Fraction 12, hydrogen distribution

Over the 120-144-hr period, mass balance, chemical analysis, and fractionation gave the fuel product and hydrogen distributions shown in Table III. Of the hydrogen consumed, 79%. was retained in the fuel products. The remainder was used to remove heteroatoms. 

The distribution of deuterium in the THF-soluble, pentane-insoluble fractions remains surprisingly constant, in contrast to the dramatic changes in hydrogen distribution and aromaticity that occur during the same reaction time (Table II). The constant distribution of deuterium may reflect the selective extraction of specific structural types rendered more soluble in pentane or that very similar structures become deuterated during the reaction and remain unchanged upon further reaction. 

N.M.R. Spectroscopy. For comparing mixtiires of saturated hydrocarbons from different fuels and for monitoring the effectiveness of silica-gel column chromatography in the separation of normal alkanes from non-normals by 100 and, especially, 220 MHz H N.M.R., the emphasis is on the chemical-shift profile (j 0) and peak areas rather than on spin-spin coupling constants (Table III). Although the 100 MHz spectra indicate that the n-hexane-soluble part of Montan wax in CCli has rather similar hydrogen distributions to the chloroform-soluble part,about of Montan wax was soluble in n-hexane presumably the n-hexane-insoluble fraction contains all the alkanes, as well as polycyclic aromatics. The spectra of n-hexane- and chloroform-soluble fractions of Turkish asphaltite indicate hydrogen distributions of about 7.8 and 12.2 Hy, 21.2 and 22.0 H, U6.0 and U3.3 Hg, and 25 and 22.5/ Hy. 

One has seen that the number of individual components in a hydrocarbon cut increases rapidly with its boiling point. It is thereby out of the question to resolve such a cut to its individual components instead of the analysis by family given by mass spectrometry, one may prefer a distribution by type of carbon. This can be done by infrared absorption spectrometry which also has other applications in the petroleum industry. Another distribution is possible which describes a cut in tei ns of a set of structural patterns using nuclear magnetic resonance of hydrogen (or carbon) this can thus describe the average molecule in the fraction under study. 

The role of oxygen and hydrogen solutions in the metal catalyst does not appear to be that of impeding the major reactions, but merely to provide a source of these reactants which is uniformly distributed diroughout the catalyst particles, without decreasing die number of surface sites available to methane adsorption. It is drerefore quite possible that a significatit fraction of the reaction takes place by the formation of products between species adsorbed on the surface, and dissolved atoms just below the surface, but in adjacent sites to the active surface sites. 

Ross (R2) measured liquid-phase holdup and residence-time distribution by a tracer-pulse technique. Experiments were carried out for cocurrent flow in model columns of 2- and 4-in. diameter with air and water as fluid media, as well as in pilot-scale and industrial-scale reactors of 2-in. and 6.5-ft diameters used for the catalytic hydrogenation of petroleum fractions. The columns were packed with commercial cylindrical catalyst pellets of -in. diameter and length. The liquid holdup was from 40 to 50% of total bed volume for nominal liquid velocities from 8 to 200 ft/hr in the model reactors, from 26 to 32% of volume for nominal liquid velocities from 6 to 10.5 ft/hr in the pilot unit, and from 20 to 27 % for nominal liquid velocities from 27.9 to 68.6 ft/hr in the industrial unit. In that work, a few sets of results of residence-time distribution experiments are reported in graphical form, as tracer-response curves. 

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