Production path

The design is viable only if it can be produced economically. The choice of production and fabrication method is largely determined by the choice of material. But the production route will also be influenced by the size of the production run, and how the component will be finished and joined to other components each class of material has its own special problems here they were discussed in Chapters 14, 19, 24 and 25. The choice of material and production route will, ultimately, determine the price of the product, so a second major iteration may be required if the costing shows the price to be too high. Then a new choice of material or component design, allowing an alternative production path, may have to be considered. 

The 5-methyl-2-cyclohexenone prefers, for stereoclectronic reasons, the half-chair B. Now, both steric- and stereoelectronic factors work in the same direction, to yield in all cases the Irani-products (path d). 

In heavy oil reservoirs with highly porous sands, cyclic steamflooding may cause the formation of stable emulsions. These emulsions can block the production paths in the wellbore. In steam cycle treatments, a blend of oxy-alkylated alkanolamines and sulfonates showed a dramatic improvement over non-chemically enhanced steam cycles [331]. 

The c,c,t-CDT and c,t,t-CDT production paths are shown to be not assisted by incoming butadiene, while the square-planar transition state involved along the all-t-CDT path is significantly stabilized by an axial coordination of butadiene. Hence, the all-t-CDT route becomes the most facile of the three CDT production paths with a free-energy barrier for reductive elimination of 23 kcal mol-1, that perfectly corresponds with experimental estimates.44 Accordingly, the production of C12-cyclo-oligomers requires moderate reaction conditions,9 although 7b represents a thermodynamic sink within the catalytic cycle. 

A cyclopropylcarbinyl cation can be trapped to form either a cyclopropane product (Path a, Eq. 3) or a homoallyl product (Path b, Eq. 3). The latter has proven useful to create acyclic units containing olefins of defined geometry as in the synthesis... 

The Rh-catalyzed cyclization of the amine 125 in scCOj affords the cyclic amine 127 as the major product (path A in Scheme 1.15), whereas in conventional sol-... 

The proposed mechanism involves either path a in which initially formed ruthenium vinylidene undergoes nonpolar pericyclic reaction or path b in which a polar transition state was formed (Scheme 6.9). According to Merlic s mechanism, the cyclization is followed by aromatization of the ruthenium cyclohexadienylidene intermediate, and reductive elimination of phenylruthenium hydride to form the arene derivatives (path c). A direct transformation of ruthenium cyclohexadienylidene into benzene product (path d) is more likely to occnir through a 1,2-hydride shift of a ruthenium alkylidene intermediate. A similar catalytic transformation was later reported by Iwasawa using W(CO)5THF catalyst [14]. 

These compounds can give two different types of products (path a 255 256 257 and path b 255 258 259). 

The results seem to indicate that arylamines do not follow the same mechanism that presumably underlies the coupling of oxygen-substituted aryls. According to the authors, N-N dimerization (70 —> 126) is a competitive pathway that is favored with hindered substrates. This N-N coupling can eventually lead to both the C-C coupled product (path a) and the carbazole product (path b). The ratio depends upon the structure of the starting material (Scheme 31). 

Figure 2.4 N-N-0+ Potential-energy diagram (schematic). The stippled curve represents reactant paths. The unstippled curve represents product paths.

Earlier in this chapter we noted that nucleophiles attack the CF2 = site in a fluorinated alkene exclusively and, in parallel with these observations, nucleophilic radicals, such as CH3S and carbon-centred radicals, give products arising predominantly from attack at this site (Path 1). Electrophilic radicals such as trifluoromethyl, on the other hand, are less selective and give a mixture of products (Paths 1 and 2) (Eigure 7.58). Examples of the regiochemistry of addition of trifluoromethyl to a variety of fluorinated alkenes are given in Table 7.10. 

Numerous semiempirical calculations have been carried out on the dioxetane decomposition, including CNDO/2 calculations with and without configuration interaction and MINDO/3 with configuration interaction. These differ in their opinions of whether first 0-0 bond homolysis occurs leading to a diradical intermediate, followed by fast C-C bond cleavage. However, on the basis of qualitative considerations it was argued that a crossover of the diradical path to the triplet excited product path, prior to reaching a bona fide stable diradical... 

The l,3 -bicyclopropenyl 119 affords a mixture of diphenylacetylene and enynes 218 on thermolysis (equation 74) Two pathways can account for the products. Path a involves... 

In this plant, unit 8 is common to both production lines, hence there are two ways in which batches can be assigned to each production line, namely one from units 1 or 9 and the other from unit 8. The set of units that a batch of materials must follow to produce a given product will be called a production path. For each product, there is one fixed production path and it is given a priori. From Figure 2, the following five production paths are possible. 

Although a production path may show a storage unit, a batch following that path does not have to go through the storage and can skip it to proceed directly to the next unit. 

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