Effects of various poisoning compounds on the activity and stereospecificity of heterogeneous Ziegler–Natta catalyst

Figures & data

Activity and tacticity of the PP without and with poisoning materials^a.

Entry	Poisoning material	Yield (kg/mmole-Ti)	mmmm
1	None	95.3	83.1
2	Methanol	58.9	82.6
3	Acetone	73.9	82.0
4	Ethyl Acetate	91.0	82.1

^aSlurry propylene polymerization was carried out with TIBA (Al/Ti=30) in heptane at 30 °C after the pretreatment of the catalyst with the poisoning materials for 1 min (poisoning material/Ti=0.1).

Figure 1 Yield of the polypropylene plotted for the polymerization time without and with a methanol pretreatment.

Figure 2 Number-average molecular weight of the polypropylene without and with methanol pretreatment plotted against polymerization time.

Kinetic parameters for propylene polymerization obtained without and with methanol^a.

Entry	Poisoning material	kp(l/mol·s)^b	[C∗] (mol.%)^b
1	None	4,800	0.40
2	Methanol	4,600	0.28

^aStopped-flow propylene polymerization was performed with TIBA (Al/Ti = 30) in heptane at 30 °C after the pretreatment of the catalyst with methanol for 1 min (methanol/Ti=0.1).

^bk_p and [C∗] were calculated from equations (1) and (2).