Ketones selective, solvent effect

While reaction solvents are not necessary for the process of this invention, suitable solvents may be employed if desired. If solvents are used it is necessary to select solvents which per se are not alkylated, i.e.,those which are inert to the alkylation effects of the dialkyl sulfate. Suitable such non-alkylatable solvents are diethyl ether, dioxane, acetone methyl ethyl ketone, ethyl acetate, butyl acetate, tetrahydrofu-ran, and the like. When the desired compound is recovered by pouring the reaction mixture into water after the completion of the reaction, solvents such as dioxane, acetone and methyl ethyl ketone miscible with water are preferably used. For instance, acetone is preferred. Agitation causes the reaction to proceed rapidly. The reaction time can be varied over a wide range depending upon conditions such as reaction temperature and agitation. For example, the reaction time can vary from several tens of minutes to several days. When the reaction is completed, which... [Pg.163]

Selected Solvents on the Relative Volatility of a Binary System Consisting of 1-Octene and 2-Flexanone," Fluid Phase Equilibria, Vol. 143, 1998, pages 173 to 184. This research is an attempt to generalize the effect on a single binary azeotrope of 31 specific solvents. The selected azeotrope, octene-1 and methyl butyl ketone (2-hexanone) (112 3 C, 31% ketone), is unique. The Ra between its two components is small, only 4.8 MPa . But the internal electrostatic properties of the olefin and ketone are quite different dipole moments are not similar (0.34 D vs. 2.66 D) nor are the dielectric constants (2.08 and 14.56) respectively. [Pg.175]

Seleninic acids Seleninic adds of the type used for alkene epoxidation (c Section 4.3.2.3) have also been employed as catalysts for the Baeyer-VUhger oxidation of ketones with hydrogen peroxide, mainly by Syper [57] and by Sheldon et al. [58,59]. In most cases, halogenated solvents such as dichloromethane or l,2-didiloroethane were used. In a study of solvent effects, Sheldon et cd. observed that, once again, TFE and in particular 1,1,1,3,3,3-hexafluoro-2-propanol are superior to dichloromethane with regard to selectivity and rate [58]. However, the effects are not as pronounced as in the case of alkene epoxidation (e.g., a factor of about 2 in rate between dichloromethane and HFIP, and 1.3 for TFE). The Baeyer-Villiger oxidation of a series of ketones and aldehydes was studied in TFE, and the results are summarized in Table 4.3 [58]. [Pg.141]

For certain surfaces, it is only necessary to wipe the surface with a selected solvent to remove oil, grease, and loose dirt. The use of detergent solutions, isopropanol, ketones, and aliphatic and aromatic hydrocarbons for this purpose can be effective. The major requirement for the process is that the wipe shall not leave a residual contaminant, but rather a clean, dry metal surface. Such a cleaning procedure is used on previously cleaned steel, stainless steel surfaces, and old paint films before overcoating, or on dirty steel prior to abrasive blasting. [Pg.660]

Santamaria, J. and Jroundi, R., Electron transfer activation — a selective photooxidation method for the preparation of aromatic aldehydes and ketones. Tetrahedron Lett., 32, 4291, 1991. Bokobza, L. and Santamaria, J., Exciplex and radical ion intermediates in electron transfer reactions. Solvent effect on the photo-oxygenation of 1,4-dimethylnaphthalene sensitized by 9,10-dicyanoan-thracene,/. Chem. Soc., Perkin Trans. 2, 269, 1985. [Pg.108]

The most selective 4-substitution is obtained in the Friedel-Crafts isopropylation of 2-acetylthiophene, which under certain conditions gives as much as 99% of this isomer and 1% of the 5-isomer. An--other case of selective 4-substitution is the bromination of 2-thienyl alkyl ketones using the swamping catalyst effect (i.e., brominating in the presence of excess AlCb without solvent), which yields 43-63% of apparently isomer-free 4-bromo-2-thienyl alkyl ketones. Gold-farb et al. also have applied this method to the chloromethylation of... [Pg.52]

In almost all theoretical studies of AGf , it is postulated or tacitly understood that when an ion is transferred across the 0/W interface, it strips off solvated molecules completely, and hence the crystal ionic radius is usually employed for the calculation of AGfr°. Although Abraham and Liszi [17], in considering the transfer between mutually saturated solvents, were aware of the effects of hydration of ions in organic solvents in which water is quite soluble (e.g., 1-octanol, 1-pentanol, and methylisobutyl ketone), they concluded that in solvents such as NB andl,2-DCE, the solubility of water is rather small and most ions in the water-saturated solvent exist as unhydrated entities. However, even a water-immiscible organic solvent such as NB dissolves a considerable amount of water (e.g., ca. 170mM H2O in NB). In such a medium, hydrophilic ions such as Li, Na, Ca, Ba, CH, and Br are selectively solvated by water. This phenomenon has become apparent since at least 1968 by solvent extraction studies with the Karl-Fischer method [35 5]. Rais et al. [35] and Iwachido and coworkers [36-39] determined hydration numbers, i.e., the number of coextracted water molecules, for alkali and alkaline earth metal... [Pg.49]

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