Preferred process route

The dinitration route from benzazepine to varenicline was high yielding, direct, and sufficiently safe for commercial operation. These characteristics defined the process chemistry objective to enable a benzazepine synthesis for manufacturing. The preferred process route to varenicline evolved with dedicated research, however, as described below. 

The preferred process route and associated waste management options identified by tiie above procedure is the Best Practical Environmental Option (BPEO). 

Tour s work showed that polymerization is still a preferred process even though large excesses ofradical traps (1,4-cyclohexadiene) were employed. They obtained poly( 1,4-naphthalene) only as an insoluble brown powder by polymerization of 1,2-diethynylbenzene in benzene solution. This route appears to be an attractive approach to a new dielectric medium ... 

High-temperature processes, based on pyrolysis, gasification or combustion of biomass are the preferred conversion routes for non-food competing biomass conversion processes to secondary energy. 

Acetylene is a tricky chemical feedstock. It is extremely reactive (and explosive) and impractical to transport. Generally, the industrial processes that use acetylene are close to the acetylene-generating source. Despite all the drawbacks, the Reppe process was for a half century the preferred process for EDO, but now the growth in EDO is being taken by the propylene oxide (PO) and butane feedstock routes. 

THE FEASIBILITY study for a chemical process design investigates both the technical and economic feasibility of the proposed project. This feasibility study is only an introductory assessment, at this stage the process route has not yet been finalised although a preferred route may be apparent. Part of the work in preparing the feasibility study is to obtain information regarding the alternative process routes, and to provide an assessment of the suitability of these routes for the particular project. 

Process (a) is the preferred synthetic route. It involves a melt polymerization which is finished at high temperatures (about 275°C) and low pressures (about 1 mm Hg) to strip out the water produced as a condensation product and drive the equilibrium depicted to the polymer side. The product is a molten polymer which is suitable for immediate formation of fibers or films or for granulation. The acid monomer is less expensive than the diester in reaction (b). Thus, while the actual polymerization of route (a) is slower and more expensive than that of (c), the overall costs of producing a finished polymer are less. 

A fermentation process is currently the preferred industrial route, despite problems related to microbe separation, control of by-products and the disposal of wastewater [360,361], Only the development of catalysts with excellent activity, selectivity and durability is expected to compete with this. 

The chemical synthesis of 7-ACA (Fig. 3) is a classical organic route, which uses equimolar amounts of chemicals. A preferred process is the so-called iminoha-lide/iminoether deacylation route, involving formation of the iminochloride by reaction with PCI5, conversion into the iminoether by treatment with alcohol and hydrolysis with water [7]. Highly purified cephalosporin C, isolated, for example as the zinc salt, is required as a dried solid as the starting material. 

QM/MM calculation on the MPS- catalyzed reaction suggested that the transition state of the two-step Micheal-aldol route is more stable than that of the concerted Diels-Alder route, indicating that the two-step route is an energetically preferred process. To evaluate the validity of the calculation results, experimental evidence must he provided. A recent finding that the first decarboxylation, the second C—C bond formation, and the third decarboxylation to 151 are rapid processes, suggested that it is difficult to distinguish between... 

The preferred industrial route to cycloaliphatic epoxy resins is based on the epoxidation of cycloolefins with peracids, particularly peracetic acid (71). Few side reactions are encoimtered. Some properties of various commercial products are given in Table 11. The peracid cannot be made in situ because the cyclic olefins are sensitive to impurities generated in this process. 

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