Bromocresol

Similarly o-sulphobeiizoic anhydride and o-cresol yields o-cresolsulphone-phthalein (o-cresol red) dibromination of the last-named gives dibromo-o-sulphonephthaleln (bromocresol purple) ... 

Dibromo-o-cresolsulphonephthalein (bromocresol purple). Dissolve 6 g. of o-cresolsulphonephthalein in 50 ml. of glacial acetic acid, heat to boiling under reflux, add slowly a solution of 2 ml. of bromine in... 

Heat reagent-grade material for 1 hr at 255-265°C. Cool in an efficient desiccator. Titrate sample with acid to pH 4-5 (first green tint of bromocresol green), boil the solution to eliminate the carbon dioxide, cool, and again titrate to pH 4-5. Equivalent weight is one-half the formula weight. 

In this experiment the equilibrium constant for the dissociation of bromocresol green is measured at several ionic strengths. Results are extrapolated to zero ionic strength to find the thermodynamic equilibrium constant. Equilibrium Constants for Calcium lodate Solubility and Iodic Acid Dissociation. In J. A. Bell, ed. Chemical Principles in Practice. Addison-Wesley Reading, MA, 1967. 

Eor each of the following, determine the forms of alkalinity (OH , HC03, C03 ) that are present, and their respective concentrations in parts per million. In each case, a 25.00-mL sample is titrated with 0.1198 M HCl to the bromocresol green and phenolphthalein end points. 

Dissolve the sample in about 100 mL of H2O, and then dilute to the mark. Using a pipet, transfer a 25-mL aliquot of this solution to a 125-mL Erlenmeyer flask, and add 25-mL of H2O and 2 drops of bromocresol green indicator. Titrate the sample with 0.1 M HCl to the indicator s end point. 

Apparent equivalent weight can be deterrnined by titration with hydrochloric acid using a bromocresol green indicator. Calculations give the equivalent weight of total amines and are not specific for the mono-, di- or tri alkan olamines. 

Bromocresol Green (3, 3",5, 5"-tetrabromo-m-cresolsulfonephthalein) [76-60-8] M 698.0, m 218-219 (dec), 225 (dec), pK 4.51. Crystd from glacial acetic acid or dissolved in aqueous 5% NaHC03 soln and ppted from hot soln by dropwise addition of aqueous HCl. Repeated until the extinction did not increase (X ,ax 423nm). Indicator at pH 3.81 (yellow) and pH 5.4 (blue-green). 

Bromocresol green (3.8...5.4) aliphatic carboxylic acids[103,187 — 204] triiodobenzoic acid [205], derivatives of barbituric acid [206] amphetamine derivatives [207, 208] phenazones, morazone [209] alkaloids [91, 209] nephopam [210] phenyramidol metabolites [211] diethylalkylacetamide derivatives [212] zipeprol (Mirsol) [213] thalidomide and hydrolysis products [214] cyclohexylamine derivatives [215] herbicide residues [216]... 

Bromocresol purple (5.2...6.8) glutamic and ketoglutaric acids [217], halide and halate anions [91,218, 219] preservatives [220, 221] products of pyrolysis of epoxy resins [222] 5-aminodibenzocyclo-heptane derivatives [223] phenylalkanolamines, eph-edrine [224]... 

Bromocresol Green — Bromophenol Blue — Potassium Permanganate Reagent... 

Dissolve 40 mg bromocresol green and 15 mg bromophenol blue in 100 ml ethanol. 

The detection of acids takes place on the basis of the pH-dependent color change of the two indicators bromocresol green (pH range 3.8 —5.4) and bromophenol blue (pH range 3.0—4.6) from yellow to blue. 

Dipping solution I Organic acids Dissolve 40 mg bromocresol purple in 100 ml 50% ethanol and adjust to pH = 10.0 (glass electrode) with caustic soda solution (c = 0.1 mol/1) [1]. 

Dipping solution II Halogen anions Dissolve 100 mg bromocresol purple in 100 ml ethanol and add a few drops of 10% ammonia solution until the color changes. 

Storage The bromocresol solution keeps well in the refrigerator before... 

The pH indicator bromocresol purple changes in color from yellow to purple in the pH range 5.2 —6.8. 

Bromocresol green Tetrabromo-m-cresolsulphonphthalein 3.6-5.2 Yellow Blue 4.7... 

Bromocresol purple Dibromo-o-cresolsulphonphthalein 5.2-6.8 Yellow Purple 6.1... 

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