Environmentally benign production economics

Currently, the SCF technology has a widespread utility ranging from food processing to pharmaceutical applications. The use of SCFs such as CO2 is proving to be environmentally benign and economical, with the added advantage of reduced residual solvents in food and pharmaceutical products. 

It has been demonstrated that enzyme-catalyzed vinyl polymerizations enable significant control over polymer properties such as molecular weight, polydisper-sity and yield. Even though a convincing demonstration of enzyme-derived stereoselectivity is missing so far, this approach exhibits an enormous potential for environmentally benign and economically feasible production of tailored polymers. 

The reaiTangement of styrene oxide and derivatives over acidic zeolites has been very successful. The efficient suppression of side-products and the possibility of avoiding salt formation makes the catalytic system based on zeolites such as [B]-MFI environmentally benign and economically superior. Even prod-... 

We have reported a simple, green, bench top, economical and environmentally benign room temperature synthesis of MSe (M=Cd or Zn) nanoparticles using starch, PVA and PVP as passivating agents. The whole process is a redox reaction with selenium acting as the oxidant and MSe as the reduction product. An entire "green" chemistry was explored in this synthetic procedure and it is reproducible. The optical spectroscopy showed that all the particles are blue shifted from the bulk band gap clearly due to quantum confinement. Starch capped CdSe nanoparticles showed the presence of monodispersed spherical... 

A more practical, atom-economic and environmentally benign aziridination protocol is the use of chloramine-T or bromamine-T as nitrene source, which leads to NaCl or NaBr as the sole reaction by-product. In 2001, Gross reported an iron corrole catalyzed aziridination of styrenes with chloramine-T [83]. With iron corrole as catalyst, the aziridination can be performed rmder air atmosphere conditions, affording aziridines in moderate product yields (48-60%). In 2004, Zhang described an aziridination with bromamine-T as nitrene source and [Fe(TTP)Cl] as catalyst [84]. This catalytic system is effective for a variety of alkenes, including aromatic, aliphatic, cyclic, and acyclic alkenes, as well as cx,p-unsaturated esters (Scheme 28). Moderate to low stereoselectivities for 1,2-disubstituted alkenes were observed indicating the involvement of radical intermediate. 

As with carboxylic acids obtained by palladium hydroxycarbonylation, their derivatives esters, amides, anhydrides and acyl halides are synthesized from alkenes, CO and HX (X = OR, NR2 etc.). The Pd-catalyzed methoxycarbonylation is one of the most studied reactions among this type of catalyzed carbonylations and has been reviewed and included in reports of homogeneous catalysis.625, 26 The methoxycarbonylation has been applied to many different substrates to obtain intermediates in organic syntheses as well as specific products. For instance, the reaction has been applied for methoxycarbonylation of alkynes666 Highly efficient homogeneous Pd cationic catalysts have been reported and the methoxycarbonylation of alkynes has been used to develop economically attractive and environmentally benign process for the production of methyl... 

The aim of process design is to create a process, which is profitable, economic, safe, environmentally benign and user friendly. This is achieved by the optimization of process alternatives according to economic and functional criteria. It is required that the safety of a process plant fulfills a certain required level. This is because of general legal requirements, company image, and also due to economic reasons, since an unsafe plant cannot be profitable due to losses of production and capital. 

There has been active work in the development of processes that are safer and have less potentially damaging environmental impacts. These environmentally benign or green process designs typically include a life-cycle analysis to account for the long-term environmental (and economic) impact of a product or design. 

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