Abstract: Five 1,3-diisopropoxyaloxanes, i. e., (PrⁱO)RO₂AlOAlO₂R(OPrⁱ) [where R=C₁₆H₃₁(Ⅰ)_C₁₈H₃₅(Ⅱ), _C₉H₁₆CH=CHC₇H₁₅(Ⅲ), _P(OCH₂(C₂H₅)CHC₄H₉)₂(Ⅳ), and _C₁₂H₂₃(Ⅴ), respectively] were syn thesized by the hydrolysiscondensation of aluminium isopropoxide with water, exchange reaction with relevant acids. They were characterized by elemental analysis, determination of molecular weight, IR,, ²⁷Al NMR. The results show that the coordination number of Al atom in the compounds is 5, they exist in monomers in benzene. The analyses of TG/DTG, DTA indicated that both the thermal hydrolysis stability, thermal stability of these compounds are in the following order:Ⅰ<Ⅱ<Ⅲ<Ⅳ. The viscosity determinations of light calcium carbonate(L-CaCO₃)/liquid paraffin suspension systems demonstrated that they had an excellent modification effect on the surface of LCaCO₃ filler, the amount needed to form a monomolecular film on the surface of LCaCO₃ particles is in the order:Ⅰ<Ⅱ<Ⅲ<Ⅳ.

Key words: 1,3-Diisopropoxyaloxane, Syn thesis, Characterization, Light calcium carbonate, Surface modification