Die Primärschritte der sauerstoffinitiierten Äthylenpolymerisation

Abstract

Die Reaktionen vor und beim Start der sauerstoffinitiierten hhylenpolymerisation wurden bei Temperaturen unter 170 ' C, Driicken bis zu 2 200 at und relativen Sauerstoffkonzentrationen bis zu 75 ppm -bezogen auf Athylen -untersucht. Die Polymerimtion setzt nach Erreichen des Startpunktes plotzlich ein. Er ist eine Folge der Selbstinhibierung der Reaktion durch Sauerstoff. Der primiire Rdikallieferant wird um so leichter gebildet, je hoher der Druck ist. Es mu13 angenommen werden, da13 dieser Stoff rascher zerfiillt, als er gebildet wird. Der Anteil des Sauerstoffs, der in nicht der Initiierung dienenden Nebenreaktionen verbraucht wird, steigt mit der Einsatzkonzentration an. SUMMARY :The reactions before and during the start of the oxygen initiated polymerization of ethylene have been investigated at temperatures less than 170°C, pressures up to 2200 at and oxygen concentrations in feed up to 75 ppm. The reaction sudden& starts when starting point is reached. This is caused by inhibition of the reaction by oxygen itself. The primarily radical delivering compound is formed the easier the higher the pressure is. It must be eaaumed that this compound decomposes more rapidly than it is produced. The amount of oxygen being consumed in not initiating side-reaotions increases with its concentration in feed.

Reaction mechanism of oxygen‐initiated ethylene polymerization at high pressure

“…(2)). Activation energy, AE; -1/2AE7: 7,l kcal/m01~>~), kd: 3 Iff is taken to be 0,l-0,2, the calculated results become close to the experimental data of Figs. 4, 5 and 6.…”

High Pressure Polymerization of Ethylene. an Improved Mathematical Model for Industrial Tubular Reactors

“…The oxygen initiation mechanism is based on the works by Tatsukami et al (1980), Ehrlich et al (1957), Brandolin (1987), Gierth (1970), Grunig et al (1983) and Hollard and Ehrlich ( 1983). It appeared, from their results, that including the inhibition effects of oxygen would help to predict the shape of the temperature profile at the peak.…”

“…Most of the reactions were chosen after reviewing the works by Ehrlich and Mortimer (1970), Chen et al (1976), Goto et al (1981), Tatsukami et al (1980), Hollard and Ehrlich ( 1983), Brandolin et al (1988), Gierth ( 1970), Grunig et al (1983), Buback ( 1980, Billmeyer ( 1971) and Allcock and Lampe ( 1981 ).…”

Magma chamber processes in the Tellnes ilmenite deposit (Rogaland Anorthosite Province, SW Norway) and the formation of Fe–Ti ores in massif-type anorthosites

“…Detailed petrographical descriptions of the Tellnes ilmenite deposit have been presented by Gierth (1970), Krause (1973, 1974), Gierth et al (1982) and Gierth (1983). Although these authors describe the mineralogical and chemical composition of the ore body as very uniform, they noticed some variability.…”