Supercritical propane

Han S.J., Lohse D.J., Radosz M., and Sperling L.H. Thermoplastic vulcanizates from isotactic olypro-pylene and ethylene-propylene-diene terpolymer in supercritical propane Synthesis and morphology. Macromolecules, 31, 5407, 1998. 

ROSE (1) [Residuum Oil Supercritical Extraction] A process for extracting asphaltenes and resins from petroleum residues, using supercritical propane or isobutane as the extractant. Developed by Kerr-McGee Corporation in 1979 and sold to the MW Kellog Company in 1995, at which time 25 units had been licensed. 

By rapid expansion of supercritical propane solution (RESS), and isobaric crystallisation (ICSS), isotactic polypropylene and ethylene-butylene copolymers were precipitated from the supercritical solution. The RESS process produced microfibres with a trace of microparticles, while the ICSS process produced microcellular products. Improvement in thermal stability was achieved by first synthesising a thermoplastic vulcanisate from polypropylene and ethylene-propylene-diene terpolymer from a supercritical propane solution, followed by RESS. 28 refs. 

Crystallisation of isotactic PP from homogeneous solution in supercritical propane yielded open-cell foams of high surface area. Their morphology usually consisted of microspheres with a dense core and a porous periphery... 

The experimental results were clear-cut. The reaction under supercritical propane gave the exo/endo ratio decreasing from 5 to 2 with increasing... 

Propane or propane/C02 mixtures as liquid, near-critical, or supercritical fluids enhance the solubility of fats and oils (Harrod et al., 2000 Weidner and Richter, 1999). The decrease in viscosity and increase in diffusivity results in a higher hydrogenation rate (Figure 14.4). Harrod et al. (2000) have also demonstrated activity increases by reducing mass-transfer limitations in supercritical propane. 

We use a solvent miscible with both oil and hydrogen, thus forming a substantially homogeneous phase to pass the catalyst surface. The solvent is near-critical or supercritical propane. The oil does not prevent the hydrogen from entering the pores of the catalyst anymore. 

Figure 7. Selectivity as a function of reflux ratio for a supercritical propane extraction unit. Feed is an equimolar mixture of Tetrapentacontane and Hexacontane. Residue is 50 mass% of the feed. Solvent to feed ratio =15 1 Number of theoretical stages = 12 Temperature = 115°C...

Borealis A/S Polyethylene Ethylene, butene Slurry-loop process uses supercritical propane and a series gas-phase reactor produce tailor-made MW, enhanced LLDPEs, MDPEs, HDPEs 4 2000... 

The nonstatistical population is the group of molecules that directly cross the diradical and produce 32x. Carpenter hypothesized that with increasing pressure, collisions will become more common such that energy will be redistributed away from the modes that lead to direct crossing of the diradical, yielding a more statistical product distribution. In other words, collisions provide the barrier so that the momentum can be redirected. The reaction of 2>l-d2 was carried out in supercritical propane in order to control the pressure. The ratio of 32x to 32n did... 

Reverse micelle and microemulsion solutions are mixtures of a surfactant, a nonpolar fluid and a polar solvent (typically water) which contain organized surfactant assemblies. The properties of a micelle phase in supercritical propane and ethane have been characterized by conductivity, density, and solubility measurements. The phase behavior of surfactant-supercritical fluid solutions is shown to be dependent on pressure, in contrast to liquid systems where pressure has little or no effect. Potential applications of this new class of solvents are discussed. 

In contrast to ethane, the maximum amount of solubilized water in the supercritical propane-reverse micelle system is much higher, having a Wq value of 12 at 300 bar and 103 C. Again, the Wq values increase as pressure increases from a Wq value of 4 at 100 bar to 12 at 300 bar, as shown in Figure 3. The phase behavior in... 

Figure 7. Conductivity of reverse micelle phases in supercritical propane and liquid iso-octane at various pressures, W = 1.

Figure 2. Phase diagram of an. 4077water/supercritical propane system in the oil-rich comer of the temaiy phase diagram. The regions to the right of the solid lines are the one-phase, clear microemulsions. The various IV value lines ([H2O]/ [AOT]) are also indicated. The temperature of the system is 103°C. (Compositions are given in weight percent.)...

The development of the Borstar PE process, by Borealis, is a relatively recent development in multi-reactor processes. The foundation of this process is the utilization of supercritical propane as diluent in the slurry loop reactor.438 Operating the slurry loop in a supercritical condition provides several advantages over the tradition diluent (isobutane). The solubility of PE drops markedly at the supercritical point of propane, allowing the process to operate... 

Table 4 Fractionation of hydroxyl-terminated polybutadiene using supercritical propane at 130 C...

The Pd-catalyzed hydrogenation of fatty acids and their derivatives has been successfully performed using supercritical propane (scCsHg) 126] and SCCO2... 

Dickinson and Meyers go on to describe triglyceride refining plants, some of which operate at throughputs as high as 200,000 Ib/day. In the same vein of excitement as exhibited by the authors who wrote about propane deasphalting, the authors of the Solexol paper describe the properties of near-critical and supercritical propane and the ability to extend these properties to the development and, more importantly, to the commercialization of a propane refining process. 

McHugh and coworkers describe the fractionation of various poly(ethylene-co-methyl acrylate) copolymers using supercritical propane, propylene, 1-butene, and chlorodifluoromethane (Meilchen, Hasch, and McHugh, 1991 Pratt, Lee, and McHugh, 1993). The objective of their work was to extend the work of Krukonis and coworkers (Scholsky et al., 1987 Watkins and Krukonis, 1991) who demonstrated the ability of fractionating by chemical composition of the polymer as well as molecular weight. This concept is also described with other polymer-SCF solvent systems in the next few sections of this chapter. 

Table 9.21 Fractionation of Hydroxy-Terminated Polybutadiene with Supercritical Propane at 130°C...

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