The production of color

The perception of color is complex, very individual, and could be categorized as 

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Phosphorescent pigments are used in military appHcations, plastics, and paints. Zinc sulfide doped with Ag" (blue) cations, or with Cu" (green) cations are important pigments for the production of color television screens. Phosphorescent sulfide pigments are produced in the United States by Radium Corp. and by Conrad Precision Ind., Inc. 

Pyrotechnic mixtures may also contain additional components that are added to modify the bum rate, enhance the pyrotechnic effect, or serve as a binder to maintain the homogeneity of the blended mixture and provide mechanical strength when the composition is pressed or consoHdated into a tube or other container. These additional components may also function as oxidizers or fuels in the composition, and it can be anticipated that the heat output, bum rate, and ignition sensitivity may all be affected by the addition of another component to a pyrotechnic composition. An example of an additional component is the use of a catalyst, such as iron oxide, to enhance the decomposition rate of ammonium perchlorate. Diatomaceous earth or coarse sawdust may be used to slow up the bum rate of a composition, or magnesium carbonate (an acid neutralizer) may be added to help stabilize mixtures that contain an acid-sensitive component such as potassium chlorate. Binders include such materials as dextrin (partially hydrolyzed starch), various gums, and assorted polymers such as poly(vinyl alcohol), epoxies, and polyesters. Polybutadiene mbber binders are widely used as fuels and binders in the soHd propellant industry. The production of colored flames is enhanced by the presence of chlorine atoms in the pyrotechnic flame, so chlorine donors such as poly(vinyl chloride) or chlorinated mbber are often added to color-producing compositions, where they also serve as fuels. 

The term textile printing is used to describe the production of colored designs or patterns on textile substrates through a combination of various mechanical and chemical means. In printing on textiles, a localized dyeing process takes place, whereby in general the chemical and physical parameters of dyeing apply. 

Treatment of the chromatogram with a reagent results in the production of colored or fluorescent chromatogram zones, which are used to evaluate the success of the separation and for quantitative analysis For this purpose it is necessary that the color or fluorescence intensities remain stable for about 30 minutes... 

Note Sulfuric acid is a universal reagent, with which almost all classes of substance can be detected by charring at elevated temperatures (150—180°C). The production of colored or fluorescent chromatogram zones at lower temperature (< 120 C) and their intensities are very dependent on the duration of heating, thf... 

Note Methanolic sodium hydroxide solution can replace potassium hydroxide solution [16] (q.v.). The production of color tones and fluorescence is very dependent on the duration and temperature of heating hence optimal conditions must be determined empirically [16]. Some thiophosphate insecticides do not form fluorescent derivatives [16]. The natural fluorescence of various cumarin derivatives is intensified [1]. 

Related ion-radicals have been prepared photochemically in rigid media by Lewis.146 When tetramethylbenzidine is exposed to ultraviolet light in a rigid medium, an electron is ejected as in the production of color centers in glass. 

The alkaline phosphatase substrates form precipitates based on either reduction of tetrazolium salts or on the production of colored diazo compounds. Substrates Vector Red, Vector Black, Vector Blue, and BCIP/NBT available from Vector Laboratories produce reaction products which are red, black, blue and purple/blue... 

Of course the chemists creating organic compounds are living (most of them anyway), but the compounds are created in laboratory flasks without the assistance of living organisms. Such synthesis is clearly different from, for example, the production of colors by flowers and aflatoxins by molds. 

Mixtures of ammonium perchlorate with fuels can produce high temperatures when ignited, and the hydrogen chloride (HCl) liberated during the reaction can aid in the production of colors. These two factors make ammonium perchlorate a good oxidizer for colored flame compositions (see Chapter 7). 

Metal catalytic activity may be expected to be a function of the solubility of the active species and/or the ease of electron transfer to the catalyst. The results given in Table IV show conclusively that the suggestion that catalysis occurs at a gas-solid interface (13) does not hold in these systems. Preliminary experiments showed that copper ion- and haemin-catalyzed systems oxidized rapidly with no trace of solid precipitation, and that cobalt and nickel catalysis were characterized by the production of colored solutions and precipitates. Filtration experiments showed these precipitates played only a small part in catalysis (Table IV). 

Phenolic antioxidants together in combination with thiodiprop-ionate compounds as synergists have been used for this purpose, e.g., n-octadecyl-3-(4 -hydroxy-3, 5 -di-ferf-butylphenyl)propionate and dilauryl thiodipropionate (14). These systems have a tendency to develop colored impurities as a byproduct of their antioxidant function. The production of colored impurities becomes particularly evident in spray drying processes that utilize partially inert atmospheres (12). 

Chrome yellow pigments stabilized with a large amount of silicate play a major role in the production of colored plastics (e.g., PVC, polyethylene, or polyesters) with high temperature resistance. Incorporation into plastics also improves their chemical resistance to alkali, acid, sulfur dioxide, and hydrogen sulfide. 

The discontinuous explosion process is the oldest technical process. It was mainly used for the production of color blacks. Continuous processes were later developed with production rates up to 500 kg/h [4.20], Acetylene or acetylene-containing gases are fed into a preheated, cylindrical reactor with a ceramic inner liner. Once ignited, the reaction is maintained by the decomposition heat that is evolved. The carbon black is collected in settling chambers and cyclones. Approximately 95-99% of the theoretical yield is obtained. 

All of the micro-organisms that had been reported before 1964 proved to be less than satisfactory for the production of 96 from D-glu-cose. Among the drawbacks associated with some of the micro-organisms were (a) the production of colored bodies, (b) the generation of such byproducts504-508 as comenic acid (98), rubinic acid (99), rubin-inol (100),504,507 508 and D-lyxuronic acid (101),509 and (c) the use of special procedures to prepare the cells in order to obtain 96. 

Dyes are used in photography for two fundamental purposes. The first is to sensitize silver halide crystals from 400 to 1300 nm. The second purpose is the production of color images. Other uses for dyes in photography are for antihalation, color filtration, and opacification. 

Of the two types of air emissions associated with the production of colorant and additive products (stack and fugitive emissions), fugitive emissions represent an insignificant potential for environmental impact. In 1996 facility fugitive emissions ranged from an estimated high of 691b to a low of less than lib (mass balance... 

The raw materials associated with the production of colorant and additive products are relatively costly and are ruined if they contact storm water. Final colorant and additive products are even more expensive. Therefore, except in the case of accidental spill while shipping or receiving, these materials are never stored in exposed positions. However, many states define significant storm water contact to include potential air emissions and require colorant and additive production facilities to participate in storm water monitoring programs. 

Copper Component of several enzymes assists in iron storage involved in the production of color pigments of hair, skin, and eyes... 

Due to absorption of incident radiation in upper layers, the drug itself may have a photostabilizing effect. Photodegradation often leads to the production of colored products which themselves absorb and further shield the sample. Consequentially, degradation rates decrease with increasing concentrations as shown by the example of nifedipine solutions (Fig. 1) (3). 

Figure 4.35. ludirect ELISA and Sandwich ELISA (A) In indirect ELISA, the production of color indicates the amount of an antibody to a specific antigen. (B) In sandwich ELISA, the production of color indicates the quantity of antigen. [After R. A. Goldsby, T. J. Kindt, B. A. Osborne, Kuby Immunology, 4th ed. (W. H. Freeman and Company,... 

One of the major uses of strontium has been in the production of color cathode ray tubes (CRTs) used in televisions and computer monitors. However, changes in electronics technology and the popularity of flat-panel screens (which use far less or even no strontium) have led to decreased strontium demand for this purpose in the United States and Europe. However, strontium is also used in the manufacture of ceramics and specialty glass. One of its radioactive isotopes is used in industry and medical studies. 

J) Color Reactions of Arylamines. To 10 ml of water in a test tube add one drop of aniline, and shake. Add one or two drops of a suspension of bleaching powder or a drop of a solution of sodium hypochlorite. Note the color. Repeat with o-toluidine, and with dimethylaniline. The production of color is due first to oxidation, and second, to condensation to complex colored compounds. 

Heterocyclic aryl amines, such as pyridine and the pyrimidines, are important in the production of colorants and pharmaceutical products and, apart from mention in the relevant sections of this chapter, have received extensive reviews. Here the emphasis is on the industrial applications of aminotriazines, for which industrial interest followed the bulk commercial availability after 1945, particularly from American Cyanamid, of the chlorotriazine cyanuric chloride (182)96. Reactions of cyanuric chloride with amines and substituted amines afford substituted melamines and various aminotriazines that have found application in pharmaceuticals and herbicides. 

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