ISSN:
0887-624X
Keywords:
copolymerization of ethylene and 1-butene
;
Cr/silica catalyst
;
yields
;
kinetics
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
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 0-50°C, 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 at 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 at 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, ka, 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 at 50°C for different ethylene to 1-butene feed ratios gave the values of the reactivity ratios, r1 = 27.3 ± 3.6 and r2 ≅ 0, for ethylene and 1-butene, respectively. © 1996 John Wiley & Sons, Inc.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
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