Acetate synthesizing

Kinetic Studies Provide Only Limited Mechanistic Information. While such studies are invaluable and frequently indicate the nature of pre-rate-determining steps, they provide almost no information concerning such vital fast steps as electron transfers and rearrangements. For example, despite extensive studies of the kinetics of acetaldehyde and vinyl acetate syntheses, it is clear only that olefin, nucleophile, and palladium combine in a complex. The nature of the rate-determining step as well as the details of post-rate determining product forming steps remains uncertain (7,94). In some cases—e.g., the metal-catalyzed autoxi-dation of thiols to disulfides—re-oxidation of metal to its catalytically... 

The ammines of cobalt(II) are much less stable than those of cobalt(III) thermal decomposition of [Co(NH3)6]Cl2 is characterized by reversible loss of ammonia, whereas that of [Co(NH3)6]Cl3 is not. In his classic dichotomy of complexes, Biltz regarded [Co (NH 3)3] Cl 2 as the prototype of the normal complex and [Co(NH3)6]Cl3 as that of the Werner or penetration complex. Hexaamminecobalt-(II) chloride has been prepared by the action of gaseous ammonia on anhydrous cobalt (II) chloride or by displacing water from cobalt(II) chloride 6-hydrate with gaseous ammonia. It may also be synthesized in nonaqueous solvents by passing dry ammonia through solutions of cobalt(II) chloride in ethanol, acetone, or methyl acetate. Syntheses in the presence of water include heating cobalt(II) chloride 6-hydrate in a sealed tube with aqueous ammonia and alcohol and the treatment of aqueous cobalt(II) chloride with aqueous ammonia followed by precipitation of the product with ethanol. The latter method is used in this synthesis. Inasmuch as the compound is readily oxidized by air, especially when wet, the synthesis should be performed in an inert atmosphere. 

The substituted cyclopropenone acetal synthesized in Step B can be readily hydrolyzed to the corresponding cyclopropenone. This synthetic sequence provides the best and most versatile current synthetic route to substituted cyclopropenones. The deficiencies of conventional procedures are precisely the synthesis of cyclopropenones with aliphatic substituents and functional groups, for which the present method has proven to be particularly useful. ... 

The chemistry of acetate on transition metal surfaces is important for a variety of selective oxidation processes. Methanol and vinyl acetate syntheses are two such important oxidation chemistries where acetate intermediates have been postulated. In VAM synthesis, acetate is a critical intermediate in both VAM formation, as well as in its decomposition to CO2. The latter unselective decarboxylation path becomes important at higher operating temperatures. Understanding the mechanism for decarboxylation and VAM synthesis may ultimately aid in the design of new catalyst formulations on new operating conditions. 

Paramethasone acetate (6a-fluoro-1 6a-methyl-11 (3-17,21 -trihydroxypregna-1,4-diene-3,20-dione 21 -acetate), synthesized in 1960, retains the 16a-methyl group, but the 9a-fluoro substituent has been moved to the 6a position. It was thought that this manipulation would reduoe the eleotrolyte loss assooiated with dexamethasone. Reports in the literature indioate that paramethasone oauses a slight loss of sodium and chloride with little or no loss of potassium (with doses as large as 15 mg). An analysis of oontinuous therapy over 9 months, however, showed that the therapeutio effioaoy of paramethasone did not differ greatly from that of fluprednisolone (74). 

Acetal (Section 16.7B) A functional group, consisting of a carbon bonded to alkoxy groups [i.e., RCH(0R )2 or R2C(OR )2], derived by adding 2 molar equivalents of an alcohol to an aldehyde or ketone. An acetal synthesized from a ketone is sometimes called a ketal. 

Table III. Ethyl Acetate Synthesized from Sodium Acetate and Ethyl Bromide, as a Function of the Catalyst Used under GL-PTC Conditions.

Characterization MJgmoX = 110000, 23 mol% methyl acrylate, 3.5 mol% vinyl acetate, synthesized in the laboratory ... 

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