Naphthalene reaction rates

When an azine-nitrogen and a leaving group are in the 2,3-relation to each other in monoaza- and polyaza-naphthalenes, there is a dramatic effect on the reaction rate (for 3-chloroisoquLnoline lO -lO -fold less than for its 1-chloro isomer and for 2-chloroquinoline 200-400-fold less than for 2-chloropyridine) due to restrictions imposed on the resonance stabilization of charge in the transition state by the bicyclic system ... 

Secondly, destannylation appears to be more sterically hindered than the hydrogen exchange reaction, since in the latter the a-position of naphthalene is rate-... 

Kinetic analysis with a Langmuir-type rate equation (Equation 13.4) [37] gave us the magnitudes of reaction rate constant (k) and retardation constant due to product naphthalene (K) for the superheated liquid film (0.30 g/1.0 mL) and the suspended states (0.30 g/3.0 mL) with the same Pt/C catalyst as summarized in Table 13.2. It is apparent that excellent performance with carbon-supported platinum nanoparticles in the superheated liquid-film state is realized in dehydrogenation catalysis on the basis of reaction rate and retardation constants. 

The same authors studied the CL of 4,4,-[oxalylbis(trifluoromethylsulfo-nyl)imino]to[4-methylmorphilinium trifluoromethane sulfonate] (METQ) with hydrogen peroxide and a fluorophor in the presence of a, p, y, and heptakis 2,6-di-O-methyl P-cyclodextrin [66], The fluorophors studied were rhodamine B (RH B), 8-aniline-l-naphthalene sulfonic acid (ANS), potassium 2-p-toluidinylnaph-thalene-6-sulfonate (TNS), and fluorescein. It was found that TNS, ANS, and fluorescein show CL intensity enhancement in all cyclodextrins, while the CL of rhodamine B is enhanced in a- and y-cyclodextrin and reduced in P-cyclodextrin medium. The enhancement factors were found in the range of 1.4 for rhodamine B in a-cyclodextrin and 300 for TNS in heptakis 2,6-di-O-methyl P-cyclodextrin. The authors conclude that this enhancement could be attributed to increases in reaction rate, excitation efficiency, and fluorescence efficiency of the emitting species. Inclusion of a reaction intermediate and fluorophore in the cyclodextrin cavity is proposed as one possible mechanism for the observed enhancement. 

Another isomerization reaction of arene oxides is equilibrium with oxe-pins [5], Here, the fused six-membered carbocycle and three-membered oxirane merge to form a seven-membered heterocycle, as shown in Fig. 10.2. An extensive computational and experimental study involving 75 epoxides of monocyclic, bicyclic, and polycyclic aromatic hydrocarbons has revealed much information on the structural factors that influence the reaction rate and position of equilibrium [11], Thus, some compounds were stable as oxepins (e.g., naphthalene 2,3-oxide), while others exhibited a balanced equilibrium... 

The importance of the strength of tt complex adsorption on the reaction rate through the operation of displacement effects is further demonstrated by naphthalene randomization reactions. Naphthalene exchanges very slowly with deuterium oxide. That this is due to the displacement of water by normal naphthalene and not due to a toxic side reaction, such as polymerization, is shown in randomization experiments with mono a-deuterated naphthalene. Randomization is completed within 24 hours at 120°, whereas no significant deuteration occurs under the same reaction conditions with water. This result furnishes additional proof for the dissociative exchange mechanism. 

In 1972, Miller made a detailed analysis of the data on the influence of electron acceptor additives on the yield of ionic products during radiolysis of organic matrices and showed this to agree quantitatively with the electron tunneling mechanism of the formation and annihilation of these particles [7], In particular, the annihilation of et) in MTHF glass containing naphthalene (Nh) as the additive was found to be accompanied by simultaneous formation of the Nh anion radical (via the reaction etj. + Nh - Nh ). The kinetic curves for this reaction at 77 and 87 K coincided, which ruled out the possibility of the reaction rate being determined by thermal diffusion. 

The presence of water in the sol ution is essential to the production of oxidized naphthalene compounds. As shown in Fig. 11.9, the reaction rate increased with increase of water content and reached the maximum at a water content of about 6%. 

The applicability of the reaction-rate formula in the intermediate-friction regime to the interpretation of conformational changes of bi-naphtyl in solution has been discussed.47 The intramolecular motion is governed by a bistable potential depending on a single variable, which is identified with the dihedral angle between the naphthalene moieties in binaphtyl. The influence of hydrodynamic interactions and coupling with the other coordinates of the molecules also are evoked. 

Continuous operations are feasible and practical (1) where the organic compound (benzene or naphthalene) can be volatilized, (2) when reaction rates are high (as in the chlorosulfonation of paraffins and the sulfonation of alcohols), and (3) where production is large (as in the manufacture of detergents, such as alkylaryl sulfonates). 

The epoxide formation is thought to proceed via Oxone-mediated dioxirane formation and inclusion of the aromatic moiety inside the cavity. The influence of the substrate binding inside the CD cavity was evaluated by inhibitory experiments with naphthalene-2-sulfonate, which is known to bind both a- and / -CD with good affinity. As expected, the addition of 2 equivalents of inhibitor to the reaction mixture resulted in a significant decrease in reaction rate. 

There is neither a partial positive nor a partial negative charge on the two nonequivalent positions 1 and 2 of naphthalene, which are poised for electrophilic substitution. One might consequently predict that electrophiles react with naphthalene without regiocontrol. Furthermore, this should occur with the same reaction rate with which benzene reacts. Both predictions contradict the experimental results For example, naphthalene is brominated with a 99 1 selectivity in the 1-position in comparison to the 2-position. The bromination at Cl takes place 12,000 times faster and the bromination at C2 120 times faster than the bromination of benzene. 

By using the additional simplifying assumptions that the number of active coal sites remains constant during the reaction and that the forward and reverse rate coefficients are equal, k = k, k. = k e and kx = k j, then the rate equations for theaincorftora-tTon or XH into the o and b positions of naphthalene reactions can be written... 

Recently Melander [88] attempted to clarify the influence of the proton loss on the nitration reaction rate by investigating this process using a number of aromatic compounds benzene, toluene, bromobenzene and naphthalene, in which one hydrogen atom had been replaced by tritium. 

Let us look at this naphthalene reaction in detail. The second-order rate constant for this reaction is... 

The selective oxidation reaction is carried out in excess air so that it can be considered pseudo-first-order with respect to naphthalene. Analysis of available data indicates that the reaction rate per unit mass of catalyst is represented by ... 

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