Mechanism of carbon nanotube growth from camphor and camphor analogs by chemical vapor deposition

Single walled nanotubes have been synthesized by chemical vapor deposition from camphor, camphor analogs (camphorquinone, norcamphor, norbornane, camphene, fenchone), and various other precursors (menthone, 2-decanone, benzene, methane). The high temperature conditions (865 °C) and Fe/Mo alumina catalyst used in the syntheses are archetypal conditions for the production of single walled carbon nanotubes. It has been shown that the mechanism of tube growth is unlikely to depend upon the production of reactive five- and six-member rings, as has been previously suggested. The results suggest that the presence of oxygen in the precursor does not significantly improve the quality of tubes by etching amorphous carbon: it is suggested that the control of the flux of the precursor to the catalyst is more important in the production of high quality tubes. There is, however, evidence for different distributions of tube diameter being produced from different precursors.     

Effects of the nitrification inhibitor N-Serve on the utilization of fall-applied urea by wheat

Four-year microplot tests were performed to study the utilization by wheat, in the presence and absence of the nitrification inhibitor N-Serve, of¹⁵N labeled urea spread in fall. The percentages of fertilizer nitrogen taken up by winter wheat (grains and straw) were 18 to 37 percent when urea was spread in fall, 33 to 45 percent when urea plus N-Serve was applied in fall, and 36 to 49 percent when urea was spread in spring. In the 0–30 cm layer of soil there were found, for the treatments listed above, 15 to 23 percent, 24 to 45 percent, and 15 to 47 percent of urea nitrogen after the harvesting of winter wheat. Application of urea plus N-Serve in fall and of urea alone in spring resulted in similar amounts of fertilizer nitrogen being taken up by spring wheat to those taken up by winter wheat. Of the urea nitrogen applied in fall, 20 to 28 percent and 47 to 50 percent were not recovered from the plants and 0–30 cm soil layer with and without additional N-Serve treatment, respectively. The utilization by winter wheat of urea nitrogen spread, with no additional N-Serve, in fall from mid-October onward was considerably lower in those cases where, after fertilizing, weather conditions were such as to favour both nitrification and leaching. On heavy and loamy soil such influences of weather were offset by application of N-Serve.     

Pressure reaction of maleic esters with vegetable oils

The reaction of dimethyl maleate and some related dienophiles with vegetable oils under pressure has been studied successfully. When safflower oil reacts with 100% excess maleate, sulfur dioxide catalyst, and hydroquinone inhibitor at 290° for 1hr., 80 to 90% yields of adduct fraction, based on linoleate, are obtained. Under the same conditions almost equally good yields result with either linseed or soybean oils. With safflower oil, dimethyl fumarate gave slightly lower yields. Di-n-butyl maleate gave even poorer yields, and much residue was formed. Paper II in a series entitled, “Reactions of Dienophiles with Vegetable Oils”. Presented at annual meeting, American Oil Chemists' Society, St. Louis, Mo., May 1–3, 1961. This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U.S. Department of Agriculture.     

N-phenylaminomethylation: A one-step route to N-substituted anilines from unsaturated fatty derivatives and olefins

Unsaturated fatty materials, such as ethyl oleate and oleonitrile, are found to react with carbon monoxide, hydrogen and aniline at 150 C to give N-monoalkylanilines. The alkyl group is derived from the unsaturated fatty material plus the group H-CH₂ added across the double bond. Similarly 1-decene, in a rapid reaction, gives N,N-di-n-undecylaniline and N-undecylaniline as major and minor products respectively. 1,2,3-Tris-(triphenylphosphine)trichlorohodium is an excellent catalyst for this reaction. Presented at the AOCS Meeting, San Francisco, April 1969.     

Thermal analysis and calorimetry of some fatty acid sodium soaps

Transition temperatures and enthalpies and some phase diagrams of pure odd and even sodium soaps have been determined by means of dif-ferential thermal analysis and scanning calorim-etry. Branched sodium soaps have been added for comparison. No essential difference has been found between the number, type, and enthalpy of the transitions of the neighboring odd and even soaps. The total enthalpy and entropy of transition are consider-ably lower than those of the corresponding par-affins and fatty acids. The entropy of the subneat-neat and perhaps of the neat isotropic transition has an alternating character, which suggests a different methyl end-group packing for even and odd soap. These two facts suggest that the melted soap is still in an organized state. Presented at the AOCS Meeting, New Orleans, May 1967.     

Chlorination of polystyrene

Chlorination of a low molecular weight polystyrene in the α position was studied by following changes in the infrared spectrum, glass transition temperature, and molecular weights of the polymer. The logarithm of the absorbance ratio at 2920 and 1500 cm^?1 as a function of mole per cent chlorination was linear. The glass transition temperatures, determined by use of a differential scanning calorimeter (DSC), were found to obey an equation developed by Dyvik for copolymers. The molecular weight of the chlorinated polystyrene decreased as a function of chlorination.     

The participation of soluble factors in the ω-oxidation of fatty acids in the liver of the sheep

The removal of soluble components from an ovine hepatic microsomal preparation decreased the ω-hydroxylation of dodecanoic and hexadecanoic acids. The results suggest that one or more soluble components play a role in the microsomal ω-hydroxylation of fatty acids. The possible roles in the reaction of catalase (known to stimulate the microsomal desaturations of fatty acids and alkylglycerols) and superoxide dismutase were investigated. The addition of these enzymes to the complete (but not the washed) microsomal preparation stimulated both the initial ω-hydroxylation reaction and the subsequent dehydrogenation reactions of the ω-oxidation pathway. The similarity of the effects of catalase and superoxide dismutase and stimulation of two different steps of the ω-oxidation pathway suggest that these agents are acting indirectly by removing active oxygen species rather than directly on the enzymes of microsomal fatty acid ω-hydroxylation.     

Determination of tocopherol in autoxidizing methyl esters of fatty acids

Summary Autoxidizing methyl esters of fatty acids interfered with the determination of α-tocopherol by ultraviolet spectrophotometry or by the bipyridine colorimetric method. Interference with the colorimetric method was removed by sulfuric acid treatment, but spectrophotometry was applicable only when the tocopherol was completely separated from oxidized fat. This separation could not be obtained by sulfuric acid treatment but was accomplished by room temperature saponification in an alcohol-petroleum ether system protected by pyrogallol. The sensitivity of the spectrophotometric method was increased by oxidizing tocopherol quantitatively to thep-quinone with 2N nitric acid. N. R. C. No. 4053. Presented in part at meeting of American Oil Chemists’ Society, Minneapolis, Minn., Oct. 11–13, 1954.     

Esters of hydroxystearic acids as primary low-temperature plasticizers for a vinyl chloride—Vinyl acetate copolymer

Summary Thirty-one acyloxy or aryloxy esters prepared from hydroxystearic acids have been evaluated as plasticizers for a vinyl chloride-vinyl acetate copolymer (95∶5). Many of them were found to be primary plasticizers, having outstanding low-temperature performance when employed at the 35% level. Formulations with these compounds compared quite favorably in tensile properties with those containing the di-2-ethylhexyl esters of phthalic, sebacic, azelaic, and adipic acids. Volatility losses were similar to those of the four di-2-ethylhexyl esters. The loss of plasticizer through migration was equal to or less than that from compositions containing the esters of sebacic, azelaic, and adipic acids but was greater than that of the phthalate ester. A mechanistic scheme of plasticizer-polymer interaction has been presented, proposing that the rate of diffusion of plasticizer through the polymer mass is a controlling factor in both good low-temperature performance and the resulting high migration losses. Methyl esters, some aromatic esters, and esters containing three or more polar centers have improved permanence but show a more rapid change in torsional modulus as the temperature is lowered during the determination of the Clash-Berg stiffening temperature. Eastern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.