The reaction mechanisms between propargyl radical and ammonia (NH3) or methyl radical (CH3) have been studied by the Density Functional Theory (DFT) using the B3LYP functional in conjunction with the 6-311++G(3df,2p) basis set. Our calculations show that the C3H3 + NH3 reaction has two main entrance channels: H-abstraction and addition while other has only one type of entrance which is addition. If two additional reaction pathways of C3H3 + NH3 have relative energies (kcal.mol-1) are found to be fairly high, the two additional directions of C3H3 + CH3 have no transition states at the beginning of entrance. In terms of thermodynamic side, all of products are possible to be produced at the investigated condition, in which the product P2 (HCCCH3 + NH2) of the first system and P6 (C2H2 + C2H4) of the second reaction are the most favorable. Besides, the analytical results of energies shown that the C3H3 + CH3 reaction takes place more easily compared to the C3H3 + NH3 system.
