Acetic acid molecular model

Ketones react with alcohols to yield products called acetals. Why does the all-cis isomer of 4- cvf-butyl-l13-cyclohexanediol react readily with acetone and an acid cataty st to form an acetal while other stereoisomers do not react In formulating your answer, draw the more stable chair conformations of all four stereoisomers and the product acetal. Use molecular models for help. 

Howardt describes a model system used to test the molecular weight distribution of a condensation polymer The polymer sample was an acetic acid-stabilized equilibrium nylon-6,6. Analysis showed it to have the following end group composition (in equivalents per 10 g) acetyl = 28.9,... 

That the high degree of torsional and other types of strain inherent in the triplet states or trans conformers of cyclohexene and cycloheptene may be responsible for their photochemical behavior is suggested by the reactions of compound (50), a moderately twisted olefin according to molecular models. Compound (50) quantitatively yields bicyclo[3.3.1]non-l-yl acetate (51) within 15 sec after being dissolved in glacial acetic acid(83> ... 

About the same time Beutier and Renon (11) also proposed a similar model for the representation of the equilibria in aqueous solutions of weak electrolytes. The vapor was assumed to be an ideal gas and < >a was set equal to unity. Pitzer s method was used for the estimation of the activity coefficients, but, in contrast to Edwards et al. (j)), two ternary parameters in the activity coefficient expression were employed. These were obtained from data on the two-solute systems It was found that the equilibria in the systems NH3+ H2S+H20, NH3+C02+H20 and NH3+S02+H20 could be represented very well up to high concentrations of the ionic species. However, the model was unreliable at high concentrations of undissociated ammonia. Edwards et al. (1 2) have recently proposed a new expression for the representation of the activity coefficients in the NH3+H20 system, over the complete concentration range from pure water to pure NH3. it appears that this area will assume increasing importance and that one must be able to represent activity coefficients in the region of high concentrations of molecular species as well as in dilute solutions. Cruz and Renon (13) have proposed an expression which combines the equations for electrolytes with the non-random two-liquid (NRTL) model for non-electrolytes in order to represent the complete composition range. In a later publication, Cruz and Renon (J4J, this model was applied to the acetic acid-water system. 

The synthesis of a water-soluble diphenylmethano-bridged fullerene 122 was achieved by hydrolyzing the bis (acetamide) 121 with acetic acid-aqueous hydrochloric acid and then converting it into the bis(succinamide) 122 by treatment with succinic anhydride (Scheme 4.25) [158]. Compound 122 is soluble in water at pH > 7. This is an important requirement for the investigation of the biological activity of fullerenes. Remarkably, 122 is an inhibitor for the HIV enzymes protease (HIV-P) and reverse transcriptase (HIV-RT) [159]. As suggested by molecular modeling. 

Fe20(0Ac)2Cl2(bipy)2 successfully hydroxylates C6, C3, and C2 alkanes when tert-butyl hydrogen peroxide (TBHP) is used as the oxygen donor ([5] [TBHP]-.[substrate] = 1 150 1100) the observed reactivity is C6 > C3 > C2 (Table IV). This work represents the first report of the oxidation of a small molecular weight alkane (ethane) by a characterized iron model compound. Reactions of this complex with Zn dust and acetic acid under 1 atm of dioxygen with cyclohexane gave rise to only cyclohexanone (turnover number 2.5). The parent tetrameric compound, 6, was reported to be a more efficient catalyst. 

Figure 2.6 Molecular models of (a) acetic acid, CH3CO2H. (al Spacefilling (b) ball-and-stick...

In this study the molecular orbital calculation program employed, ARCANA, utilized only atomic data and iterated to charge self-consistency (see Calculation Note). The substrates, ACh and ASCh, and the products of hydrolysis, choline, thiocholine, and acetic acid, were represented in their entirety, while the AChE enzymic active site was modeled by representing the histidine residue and the serine residue thought to be at the active site by imidazol and methanol respectively. Molecular orbital calculations have been performed for reactants, three possible intermediate acylation complexes, and the acylation products. Since the deacylation mechanism is identical for both ACh and ASCh and has been reported elsewhere (14), those results will not be repeated here. For eacF of the acylation steps, three cases were calculated (a) general acid catalyzed,... 

Fig. 2 Reactions at the hydroxyl groups of glycosyl residues of oligo-/polysaccharides. (A) Basic a(l 4) linked glycosyl residue. (B) Oxidation at C6 position to form uronic acid. (C) Oxidation/substitution at C2 position to form acetate. (D) Oxidation/ substitution at C2 position to form glucosyl-2-amine. (E) Oxidation/substitution/compatibilization at C2 position to form glucosyl-2-A-acetyl. (F) Oxidation/substitution/compatibilization at C4 position compatibilization glycosyl-4-sulfate. (G) Oxidation/activation at C6 position compatibilization glucosyl-6-phosphate. (Molecular modeling SWEET, http //www.dkfz-heidelberg.de/spec/sweet2/doc/index.php. Chemistry MDL ISIS/draw.) (View this art in color at www.dekker.com.)...

Make molecular models of formic acid, a component of the sting of ants, and acetic acid, which is 5% of most vinegars. 

---