Butane solubility

Water extraction would be a very poor choice for isolation of butanal, because, butanal solubility in water is relatively low. Considerable energy would be required to isolate butanal that is dissolved in the aqueous fraction. The solubility of aldehyde... 

Fig. 19. Solubility of aluminum chloride and antimony chloride in normal butane. (Solubility of AlCb-Hydrocarbon Complex is less than 0.1%.)...

Insoluble in water, soluble in organic solvents b.p. — 15°C. Prepared by treating 1,4-dibromo-butane with metallic sodium. Reduced to n-butane by hydrogen at 200" C in presence of nickel catalysts. 

About 86% of Hoechst s butanal is produced with the Rhc )ne-Poulenc water-soluble rhodium catalyst the remainder is stiU based on cobalt. 

The butanes and butenes have only limited physical solubility in ammoniacal cuprous acetate solutions. Compounds of higher unsaturation (dienes and acetylenes) form addition complexes, so their effective solubilities are much higher. 

Table 5.3-3 Solubilities of 1-butene and M-butane in the acidic mixture composed of l-butyl-3-methylimida-zolium ([BMIM]) chloride/alumini-um chloride/ ethylaluminium dichloride (1 1.22 0.06 molar ratio) as a function of temperature under atmospheric pressure.

Alcohols with low molar masses are liquids, and alcohols have much lower vapor pressures than do hydrocarbons with approximately the same molar mass. For example, ethanol is a liquid at room temperature, but butane, which has a higher molar mass than ethanol, is a gas. The relatively low volatility of alcohols is a sign of the strength of hydrogen bonds. The ability of alcohols to form hydrogen bonds also accounts for the solubility in water of alcohols with low molar mass. 

The simplest transition metal carbonyls are mononuclear of the type M(CO)x, in other words those with only one metal atom. They are hydrophobic but soluble to some extent in nonpolar liquids, such as n-butane or propane. The dinuclear carbonyls are more complex but have the same general characteristics as the mononuclear carbonyls. The carbonyls, which are or could be used in CVD, are listed in Table 3.4 with some of their properties. 

An example of a large scale application of the aqueous biphasic concept is the Ruhrchemie/Rhone-Poulenc process for the hydroformylation of propylene to n-butanal (Eqn. (15)), which employs a water-soluble rhodium(I) complex of trisulphonated triphenylphosphine (tppts) as the catalyst (Cornils and Wiebus, 1996). 

FIGURE 2.1.1.1.6.1 Logarithm of mole fraction solubility (In x) versus reciprocal temperature for 2,3-dimethyl-butane. 

Bidentate chiral water-soluble ligands such as (S,S)-2,4-bis(diphenyl-sulfonatophosphino)butane BDPPTS (Fig. 2) or (R,R) 1,2-bis(diphenylsul-fonatophosphinomethyl)cyclobutane have been prepared [25]. Their palladium complexes catalyze the synthesis of chiral acids from various viny-larenes and an ee of 43% has been reached for p-methoxystyrene with the BDPPTS ligand. Furthermore, recycling of the aqueous phase has shown that the regio- and enantioselectivity are maintained and that no palladium leaches. 

H2 3 8 and H2 4H10 systems, however, agreement is excellent in all cases including the liquid-liquid equilibria at lower temperatures. With butane, deviations occur at 477 K, but the rather unusual behaviour of the liquid solubility line is well represented. 

The third generation process concerns the Ruhrchemie/Rhone-Poulenc process utilizing a two-phase system containing water-soluble rhodium-tppts in one phase and the product butanal in the organic phase. The process has been in operation since 1984 by Ruhrchemie (or Celanese, nowadays). The system will be discussed in section 8.2.5. Since 1995 this process is also used for the hydroformylation of 1-butene. 

Blais, C. and Hayduk, W. Solubility of butane and isobutane in butanol, chlorobenzene, and carbon tetrachloride. /. Chem. Eng. Data, 28(2) 181-183, 1983. 

Hayduk, W., Asatani, H., and Miyano, Y. Solubilities of propene, butane, isobutane and isobutene gases in n-octane, chlorobenzene and n-butanol solvents, Can. J. Chem. Eng., 66 466-473, 1988. 

The only other olefin feedstock which is hydroformylated in an aqueous/organic biphasic system is a mixture of butenes and butanes called raffinate-II [8,61,62]. This low-pressure hydroformylation is very much like the RCH-RP process for the production of butyraldehyde and uses the same catalyst. Since butenes have lower solubility in water than propene, satisfactory reaction rates are obtained only with increased catalyst concentrations. Otherwise the process parameters are similar (Scheme 4.3), so much that hydroformylation of raffinate-11 or propene can even be carried out in the same unit by slight adjustment of operating parameters. 

The liquid solubilities of propane, isobutane, and normal butane in hydrogen fluoride and the liquid solubilities of hydrogen fluoride in these three hydrocarbons in the temperature range 0 to 50°C. are given by the following equations. 

Figure 6.6 The water solubility of butane derivatives by substitution groups...

---