Dissociation reversible

BrNO dissociates reversibly into NO and Br, the extent of dissociation being 7% at room temperature and 1 atm pressure. A similar reversible dissociation occurs with CINO at higher temperatures. 

Blue solid (mp -100.7°), dissociates reversibly in gas phase into NO and NO2... 

All six possible diatomic compounds between F, Cl, Br and I are known. Indeed, ICl was first made (independently) by J. L. Gay Lussac and H. Davy in 1813-4 soon after the isolation of the parent halogens themselves, and its existence led J. von Liebig to miss the discovery of the new element bromine, which has similar properties (p. 794). The compounds vary considerably in thermal stability CIF is extremely robust ICl and IBr are moderately stable and can be obtained in very pure crystalline form at room temperature BrCl readily dissociates reversibly into its... 

Most acids of physiologic importance are weak acids, which tend to dissociate reversibly into a proton and a conjugate base. 

Like chalk, limestone is largely calcium carbonate and dissociates reversibly to lime and carbon dioxide at sufficiently high temperatures (calcination) ... 

Generation of dichlorocarbene and its addition to an alkene in a two-phase system proceeds somewhat differently. Here a solution of an alkene in chloroform forms the organic phase the other is concentrated aqueous NaOH. The first step, deprotonation of chloroform, occurs at the phase boundary then the trichloromethyl anion formed at the phase boundary enters the organic phase in the form of ion pairs with Q+. Inside the organic phase the anions dissociate reversibly to dichlorocarbene and Q+C1 exchanges anions at the phase boundary so that Cl passes into the aqueous phase and another trichloromethyl anion into the organic phase. Anions are transferred to the organic phase not from the aqueous phase but from the phase boundary. Reference 5 contains additional details. 

Fio. 7. Schematic diagram of RNase-S system. The single bond is cleaved converting RNase-A to RNase-S. Ribonuclease-S dissociates reversibly to S-peptide-f-S-protein. The latter can recombine with denatured forms of RNase-A where the tail is loosened from the rest of the molecule. Reproduced from Richards (91a). 

Valinomycin is one of a group of compounds termed ionophores, which facilitate movement of ions across phospholipid membranes. Valinomycin has the cyclic structure f-t>valine-lactate-L-valine-hydroxy valerate-] 3. This figure shows the structure of the complex formed between valinomycin and K+. The complex is soluble in organic solvents and can pass through the phospholipid bilayer of the mitochondrial inner membrane. K+ dissociates reversibly from the complex in the aqueous solution on either side of the membrane. 

In Section 11.7 of Chapter 11, we summarized equations that can be used with electrochemical cell measurements to determine Ka and Kw for the dissociation (reverse of association) of an acid and of water, assuming a weak electrolyte standard state. If care is taken to obtain reversible conditions, this method, which does involve thermodynamic measurements, is a good one for determining K. Another method often employed involves using conductance measurements. The assumption is made that a, the degree of ionization or dissociation of an electrolyte is given by the ratio A/A. That is,... 

Thermal cycloreversion of the adducts can be accomplished at a convenient rate when heated in toluene under reflux. If a new diene is present in the reaction mixture, the thioaldehyde thus generated in the retro-Diels-Alder reaction may give a new adduct. Therefore, adducts 81 and 82 act as thioaldehyde or thioketone transfer reagents. These adducts dissociate reversibly on heating, thus ensuring that the concentration of the labile species remains very low. For this reason, polymerization is not a serious problem especially in the case of thioaldehydes224. The transient thiocarbonyl compounds can be trapped not only by dienes but also by 1,3-dipolar cycloadditions332 (equation 85). 

Me3Si)2C5H3]U CO [(Me3Si)2C5H3]U(CO) n Uranium-to-carbonyl n-backbonding takes place. The product dissociates reversibly 268... 

Triorganoantimony(V) carboxylates are monomeric. Pyrolysis of trimethylantimony bis phenylbromoacetate in xylene yields trimethylantimony(V) bromide and mandelic acid polyester325. However, the pyrolysis of triphenylantimony(V) acetate proceeds via a radical reaction and yields triphenylantimony and acetic acid333. Trimethylantimony bis thio benzoate, on the other hand, appears to dissociate reversibly as shown below334 ... 

To explain the half power relationships in hydrogen concentration Natta et al. [137] have suggested that the hydrogen dissociates reversibly under the influence of the catalyst. A rate coefficient of 3 1 mole s" has been obtained for the system 7-TiCl3/AlEt2 Cl and ethylene [133], approximately one-thirtieth of the propE ation rate coefficient. 

The Pt(IV) product dissociates reversibly in solution to generate a Pt(II) complex and MeaSnH ... 

The dissociations (reversible) and decompositions (irreversible) of oxides have not been the subject of many reviews, though the properties of these phases have been discussed with reference to allied topics, including the oxidation of metals, catalysis, etc. Dollimore [22] has reviewed the applications of the techniques of thermal analysis to the dissociation of single oxide systems. 

On heating, many hydrides dissociate reversibly into the metal and Hj gas. The rate of gas evolution is a function of both temperature and /KH2) but will proceed to completion if the volatile product is removed continuously [1], which is experimentally difficult in many systems. The combination of hydrogen atoms at the metal surface to yield Hj may be slow [2] and is comparable with many heterogeneous catalytic reactions. While much is known about the mobility of H within many metallic hydride phases, the gas evolution step is influenced by additional rate controlling factors. Depending on surface conditions, the surface-to-volume ratio and the impurities present, the rate of Hj release may be determined by either the rate at which hydrogen arrives at the solid-gas inteifece (diffusion control), or by the rate of desorption. 

In chemistry and biochemistry, a dissociation constant is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions. The dissociation constant is often also denoted as Kj and is the inverse ofthe affinity constant. In the special case of salts, the dissociation constant can also be called ionization constant. 

---