Bromophenol-blue

Other Names Bromophenol Blue Phenol, 4,4 -(3H-2,l-benzoxathiol-3-ylidene)hM[2,6-dibromo-, S,S-dioxide 3H-2,l-Benzoxathiole, phenol deriv. 3, 3 ,5, 5 -Tetrabromophenolsulfophthalein Albutest Bromphenol blue NSC 7818 Tetrabromophenolsulfophthalein CA Index Name Phenol, 4,4 -(l,l-dioxido-3H-2,l-benzoxathiol-3-ylidene)hi5 [2,6-dibromo-CAS Registry Number 115-39-9 Merck Index Number 1444 Chemical Structure 

Chemical/Dye Class Sulfonephthalein Molecular Formula Ci9HioBr405S Molecular Weight 669.96 pH Range 3.0-4.6 

Solubility Sparingly solnble in water soluble in ethanol, methanol, benzene UV-Visible (7.max) 598 nm, 592 nm, 436 mn, 422 mn, 273 mn Melting Point 279°C (decompose) 

Boiling Point (Calcd.) 605.6 + 55.0°C Pressure 760 Torr Synthesis Synthetic methodsi-5 

Major Applications Nanotechnology, semiconductors, sol-gel matrix, fuel ceUs,9 display device,10 paints,n packaging system,i2 diapers,i3 contact lens,i4 determining nucleic acids,i mucin in sahva,i water alkalinity,preserving genetic materials,i detecting bacteria,i9 vaginal infection test method o 

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By condensing o sulphobenzoic anhydride with phenol in the presence of anhydrous zinc chloride, phenolsulphonephthalein (phenol red) is formed. Tetrabromination of the latter afibrds tetrabromophenolsulphonephthalein (bromophenol blue) ... 

Bromophenol blue 2, 7 -DichIorofluorescein Eosin, tetrabromofluorescein Fluorescein Potassium rhodizonate, C404(0K)2 Rhodamine 6G Sodium 3-aIizarinsuIfonate Thorin Dissolve 0.1 g of the acid in 200 mL 95% ethanol. Dissolve 0.1 g of the acid in 100 mL 70% ethanol. Use 1 mL for 100 mL of initial solution. See Dichlorofluorescein. Dissolve 0.4 g of the acid in 200 mL 70% ethanol. Use 10 drops. Prepare fresh as required by dissolving 15 mg in 5 mL of water. Use 10 drops for each titration. Dissolve 0.1 g in 200 mL 70% ethanol. Prepare a 0.2% aqueous solution. Use 5 drops per 120 mL endpoint volume. Prepare a 0.025% aqueous solution. Use 5 drops. 

A double end point, acid—base titration can be used to determine both sodium hydrosulfide and sodium sulfide content. Standardized hydrochloric acid is the titrant thymolphthalein and bromophenol blue are the indicators. Other bases having ionization constants in the ranges of the indicators used interfere with the analysis. Sodium thiosulfate and sodium thiocarbonate interfere quantitatively with the accuracy of the results. Detailed procedures to analyze sodium sulfide, sodium hydro sulfide, and sodium tetrasulfide are available (1). 

A good technical grade of carbon tetrachloride contains not more than the following amounts of impurities 1 ppm acidity as HCl, 1 ppm carbon disulfide if manufactured by carbon disulfide chlorination, 20 ppm bromine, 200 ppm water, and 150 ppm chloroform. The residue should not exceed 10 ppm on total evaporation. The product should give no acid reaction with bromophenol blue, and the starch iodine test should indicate the absence of free chlorine. 

Bromophenol blue (3.0...4.6) aliphatic carboxylic acids [225 — 228] malonic and lactic acids [229] palmitic and lactic acids [230] malonic, glycolic, malic, citric, tartaric, ketoglutaric, galacturonic and oxalic acids [196] dicarboxylic acids, succinic acid [231] indoleacetic acid, trichloroacetic acid [232] palmitic acid, palmityl- and stearyllactic acid [223] benzoic, sorbic and salicylic acid [234] metabolites of ascorbic acid [235] chloropropionic acid [236] oligogalacturonic acids [237] amino acids, hydrocarbons, mono-, di- and triglycerides [238] xylobiose, xylose, glucose and derivatives [239] sugar alcohols [91] toxaphene [240]... 

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

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

Bromophenol blue Potassium permanganate Sodium carbonate decahydrate 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. 

Papaverine crystallises in rhombic prisms or needles, m.p. 147°, [a]n 0°, is insoluble in water, soluble in hot alcohol or chloroform, and slightly so in cold alcohol or ether. It is a weak base for which, according to Wales, there is no satisfactory indicator, though bromophenol-blue has its colour change at the right point for this alkaloid. The hydrochloride, B. HCl, forms monoclinic plates, m.p. 225-6°, sparingly soluble in water (1 in 37 at 18°). The picrate forms quadratic plates, m.p. 186°. ... 

The mixture is allowed to stand at room temperature overnight, the crystals filtered off and washed on a filter with acetone. The product Is obtained as colorless needles, which melt at 111° to 112.5°C. The methylsulfate is not stable indefinitely. For preparation of pure chloride salt it is desirable to use methylsulfate which gives no titratable acidity with sodium hydroxide using bromophenol blue as indicator. 

Chemicals. Indicator solutions ( 0.1 per cent, aq.). Bromophenol blue Congo red phenol red. 

Carefully scrape the separated bromophenol blue spots on to a sheet of clean smooth-surfaced paper using a narrow spatula (this is easier if two grooves are made down to the glass on either side of the spots). Pour the blue powder into a small centrifuge tube, add 2 mL of ethanol, 5 drops of 0.880 ammonia solution, and stir briskly until the dye is completely extracted. Centrifuge and remove the supernatant blue solution from the residual white powder. Repeat this procedure with the separated Congo red and phenol red spots . 

An alternative elution technique is to transfer the powder (e.g. for bromophenol blue) to a glass column fitted with a glass-wool plug or glass sinter, and elute the dye with ethanol containing a little ammonia. The eluted solution, made up to a fixed volume in a small graduated flask, may be used for colorimetric/ spectrophotometric analysis of the recovered dye (see Chapter 17). A calibration curve must, of course, be constructed for each of the individual compounds. 

Sulphonphthaleins. These indicators are usually supplied in the acid form. They are rendered water-soluble by adding sufficient sodium hydroxide to neutralise the sulphonic acid group. One gram of the indicator is triturated in a clean glass mortar with the appropriate quantity of 0.1 M sodium hydroxide solution, and then diluted with water to 1 L. The following volumes of 0.1 M sodium hydroxide are required for 1 g of the indicators bromophenol blue, 15.0 mL bromocresol green, 14.4 mL bromocresol purple, 18.6 mL chlorophenol red, 23.6 mL bromothymol blue, 16.0 mL phenol red, 28.4 mL thymol blue, 21.5 mL cresol red, 26.2 mL metacresol purple, 26.2 mL. 

It is clear that neither thymolphthalein nor phenolphthalein can be employed in the titration of 0.1 M aqueous ammonia. The equivalence point is at pH 5.3, and it is necessary to use an indicator with a pH range on the slightly acid side (3-6.5), such as methyl orange, methyl red, bromophenol blue, or bromocresol green. The last-named indicators may be utilised for the titration of all weak bases (Kb> 5 x 10-6) with strong acids. 

For the weak base (Kb = 1 x 10 7), bromophenol blue or methyl orange may be used no sharp colour change will be obtained with bromocresol green or with methyl red, and the titration error will be considerable. 

Boric acid behaves as a weak monoprotic acid with a dissociation constant of 6.4 x 10-10. The pH at the equivalence point in the titration of 0.2M sodium tetraborate with 0.2 M hydrochloric acid is that due to 0.1 M boric acid, i.e. 5.6. Further addition of hydrochloric acid will cause a sharp decrease of pH and any indicator covering the pH range 3.7-5.1 (and slightly beyond this) may be used suitable indicators are bromocresol green, methyl orange, bromophenol blue, and methyl red. 

The pH at the equivalence point is thus approximately 3.7 the secondary ionisation and the loss of carbonic acid, due to any escape of carbon dioxide, have been neglected. Suitable indicators are therefore methyl yellow, methyl orange, Congo red, and bromophenol blue. The experimental titration curve, determined with the hydrogen electrode, for 100 mL of 0.1 M sodium carbonate and 0.1M hydrochloric acid is shown in Fig. 10.7. 

The pH range for bases with Kb> 10 5 is 3-7, and for weaker bases (Kb > 10 6) 3-5. Suitable indicators will be methyl red, methyl orange, methyl yellow, bromocresol green, and bromophenol blue. 

If the solution contains carbonate (Procedure A), methyl orange, methyl orange-ihdigo carmine, or bromophenol blue must be used in standardisation against hydrochloric acid of known molar concentration. Phenolphthalein or indicators with a similar pH range, which are affected by carbon dioxide, cannot... 

Another titration is performed with methyl orange, methyl orange-indigo carmine or bromophenol blue as indicator. Let the volume of acid be V mL. 

Procedure B. The experimental details for the preparation of the initial solution are similar to those given under Procedure A. Titrate 25 or 50 mL of the cold solution with standard 0.1M hydrochloric acid and methyl orange, methyl orange-indigo carmine, or bromophenol blue as indicator. Titrate another 25 or 50 mL of the cold solution, diluted with an equal volume of water, slowly with the standard acid using phenolphthalein or, better, the thymol-blue cresol red mixed indicator in the latter case, the colour at the end point is rose. Calculate the result as described in the Discussion above. 

The two methods available for this determination are modifications of those described in Section 10.32 for hydroxide/carbonate mixtures. In the first procedure, which is particularly valuable when the sample contains relatively large amounts of carbonate and small amounts of hydrogencarbonate, the total alkali is first determined in one portion of the solution by titration with standard 0.1M hydrochloric acid using methyl orange, methyl orange-indigo carmine, or bromophenol blue as indicator ... 

Another sample of equal volume is then titrated with the same standard acid using methyl orange, methyl orange-indigo carmine or bromophenol blue as indicator. The volume of acid used (say, ymL) corresponds to carbonate+ hydrogencarbonate. Hence 2y = carbonate, and y — 2Y = hydrogencarbonate. 

In the direct method, a solution of the ammonium salt is treated with a solution of a strong base (e.g. sodium hydroxide) and the mixture distilled. Ammonia is quantitatively expelled, and is absorbed in an excess of standard acid. The excess of acid is back-titrated in the presence of methyl red (or methyl orange, methyl orange-indigo carmine, bromophenol blue, or bromocresol green). Each millilitre of 1M monoprotic acid consumed in the reaction is equivalent to 0.017032 g NH3 ... 

Procedure. Take an aliquot portion of the unknown slightly acid solution containing 0.1-0.5 mg iron and transfer it to a 50 mL graduated flask. Determine, by the use of a similar aliquot portion containing a few drops of bromophenol blue, the volume of sodium acetate solution required to bring the pH to 3.5 1.0. Add the same volume of acetate solution to the original aliquot part and then 4 mL each of the quinol and 1,10-phenanthroline solutions. Make up to the mark with distilled water, mix well, and allow to stand for 1 hour to complete the reduction of the iron. Compare the intensity of the colour produced with standards, similarly prepared, in any convenient way. If a colorimeter is... 

In this case the sulphonic acid group is present in a sulphon-phthalein dye namely the indicator bromophenol blue. As in the previous example, the species (R3NH + )(R S03 ) can be extracted into chloroform whilst the indicator itself is not extracted, and the colour of the extract is proportional to the quantity of surfactant in the material under test. 

Bromides, D. of as silver bromide, (g) 491 by EDTA, (ti) 339 by mercury(I), (cm) 542 by oxygen flask, 113 by silver ion, (cm) 546 by silver nitrate, (ti) 351 by Volhard s method, (ti) 356 with iodide, (ti) 352 4-Bromomandelic acid 473 Bromophenol blue 265, 267 Bromopyrogallol red 182, 319 Bronsted-Lowry bases titration with strong acids, 277... 

Testing is undertaken by several methods, including chloroform extraction and use of a sulfonphthalein dye (absorbance of yellow-colored complex using bromophenol blue and bromocresol green) or the use of eosin (sodium tetrabromofluorescein) solution in acetone and tetrachloroethane solvent. After shaking with a citric acid buffer and eosin addition, upon standing the lower layer turns pink if filmer is present. Subsequent titration with Manoxol OT (sodium dioctyl sulfosuccinate) quantifies the filmer, with loss of the pink color indicating the end point. 

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