Propane as solvent

Daniels and Johnston have studied this decomposition in the gas phase and in a wide range of solvents and found that, except for nitric acid and 1,2-dichloro-propane as solvents, the rate of reaction was little affected by the medium (Table iy°. This is typical of unimolecular reactions occurring in both gaseous and liquid phases ... 

At this writing there are five commercial Solexol plants in regular service, and a sixth is under construction. Furthermore two of the Solexol units are supplemented by a continuous fractional crystallization (or winterizing) process, not heretofore announced, which goes by the name of Propane Destearnizing. As the name suggests, it also employs versatile propane as solvent. (Dickinson and Meyers, 1952.)... 

M. Harrod and 1. Elfman Enzymatic synthesis of phosphatidylcholine with fatty acid, isooctane, carbon dioxide, and propane as solvents. Journal of the American Oil Chemists Society 72 (1995) 641-646. 

A mixture of 50% oleic acid, 50% abietic acid is to be separated with the help of liquid propane as solvent in a countercurrent extraction with reflux. Equilibrium data are available at 81, 91, and 96.7°C. (Hixson and Hixson, Trans. Am. Inst. Cliem. Engrs. 37, 927 (1941). 

Propane deasphalting uses propane as an anti-solvent for asphaltenes. 

Determination of organic compounds. The application of photometric titrimetry to organic compounds may be exemplified by the titration of phenols. This can be carried out by working at the /max value (in the ultraviolet) for the phenol being determined (see Section 17.50). It has been shown that by titrating with tetra-n-butylammonium hydroxide and using propan-2-ol as solvent, it is possible to differentiate between substituted phenols.24... 

Cu(II) EPR signal in nitriles as solvent as well as by polarographic measurements 144>. Similarly, the EPR signal disappeared when Cu(OTf)2 was used for catalytic cyclo-propanation of olefins with diazoesters 64). In these cases, no evidence for radical-chain reactions has been reported, however. The Cu(acac)2- or Cu(hfacac)2-eatalyzed decomposition of N2CHCOOEt, N2C(COOEt)2, MeCOC(N2)COOEt and N2CHCOCOOEt in the presence of cyclopropyl-substituted ethylenes did not furnish any products derived from a cyclopropylcarbinyl - butenyl rearrangement128. These results rule out the possible participation of electron-transfer processes and radical intermediates which would arise from interaction between the olefin and a radical species derived from the diazocarbonyl compound. 

Micelle formation of our block copolymers in fluorinated solvents indicates that these polymers might act as stabilizers or surfactants in a number of stabilization problems with high technological impact, e.g., the surface between standard polymers and media with very low cohesion energy such as short-chain hydrocarbons (isopentane, butane, propane), fluorinated solvents (hexafluoroben-zene, perfluoro(methylcyclohexane), perfluorohexane) and supercritical C02. As... 

Propane was selected as solvent for the isobutene for experiments down to -145° the aluminium chloride was dissolved in ethyl chloride, for the work at lower temperatures a mixture of ethyl chloride and vinyl chloride was used. Although these catalyst solutions were made up at -78° they were yellow, and as stated above, they probably contained some hydrogen chloride and other catalytically active decomposition products. The polymerisations were carried out by running the cooled catalyst solution into the monomer solution. Polymer was formed, and came out of solution, almost immediately, and the reaction was very fast even at the lowest temperature (-185°) and lowest monomer concentration (0.6 mole/1). After the reaction was over, propanol at the reaction temperature was added to the reaction mixture to deactivate the catalyst. 

Propane deasphalting solvent deasphalting using propane as the solvent. 

Propane dewaxing a process for dewaxing lubricating oils in which propane serves as solvent. 

The homogeneous solvolysis of this substrate in aqueous ethanolic solvents can be monitored by the change in conductance as HCl is produced. Initial studies of the reaction in aqueous ethanol as solvent at 25 °C using a cleaning bath (45 kHz) revealed modest rate enhancements (up to about 2-fold) with the larger values being obtained in the more alcoholic media [37]. Similar results were found for the solvo-lyses in aqueous propan-2-ol and 2-methylpropan-2-ol. More substantial rate enhancements were obtained in the more ethanolic media and at lower temperature [38,39]. Detailed studies of the aqueous ethanol system led to the following main conclusions ... 

Propylene glycol. looks like propane with hydroxyl groups, -OH, substituted for a hydrogen on two adjacent carbons. Propylene glycol is also used to make polymers and in a variety of smaller applications such as solvents, humectants, and food additives. 

The first reported instance of stereoselective polymerization was probably the cationic polymerization of isobutyl vinyl ether in 1947 [Schildknecht et al., 1947]. A semicrystalline polymer was obtained when the reaction was carried out at —80 to —60°C using boron tri-fluoride etherate as the initiator with propane as the solvent. The full significance of the polymerization was not realized at the time as the crystallinity was attributed to a syndiotactic structure. X-Ray diffraction in 1956 indicated that the polymer was isotactic [Natta et al., 1956a,b], (NMR would have easily detected the isotactic structure, but NMR was not a routine tool in 1947.)... 

Nine units have been installed using liquid propane as a dewaxing solvent. 

Synthesis (Pohland, 1953 1955 1963 janssen and Karel (Janssen)1956 Sullivan et al., 1963) In the Grignard reaction of 3-dimethylamino-2-methyl-1-phenyl-propan-lone with benzylmagnesium chloride 4-dimethylamino-3-methyl-1,2-diphenyl-butan-2-ol is formed. The preferred product is the a-diastereomer(75 % a-form, 15 % p-form). The a-form crystallizes and the diastereomeric p-form remains in solution, because of its better solubility. Racemic resolution to obtain the analgetically (+) enantiomer can be achieved on the pure a-Grignard product via fractional crystallization of the salts with D-camphorsulfonic acid. Alternatively the resolution can be achieved by treating the racemic mannich product 3-dimethylamino-2-methyl-1-phenyl-propan-1-one with (-)-dibenzoyltartaric acid in acetone as solvent. 

All four compounds are produced by the vapor-phase nitration of propane.197-199 Nitroalkanes are important as solvents and intermediates.199... 

Some Available Data. A brief list of extractive distillation processes of actual or potential commercial value is in Table 13.7 the column of remarks explains why this mode of separation is adopted. The leading applications are to the separation of close-boiling aromatic, naphthenic, and aliphatic hydrocarbons and of olefins from diolefins such as butadiene and isoprene. Miscellaneous separations include propane from propylene with acrylonitrile as solvent (DuPont, U.S. Pat. 2,980,727) and ethanol from propanol with water as solvent [Fig. 13.24(b)],... 

A well-stirred solution of 0.09 g l-(2,5-dimethoxy-4-(2-hydroxy-ethyl)phenyl)-2-(2,2,2-trifluoroacetamido)propane in 15 mL CH,C12 was cooled to -78 °C and treated with 0.05 g diethylaminosulfur trifluoride (DAST) added dropwise. The pale yellow reaction solution was stirred an additional 5 min and then brought up to room temperature and stirred for 1 h. There was then added (cautiously) 3 mL H20 followed by additional CH2C12. The phases were separated, the organic phase washed with H20, dried with anhydrous Na.SO, and, after filtering off the drying agent, stripped of solvent under vacuum. There was thus obtained 0.088 g of l-[2,5-dimethoxy-4-(2-fluoroethyl)phenyl]-2-(2,2,2-trifluoro-acetamido)propane as a white solid with a mp of 102-104 °C. 

The promise shown by supercritical fluid extraction led to the development of the Solexol process for the purification and separation of vegetable and fish oils. This process concentrated the polyunsaturated triglycerides in vegetable oils and the so-called vitamin A values from fish oils using propane as a selective solvent [5]. 

Propane fractionation a continuous extraction process employing liquid propane as the solvent a variant of propane deasphalting (q.v.). 

---