Generated Indole Reaction Mechanism Of Aniline And Ethylene Glycol

Indole is an important raw organic material and chemical product, which used in many fields such as industry, agriculture and medicine and so on. In recent years, the methods of synthesis indole are close to perfect, especially the one that indole is produced from aniline and glycol, which is the more economical than others. In this paper, it is based on the general transition state theory to study the intrinsic reaction mechanism of production of indole from aniline and glycol, and the rate constants of each reaction path are calculated, then the main reaction path is concluded from above calculation. The results as following:1 Because the products of indole, H2O and H2 were got from the experiment result, it is concluded that the reaction processes include the steps of dehydrogenation and dehydration. We projected four reaction paths as follows:2 The geometries of all reactants, immediate, transition states and productions are got from the option by using density function theory of GAUSSIAN 98 program. The geometry of indole we got from the calculation is consist with those got from theoretical and experimental results by others. 3 We illustrated the possible reaction paths of each channel, and gave the transition states of each reaction channels, then calculated the active energy of each reaction path.4 Analysis the imaginary vibration mode of all transition states in order to test the transition states. IRC (intrinsic reaction coordinate) is made using 6-31G* of the density function theory to confirm the existence of the transition states, further.5 Calculated the rate constant of each reaction path by using TST method under the temperature changed from 300K to 1000K. Three results were got from that. First, when the temperature is increasing, the rate constant also increasing. Second, (1) reaction channel is the mail reaction path. Third, when the temperature is close to 600K,the step of determinable reaction rate path is the one through the transition state TS1.6 It is glycol, not aniline, adopted in the surface of metal Ag in the step of determinable reaction rate path in the process of product indole from aniline and glycol catalyzed by metal Ag, then N7on aniline attack C15on the glycol-Ag complex. The active energy through transition state TS1' is 31.5kcal/mol, it is 26.5kcal/mol higher lower than transition state TS1 which is not catalyzed by metal Ag. In words, it takes an important role in the reaction path for the metal Ag to really decrease the active energy and quicken the reaction rate in the determinable reaction rate path.