Isolation of gram quantities

Jeffrey, L. M. (1969). Development of a method for isolation of gram quantities of dissolved organic matter from seawater and some chemical and isotopic characteristics of the isolated materials. Ph.D. Thesis, Texas A M University, College Station, 152 pp. 

An Alternative Method for the Isolation of Gram Quantities of Cell Wall Material from Fresh Potatoes... 

The second mode is referred to as the sample overload technique and sacrifices column efficiency and resolution in favour of sample throughput. The use of wide diameter columns (>10mm) packed with large microporous particles (>50pm) allows isolation of gram quantities of material in relatively short elution times as the column can be operated at high flow rates without seriously degrading resolution. By its nature this technique... 

Resting cells, or extracts, of Streptococcus faecalis rapidly degrade th3uni-dine to thymine, and 2-deoxy-D-erythro-pentose ( 2-deoxy-D-ribose ) disappears. Azathymine [6-methyl-os2/m-triazine-3,5(2,4)-dione] or 5-bro-mouracil, when added, inhibits the disappearance of 2-deoxy-D-ri-bose by trapping it. Azathymidine can be isolated in gram quantities by this procedure. A 2-deoxy-D-ribofuranosyl derivative of 5-fluorouracil has been prepared in a similar way. ... 

The meta photocycloaddition of ( )-l,2-dichloroethene with benzonitrile, toluonitriles, benzene, phenol, cresols, fluorobenzene, chlorobenzene, trifluoromethylbenzene and 3-trifluoro-methylbenzonitrile shows not only the influence of the aromatic substituents on the direction of the alkene attack, but also a control of the cyclopropane closure by the vinyl chlorine to give exclusively the exo-(>, ent/o-7-dichloro adduct isomer 5 which was, in the most favorable cases, isolated in gram quantities. ... 

In this chapter an attempt has been made to discuss the methods available for the isolation and analysis of higher plant cell walls. Because the structures and properties of the cell wall polymers from various tissue tyjDes show considerable differences, it is emphasized that, where possible, separation of the tissues in a plant organ prior to preparation of the cell walls is desirable. Attention is drawn to the problems associated with coprecipitation of intracellular compounds with cell wall polymers, particularly in view of the occurrence of small amounts of proteoglycan and proteoglycan-polyphenol complexes in the walls and the covalent attachment of phenolics and phenolic esters with some of the cell wall polymers of parenchymatous and suspension-cultured tissues. The preparation of gram quantities of relatively pure cell walls from starch- and protein-rich tissues is discussed at some length because of the importance of dietary fiber in human nutrition and an understanding of the composition, structure, and properties of dietary fiber would be hampered without such methods (Selvendran, 1984). 

The system has been used to effect the isolation and final purification of gram quantities of Np. Interestingly, the only difficulty encountered is in maintaining uranium in the uranium(VI) state, since in this system uranium-(IV) closely resembles neptunium(IV) in its extraction behavior. So after two to three aqueous HCl scrubs to remove contaminants from the neptunium product in the organic phase an oxidation cycle must be inserted to oxidize uranium(IV) to uranium(VI). Under the oxidizing conditions used, neptun-ium(IV) is oxidized to neptunium(VI). But through the action of hydro-quinone, following the oxidation step, neptunium(VI) is rapidly reduced to... 

Triose phosphate dehydrogenase has been studied both as a chemical molecule and as a catalyst. These studies were made possible by the availability of gram quantities of crystalline enzyme from rabbit muscle, by the procedure of Cori, Slein, and Cori, and from yeast, by the procedure of Warburg and Christian. Krebs has isolated four fractions from yeast with equivalent specific activity, one of which is the enzyme crystallized by Warburg and Christian. The four components make up about 5 per cent of the total extractable protein of the yeast. 

In industry and academia the need often arises to isolate portions of a polymer sample, whether it be to separate low molecular weight material from a sample or to actually fractionate the polymer across its molecular weight distribution. If gram quantities of isolated polymer are needed, true preparative chromatography equipment and techniques are usually necessary. 

Hotchkiss, Jr., A. T., Haines, R. M., and Hicks, K. B., Improved gram-quantity isolation of malto-oligosaccharides by preparative HPLC, Curb. Res., 242, 1, 1993. 

With this encouraging result from the model system, a gram quantity of the racemic sulfoxide 40 was prepared by oxidation of benzoxathiin 16 with mCPBA and a small amount of chiral sulfoxide (A)-40 with 94% ee was isolated by subsequent chiral HPLC separation (Scheme 5.12). When chiral sulfoxide (S)-40 was treated with borane-dimethylsulfide, a clean reduction of the olefin and the sulfoxide was observed. More surprisingly, only the desired cis-diaryl dihydrobenzoxathiin 12 was observed in high yield and unchanged 94% ee. No trans-isomer or 16 was observed. With this proof of concept in hand, an efficient... 

More recently, Brauns and Seiler (12), (13) extracted native lignin from spruce wood and then homogenized the wood in a colloidal mill. A suspension of approximately one gram of colloidal wood per liter of water was obtained. After the colloidal wood was changed to a solid form, it was found that its cell structure was completely destroyed. However, extraction of this wood with ethyl alcohol at room temperature did not yield further quantities of native lignin. These investigators have also reported the isolation of a lignosulfonic acid-carbohydrate compound. 

In addition to the ability to prepare multiple products, it was also demonstrated that it was possible to scale-out the reaction using prolonged reaction times. In this way, multi-gram quantities of material could be readily isolated (Scheme 2). The reactions were very efficient... 

During the period 1960-1980, work was carried out in the United States [64] and in France [65] to isolate macro quantities of transpiutonium elements obtained from irradiated plutonium. Particular emphasis was placed upon separation and purification of gram to kilogram amounts of for use... 

The increased cooling efficiency of thin-walled reactors also has permitted the use of more volatile substrates in near molar quantities. (l-3 6-7 10-12-rj 2,6,10-Dodecatriene-l,12-diyl)nickel has been prepared in multiple gram quantities by cocondensation of nickel vapor and 1,3-butadiene. This method has provided a clean one-step route to this complex, which was first isolated and identified by Wilke et al.1 as an intermediate in the cyclotrimerization of 1,3-butadiene by nickel catalysts. 

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