I. Hydrogenation of cinnoline. II. Chromatographic examination of gilsonite


Part I. Although substituted cinnolines have been studied quite thoroughly as to the products derived from their hydrogenation, very little work has been done on the catalytic reduction of cinnoline. The purpose of this investigation was to partially complete our knowledge concerning the chemistry of cinnoline by studying its catalytic hydrogenation. Cinnoline was hydrogenated using five different catalysts: 5% Rh/Al_2O_3, 5% Rh/C, 5% Pd/C, RuO_2, and PtO_2. Each of these catalysts was used under neutral and acid conditions with variations in temperature and pressure. Seven compounds were isolated from these hydrogenations, six of which were positively identified as: 1,4-dihydrocinnoline; 1,2,3,4-tetrahydrocinnoline; o-aminophenethylamine; indole, 2,3-dihydroindole; and cis-octahydroindole. The seventh compound that was not positively identified is proposed to be 1,1',4,4' -tetrahydro-4,4'-bicinnoline. An authentic sample of indole was obtained commercially; whereas, 2,3-dihydroindole and cis-octahydroindole were prepared by the hydrogenation of indole by known procedures. An authentic sample of o-aminophenethylamine was prepared by a new unambiguous route, which is reported in this investigation. 1,4-Dihydrocinnoline and 1,2,3,4-tetrahydrocinnoline were identified by their physical constants and infrared spectra. Gas chromatography and thin-layer chromatography were used to identify the products from the catalytic hydrogenation of cinnoline. Qualitative as well as quantitative analyses were carried out using the gas chromatograph, and thin-layer chromatography provided additional qualitative data. Possible mechanisms for the formation of the various compounds resulting from the hydrogenation of cinnoline are discussed. Low-pressure hydrogenations (60 p.s.i. or less) under neutral conditions provided good yields of 1,4-dihydrocinnoline and 1,1',4,4'-tetrahydro-4,4'-bicinnoline. Under acid conditions with low pressure, all catalysts except Adam's catalyst (PtO_2) produced 1,4-dihydrocinnoline-hydrochloride. 1,2,3,4-Tetrahydrocinnoline was the major product from the low-pressure reduction of cinnoline under acid conditions using Adam's catalyst. High-pressure hydrogenations (2000 p.s.i. or greater) were carried out at temperatures of about 125°; these conditions produced more highly reduced products than the low-pressure hydrogenations as would be expected. Very little selectivity is shown by the different catalysts at high pressures. Part II. Gilsonite is a black-shiny carbonaceous material found only in huge vertical fissures located in the Uintah Basin of eastern Utah. While superficially resembling certain types of asphalt, it is remarkable for its unusually high softening temperature and low ash content. These properties make it unique among naturally-occurring hydrocarbon deposits. Gilsonite is presently being used as raw material for gasoline and electrolytic coke. Since the amount of gilsonite available will be consumed before too many years have gone by, it was considered desirable to study some of the naturally-occurring components which make up gilsonite. A knowledge of these components might provide better utilization of this material. Preliminary fractionation of gilsonite was accomplished by extraction with acetone and the removal of the asphaltenes from the acetone extract by precipitation with n-pentane. Further fractionation of the acetone extracts was accomplished using column chromatography followed by thin-layer chromatography. Three fractions were isolated from gilsonite. The first was an asphaltenic mixture obtained by precipitation with n-pentane; the separation of this complicated mixture was not pursued further in this work. The second fraction was a yellow material obtained by elution of the n-pentane soluble fraction with benzene from an alumina chromatographic column. The second fraction was not identified. The third fraction, which was red in color, was obtained chromatographically homogeneous after extensive purification by means of column and thin-layer chromatography. From chemical and spectral data, it is proposed that the red material isolated from gilsonite is a mixture of at least two nickel porphyrins.



College and Department

Chemistry and Biochemistry



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Hydrogenation, Chemistry, Organic, Cinnoline, Gilsonite



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