The adsorption behavior of BCl3-SiHCl3 on aliphatic amine by DFT method

Background: The removal of trace amount of BCl3 from SiHCl3 by adsorption is an efficient method in manufacture of electronic grade polysilicon.Objective: DFT simulations were used to investigate the adsorption mechanism of aliphatic amine adsorbents and to compare the performance of these adsorbents.Methods: The adsorption energies, mulliken charges, dipole moments and FMOs of aliphatic amines on SiHCl3 and BCl3 were calculated using the DFT method at the B3LYP/6-311++G (2d, p) level, and on this basis the factors affecting the adsorption capacity and selectivity were explored in depth.Results: The results indicates that these adsorbents show good adsorption performance and high separation efficiency for BCl3. In particular, (CH3)(2)NH has the highest adsorption capacity for BCl3 at 298 K and 1 atm and achieves effective desorption at high temperatures to allow the adsorbent to be reused.Conclusions: The adsorption behaviors are strongly affected by frontier orbitals, dipoles and polarizabilities of aliphatic amines, among which HOMO of amines plays the decisive role for adsorbing BCl3, providing theoretical guidance for adsorbent design associated with removal of BCl3 from SiHCl3.