Carbon dioxide fractionation

Table VII. Average Recoveries and Percent RSDs for 15 Target Analytes Extracted from a Certified Soil (SRS103-100) with Supercritical Carbon Dioxide (Fraction l)a...

Polyakov VB, Kharlashina NN (1995) The use of heat capacity data to calculate carbon dioxide fractionation between graphite, diamond, and caibon dioxide A new approach. Geochim Cosmochim Acta 59 2561-2572... 

Vazquez L., Fornari T., Senorans F.J., Reglero G., Torres C.F. Supercritical carbon dioxide fractionation of nonesterified atkoxyglycerols obtained from shark liver oil. Journal of Agricultural and Food Chemistry, 56 1078-1083 (2008). 

Dunford NT, King JW. 2000. Phytosterol Enrichment of Rice Bran Oil by a Supercritical Carbon Dioxide Fractionation Technique. J. Food Sd. 65 1395-1399. 

G. Perretti, A. Motori, E. Bravi, F.Favati, L. Montanari, P. Fantozzi, Supercritical carbon dioxide fractionation of fish oil fatty acid ethyl esters. The Journal of Supercritical Fluids 40 (2007), p. 349-353. 

A substantial fraction of the named enzymes are oxido-reductases, responsible for shuttling electrons along metabolic pathways that reduce carbon dioxide to sugar (in the case of plants), or reduce oxygen to water (in the case of mammals). The oxido-reductases that drive these processes involve a small set of redox active cofactors , that is, small chemical groups that gain or lose electrons. These cofactors include iron porjDhyrins, iron-sulfur clusters and copper complexes as well as organic species that are ET active. 

Industrially, elemental nitrogen is extracted from the air by the fractional distillation of liquid air from which carbon dioxide and water have been removed. The major fractions are nitrogen, b.p. 77 K and oxygen, b.p. 90 K, together with smaller quantities of the noble gases. 

The factor represents the fraction by weight of the element sought (Column i) in the final compound weighed (Column 2), e.g., the weight of carbon in x g. of carbon dioxide is therefore 0 2y2yx g. 

Ca.rhona.tlon, GalHum can be extracted by fractional carbonation which consists of treating the aluminate solution with carbon dioxide in several controlled stages. This process is no longer under industrial operation (6). 

FoodApphca.tlons, Carbon dioxide, a nontoxic material, can be used to extract thermally labde food components at near-ambient temperatures. The food product is thus not contaminated with residual solvent, as is potentially the case when usiag coaveatioaal Hquid solveats such as methylene chloride or hexane. In the food iadustry, CO2 is not recorded as a foreign substance or additive. Supercritical solvents not only can remove oils, caffeiae, or cholesterol from food substrates, but can also be used to fractionate mixtures such as glycerides and vegetable oils iato aumerous compoaeats. 

A number of acidic phosphates which vary in their rate of reaction are available for use in a wide variety of bakery appHcations. These acids, which include monocalcium phosphate, sodium aluminum phosphate, and sodium acid pyrophosphate, release carbon dioxide at a controlled rate to give a certain fraction prior to baking the remaining fraction is released at a specific time during baking. Controlled releasing of carbon dioxide at the time it is needed can also be achieved by a mixture of different types of leavening acids. 

Catalyst Selectivity. Selectivity is the property of a catalyst that determines what fraction of a reactant will be converted to a particular product under specified conditions. A catalyst designer must find ways to obtain optimum selectivity from any particular catalyst. For example, in the oxidation of ethylene to ethylene oxide over metallic silver supported on alumina, ethylene is converted both to ethylene oxide and to carbon dioxide and water. In addition, some of the ethylene oxide formed is lost to complete oxidation to carbon dioxide and water. The selectivity to ethylene oxide in this example is defined as the molar fraction of the ethylene converted to ethylene oxide as opposed to carbon dioxide. 

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