High Production Volume chemicals defined

Production volume was assumed to provide a crude indication of potential human and environmental exposure. Thus high-production-volume chemicals were considered to be associated with the highest potential risk, and were flagged for priority attention. High-production-volume chemicals were defined as those produced in one OECD member country at quantities above 10,000 tonnes a, or by member countries at quantities above 1000 tonnes a. ... 

A threshold for a sufficiently high yield is hard to define, as the threshold value seems to correlate inversely with the unit value of the product. While for basic, large-volume chemicals yields of 98 or 99% are absolutely essential, the situation in fine chemicals calls for 90-95% yield, and in the initial stage of production of extreme performance chemicals, such as pharmaceuticals, yields of > 80% are very acceptable sometimes values down to 50% have to be encountered. Acceptable yields depend on the number of process steps, including product isolation. If all the steps are assumed to fetch 90% yield, the overall yield depends on the number of steps n as in Eq. (2.22). 

Differentiated and Undifferentiated Products. An undifferentiated chemical product is one that has a specific chemical formula and particular physical specifications regardless of who produces it. An example is ethylene glycol defined by the specifications found in Table 5.2. Most of the high-volume chemicals produced by the chemical industry (H,SO j, O, N, ethylene, NH3, benzene, etc.) can be classified as undifferentiated. 

While the production of fine chemicals is defined by a high added value and relatively low production volumes, specialty chemicals are formulations of several compounds containing one fine chemical or a mixture of several fine chemicals as active ingredients. Specialty chemicals are usually sold under brand names and are identified by their performance. For example, the active ingredients of a drug are fine chemicals, whereas the formulated drug itself is a specialty chemical. 

A toxic industrial chemical (TIC) is defined as an industrial chemical which has an LCtso (50% lethal vapour concentration) value of less than 100 000 mg/min/m in any mammalian species and is produced in quantities exceeding 30 tonnes per year at one production facility. This definition differentiates TICs from highly toxic specialised chemicals which are only produced in very limited volumes. However, the number of potential TICs still runs into thousands. 

Thermodynamic equilibrium is found by balancing chemical potentials, where the chemical potentials of condensed species are just functions of pressure and temperature, while the potentials of gaseous species also depend on concentrations. In order to solve for the ehemical potentials, it is necessary to know the pressure-volume relations for species that are important products in detonation. Moreover, it is necessary to know these relations at the high pressures and temperatures that typically characterize the CJ state. Thus, there is a need for improved high-pressure equations of state for fluids, particularly for molecular fluid mixtures. The exponential-6 (exp-6) potential model defines the energy of interaction of a classical fluid composed of identical spherical particles. This model has been used with considerable success to describe the equation of state of many materials over a wide range of pressure and temperature[36]. 

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