Reaction path branching

Such nuances notwithstanding, the symptom of a network with parallel first-order reactions to all three products emerges quite clearly from this single experiment. Even so, however, the question remains open where exactly the reaction path branches and how the rate depends on the partial pressures of CO and H2. We shall return to this interesting type of reaction in later examples (Examples 5.3, 6.5, 7.5, 11.2, 12.1, and 12.2). 

Quapp, W. How does a reaction path branching take place A classification of bifurcation events. /. Mol. Struct. 2004, 695, 95-101. 

Baker J and Gill P M W 1988 An algorithm for the location of branching points on reaction paths J. Comput. Chem. 9 465... 

The issue of regioselectivity arises with arylhydrazones of unsymmetrical ketones which can form two different enehydrazine intermediates. Under the conditions used most commonly for Fischer cyclizations, e g. ethanolic HCI, the major product is usually the one arising from the more highly substituted enehydrazine. Thus methyl ketones usually give 2-methy indoles and cycliz-ation occurs in a branched chain in preference to a straight chain. This regioselectivity is attributed to the greater stability of the more substituted enhydrazine and its dominance of the reaction path. 

Our hypothesis for discussion in this section has been that the conical intersection can be characterized like any other reactive intermediate. On examining Figure 9.3 or 9.10, it is clear that a conical intersection divides the excited-state branch of the reaction path from the ground-state branch in a photochemical transformation. (We shall... 

We have established an important principle in electron transfer theory that is not present in conventional one-dimensional models. The reaction coordinate is always localizing and corresponds to coordinate Aj. The coordinate X2 corresponds to the direction in which the matrix element between ground and excited states is switched on. If this coordinate has zero length then the branching space becomes one dimensional and an adiabatic reaction path does not exist. We now consider two examples. 

There was a thermodynamic preference for the reaction to take place at the terminal alkene carbon, which favors the yield of linear aldehyde, but the TS to linear aldehyde path was higher than the TS for the branched aldehyde path. Regioselectivity was evaluated from the products relative stability, i.e. considering that the reaction is under thermodynamic rather than under kinetic control. The linear to branched ratio (l b) of 94 6 was in excellent agreement with the ratio 95 5 reported for PPh3 [25], However, this nice coincidence must be viewed cautiously because the model is simple, reaction paths were partially considered, so a subtle cancellation of errors may have been made. 

Abstract PAMAM types polyether based dendrimers were synthesized from three branched Jeffamines . Synthesized compounds bears metylester/ferf-butylester, caiboxylic acid or amine groups. In the synthesis iterative Micheal type of reaction paths were followed. Catalytic properties of the molecules were studied in homogenous phase. 

A branch reaction is when the reactants may form different products. It is similar to a parallel reaction in that there are different paths, but unlike a parallel reaction in that the different paths lead to different products for a branch reaction but to the same product (eventually) for a parallel reaction. For example, undergoes a branch reaction, one branch to " Ar and the other to °Ca. 

The interpretation of the anodic branch of LSV for p-Si is apparently more simple because the current increases following an exponential variation with a Tafel slope of 60-80 mV/decade. In this case, an accumulation layer is generated, and then the current is only controlled by the kinetics of the electrochemical reaction, which involves several successive steps. It is not necessary to account for the various reaction paths proposed by many authors. 

Unsaturated fluorinated compounds are fundamentally different from those of hydrocarbon chemistry. Whereas conventional alkenes are electron rich at the double bond, fluoroal-kenes suffer from a deficiency of electrons due to the negative inductive effect. Therefore, fluoroalkenes react smoothly in a very typical way with oxygen, sulfur, nitrogen and carbon nucleophiles.31 Usually, the reaction path of the addition or addition-elimination reaction goes through an intermediate carbanion. The reaction conditions decide whether the product is saturated or unsaturated and if vinylic or allylic substitution is required. Highly branched fluoroalkenes, obtained from the fluoride-initiated ionic oligomerization of tetrafluoroethene or hexafluoropropene, are different and more complex in their reactions and reactivities. 

One of the reaction intermediates seems to be swiftly and reversibly converted to 1,4- dihydropyridine structure via a side path branching off from the main path. 

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