Abstract: The invention relates to the technical field of membrane separation, and discloses a hollow fiber membrane and preparation method and use thereof. The hollow fiber membrane includes a support, a selective layer, and a transition layer between the support and the selective layer, wherein at least a portion of the transition layer is embedded in the support. The hollow fiber membrane has a high selectivity and good mechanical properties.

Abstract: The present invention relates to a process for producing succinic anhydride by maleic anhydride hydrogenation, comprising (1) feeding a maleic anhydride solution and a hydrogen raw material respectively to a first-stage hydrogenation reactor from an upper liquid-phase feed port and a top gas-phase feed port of the first-stage hydrogenation reactor for a first-stage hydrogenation reaction to obtain a first-stage hydrogenation product; (2) feeding the first-stage hydrogenation product to a second-stage hydrogenation reactor for a second-stage hydrogenation reaction to obtain a second-stage hydrogenation product, optionally, before entering the second-stage hydrogenation reactor, subjecting the first-stage hydrogenation product to a first-stage gas-liquid separation to obtain a first-stage gas phase and a first-stage liquid phase, and then feeding the first-stage gas phase and the first-stage liquid phase respectively from a top gas-phase feed port and an upper liquid-phase feed port of the second-stage hydrogen

Abstract: An ethylene-copolymerized olefin copolymer having a high comonomer dispersion index, a preparation method therefor, an application thereof, and a composition comprising an ethylene-?-olefin copolymer are disclosed. The ethylene-?-olefin copolymer contains 70-95 mol % a structural unit derived from ethylene and 5-30 mol % a structural unit derived from ?-olefin. The ?-olefin is an olefin having 5-10 carbon atoms. The dispersion index RMD of the ?-olefin structural unit in the molecular chain is greater than 102%. The ethylene-?-olefin copolymer has a high comonomer dispersion index.

Abstract: A catalyst composition includes the following components: a) a metallocene compound, b) a co-catalyst component, and c) a phenol, the co-catalyst component being a combination of an organoaluminum compound and an alkyl aluminoxane, or a combination of an organoaluminum compound and an organoboron compound. The catalyst composition is used for the copolymerization of ethylene and a cycloolefin or an alkenol, which can increase the molecular weight of the polymer as well as the content of cycloolefin or alkenol structural unit in the copolymer.

Abstract: A polyimide random copolymer has a structure represented by formula (I). A method for preparing the polyimide random copolymer, a membrane made of the polyimide random copolymer, and a method for preparing a polyimide-based hollow fiber membrane are also provided. A system for purifying helium gas and a method for purifying helium gas are related to the membrane made of the polyimide random copolymer.

Abstract: A polymer ultrafiltration membrane with a bicontinuous highly interconnected porous structure, a preparation method and applications thereof are provided. The ultrafiltration membrane has a bottom layer and a polymer layer. The polymer layer is divided into a sublayer and a surface layer. The surface layer is of a uniform small pore structure with a narrow pore size distribution. The sublayer is of a bicontinuous highly interconnected three-dimensional network porous structure. The bicontinuous highly interconnected porous structure of the bicontinuous highly interconnected porous ultrafiltration membrane is characterized as follows: in the thickness direction of the sublayer, the cross-sectional porosity on any XY cross-section perpendicular to the thickness direction is 40-90%, preferably 60-90%, and further preferably 70-90%; and the difference in the cross-sectional porosities between any two XY cross-sections does not exceed 10%, preferably not exceed 8%, and also preferably not exceed 5%.

Abstract: A metal-organic framework material separation membrane and a preparation method for the metal-organic framework material separation membrane are provided. The metal-organic framework material separation membrane has a base membrane and a metal-organic framework material functional layer. The metal-organic framework material functional layer comprises has an inter-embedded polyhedron structure. The preparation metal-organic framework material separation membrane includes the steps of: (1) preparing a solution containing a first organic solvent, an organic ligand, a metal compound, and an auxiliary agent; (2) subjecting a base membrane to a pretreatment, involving introducing, on the surface of the base membrane, metal atoms from the metal compound of step (1); and (3) mixing the pretreated base membrane of step (2) with the solution of step (1) to obtain a first mixture, and then heating the first mixture for reaction, so as to prepare a metal-organic framework material separation membrane.

Abstract: The present invention relates to silicon ether compounds having a general formula (I), a method for the preparation thereof and use thereof as a component of catalysts for polymerization of olefins. In particular, in propylene polymerization, catalyst systems comprising the silicon ether compounds as external electron donor component exhibit good hydrogen response, and can be used to prepare polymer having high isotacticity at high yield. wherein R1-R10 groups are as defined in the description.

Abstract: The present invention relates to silicon ether compounds having a general formula (I), a method for the preparation thereof and use thereof as a component of catalysts for polymerization of olefins. In particular, in propylene polymerization, catalyst systems comprising the silicon ether compounds as external electron donor component exhibit good hydrogen response, and can be used to prepare polymer having high isotacticity at high yield. wherein R1-R10 groups are as defined in the description.

Abstract: The present invention relates to a silicon ether compound having general formula (I): wherein, R and R1-R10 groups, which may be Identical or different, represent hydrogen, halogen, C1-C20 linear or branched alkyl, C3-C20 cycloalkyl, C8-C20 aryl, C7-C20 alkaryl or C7-C20 aralkyl group, and two or more R groups can be linked to form saturated or unsaturated condensed ring structure which is optionally substituted by a group having the same meanings with that of R1, R and R1-R10 groups optionally contain one or more hetero-atoms replacing carbon atom, hydrogen atom or the both, said heteroatom is selected from the group consisting of nitrogen, oxygen, sulfur, silicon, phosphorus and halogen atom, and A represents carbon atom or silicon atom. The present invention also relates to a method for the preparation of the silicon ether compounds of general formula (I) and a process for polymerization of olefins.

Abstract: The present invention relates to a silicon ether compound having general formula (I): 1