Abstract: A gradient copolymer comprises or consists of n polymer components. The n polymer components each independently represents an addition polymer of a monomer of the formula (I), and/or a mixture thereof, or the n polymer components each independently comprises or consists essential of one or more structural units represented by the formula (I-1), The symbol n represents an integer within the closed interval [5, ?]. The average side chain carbon number of the i-th polymer component as determined according to the nuclear magnetic resonance method is expressed as Xi, with the symbol i representing an arbitrary integer from 1 to n, the relationship X1<X2< . . . <Xn?1<Xn holds.

Abstract: The present invention provides a catalyst and the preparation process thereof and a process of epoxidising olefin using the catalyst. The catalyst contains a binder and a titanium silicate, the binder being an amorphous silica, the titanium silicate having a MFI structure, and the crystal grain of the titanium silicate having a hollow structure, with a radial length of 5-300 nm for the cavity portion of the hollow structure, wherein the adsorption capacity of benzene measured for the titanium silicate under the conditions of 25 degrees C., P/P0=0.

Abstract: Disclosed is a process for producing dimethyl ether from methanol, which is characterized in that the absorbing liquid used in said absorbing column is the bottom liquid of DME-fractionating column and/or bottom waste water of the methanol-recovering column. Said process can significantly reduce energy consumption of the apparatus.

Abstract: The present invention relates to a hydrocracking catalyst comprising an acidic silica-alumina, an optional alumina, an effective quantity of at least one VIII Group metal component(s), an effective quantity of at least one VIB Group metal component(s) and an organic additive, wherein the organic additive is one or more selected from the group consisting of an oxygen-containing or nitrogen-containing organic compound, and the molar ratio of the organic additive to the VIII Group metal component(s) is 0.01-10. The present invention relates further to a process for producing the hydrocracking catalyst and use of the catalyst in a process for hydrocracking hydrocarbon oils. The hydrocracking catalyst provided according to the present invention shows a higher activity for aromatic hydrosaturating and ring-opening reaction, as compared with the prior art hydrocracking catalyst.