Linear R-olefins (LAOs) find industrial use as high-value chemical intermediates. Most of the LAO production is based on ethylene oligomerization and does not yield a market-related product distribution. Various nonethylene-based LAO production routes have been evaluated and it was found that a process based on boron chemistry was the most likely to be successfully commercialized. Process flow diagrams for a low-temperature (150-200 °C) continuous boron-based process to produce LAOs from linear internal olefins are presented, showing that it can be designed with or without a solvent in the boron cycle. Experimental data are presented to illustrate progress made in understanding the chemistry associated with such a process. It is shown that (a) solvent exchange competes with hydroboration and is rate-controlling by regulating borane availability, (b) reactivity of substituted boranes is determined by the availability of the empty p z orbital of boron, (c) steric effects influence the rate of hydroboration and isomerization, (d) alkylborane isomer distribution is temperaturedependent and back-isomerization of terminally bonded alkylboranes is possible, and (e) thermal dehydroboration is more efficient than olefin liberation by displacement.
The direct liquefaction of coal in the iron-catalyzed Suplex process was evaluated as a technology
complementary to Fischer−Tropsch synthesis. A distinguishing feature of the Suplex process, from other direct
liquefaction processes, is the use of a combination of light- and heavy-oil fractions as the slurrying solvent.
This results in a product slate with a small residue fraction, a distillate/naphtha mass ratio of 6, and a 65.8
mass % yield of liquid fuel product on a dry, ash-free coal basis. The densities of the resulting naphtha (C5−200 °C) and distillate (200−400 °C) fractions from the hydroprocessing of the straight-run Suplex distillate
fraction were high (0.86 and 1.04 kg/L, respectively). The aromaticity of the distillate fraction was found to
be typical of coal liquefaction liquids, at 60−65%, with a Ramsbottom carbon residue content of 0.38 mass
%. Hydrotreatment of the distillate fraction under severe conditions (200 °C, 20.3 MPa, and 0.41 gfeed h-1
gcatalyst
-1) with a NiMo/Al2O3 catalyst gave a product with a phenol content of <1 ppm, a nitrogen content
<200 ppm, and a sulfur content <25 ppm. The temperature was found to be the main factor affecting diesel
fraction selectivity when operating at conditions of WHSV = 0.41 gfeed h-1 gcatalyst
-1 and P
H
2
= 20.3 MPa,
with excessively high temperatures (T > 420 °C) leading to a decrease in diesel selectivity. The fuels produced
by the hydroprocessing of the straight-run Suplex distillate fraction have properties that make them desirable
as blending components, with the diesel fraction having a cetane number of 48 and a density of 0.90 kg/L.
The gasoline fraction was found to have a research octane number (RON) of 66 and (N + 2A) value of 100,
making it ideal as a feedstock for catalytic reforming and further blending with Fischer−Tropsch liquids.
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