Synthetic colorants green

The combined use of a continuous flow system and a spectrophotometer for sample screening to discriminate between synthetic and natural colorants is also available. With a very simple flow system on a column packed with natural materials, one can discriminate natural and synthetic colorants. The natural (not retained) ones can be determined in the first step and the synthetic (retained) ones in the second step after their elution. For yellow, red, green, blue, and brown, natural or synthetic colorants were chosen as models. The specific maximum wavelength for each color (400,530, and 610 mn, respectively) was selected by a diode array system. A complete discrimination of natural and synthetic colorants was obtained for concentrations of natural colorants (in the absence of synthetic ones) up to 2000 (yellow), 2000 (red), and 10,000 (brown) times that of the detection limits (DLs) of synthetic additives. This method was applied to screen fruit drinks and candies. ... 

The relentless search for new and cheaper colors produced its own casualties. The Empress aldehyde green was swept aside by iodine green, methyl green, malachite green, and so on. Natural dyes were also falling by the wayside. Canary Island farmers who raised cacti for tiny cochineal beetles were bankrupted 70,000 of the dried beetles made only 1 pound of crimson dye, and the new synthetic colors were much cheaper. 

Other Synthetic Materials. Many other natural gemstone materials have been duplicated in the laboratory on an experimental basis, often only in small sizes. Examples include tourmaline [1317-93-7], topaz [1302-59-6], and zircon [1490-68-2]. Of some potential is synthetic jadeite [12003-54-2], one of the two forms of jade. This crystallizes under medium pressure in polycrystalline form from an NaAlS Og glass (qv) and can be colored green by Fe or lavender by Mn (16). Many gemstone-like materials have been grown for technological purposes and such material is sometimes faceted. 

Emerald synthetic-flux grown Match 13.17 Color Green Group Beryl... 

To this day the use of dyes in Persian communities by tradition, is fairly restricted while those tribes which work in the Soviet area, more commonly use pinks and greens which are difficult to get in naturalf not synthetic colors. It is necessarily to recognize that quick fixes are dangerous. 

Beryl. Beryl [1302-52-9] Be Al Si O g, is called aquamarine [1327-51 -1] when pale green or blue from inclusion of Fe emerald [12415-33-7] when dark green from Cr or at times V, and morganite or red beryl when pink or red, respectively, from Mn. Only the synthetic emerald is in commercial production, although the other colors can also be grown. Both the flux and hydrothermal techniques are used to grow this luxury synthetic. 

A thin layer of dark green beryl had been grown by a hydrothermal technique over the surface of a pale beryl to imitate emerald. It has been suggested that such stones should be called synthetic emerald-beryl doublets (16). The abiHty to grow thin, but not thick, single-crystal diamond on the surface of natural diamond (17) leads to the possibiHty of growing such a thin film colored blue with boron this has been done experimentally (18). 

Dyestuffs. The use of thiophene-based dyestuffs has been largely the result of the access of 2-amino-3-substituted thiophenes via new cycHzation chemistry techniques (61). Intermediates of type (8) are available from development of this work. Such intermediates act as the azo-component and, when coupled with pyrazolones, aminopyrazoles, phenols, 2,6-dihydropyridines, etc, have produced numerous monoazo disperse dyes. These dyes impart yeUow—green, red—green, or violet—green colorations to synthetic fibers, with exceUent fastness to light as weU as to wet- and dry-heat treatments (62-64). 

With the increased awareness of environmental and green issues there has been an increased interest in natural dyes accompanied by a lobby for natural fibers in favor of synthetic fibers. However, studies have shown (3) that if 1990 s volume of cotton were colored with natural dyes, at least 31% of the available world s agricultural land would be needed to cultivate the requisite plants. The estimate is based on it taking, on average, 440 g of fresh dye plant to achieve the same tinctorial effect as 1 g of synthetic dye. 

Sapphyrins were discovered serendipitously by Woodward33 during the course of synthetic studies directed towards the total synthesis of vitamin B, 2. The sapphyrins were the first example of expanded porphyrins in the literature. Due to sapphyrin exhibiting a deep-blue color in the crystalline state and intense green in solution. Woodward coined the expression sapphyrin with reference to the deep-blue color of sapphire stones. 

Synthetic food colorants offer the primary colors (red, green, bine) and others offer yellow and orange. The food, textile, and cosmetic indnstries continne to need wider ranges of shades and hnes. These can be obtained by the process of colorant blending. 

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