The invention relates to modified
aluminoxane and a preparation method and application thereof.The preparation method of the modified
aluminoxane comprises the following steps that S1, an
oxygen-containing compound containing carbonyl and trimethyl aluminum are dispersed in an
organic solvent and heated, a transparent solution without gel is formed, and an MAO solution is obtained; and S2, dropwise adding the MAO solution obtained in the step S1 into a trifluoroaryl
boron compound solution, mixing, heating for reaction, and washing and
drying an obtained precipitated
solid to obtain the modified
aluminoxane. Compared with the prior art, the method has the advantages that
silicon dioxide and the like are not used as carriers, the alkylaluminoxane solution is prepared only through the non-
hydrolysis reaction, and near-particulate
solid alkylaluminoxane with the median
diameter of 1-80 microns is separated out from the alkylaluminoxane solution, so that when the alkylaluminoxane is applied to a
polyolefin catalytic
system, the
high activity of a catalyst can be maintained; the content of inorganic components in
polyolefin is reduced, and the processability of a
polymer is improved.