Abstract:

Trimethyltin chloride and mesoporous molecular sieve Al-MCM-41 were heated at 135 ℃ for 4.5 h under stirring conditions and nitrogen atmosphere, to obtain (CH3)3Sn-O-MCM-41[(CH3)3SnM]. The composition, structure, and physical and chemical surface properties of the resulted solid were characterized by inductively coupled plasma mass spectrometry(ICP-MS), Fourier transform infrared spectroscopy(FTIR), N2 adsorption-desorption, NH3 chemisorption(NH3-TPD), X-ray diffraction(XRD), and transmission electron microscopy(TEM). The results showed that the grafting yield was 14.44% for Sn in mass fraction. TPD acid (NH3) of Al-MCM-41 before and after reaction with trimethyltin chloride increased from 0.652 6 mmol/g to 1.294 4 mmol/g. (CH3)3-SnM resulted in a decrease of the surface areas and the pore size and an increase of the mesopous volume and surface acidity compared to Al-MCM-41. The thermal stability for the sample grafted with organotin was improved. The sample that was grafted with organotin on the Al-MCM-41 had the ordered hexagonal mesopore structure. The conversion rate is 96% when n(isoamyl alcohol)∶n(acetic acid)=1.0∶1.0, w((CH3)3SnM)=5%, 138 ℃ for 5 h, and the catalyst can be reused. A conversion rate of 86% can be attained when catalyst was reused five times under the same catalytic conditions.

Key words: Trimethyltin Chloride, Al-MCM-41, grafting reaction, characterization