standard grade potassium biphthalate is a popular choice. Also called potassium hydrogen phthalate, potassium acid phthalate, or simply KHP, it is the salt representing partially neutralized phthalic acid and is a monoprotic weak acid. The true formula is KHC8H404. Figure 5.8 shows the chemical structure of phthalic acid and KHP. The reaction with a base is as follows ... 

In usual practice, potassium hydrogen phthalate (or potassium biphthalate, KHC8H404) is employed as a standardizing agent for acetous perchloric acid. The reaction may be expressed as follows ... 

Synonyms potassium biphthalate potassium acid phthalate acid potassium phtalate phthalic acid potassium acid salt KHP... 

BOR borate or borax KHP potassium biphthalate THAM, TRIS J tr i s(hydroxymethyl)-... 

P 79] A quantitative analysis of mixing performance was made by use of pH analysis [163], Solutions ofdifferentpH were mixed and the corresponding changes in pH were collected from four outlet ports. Then, 0.05 M potassium biphthalate... 

Potassium Biphthalate, 0.2 M Dissolve 40.84 g of potassium biphthalate [KHC6H4(COO)2] in sufficient water to make 1000.0 mL. 

Standardize the solution as follows Weigh accurately about 700 mg of primary standard potassium biphthalate [KHC6H4(COO)2, previously dried at 105° for 2 h, and dissolve in 50 mL of glacial acetic acid in a 250-mL flask. Add 2 drops of Crystal Violet TS, and titrate with the perchloric acid solution until the violet color changes to blue-green. Deduct the volume of the perchloric acid consumed by 50 mL of the glacial acetic acid, and calculate the normality. Each 20.42 mg of KHC6H4(COO)2 is equivalent to 1 mL of 0.1 N Perchloric Acid. 

Potassium Acid Phthalate, 0.1 N [20.42 g KIICfin4(COO)2 per 1000 mL] Dissolve 20.42 g of primary standard potassium biphthalate [ KHC6H4(COO)2], previously dried at 105° for 2 h, in glacial acetic acid in a 1000-mL volumetric flask, wanning on a steam bath if necessary to effect solution and protecting the solution from contamination by moisture. Cool to room temperature, dilute to volume with glacial acetic acid, and mix. 

Sodium Hydroxide, 1N (40.00 g NaOH per 1000 mL) Dissolve about 40 g of sodium hydroxide (NaOH) in about 1000 mL of carbon dioxide-free water. Shake the mixture thoroughly, and allow it to stand overnight in a stoppered bottle. Standardize the clear liquid as follows Transfer about 5 g of primary standard potassium biphthalate [ KHCgH4(COO )2], previously dried at 105° for 2 h and accurately weighed, to a flask, and dissolve it in 75 mL of carbon dioxide-free water. If the potassium biphthalate is in the form of large crystals, cmsh it before drying. To the flask add 2 drops of Phenolphthalein TS, and titrate with the sodium hydroxide solution to a permanent pink color. Calculate the normality. Each 204.2 mg of potassium biphthalate is equivalent to 1 mL of 1 N Sodium Hydroxide. 

Potassium biphthalate is obtained in the manner described by Dodge,2 but modified slightly by Clark and Lubs (l.c.). Sixty grams of pure potassium hydroxide (containing a minimum of carbonate) are dissolved in 400 c.c. water, and 85 g. of ortho-... 

S. B. Smith, who has made a thorough examination of the phthalic acid-potassium biphthalate system, found that the recrystallization must not be carried out below 35°. When the preparation is pure or contaminated only with potassium phthalate, the crystallization may take place at 25°. If it is too acid, however, the impurity can be eliminated only by recrystallizing above 35°, for otherwise a small portion of the salt 1 potassium phthalate-4 phthalic acid-4H20 separates out. In any event it is advisable to test the composition of the final recrystallized product by titrating with alkali in the presence of phenolphthalein as indicator. The molecular weight of potassium biphthalate is 204.2. 

N NaOH with 0.1 Molar Potassium Biphthalate 20.j 2 g. per Liter)... 

Sodium bimaleate (NaHC4H204 3H20) and sodium hydroxide mixtures have been proposed by J. W. Temple as buffers for use in the pH region 5.2-6.S. The acid sodium salt is prepared from maleic acid and sodium hydroxide just as in the case of potassium biphthalate. The salt is ready for use after recrystallization and drying. No details are given by the author. 

Biphthalate-Phthalate Buffer of Clark (Cf. Section 2 above). 50 c.c. 0.1 Molar Potassium Biphthalate + 29.95 c.c. 0.1 Normal NaOH Diluted to 100 c.c. with Water. pII = 5.20 (Clark)... 

Potassium hydrogen phthalate Potassium biphthalate CsHsKO, 877-24-7 204.222 1.636 s HjO si EtOH... 

Figure 2. Alternating photocurrent amplitude (111) as a function of bias potential (4 ) for the LAPS illuminated with 10 kHz intensity-modulated light. The three curves shown were obtained with 50mM potassium biphthalate buffer, pH 4.0 50 mM potassium phosphate buffer, pH 7.0 and 50 mM potassium borate buffer, pH 10.0. The photocurrent inflection potentials (4 pip), marked by dashed lines, were -138 mV, 39 mV, and 215 mV respectively. Photocurrent is given in RMS amplitude.

Benzenedicarboxylic acid, monopotassium salt. See Potassium biphthalate... 

Phthalic acid, monopotassium salt. See Potassium biphthalate Phthalic acid, tetrabromo-bis (2-ethylhexyl) ester. See Tetrabromobis (2-ethylhexyl) phthalate... 

Potassium biphthalate CAS 877-24-7 EINECS/ELINCS 212-889-4 Synonyms 1,2-Benzenedicarboxylic acid, monopotassium salt Hydrogen potassium phthalate Monopotassium 1,2-benzenedicarboxylate Phthalic acid, monopotassium salt Potassium acid phthalate Potassium hydrogen phthalate Classification Salt Empirical CsH604 K... 

Potassium biphthalate Potassium carbonate Potassium citrate Potassium hydroxide Potassium phosphate Potassium sodium tartrate Potassium tetraborate Potassium tripolyphosphate Sebacic acid Sodium acetate anhydrous Sodium aluminate Sodium aluminum lactate Sodium bicarbonate Sodium bisulfate Sodium borate... 

Isophthalic acid Phthalic acid Terephthalic acid C8H6O4 K Potassium biphthalate C8H6O7S... 

---