Acetone substitution catalyst

The Tokuyama Soda single-step catalyst consists of a zirconium phosphate catalyst loaded with 0.1—0.5 wt % paHadium (93—97). Pilot-plant data report (93) that at 140°C, 3 MPa, and a H2 acetone mole ratio of 0.2, the MIBK selectivity is 95% at an acetone conversion of 30%. The reactor product does not contain light methyl substituted methyl pentanes, and allows MIBK recovery in a three-column train with a phase separator between the first and second columns. 

Cellulose acetate [9004-35-7] is the most important organic ester because of its broad appHcation in fibers and plastics it is prepared in multi-ton quantities with degrees of substitution (DS) ranging from that of hydrolyzed, water-soluble monoacetates to those of fully substituted triacetate (Table 1). Soluble cellulose acetate was first prepared in 1865 by heating cotton and acetic anhydride at 180°C (1). Using sulfuric acid as a catalyst permitted preparation at lower temperatures (2), and later, partial hydrolysis of the triacetate gave an acetone-soluble cellulose acetate (3). The solubiUty of partially hydrolyzed (secondary) cellulose acetate in less expensive and less toxic solvents such as acetone aided substantially in its subsequent commercial development. 

Production of cellulose esters from aromatic acids has not been commercialized because of unfavorable economics. These esters are usually prepared from highly reactive regenerated cellulose, and their physical properties do not differ markedly from cellulose esters prepared from the more readily available aHphatic acids. Benzoate esters have been prepared from regenerated cellulose with benzoyl chloride in pyridine—nitrobenzene (27) or benzene (28). These benzoate esters are soluble in common organic solvents such as acetone or chloroform. Benzoate esters, as well as the nitrochloro-, and methoxy-substituted benzoates, have been prepared from cellulose with the appropriate aromatic acid and chloroacetic anhydride as the impelling agent and magnesium perchlorate as the catalyst (29). 

Regardless of substrate and solvent, isomerization fell in the order 5% Pd-on-C 5% Rh-on-C > 5% Pt-on-C, and, regardless of substrate or catalyst, isomerization fell with solvent in the order ethanol > pentane > 1 1 benzene-ethanol. Benzene is effective as an isomerization inhibitor mixed with other solvents as well 1 20 benzene-acetone showed marked inhibition. Substituted benzenes are less effective than benzene. 

The ligandless Beletskaya catalysts, PdCl2(CH3CN)2 used in DMF or acetone with tin-substituted alkynes and sp -hybridized iodides and bromides. This system is very reactive and relatively cheap. The disadvantage is that it decomposes quickly under development of catalyticaUy inactive Pd-black particles [20 c]. 

The mono-ruthenium-substituted silicotungstate, [SiWn039Ru3+(H20)]5, synthesized by reaction of the lacunary POM Si Vn039 x with Ru3+ in acetone, was an efficient catalyst for the... 

Another use of acetone in the chemical industry is for bisphenol A ( ). BPA results form the condensation reaction of acetone and phenol in the presence of an appropriate catalyst. BPA is used in polycarbonate plastics, polyurethanes, and epoxy resins. Polycarbonate plastics are tough and durable and are often used as a glass substitute. Eyeglasses, safety glasses, and varieties of bullet-proof glass are made of polycarbonates. Additional... 

The crude N-methyltryptamine obtained above (which can be substituted with 1.20 g of pure NMT) was dissolved in 50 mL ethanol, treated with 1.0 mL acetone, then with 0.5 g 10% Pd/C, and the reaction mixture shaken under a hydrogen atmosphere at 50 psi for 15 h. The catalyst was removed by filtration through a bed of Celite, the filtrate was stripped of solvent under vacuum, and the solid residue recrystallized from Et20/hexane to give 0.93 g N-methyl-N-isopropyltryptamine (MIPT) which had a mp 82-83 °C. Fom the benzyloxycarbonyltryptamine,... 

Bender et al.136 have measured the rate of incorporation of, 80 from enriched water into several substituted benzoic acids. The catalyst was 0.07 M HC1, and the solvent 33% dioxan-water. The rate coefficients for exchange at 80°C are given in Table 14, which also contains a comparison of these rate coefficients with those for the hydrolysis of the corresponding ethyl esters, measured by Timm and Hinshelwood128 in 60% acetone and 60% ethanol. As noted earlier by Roberts and Urey, the absolute rates are very similar for the two reactions. Also, as expected, the exchange rate of benzoic acid, with two equivalent oxygen atoms, is almost exactly twice as fast as that of ethyl benzoate, with only one ( h.vdM< xch is 5.2 for the ester). 

It is worthy of note that - similarly to the proline catalyzed aldol reaction - the Mannich reaction can also be extended to an enantio- and diastereoselective process in which two stereogenic centers are formed in one step, although using non-chiral starting materials (Scheme 5.16) [22, 23, 26, 27, 28]. In these reactions substituted acetone or acetaldehyde derivatives, rather than acetone, serve as donor. In contrast with the anti diastereoselectivity observed for the aldol reaction (Section 6.2.1.2), the proline-catalyzed Mannich reaction furnishes products with syn diastereoselectivity [23]. A proline-derived catalyst, which led to the formation of anti Mannich products has, however, been found by the Barbas group [29]. 

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