The Environmental Factor

Industry segment Volume (ty-y E factor (kg waste/kg product) 

As noted above, a knowledge of the stoichiometric equation allows one to predict the theoretical minimum amount of waste that can be expected. This led to the concept of atom economy [8] or atom utilization [9] to quickly assess the environmental acceptabihty of alternatives to a particular product before any experiment is performed. It is a theoretical number, that is, it assumes a chemical yield of 100% and exactly stoichiometric amounts and disregards substances which do not appear in the stoichiometric equation. 

In short, the key to minimizing waste is precision or selectivity in organic synthesis which is a measure of how efficiently a synthesis is performed. The standard definition of selectivity is the yield of product divided by the amount of substrate converted, expressed as a percentage. Organic chemists distinguish between different categories of selectivity  

The Green Chemistry Institute (GCl) Pharmaceutical Roundtable has used the Process Mass Intensity (PMl) [12], defined as the total mass used in a process divided by the mass of product (i.e. PMl = E factor -i- 1) to benchmark the environmental acceptability of processes used by its members (see the GCl website). The latter include several leading pharmaceutical companies (Eh Lilly, GlaxoSmithKline, Pfizer, Merck, AstraZeneca, Schering-Plow, and Johnson Johnson). The aim was to use this data to drive the greening of the pharmaceutical industry. We believe, however, that the E factor is to be preferred over the PMl since the ideal E factor of 0 is a better reflection of the goal of zero waste. 

The E factor, and derived metrics, takes only the mass of waste generated into account. However, the environmental impact of waste is determined not only by its amount but also by its nature. Hence, we introduced [13] the term environmental quotient , EQ, obtained by multiplying the E factor by an arbitrarily 

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Environments. Among the environmental factors that can shorten life under thermal fatigue conditions are surface decarburization, oxidation, and carburization. The last can be detrimental because it is likely to reduce both hot strength and ductility at the same time. The usual failure mechanism of heat-resistant alloy fixtures in carburizing furnaces is by thermal fatigue damage, evidenced by a prominent network of deep cracks. 

The value of the environmental factor, F, depends on the thermal conductance of the insulation on the vessel other environmental effects are ignored. The chart in Figure 19 shows approximate values for F- for a bare vessel (F=1.0) and with insulation having a conductance of 6 to 23 W/m - °C. 

If you cannot select suitable equipment for your current environment, you may need to control the environment in order to carry out the measurements. In such areas the environmental factors important to maintaining stable measurement should be monitored and the monitoring equipment calibrated. Chart recorders enable you to monitor conditions without having to be in constant attendance. The environment should be controlled in areas where calibration is carried out in order to provide stable conditions in which accurate and precise measurement can be taken. However, some modern equipment is so stable that environmental controls are unnecessary except in special circumstances. 

The results obtained with this equipment show that the corrosion rate in the rig is about four times that encountered in an industrial UK atmosphere. This acceleration, however, is not achieved by accentuating any of the environmental factors, but rather by holding them near to the worst natural conditions for as long as possible. The procedure used ensures that the rust film is completely dried for short periods, thus simulating the conditions that bring out the beneficial effects of protective rust films on the steels under study. 

In developing and applying the erosional-depositional system, careful consideration was given to the environmental factors which influence the potential for erosion, transport and deposition climate, topography, geology and soils, as well as human activity. 

Inputs and outputs assessed in mass balancing are shown in Figure 5.3. The software EATOS was used to calculate all mass balances of processes. Outputs of EATOS are the mass index (equation (5.1), mass of raw material per mass of product output), and the environmental factor (equation (5.2), mass of waste output per mass of product output). EATOS also allows the calculation of cost indices (e.g., reference [15]) (equation (5.3), cost of raw material per mass of product output). 

Figure 5.7 Environmental factors E for the biocatalytic (a) and chemical catalytic (b) synthesis of (S)-styrene oxide (Scheme 5.3) using the software EATOS. The reduction of the environmental factor achieved by solvent recycling is indicated.

A major difference in the evaluation of the two approaches concerns catalyst synthesis. Whereas catalyst production is integrated in the biocatalytic procedure (Scheme 5.4) and thus also contained in the cost index and the environmental factor, it is not considered in the chemical catalytic approach. A more realistic approach is to include the synthesis of the Jacobsen catalyst (Scheme 5.5) in the mass balance. In Figure 5.8, resources used for catalyst production are separately indicated ( Further Syntheses ). For the biocatalytic procedure, water dominates the environmental factor. The environmental factor increases for the chemical procedure, whereas the cost index, when representing only the raw material costs, declines if the (salen)Mn-catalyst is assumed to be synthesized and not bought. 

In contrast to the quantity of solvent 1 used during the reaction, the quantity of extraction solvent 2 (work up) increases during scale up (Laboratory 100% Operation 103%), especially when it is related to substrate 2 (Laboratory 100% Operation 169%). Compared to the yield obtained from the literature protocol in which an extraction procedure is missing, an efficient extraction seems to be important in order to achieve sufficient product accumulation. However, as the mass index and the environmental factor demonstrate with respect to the possibility for reducing the volume of water used (see above), solvent 2 demand should be able to be reduced as well, since less water use means less solvent is required for extraction. StiU, at least the recycle rate of solvent 2 is as high as 72.8% (from 169% to 46%, Table 5.1), regarding the current data of the technical operation scale. 

The mass-related metrics shown in Figure 5.11 indicate that the amount of a substrate (see also byproduct formation), an auxiliary material for reaction, and of a solvent have to be reduced. The detailed view of the mass indices of the pilot scale, for example, the segments Substrates and Aux (R) and the size of segments Substrates (excess) and Aux (R) of the environmental factor E, deliver the information listed in Table 5.2 108% base and 162% auxiliary (R) are used. The measure to increase base addition for recycling purposes was successful at the expense of 193% base, much auxiliary material Aux (R) was saved in operation scale (reduction from 162% to only 13%). This leads to an overall... 

In this section, the latest developments and recent publications on the biosynthesis of A9-THC and related cannabinoids as precursors are discussed. Special points of interests are the genetic aspects, enzyme regulation, and the environmental factors that have an influence on the cannabinoid content in the plant. Because of new and innovative developments in biotechnology we will give a short overview of new strategies for cannabinoid production in plant cell cultures and in heterologous organisms. 

Table 20.3 lists the reversible and irreversible processes that may be significant in the deep-well environment.3 The characteristics of the specific wastes and the environmental factors present in a well strongly influence which processes will occur and whether they will be irreversible. Irreversible reactions are particularly important. Waste rendered nontoxic through irreversible reactions may be considered permanently transformed into a nonhazardous state. A systematic discussion of mathematical modeling of groundwater chemical transport by reaction type is provided by Rubin.30... 

Oxidation-reduction reactions may affect the mobility of metal ions by changing the oxidation state. The environmental factors of pH and Eh (oxidation-reduction potential) strongly affect all the processes discussed above. For example, the type and number of molecular and ionic species of metals change with a change in pH (see Figures 20.5-20.7). A number of metals and nonmetals (As, Be, Cr, Cu, Fe, Ni, Se, V, Zn) are more mobile under anaerobic conditions than aerobic conditions, all other factors being equal.104 Additionally, the high salinity of deep-well injection zones increases the complexity of the equilibrium chemistry of heavy metals.106... 

ESRI is a nondestructive method for the study of degradation, which is an important advantage, especially for crystalline polymers. The major advantage of ESRI compared with FTIR methods is its sensitivity to early events in the aging process. Further developments of ESRI methods are expected to be of help in the ultimate goal accurate predictions of lifetimes for polymeric materials and a better understanding of the environmental factors. 

Drugs, among all the environmental factors that we are exposed to, may be particularly likely to interact specifically and selectively with the genetic properties of a given individual, as their potency pitches them into a narrow therapeutic window , precariously balanced between potent potions and perilous poisons. We would predict that, based on a patients innate, individual biological makeup -as it affects the interaction with a drug - one or the other of these properties may manifest itself this phenomenon is covered by the term pharmacogenetics. 

List the environmental factors that may influence a result. 

This chapter covers briefly the environmental factors which contribute to the reliability of results, including laboratory design, siting of instruments and their maintenance. Mistakes often happen because simple actions are omitted, e.g. containers are not correctly or adequately labelled, incorrect containers are used or instructions are ambiguous. 

Any composition of crude oil depends on the combination of various factors. Among the environmental factors, those that influence the nature of the organic matter in the source rock and its mineral composition are of primary significance. 

The construction of exposure racks will influence the effects of the environmental factors, such as the temperature of the test pieces. 

Bioavailability. Cyanide is known to be absorbed following inhalation, oral, and dermal contact (Gosselin et al. 1976 Rieders 1971). The environmental factors that may influence the bioavailability of cyanide from contaminated air, water, soil, or plant material have not been studied. Since cyanides are not strongly sorbed to soil and sediments (Callahan et al. 1979), the role of sorption may not be significant in determining the bioavailability of cyanides from different soils or waters. The bioavailability of cyanide from an environmental medium is expected to increase if the cyanide is present in water-soluble forms,... 

Minerals formed in natural waters and in sediments provide a record of the physical chemical processes operating during the period of their formation they also give us information on the environmental factors that regulate the composition of natural waters and on the processes by which elements are removed from the water. The memory record of the sediments allows us to reconstruct the environmental history of the processes that led to the deposition of minerals, in the past. 

Such investigations as Fox s are not in vogue, and there is no ready outlet for the publication of such results as he obtained. Taste reactions are admittedly not easy to study and, of course, as soon as one begins to experiment he finds inconsistencies People do not always agree with themselves. The fact that there are intra-individual differences makes those who are disinclined to look at inter-individual differences turn their attention to the environmental factors which may operate to cause the intra-individual differences. It is difficult, however, to avoid recognizing that each individual has his own taste characteristics and that these are doubtless related to his genetically determined biochemical individuality. 

This section focuses on (1) a discussion of the overall process of biodegradation, (2) a review of the different types, aspects and phases of biodegradation of several classes of organic pollutants, (3) an examination of the environmental factors affecting biodegradation and biotransformation mechanisms, and (4) a description of the different biodegradation and biotransformation pathways. 

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