Petroleum-based feedstock

Although the rapid cost increases and shortages of petroleum-based feedstocks forecast a decade ago have yet to materialize, shift to natural gas or coal may become necessary in the new century. Under such conditions, it is possible that acrylate manufacture via acetylene, as described above, could again become attractive. It appears that condensation of formaldehyde with acetic acid might be preferred. A coal gasification complex readily provides all of the necessary intermediates for manufacture of acrylates (92). 

Anhydrous Acetic Acid. In the manufacture of acetic acid by direct oxidation of a petroleum-based feedstock, solvent extraction has been used to separate acetic acid [64-19-7] from the aqueous reaction Hquor containing significant quantities of formic and propionic acids. Isoamyl acetate [123-92-2] is used as solvent to extract nearly all the acetic acid, and some water, from the aqueous feed (236). The extract is then dehydrated by azeotropic distillation using isoamyl acetate as water entrainer (see DISTILLATION, AZEOTROPIC AND EXTRACTIVE). It is claimed that the extraction step in this process affords substantial savings in plant capital investment and operating cost (see Acetic acid and derivatives). A detailed description of various extraction processes is available (237). 

Most of the plastics and synthetic polymers that are used worldwide are produced from petrochemicals. Replacing petroleum-based feedstocks with materials derived from renewable resources is an attractive prospect for manufacturers of polymers and plastics, since the production of such polymers does not depend on the limited supply of fossil fuels [16]. Furthermore, synthetic materials are very persistent in the environment long after their intended use, and as a result their total volume in landfills is giving rise to serious waste management problems. In 1992,20% of the volume and 8% of the weight of landfills in the US were plastic materials, while the annual disposal of plastics both in the US and EC has risen to over 10 million tons [17]. Because of the biodegradability of PHAs, they would be mostly composted and as such would be very valuable in reducing the amount of plastic waste. 

Although technologies have been developed over past 50 years to process petroleum-based feedstock efficiently to generate hydrogen, its production from rene v-able biomass-derived resources remains a major challenge, because conversion processes often suffer from low hydrogen production rates and/or complex processing requirements [24, 25]. 

Ethylene [74-85-1] (ethene), H2C=CH2, is the largest volume building block for many petrochemicals. This olefin is used to produce many end products such as plastics, resins, fibers, etc. Ethylene is produced mainly from petroleum-based feedstocks by thermal cracking, although alternative methods are also gaining importance. 

Energy prices and availability of petroleum-based feedstocks are problematic. 

Gulf Canada has been active in this area for sometime and recently has developed a process that produces a high quality electrode binder pitch from a petroleum-based feedstock (7). This pitch has been used on a commercial scale by the aluminum industry in both vertical stud Soderberg and prebaked electrodes. 

Four billion pounds of adipic acid are produced each year using petroleum-based feedstocks, carcinogenic benzene as starting material, and extreme reaction conditions. Nitrous oxide, which plays a role in ozone layer depletion, is emitted as a byproduct. As an alternative to the currently employed synthetic methcdology, a two-step synthesis of adipic acid from D-glucose has been developed which eliminates each of these problems. A microbial catalyst was created which possesses a novel biosynthetic pathway that synthesizes cis, cis-muconic acid from D-glucose. This pathway does not occur in nature but has been created in a strain of Escherichia colL Cis, cw-muconic acid is exported to the culture supernatant, where it is hydrogenated under mild conditions to yield adipic acid. 

More recently, bitumen from oil sand deposits and other heavy petroleum-based feedstocks have also been employed as reactive solvents with a degree of success that warrants further work and investigation (see, for example, Aitchison et al 1990 Wang and Curtis, 1992). 

Different resins are manufactured from different petroleum based feedstocks (Table 1.1). Monomers, compounds which can be used to react with itself or another similar compound or molecule, form polymers. The feedstocks shown in Table 1.1 are either monomers or used to form monomers. For example, ethylene is a monomer for producing polyethylene, and benzene is used to produce styrene, the monomer for polystyrene. 

In the production of paper from recycled materials, this enzyme eliminates the need for using hydrocarbon solvents or similar chemicals that are more toxic, more flammable, and derived from non-renewable petroleum-based feedstocks. Paper mills adopting Optimyze have been able to greatly reduce the use of hazardous, flammable solvents. 

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