Pigments greens

A variety of mineral ores, mosfly copper minerals such as malachite and chrysocolla, were probably fhe mosf used green pigments in the past. Various green minerals derived from mefals ofher than copper, such as green earth (see below) were used in confined regions. 

Green earth, best known by the Italian name terra verte, is probably the main green pigment not derived from copper. Terra verte is a mixture of two minerals, caledonite and glauconite, both complex silicates of aluminum, calcium, iron, magnesium, and potassium silicate (Grissom 1986). 

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Phthalocyanine pigments account for approximately 23% of the total worldwide organic pigment consumption of 225,000 tons. Approximately 20,000 t are used in printing inks, 10,000 t in paints, 9,000 t in plastics, 3,000 t in textiles, 7,000 t in dyes, and 2,000 t in specialty uses. Table 1 shows the worldwide distribution of cmde phthalocyanine capacity. The production history of phthalocyanine in the United States from 1980 to 1990 is given in Table 2 (161). The 1990 prices of phthalocyanine blue and green pigments were ca 11—22/kg and 21—27/kg, respectively. 

Table 2. U.S. Production of Phthalocyanine Blue and Green Pigments, t ...

Ghromium(III) Pigments. There are two green pigments based on chromium ia the +3 oxidatioa state. The first oae is chromium oxide [1308-38-9] the secoad is hydrated chromium oxide, Ct203 XH2O. Worldwide productioa is about 20,000 metric toas. Principal producers are... 

Copper Phthalocyanine Green. CPC green is obtained by electrophilic substitution of CPC blue with chlorine, the degree of chlorination reaching 14—15 chlorines per molecule. The typical polychloro-CPCs are blue-shade green pigments. To provide yellower shades of green, substitution of... 

Phthalocyanines. The pyrrole ring system is also the fundamental stmctural unit of the important group of blue and blue-green pigments known as the phthalocyanines (see Phthalocyanine compounds). 

A grass-like artificial surface was installed for the first time in 1964, at Moses Brown School (Providence, Rhode Island) (1). In 1966, artificial turf was installed in the Houston Astrodome in Texas. These surfaces consisted of green pigmented, nylon-6,6 pile ribbon, with a cross-section resembling that of natural grass. Since that period, other fabrics of various pile ribbon and constmctions have continued to become available commercially for indoor and outdoor facihties. 

Chrornium—cobalt—alurninum oxide [68187-11-1]—Cl Pigment Blue 36, Cl No. 77343. A blue—green pigment obtained by calcining a mixture of chromium oxide, cobalt carbonate, and aluminum oxide. It may contain small amounts (<1% each) of oxides of barium, boron, siUcon, and nickel. 

The +3 state of chromium is best represented by chromium(III) oxide, Cr2Os, which is a green, inert solid used as a green pigment. It can be made in rather spectacular fashion by heating ammonium dichromate. Once started, the reaction... 

Chromic oxide, Cr,03, is used as a green pigment and is often made by the reaction between NajCrjOjfs) and NH(ClfsJ to give Cr >rfs), NaCl(s), Nifg), and HjO(g). Write a balanced equation and calculate how much pigment can be made from 1.0 X 101 kg of sodium dichromate. 

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