Method for oligomerizing an alpha-olefin

A method for oligomerizing an .alpha.-olefin in the presence of a catalyst comprising a chromium compound having at least one chromium-pyrrolyl bond and an alkylaluminum compound, comprising contacting the .alpha.-olefin with the chromium compound and the alkylaluminum compound without preliminarily contacting the chromium compound with either the .alpha.-olefin or the alkylaluminum compound, and wherein as the catalyst, a catalyst comprising a chromium compound obtained by reacting a chromium salt and a compound containing a pyrrolyl group or radical in a hydrocarbon solvent, and an alkyl aluminum compound, is used wherein the oligomerization is conducted at a temperature of from 0.degree.to 250.degree. C. under a pressure from atmospheric pressure to 250 kg/cm.sup.2, and the concentration of the chromium compound is from 0.1 mg to 5 q per liter of the solvent, and the alkylaluminum compound is in an amount of at least 0.1 mmol per gram of the chromium compound.

A method for oligomerizing an .alpha.-olefin in the presence of a catalyst comprising a chromium compound having at least one chromium-pyrrolyl bond and an alkylaluminum compound, comprising contacting the .alpha.-olefin with the chromium compound and the alkylaluminum compound without preliminarily contacting the chromium compound with either the .alpha.-olefin or the alkylaluminum compound, and wherein the chromium compound having at least one chromium-pyrrolyl bond is a compound obtained by reacting a chromium salt of the formula CrX.sub.n wherein X is an organic or inorganic group, and n is an integer of from 1 to 6, provided that when n is more than 1, the plurality of X may be the same or different from one another, and a metal pyrrolide in an electron pair donor solvent, comprising oligomerizing the e-olefin at a temperature of from 0.degree. to 250.degree. C. under a pressure from atmospheric pressure to 250 kg/cm.sup.2, and the concentration of the chromium compound is from 0.1 mg to 5 g per liter of the solvent, and the alkylaluminum compound is an amount of at least 5 mmol per gram of the chromium compound.

A method for oligomerizing an .alpha.-olefin in the presence of a catalyst comprising a chromium compound and an alkylaluminum compound, wherein as the catalyst, a catalyst comprising a chromium compound obtained by admixing a chromium salt and a compound containing a pyrrolyl group or radical in a hydrocarbon solvent, and an alkyl aluminum compound, is used, and comprising the steps of:

• (a) contacting the .alpha.-olefin with the chromium compound and the alkylaluminum compound simultaneously without preliminarily contacting the chromium compound with either the .alpha.-olefin or the alkylaluminum compound,
• (b) oligomerizing the .alpha.-olefin at a temperature of from 0.degree. to 250.degree. C. under a pressure from atmospheric pressure to 250 kg/cm.sup.2, and the concentration of the chromium compound is from 0.02 mg to 1 g of chromium metal per liter of solvent, and said alkylaluminum compound is in an amount of at least 0.1 mmol per gram of the chromium compound.

A method for oligomerizing an .alpha.-olefin in the presence of a catalyst comprising a chromium compound having at least one chromium-pyrrolyl bond and an alkylaluminum compound, comprising the steps of:

• (a) contacting the .alpha.-olefin with the alkylaluminum compound without preliminarily contacting the chromium compound with either the .alpha.-olefin or the alkylaluminum compound,
• (b) contacting the chromium compound with the .alpha.-olefin and the alkylaluminum compound, and
• (c) oligomerizing the .alpha.-olefin at a temperature of from 0.degree. to 250.degree. C. under a pressure from atmospheric pressure to 250 kg/cm.sup.2, and the concentration of the chromium compound is from 0.1 mg to 5 g per liter of solvent, and the alkylaluminum compound is in an amount of at least 5 mmol per gram of the chromium compound.

A method for oligomerizing an .alpha.-olefin in the presence of a catalyst comprising a chromium compound and an alkylaluminum compound, wherein as the catalyst, a catalyst comprising a chromium compound obtained by admixing a chromium salt and a compound containing a pyrrolyl group or radical in a hydrocarbon solvent, and an alkyl aluminum compound, is used, and comprising the steps of:

• (a) contacting the .alpha.-olefin with the alkylaluminum compound without preliminarily contacting the chromium compound with either the .alpha.-olefin or the alkylaluminum compound,
• (b) contacting the chromium compound with the .alpha.-olefin and the alkylaluminum compound, and
• (c) oligomerizing the .alpha.-olefin at a temperature of from 0.degree.to 250.degree. C. under a pressure from atmospheric pressure to 250 kg/cm.sup.2, and the concentration of the chromium compound is from 0.02 mg to 1 g of chromium metal per liter of solvent, and said alkylaluminum compound is in an amount of at least 0.1 mmol per gram of the chromium compound.