Pink grade

Since the flux in the alumina substrate promotes migration of the interface reactants, MnO is added to the paste when using high purity alumina substrates [12]. Furthermore, in order to increase the reliability of the bond, in some cases an alumina substrate with added MnO (called pink grade because it is pink) is used first. 

Purifying the Benzene. Occasionally a drum of technical grade benzene is encountered, the contents of which will develop a pronounced pink color when subjected to the analytical procedure. A typical transmittance-wave-length curve from a 250-ml. specimen of such processed benzene is shown in Figure 4. By comparison with... 

Dimethylquinacridone is more weatherfast than most other unsubstituted types. It possesses excellent fastness to migration and outstanding heat stability. P.R.122 offers a very clean bluish shade of red, which is usually referred to as pink or magenta. Its main areas of application are in high grade paints, printing inks, and plastics, which is also true for the y-modification of unsubstituted quinacridone. 

Procedure Weigh accurately about 6.3 g of pure oxalic acid (AnalaR-Grade) into a 1 litre volumetric flask, dissolve in sufifcient DW and make up the volume upto the mark. Pipette out 25 ml of this solution, add to it 5 ml of concentrated sulphuric acid along the side of the flask, swirl the contents carefully and warm upto 70°C. Titrate this against the potassium permanganate solution from the burette till the pink colour persists for about 20 seconds. 

An interesting way in which individuals differ in their response to alcohol is the reaction when a small amount (0.03 cc.) of 60 per cent alcohol is injected into the skin. 11 In all individuals there is produced a localized wheal about 1 cm. in diameter, but the reaction in the surrounding area varies greatly from individual to individual. In about 18 per cent of the cases tested, the surrounding area was unaffected in the others the inflammation graded from a small, very slightly pink corona to a highly inflamed area 4 cm. in diameter. 

Note that color develops immediately and fades quickly. A pink to red, or beet color, indicates a positive. Grade the positives on a scale of trace to 4 +. 

After it has settled, if the bottom layer is pink, the sample is urobilinogen positive and PBG negative. Grade the color intensity (trace, 1 +, 2 +, 3 +, 4 +) and record the results. 

Grades resistant to transient acidity are available, in which the pigment particles are protected by a coating of impervious silica. Blue and violet grades are stable in mildly alkaline conditions, but pink tends to revert to a violet shade. 

Violet ultramarine can be prepared by heating a mid-range blue grade with ammonium chloride at ca. 240 °C in the presence of air. Treating the violet with hydrogen chloride gas at 140 °C gives the pink derivative. 

A mixture of 45 g of paraformaldehyde and 750 ml of reagent-grade coned, hydrochloric acid in a 2-liter Erlenmeyer flask is cooled in an ice-bath to 5-10°C and 155 g of ice-cold salicylaldehyde (Note 1) are added with swirling by hand (Note 2). After 4 h in the ice bath with occasional swirling, during which time a pale yellow oil precipitates, the flask is removed from the bath and allowed to stand at room temperature (20-27°C) for 36-40 h. During this time the oil slowly becomes a slush of pale orange or pink crystals (Note 3) of crude 5-chloromethylsalicylaldehyde. 

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