Renewable carbon

The chemical recycling of carbon dioxide into usable fuels provides a renewable carbon base to supplement and eventually replace our diminishing natural hydrocarbon resources. Methanol (or dimethyl ether), as discussed, can be readily converted into ethylene or, by further reaction, into propylene. 

Renewable carbon resources is a misnomer the earth s carbon is in a perpetual state of flux. Carbon is not consumed such that it is no longer available in any form. Reversible and irreversible chemical reactions occur in such a manner that the carbon cycle makes all forms of carbon, including fossil resources, renewable. It is simply a matter of time that makes one carbon from more renewable than another. If it is presumed that replacement does in fact occur, natural processes eventually will replenish depleted petroleum or natural gas deposits in several million years. Eixed carbon-containing materials that renew themselves often enough to make them continuously available in large quantities are needed to maintain and supplement energy suppHes biomass is a principal source of such carbon. 

The percentage of energy demand that could be satisfied by particular nonfossil energy resources can be estimated by examination of the potential amounts of energy and biofuels that can be produced from renewable carbon resources and comparison of these amounts with fossil fuel demands. 

Most of the renewable carbon sources Hsted in Table 8 have carbon contents near this value. When adjusted for moisture and ash contents, it is seen that with the exception of the sludge sample, the carbon contents are slightly higher than that of cellulose, but span a relatively narrow range. 

The greenhouse gas CO2 is a valuable and renewable carbon source for the production of fine chemicals and fuels because it is readily... 

This problem could eventually severely constrain both the fossil and renewable carbon basis of future fuels, yet today a form of paralysis is the sole R D activity discernible. 

By using renewable carbon from biomass, an improvement in the CO2 balance can be achieved. However, significant effects beyond the impacts on greenhouse gas emissions are possible, e.g., soil modification, eutrophication, impact on biodiversity, land requirements and water consumption. These aspects depend on different factors like feedstock type, scale of production, cultivation and land-management practices, location and downstream processing routes. The environmental implications of agriculture are sometimes difficult to assess by the LCA methodology and require further research. 

The use of naturally derived complex carbon compounds as raw materials for polyurethane polymers is not new to the industry. Since the advent of polyether polyols, polyurethane polymers have utilized natural sources of renewable carbon. 

As renewable raw materials began to enter the marketplace, it was inevitable that claims to the level of renewable content in commercial offerings would become an issue of public debate. As previously pointed out in this article, some renewable raw materials have been common to the polyol chemistry for many decades, so claims to at least some renewable content are justified. Because the commercialization of different renewable polyol chemistries has created a highly competitive environment, some scientists in the field have promoted a method for the independent verification of the renewable sourced carbon in the final product [153]. ASTM International has published a concise and informative briefing paper on the method development for the determination of renewable carbon content in carbon-containing substances [154]. The method involves the analysis of content in the finished polyurethane products via radiocarbon dating [155]. The technique is fast and accurate, and has become commonly available by contract analysis through independent analytical laboratories [156]. 

Property Generation 1 (18% renewable carbon) Generation 2 (14% renewable carbon) Units... 

Polyurethanes prepared via the use of renewable carbon sources are a relatively recent introduction to the commercial market. The opportunity is driven primarily by the high and volatile cost of petroleum, and by societal concerns over the... 

Beta Analytic (2011) World leader in ASTM D6866. http //www.betalabservices.com/ renewable-carbon.html. Accessed 30 May 2011 Hoyle F (1946) Mon Notices R Astron Soc 106 343-383 Hoyle F (1954) Astrophys J l(Suppl 1) 121-146... 

As an abundant, nontoxic, non-flammable, easily available, and renewable carbon resource, C02 is very attractive as an environmentally friendly feedstock for making commodity chemicals, fuels, and materials [1-7]. In this respect, PEGs-functionalized catalysts have been developed for efficient transformation of C02 into value-added chemicals or fuels such as cyclic carbonates, dimethyl carbonate (DMC), oxazolidinones, organic carbamates and urea derivatives. 

Plant oils or their derived fatty acids are inexpensive renewable carbon sources. In addition, the theoretical yield coefficient of bioproducts (PHA) from plant oil and fatty acid is considerably higher than that from sugars. High cell density fed-batch cultures produced value-added products from soybean oil or oleic acid as the carbon source. PHAs with high yield were produced by fed-batch culture of R. eutropha or its recombinant strain from soybean oil. High cell concentrations obtained by fed-batch cultures from oleic acid improved lipase activity by C. cylindracea and 10-KSA by Flavobacterium, sp. DS5, compared with those of flask cultures. There are still many industrially important value-added products that can be produced from inexpensive substrates such as soybean oil. 

Akiyama, M.,Tsuge,T., and Doi, Y. 2003. Environmental life cycle comparison of poly-hydroxyalkanoates produced from renewable carbon resources by bacterial fermentation. Polym. Degrad. Stab., 80,183-194. 

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