METHODS FOR MAKING SUPPORTED CHROMIUM CATALYSTS WITH INCREASED POLYMERIZATION ACTIVITY

• Main Authors: CLEAR KATHY S, MCDANIEL MAX P
• Format: Patent
• Language: Chinese; English
• Published: 16.04.2021
• Subjects: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; COMPOSITIONS BASED THEREON; MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVINGCARBON-TO-CARBON UNSATURATED BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; THEIR PREPARATION OR CHEMICAL WORKING-UP; THEIR RELEVANT APPARATUS; TRANSPORTING

Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650 DEG C to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions. 公开了用于制备负载型铬催化剂的方法，所述方法可包括使含有至少30重量％的二氧化硅的二氧化硅涂覆的氧化铝与含铬化合物在液体中接触，干燥，并在氧化气氛中在至少650℃的峰值温度下煅烧以形成所述负载型铬催化剂。所述负载型铬催化剂可含有0.01重量％至20重量％的铬，并且通常可具有0.5mL/g至2mL/g的孔隙体积和275m2/g至550m2/g的BET表面积。随后可以使用负载型铬催化剂来使烯烃聚合，以产生例如具有高分子量和宽分子量分布的基于乙烯的均聚物和共聚物。