III International Conference

PP-I-39INVESTIGATION OF AMINO-CONTAINING SILICA MATERIALSPozimenko V.A., Panchenko V.N., Timofeeva M.N., Zakharov V.A.Boreskov Institute of Catalysis SB RAS, Novosibirsk, RussiaE-mail: vasil-241@yandex.ruAmino-containing silica have attracted significant attention as supports for thepreparation of various type catalysts due to their unique physicochemical and texturalproperties. NH 2 -SiO 2 (I), NH 2 -Si(R 1 R 2 )-SiO 2 (II) and NH 2 -CH 2 CH 2 CH 2 -Si(OCH 2 CH 3 ) 2 -SiO 2(III) (where R 1 = OCH 2 CH 3 and R 2 = Cl) were prepared according to [1,2]. IR spectroscopy[3] and pH titration method [2] were used for characterization of base properties of thesematerials.The process of chemically anchoring of NH 2 -groups was investigated by IR spectroscopy.According to IR data the band position of NH 2 -groups (ν N-H ) in region of 3200 -3550 сm -1depends on the ligand’ nature of NH 2 -groups and increases as follows: (III) → (II) → (I).Base properties of samples (I)- (III) have been studied by IR spectroscopy (CDCl 3adsorption as probe molecule). This method first was used for the investigation of aminocontainingsilica. Based on data of CDCl 3 adsorption PA value was calculated. It has beenshown that PA value depends on the nature of surface NH 2 -groups. The strength of NH 2 -groups changes as follows:829 kJ/mol (I) ≈ 829 kJ/mol (II) < 938 kJ/mol (III).The influence of amount of chemically anchoring NH 2 -groups on the base properties of(III) sample was studied. It has been shown that several types of NH 2 -groups are formed onthe surface of sample (III):H HNH HNEtOSiOOEtSi OEtO OEtOOEtSiONH 2EtOOEtSiONH 2EtOOEtSiONH 2HO(A)(B) (C)isolated (A) and hydrogen-bonding (B) NH 2 -groups. It is proposed that the weak base sitesare formed due to the intermolecular interaction of NH 2 -groups (B) or interaction of NH 2 -groups with Si-OH groups of support (C). It was demonstrated that strength of base sites78