Environmental pressures

Chlorine Per Capita Consumption. The U.S. per capita consumption of chlorine increased rapidly from 1955 to 1970, with an average aimual growth of 5.8% (Fig. 3). There has beenUtde, if any, growth since 1970 however, and recessionary effects, product maturity, and environmental pressures are evidenced in the cycHc fluctuations. Fluctuations in per capita consumption of chlorine and caustic have more or less tracked each other over the years, although chlorine per capita consumption has consistently exceeded that of caustic soda since 1967. 

Methane is also used for the production of several halogenated products, principally the chloromethanes. Due to environmental pressures, this outlet for methane is decreasing rapidly. 

Capacities of maleic anhydride faciUties worldwide are presented in Table 7. The switch of feedstock from benzene to butane was completed in the United States in 1985, being driven by the lower unit cost and lower usage of butane in addition to the environmental pressures on the use of benzene. Worldwide, the switch to butane is continuing with 58% of the total world maleic anhydride capacity based on butane feedstock in 1992. This capacity percentage for butane has increased from only 6% in 1978. In 1992, 38% of the total world maleic anhydride capacity was based on benzene feedstock and 4% was derived from other sources, primarily phthaUc anhydride by-product streams. 

For aqueous inks, the resins are water- or alkali-soluble or dispersible and the solvent is mosdy water containing sufficient alcohol (as much as 25%) to help solubilize the resin. To keep the alkah-soluble resin in solution, pH must be maintained at the correct level. Advances include the development of uv inks. These are high viscosity inks that require no drying but are photocurable by uv radiation. In these formulations, the solvent is replaced by monomers and photoinitiators that can be cross-linked by exposure to uv radiation. The advantage of this system is the complete elimination of volatile organic compounds (VOC) as components of the system and better halftone print quaUty. Aqueous and uv inks are becoming more popular as environmental pressure to reduce VOC increases. 

The demand for arsenic metal is limited. The 1990 U.S. requirement for metallic arsenic was supphed by the People s Repubhc of China. Arsenic was formerly supphed domestically (1974—1986) by ASARCO Inc., which dismantled its operation because of economic and environmental pressures, and by imports from Bohden Metah, Sweden, which suspended production in late 1987 because of the low price offered by China. 

Annua.1 Production. The United States is the largest single producer of lumber with about 25% of all the logs cut in the world. The current soft housing and constmction markets as well as environmental pressures to limit logging are reducing the percentage. Still the value of wood harvested was about 12.6 biUion in 1989. 

Environmental pressures on the process industries will prove to be the most significant change for the next 50 years. Not only will new processes cnange, but mature industries will have to develop new process technology to suiwive (Benson et al., op. dt.). 

While the majority of cooling tower installations work efficiently, the normal requirements of maintenance and good efficiency practice have still to be applied. This may not always be the case. Time for maintenance is limited, and plant engineers have other pressing problems or, as is well known, forget about the towers With the increasing economic and environmental pressures on the use of water, this situation must change. 

Consequently, as a result of increasing environmental pressure many chlorine and nitric acid based processes for the manufacture of substituted aromatic acids are currently being replaced by cleaner, catalytic autoxidation processes. Benzoic acid is traditionally manufactured (ref. 14) via cobalt-catalyzed autoxidation of toluene in the absence of solvent (Fig. 2). The selectivity is ca. 90% at 30% toluene conversion. As noted earlier, oxidation of p-xylene under these conditions gives p-toluic acid in high yield. For further oxidation to terephthalic acid the stronger bromide/cobalt/manganese cocktail is needed. 

Today we face a different challenge. Environmental pressure is pushing away from S)mthetic or petro-chemically derived products, while economic factors are pulling back from often more expensive "green" options. This paradox is what fuels research into materials and products whose properties fulfill environmental and economic requirements. 

The current biocide industry trends are dominated by increased regulatory and environmental pressures from ... 

Deal, H., Environmental Pressure Causes Changes in Bleaching Technologies, Chemicals, Pulp Paper, November 1991. 

Despite its technical usefulness, hypochlorite bleaching faces severe environmental pressures because it yields A OX values well in excess of permitted levels. The A OX value observed increases with the active chlorine content of the bleach liquor (Figure 10.31) and with the time of treatment (Figure 10.32). 

The growth in numbers of a population of animals in the absence of any environmental pressure. 

Use peaked in the 1950s and has fallen steadily since then. Recent environmental pressures have raised the profile of recycling and reclaiming and there is now much research in this field with a view to finding effective disposal methods for waste tyres. See Refining. 

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