Copolymerization of ethylene and 1-butene using a Cr—silica catalyst in a slurry reactor

✍ Scribed by H. A. Rangwala; I. G. Dalla Lana; J. A. Szymura; R. M. Fiedorow

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 725 KB
• Volume: 34
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19961130)34:16<3379::aid-pola15>3.0.co;2-d

✦ Synopsis

A novel slurry reactor was used to investigate the copolymerization behavior of ethylene and 1-butene in the presence of 1 wt % Cr on Davison silica (Phillips-type) catalyst over the temperature range of O-5O0C, space velocity of about 0.0051 [m3 (STP)]/(g of catalyst) h, and a fixed ethylene to 1-butene feed mole ratio of 95 : 5. The effect of varying the ethylene to 1-butene feed ratios, 100 : 0,96.5 : 3.5, 95 : 5, 93 : 7, 90 : 10,80 : 20, and 0 : 100 mol/mol a t 50°C was also studied. The addition of 1-butene to ethylene typically increased both copolymerization rates and yields relative to ethylene homopolymerization with the same catalyst, reaching a maximum yield for an ethylene : 1-butene feed ratio of 95 : 5 a t 50°C. The incorporation of 1-butene within the copolymer in all cases was less than 5 mol %. The average activation energy for the apparent reaction rate constant, k,, based on total comonomer mole fraction in the slurry liquid for the ethylene to 1-butene feed mole ratio of 95 : 5 in the temperature range of 50-30°C measured 54.2 kJ/mol. The behavior for temperatures between 30 to 0°C differed with an activation energy of 98.2 kJ/mol; thus, some diffusion limitation likely influences the copolymerization rates at temperatures above 30°C. A kinetics analysis of the experimental data a t 50°C for different ethylene to 1butene feed ratios gave the values of the reactivity ratios, rl = 27.3 +-3.6 and r2 z 0, for ethylene and 1-butene, respectively. 0 1996 John Wiley & Sons, Inc.