Methanol acetophenones

Tert-butyl cumyl peroxide 1,1-Dimethyl benzene methanol Acetophenone Tertiary butanol... 

To a few drops of formalin solution add a few drops of dinitro-phenylhydrazine reagent A (p. 263) a yellow precipitate is produced in the cold. Acetaldehyde and acetone give orange-coloured precipitates. Dissolve water-insoluble compounds e.g-y benzaldehyde, salicylalde-hyde, acetophenone and benzophenone) in a small volume of methanol before adding reagent B. With benzophenone the precipitate forms slowly. 

Oxidation of cumene to cumene hydroperoxide is usually achieved in three to four oxidizers in series, where the fractional conversion is about the same for each reactor. Fresh cumene and recycled cumene are fed to the first reactor. Air is bubbled in at the bottom of the reactor and leaves at the top of each reactor. The oxidizers are operated at low to moderate pressure. Due to the exothermic nature of the oxidation reaction, heat is generated and must be removed by external cooling. A portion of cumene reacts to form dimethylbenzyl alcohol and acetophenone. Methanol is formed in the acetophenone reaction and is further oxidized to formaldehyde and formic acid. A small amount of water is also formed by the various reactions. The selectivity of the oxidation reaction is a function of oxidation conditions temperature, conversion level, residence time, and oxygen partial pressure. Typical commercial yield of cumene hydroperoxide is about 95 mol % in the oxidizers. The reaction effluent is stripped off unreacted cumene which is then recycled as feedstock. Spent air from the oxidizers is treated to recover 99.99% of the cumene and other volatile organic compounds. 

More recently, the same type of hgand was used to form chiral iridium complexes, which were used as catalysts in the hydrogenation of ketones. The inclusion of hydrophihc substituents in the aromatic rings of the diphenylethylenediamine (Fig. 23) allowed the use of the corresponding complexes in water or water/alcohol solutions [72]. This method was optimized in order to recover and reuse the aqueous solution of the catalyst after product extraction with pentane. The combination of chiral 1,2-bis(p-methoxyphenyl)-N,M -dimethylethylenediamine and triethyleneglycol monomethyl ether in methanol/water was shown to be the best method, with up to six runs with total acetophenone conversion and 65-68% ee. Only in the seventh run did the yield and the enantioselectivity decrease slightly. 

Acetophenone was reduced in methanol to 1-phenylethanol at 20 °C by boro-hydride moieties coupled to a porous polymer resin [3], In principle, four hydrogen atoms can be released from the borohydride the reactivity, however, decreases with each hydrogen atom lost Experimentally it was shown that the first two atoms mainly contribute and to the reduction the other two remain on the polymer site. 

Detectability may be a significant problem with homologous series of unsaturated compounds, particularly //-alkanes. For these compounds, refractive index detection or evaporative light-scattering, both of which are described elsewhere in the book, may be of use. Indirect photometry is a useful detection scheme for compounds that do not absorb in the UV. Acetone, methylethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, and acetophenone are added to an acetonitrile/water mobile phase, generating a negative vacancy peak when the nonchro-mophoric analyte emerges and a positive peak if the ketone is adsorbed and displaced.70 Dodecyl, tetradecyl, cetyl, and stearyl alcohols also have been derivatized with 2-(4-carboxyphenyl)-5,6-dimethylbenzimidazole and the derivatives separated on Zorbax ODS in a mobile phase of methanol and 2-propanol.71... 

Product distributions and reaction conversions of several different photochemical systems, irradiated by conventional UV source and by EDL in a MW-UV reactor (Fig. 14.5), were compared to elucidate the advantages and disadvantages of a micro-wave photochemical reactor [90], Some reactions, e.g. photolysis of phenacyl benzoate in the presence of triethylamine or photoreduction of acetophenone by 2-propa-nol, were moderately enhanced by MW heating. The efficiency of chlorobenzene photosubstitution in methanol, on the other hand, increased dramatically with increasing reaction temperature. 

A value of kjkp = 17 000 has been determined for partitioning of the acetophenone oxocarbenium ion [12+] in water.15,16 It is not possible to estimate an equilibrium constant for the addition of water to [12+], because of the instability of the hemiketal product of this reaction. However, kinetic and thermodynamic parameters have been determined for the reaction of [12+] with methanol to form protonated acetophenone dimethyl ketal [12]-OMeH+ and for loss of a proton to form a-methoxystyrene [13] in water (Scheme 10).15,16 Substitution of these rate and equilibrium constants into equation (3) gives values of AMeoH = 6.5 kcal mol-1 and Ap = 13.8 kcal mol-1 for the intrinsic... 

When a solution of phenacyl halide 258 and excess tosyl hydrazide in methanol is heated to reflux, l-(tosylamido)-4-aryltriazole 261 is formed. The reaction proceeds presumably via dihydrazide derivative 259 that subsequently undergoes intramolecular cyclocondensation to triazoline 260. In the following step, the triazoline must be oxidized to the final triazole product 261. Mechanism of the oxidation is not quite clear, but the probable oxidant is the starting phenacyl halide, as a half of it is converted to the corresponding acetophenone tosylhydrazone that is isolated as the main side product of the reaction (Scheme 37) <2004H(63)1175>. 

Although the complex [RhCl(PPh3)3] is inactive towards the hydrogenation of ketones, the addition of triethylamine dramatically increases the rate. Yields were increased from only 0.5% to over 98% for the reduction of acetophenone at 50 °C under 71 bar H2 in a 1 1 mixture of methanol and benzene [45]. Several other ketones have been reduced this manner, including benzophenone, which has proved difficult (see above Fig. 15.8). 

The metal carbonyls Cr(CO)6, Mo(CO)6, W(CO)6 and Fe(CO)5 have all been tested in the hydrogenation of acetophenone in the presence of a strong base [61, 62]. In reactions performed in either triethylamine of sodium methoxide in methanol using 5 mol% of catalyst, the Mo and Cr complexes proved to be superior. The different bases had an effect on the yield that was further demonstrated when Cr(CO)6 was used in the hydrogenation of a series of ketones under the same conditions. In most cases, the reactions were found to be better in the methoxide system, with over 98% yields obtained in reactions lasting 3 h at 120 °C. 

Treatment of the nitronate salt 397 (from nitroethane and methanolic sodium methoxide) with benzene in the presence of trifluoromethanesulphonic acid gives acetophenone oxime, which is obtained mainly as the (E)-isomer 398433. 

Monomer I (MAA) was dissolved in methanol and I moI% of crosslinking agent, tetraethyleneglycol dimethylacrylate (TEGDMA) (Polysciences, Inc., Warrington, PA), and I wt% of initiator, 2,2-dimethoxy-2-phenyI acetophenone (DMPA Aldrich, Milwaukee, WI) were added. The solution was cast on glass plates equipped with spacers and reacted under an UV source with an intensity of 1 mW/cm for 30 min. Polymer I (PMAA) was removed from the plates, washed in deionized water to remove all unreacted monomers, cut into discs, and dried in a vacuum oven. 

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