Xylene blue

Xylene blue VS from the leuco compound (Pb02). 304... 

Leuco xylene blue VS from benzaldehydedisulfonic acid... 

Manganese dioxide (Mn02), or the so-called Weldon mud which is a manganous-manganic oxide (xylene blue V, page 303). 

There is, however, another process which favors, to a considerable degree, the formation of benzoic acid, a valuable product, and which is also used on a large scale. This method involves the oxidation of toluene in concentrated sulfuric acid by means of pyrolusite or manganite (see xylene blue VS). 

The chlorine atom in o-chlorobenzaldehyde is easily replaceable by a sulfo group by heating the chloro compound with neutral sulfite at 150°C. Ortho sulfo-nated benzaldehyde give alkali fast triphenylmethane dyes (patent blue, erioglau-cine, xylene blue). 

Xylene blue belongs to the group of so-called patent blues which are sulfonated triphenylmethane dyes that are stable to alkali. The dyes are all characterized by having a sulfo group in the position ortho to the central carbon atom as in the following general formula ... 

PATENT BLUE AE PEACOCK BLUE X-1756 SCHULTZ No. 770 TRIANTINE LIGHT BROWN 3RN XYLENE BLUE VSG... 

Chloride is determined by titrating with Hg(N03)2, forming soluble HgCb-The sample is acidified to within the pH range of 2.3-3.8 where diphenylcarbazone, which forms a colored complex with excess Hg +, serves as the visual indicator. Xylene cyanol FF is added as a pH indicator to ensure that the pH is within the desired range. The initial solution is a greenish blue, and the titration is carried out to a purple end point. 

Sodium acetylide [1066-26-8] M 48.0, was prepd by dissolving Na (23g) in liquid NH3 (IL) and bubbling acetylene until the blue color was discharged (ca 30min) and evapd to dryness [Saunders Org Synth Coll Vol III 416 7955] and is available commercially as a suspension in xylene/light mineral oil. [See entry in Chapter 5.]... 

Calcium Chloride [25]. Calcium chloride estimation is based on calcium titration. To 20 ml of 1 1 mixture of toluene (xylene) isopropyl alcohol, add a 1-ml (or 0.1-ml, if calcium is high) sample of oil-base mud, while stirring. Dilute the mixture with 75 to 100 ml of distilled water. Add 2 ml of hardness buffer solution and 10 to 15 drops of hardness indicator solution. Titrate mixture with standard versenate solution until the color changes from wine-red to blue. If common standard versenate solution (1 ml = 20 g calcium ions) is used, then... 

After cooling and dilution with methyl-Cellosolve (2-methoxyethanol), acetic anhydride is slowly added (in order to convert the secondary amine to amide) and the solution is cooled to room temperature. Finally, the resulting tertiary amine, representing the original unsaturate, is titrated with 0.5 N perchloric acid in methyl-Cellosolve, either visually (with thymol blue + xylene cyanol... 

CHARACTERIZATION. The intrinsic viscosity of the soluble fractions was determined in toluene at 30 C. The MAH content of the soluble fractions was determined by heating a 0.5-1.0g portion in refluxing water-saturated xylene for 1 hr and titrating the hot solution with 0.05N ethanolic KOH using 1% thymol blue in DMF as indicator. 

Decolorize the smear in aniline-xylene, agitating the slide gently until no purple runs from it (the use of a second Coplin jar of aniline-xylene after the majority of blue stain has been removed aids the visual assessment of decolorization). 

Immediately after irradiation, stop the reaction by the addition of 7 pi of 4 X SDS electrophoresis loading buffer or the equivalent (with a high concentration of reducing agent present) 0.2M Tris, 8 percent SDS, 2.88M P-mercaptoethanol, 40 percent glycerol, 0.4 percent xylene cyanol, 0.4 percent bromophenol blue. Heat the sample at 95°C for 5 minutes and analyze the complexes formed by electrophoresis. 

In a 1-1. three-necked flask equipped with a dry ice-acctone condenser and a sealed mechanical stirrer is placed 700 ml. of commercial, anhydrous, liquid ammonia. To the stirred ammonia is added a small piece of potassium metal. (Caution1 Care should he exercised in handling potassium metal, since it is extremely reactive and it ignites on contact with water, atmospheric moisture, or alcohol. It should he manipulated under toluene or xylene, and blotted with filter paper before addition.) After the appearance of a blue color a few crystals of ferric nitrate hydrate (ca. 0.1 g.) are added, followed by small pieces of freshly cut potassium metal until 7.0 g. (0.18 g. atom) has been added. After all the potassium has been converted to the amide (Note 7), 24.9 g. (0.154 mole) of sodio-2-formyl-6-methylcyclohexanone is added carefully through a powder funnel (Note 8). After 1 hour a solution of 28.2 g. (0.21 mole) of w-butyl bromide (Note 9) in 50 ml. of anhydrous ether is added dropwise from an addition funnel. The mixture is stirred for 3 hours, and then the dry ice-acetone condenser is replaced by a water condenser. A steam bath is placed under the flask, and the ammonia is evaporated (Caution ) as 400 ml. of anhydrous ether is added. When the... 

Xylene two changes, 5 min each Mount in Permount, Polymount, or Euparol DNA = blue green RNA = purple or dark blue Total protein—ninhydrin—alloxan— Schiff s reaction (see Jensen, 1952 for Deamination and Acetylation Controls)... 

A flocculation-resistant 3-form is obtained by milling crude Copper Phthalocyanine Blue with salt in the presence of xylene or a similar hydrocarbon. In this... 

Figure 10.7 Electrophoretogram of dendritic nucleic acid 4 (lane 2) and a linear analog of identical base composition (lane 3). Lanes 1 and 4 marker dyes xylene cyanol (XC) and bromophenol blue (BPB). (Reprinted with permission from reference 23, copyright (1993) American Chemical Society.)...

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