Co-proportionation reactions

Most interesting is the co-proportionation reaction 67, which is responsible for the accumulation of Mn centers. The Mn centers react much faster with Or than the... 

The most universal and facile techniques for the preparation ofthe derivatives of all three types of complexes are reactions of co-proportionation of TiHal4 with Ti(OR)4 [1204,1199] and also of action of AcOHal on Ti(OR)4 (in 1 1, 1 2 and 1 3 ratios). In the latter case the crystallization of solvates of TiCln(OR)4 AcOR composition is observed [215]. The preparation ofalkox-ofluorides has been achieved also with the use of SbF3 instead ofAcOF [259], The vacuum distillation of alkoxide chlorides is often accompanied by their disproportionation, and the separation in the form of adducts with pipyridine C5H10NH has been therefore proposed as an alternative [1204],... 

Carbon monoxide is the product of partial combustion of carbon, the A// being —110.4kJmol. Its enthalpy of dissociation (1073kJmol ) is the highest known for a diatomic molecule. In agreement with the oxidation state +11 for carbon, CO can be prepared by a syn-proportionation reaction (AG = +120.1 kJmoU ), favored at high temperature (equation 1). 

In preparative coordination diemistry mixed-ligand complexes are often prepared by co-proportionation of homoleptic complexes. The reaction between K2[Pt(NC>2)4] and K2[PtBr4] is representative/ Eq. 1.4 ... 

Linearity of Response and Reaction Products. The response vs. concentration curves obtained for CO, NO and NO2 gas sensor cells are depicted in Figures 5, 6 and 7 respectively. In all instances good linearity over the range studied was observed between current and partial pressure of each of the above gases (as depicted by equation (k)). The proportionality constants, K, with standard de-... 

The proportionality factor kAP in a rate equation such as 1.2 is the rate coefficient. In this book, rate coefficients are identified where necessary by double indices the first member refers to the reactant of the step, the second to the product. For example, the forward and reverse rate coefficients of a step A — K are kAK and kKA, respectively. Any co-reactants or co-products are ignored in the indices. Thus, the coefficient of the step K+B — L in the pathway 1.1 appears simply as kKL. The dimension of the rate coefficient depends on the reaction order (see Section 1.5) and the choice of concentration units. For example, the coefficient in eqns 1.2 has the dimension [V mol -1 t 1],... 

We have measured the synergism of dibutyltin dilaurate (DBTDL)-triethylenediamine catalyzed reactions of phenyl isocyanate with butanol and water at various concentrations of the tin and amine. As Tables I and II show, there is a lack of proportionality between the acceleration of the reaction and the concentration of the additives. If one assumes the tin catalyzed reaction is of second order and calculates the increase in rate constant due to the addition of amine co-catalyst, one finds that the addition of 0.02% amine based on isocyanate increases the rate of DBTDL catalyzed NCO-2-butanol by a factor of A.2. If one increases this amount of amine ten times, the resulting increase in the rate is only 5.30 times, while increasing the concentration of the amine by a factor of 100 results in an increase of the rate constant only by a factor of 7.1. 

The effect of the residence time on the IBA conversion and products selectivity at the temperature of 235C is drawn in Figure 1, for the Ko sample (ammoniacal salt) calcined at 320C. The proportionality between conversion and residence time allows to exclude diffusion as the rate-determining step. Moreover, it is shown that the selectivities to the various products were substantially independent on the conversion. This is in favour of a reaction network constituted of parallel reactions (probably sharing a common reaction intermediate, obtained by IBA activation) for the formation of methacryhc add, acetone plus CO2, propylene plus CO, and carbon oxides from combustion (1,4,7). 

The association reactions with CO and Hg were also measured with the SIFT method at 80 K. The rate constants k (80 K) = 2.9 x1and 3.6x10" cm molecule" s" together with k (300 K) (see footnotes and 9 of the table above) exhibit proportionality of k with T- and T- 3 [4]. 

Measurements of the reaction rate in rarefied carbon monoxide flames show a direct proportionality between the conversion of CO to CO2 (at low extents of conversion ruling out substantial heating of the gas) and the moisture content of the mixture [229] as well as the virtually complete termination of the reaction upon removal of moisture from the combustion zone in the course of the reaction. This is evidence that water vapour acts as a homogeneous catalyst in CO combustion. 

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