The comparison of tetrahydrofuran and 1,4-dioxane as modifiers and the effect of its mixture on Ti-based catalyst at ethylene dimerization reaction

In this research, we founded that 1, 4-dioxane was a suitable modifier at ethylene dimerization reaction which could be replaced instead of tetrahydrofuran (THF) as commercial modifier. We performed studies on 1H-NMR spectra of relevant catalytic systems and they confirmed results of reactor tests. In addition to results of 1H-NMR spectra and on base of chemical structure of two modifiers, it was suggested that the increase of O atom from one in ring of THF to two in ring of 1, 4- dioxane, led to the formation of strong electrostatic bond between oxygens of dioxane and titanium center and finally the polar active dimerization sites were formed. Also, as part of our researches, the influence of mixture of 1, 4-dioxane and THF at reaction of ethylene dimerization was investigated. The experimental results showed that with the increase of 1,4- dioxane to Ti(OC4H9)4)/THF/TEA catalyst system, ethylene conversion, overall selectivity to 1-butene and yield of reaction were improved. Also, heavy and polymeric compounds were remarkably deacreased. It is probably attributed to the desirable synergistic effect, the suitable interaction and electronic properties of 1,4-dioxane and THF

ethylene dimerization, 1, 4-dioxane, THF, 1H-NMR spectra, polymeric compounds