Current Commercial Processes

A living cationic polymeriza tion of isobutylene and copolymeriza tion of isobutylene and isoprene has been demonstrated (22,23). Living copolymerizations, which proceed in the absence of chain transfer and termination reactions, yield the random copolymer with narrow mol wt distribution and well-defined stmcture, and possibly at a higher polymerization temperature than the current commercial process. The isobutylene—isoprene copolymers are prepared by using cumyl acetate BCl complex in CH Cl or CH2CI2 at —30 C. The copolymer contains 1 8 mol % trans 1,4-isoprene... 

The extrusion process of Swisher (1 ) has formed the basis of the current commercial processes which exist today. Swisher (1) added an essential oil (e.g., orange peel oil), which contained antioxidant and a dispersing agent, to an aqueous melt of corn... 

Indeed, free radical polymerization of fluoroolefins continues to be the only method which will produce high-molecular weight fluoropolymers. High molecular weight homopolymers of TFE, CFC1 = CF2, CH2CF2, and CH2=CHF are prepared by current commercial processes, but homopolymers of hexafluoro-propylene or longer-chain fluoroolefins require extreme conditions and such polymerizations are not practiced commercially. Copolymerization of fluoroolefins has also led to a wide variety of useful fluoropolymers. Further discussion of the subject of fluoroolefin polymerization may be found elsewhere and is beyond the scope of this review [213-215]. 

Plant derived pharmaceuticals are estimated to have an annual value of 9 billion in the U.S. alone (4). Flavors and fragrances have a current worldwide market of about 1.5 billion. Market data for insecticides and other fine chemicals such as pigments are not readily available. The first example, and the only current commercial process based on plant cell culture, is for the production of shikonin in Japan. This compound is both used in medicine and as a pigment (5-7. ... 

Can current commercial processes (emulsion, solution, suspension bulk) be used Is the methodology robust, tolerant to water and achievable under nitrogen (with oxygen not rigorously excluded) ... 

Current commercial processes for syngas and H2 production largely depends on fossil fuels both as the source of hydrogen and as the source of energy for the production processing.4 Fossil fuels are nonrenewable energy resources, but they provide a more economical path to hydrogen production in the near term (next 5-20 years) and perhaps they will continue to play an important role in the midterm (20-50 years from now). Alternative processes need to be developed that do not... 

Current commercial processes for catalytic dehydrogenation of propane to propylene are based on adiabatic reactor systems. Typical examples are ... 

Perhaps for obvious reasons, most of the current commercial processes using shape selective catalysts are in the petroleum and petrochemical industries. 

The most important product in ethylene oligomerization is a-olefins. Oligomerization of ethylene is at present the primary source of linear olefins and is likely to be the basis for such production for many decades. Current commercial processes... 

The dominant current commercial process for the production of isophthalic acid (lA) and terephthalic acid (TA) is the catalytic oxidation of m-xylene and p-xylene (PX). Xylenes are oxidized to lA or TA, respectively, in the so called Amoco process at 110-205 °C and 15-30 bar and in the presence of 95% acetic acid [128]. Furthermore, Co and Mn need to be added as catalysts and NIttBr and tetrabromoethane as co-catalysts. It is important to realize that some routes towards bio-based lA and TA may involve the production of the xylenes as an intermediate, whereas others might not. Furthermore, production routes may rely on technologies generating a slate of products comprising mostly fuel components next to chemicals like PX, whereas other technologies rely on the dedicated production of PX. 

The current commercial process simulators include special programs for calculating vapor-liquid equilibrium under different conditions. 

Cost is the key point to fabricate PUN products for engineering concerns. The addition of nanofillers in PUs can be achieved with slight modification to the current commercial process. High cost of nanofiller is still the barrier to develop PUN products. The nanofillers from natural sources such as nanoclay, nanographite, and natural nanotubes are cheaper than CNTs and POSS, which should have more chance to be used in PUNs. The effort should also be placed on developing the simple and effective methods for surface treatment with scaling-up potential. 

Industrial chemical processes actually developed are in general well optimized in terms of yield, productivity, and efficiency, which give very limited improvement options with respect to reducing both costs and CO2 emissions. Therefore, when a replacement of a well-established current commercial process is proposed, several considerations must be taken into account. Overall the most important are the economic benefits that justify both the high capital investments required and operational risks assumed for any new process. The major costs of production are related to the feedstock, and in this sense light alkanes could be a cheaper alternative. 

From an environmental point of view, a substantial decrease in CO2 emissions would follow the replacement of propylene with a propane feedstock, considering the overall process ca. five times higher in the propylene process than for propane). In this way, a recent study on the evaluation of the environmental impact by a systematic analytical method comparing the current commercial process from propylene with a hypothetical propane process (assuming in both a yield to acrylic acid close to 90%, currently obtained with the propene process) concluded that the propane process implied a decrease of 20% in the environmental impact of the industrial process. Moreover, a yield to acrylic acid higher than 61% was calculated to be enough for the propane process to be more enviromnentally benign. 

However, despite its prospective cost-effectiveness, commercialization attempts at such high temperature reactimis (T = 873-1 173 K) have not been successful so far because of the low C2 yields. As a matter of fact, the current commercialized process for ethene production is based on the pyrolysis of naphtha or the steam-based dehydrogenation of ethane [8], Returning to oxidative coupling reactions, to prevent loss of C2, the utilization of an oxidant softer than O2 is desirable [7, 8], which does not promote the formation of radicals. CO2 can play such a role and offers interesting advantages over O2 because utilization of CO2 prevents deep... 

In 1992, about 6.5 billion lb acetic acid was produced worldwide, of which about 3.6 billion lb was produced in the United States [1]. The current commercial processes for its production include oxidation of ethanol (acetaldehyde), oxidation of butane-butene mixture or naphtha, and carbonylation of methanol or methyl acetate. These are catalytic processes. The last, liquid-phase carbonylation of methanol using a rhodium and iodide catalyst, has become the dominant process since its introduction in the late 1960s, and accounted for about half the production of acetic acid in the United States [2]. That represents a conversion of 1.5 x 106 ton per year of methanol into 2.8 x 106 ton per year of acetic acid. In the United States, 80% of actual plant operation capacity is based on this technology [3]. The reaction is thermodynamically favorable [4], and the theoretical conversion is practicalty 100% at 389 K ... 

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