Chemistry of hydrocarbon compounds – Unsaturated compound synthesis – By addition of entire unsaturated molecules – e.g.,...
Reexamination Certificate
2001-08-03
2003-04-29
Dang, Thuan D. (Department: 1764)
Chemistry of hydrocarbon compounds
Unsaturated compound synthesis
By addition of entire unsaturated molecules, e.g.,...
C585S511000, C585S512000, C585S513000, C585S522000, C585S527000
Reexamination Certificate
active
06555723
ABSTRACT:
FIELD OF THE INVENTION
A continuous manufacturing process for &agr;-olefins using certain iron containing ethylene oligomerization catalysts together with alkylaluminum cocatalysts, in which using a low ratio of Al:Fe in the process results in a lowered formation of undesired polyethylene waxes and polymer.
TECHNICAL BACKGROUND
&agr;-Olefins are important items of commerce, billions of kilograms being manufactured yearly. They are useful as monomers for (co)polymerizations and as chemical intermediates for the manufacture of many other materials, for example detergents and surfactants. Presently most &agr;-olefins are made by the catalyzed oligomerization of ethylene by various catalysts, especially certain nickel complexes or aluminum alkyls, see for instance U.S. Pat. No. 4,020,121 and I. Kroschwitz, et al., Ed.,
Kirk
-
Othmer Encyclopedia of Chemical Technology,
4
th
Ed., Vol. 17, John Wiley & Sons, New York, p. 839-858.
Recently, as reported in U.S. Pat. No. 5,955,555 and U.S. Pat. No. 6,103,946, both of which are hereby incorporated by reference herein for all purposes as if fully set forth, it has been found that iron complexes of certain tridentate ligands are excellent catalysts for the production of &agr;-olefins from ethylene. Among the options for using such catalysts are those in which the iron complexes are used in conjunction with a cocatalyst, particularly an alkylaluminum cocatalyst such as an alkylaluminoxane.
It has recently been found, particularly in continuous processes using such iron complexes, that high molar ratios of Al:Fe lead to the undesirable formation of polyethylene waxes and polymers, which tend to foul the oligomerization apparatus. It has now been found that lower Al:Fe ratios diminish the formation of these undesirable polyethylenes, while not otherwise significantly deleteriously affecting the process.
SUMMARY OF THE INVENTION
This invention concerns a continous process for the production of a linear &agr;-olefin product, comprising the step of contacting, in a continuous reactor, process ingredients comprising an ethylene oligomerization catalyst composition, ethylene and a cocatalyst, wherein:
(a) the ethylene oligomerization catalyst composition comprises an iron complex of a compound of the formula
wherein:
R
1
, R
2
and R
3
are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group, provided that any two of R
1
, R
2
and R
3
vicinal to one another taken together may form a ring;
R
4
and R
5
are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group;
R
6
and R
7
are each independently a substituted aryl having a first ring atom bound to the imino nitrogen, provided that
in R
6
, a second ring atom adjacent to said first ring atom is bound to a halogen, a primary carbon group, a secondary carbon group or a tertiary carbon group; and further provided that
in R
6
, when said second ring atom is bound to a halogen or a primary carbon group, none, one or two of the other ring atoms in R
6
and R
7
adjacent to said first ring atom are bound to a halogen or a primary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom; or
in R
6
, when said second ring atom is bound to a secondary carbon group, none, one or two of the other ring atoms in R
6
and R
7
adjacent to said first ring atom are bound to a halogen, a primary carbon group or a secondary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom; or
in R
6
, when said second ring atom is bound to a tertiary carbon group, none or one of the other ring atoms in R
6
and R
7
adjacent to said first ring atom are bound to a tertiary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom;
(b) the cocatalyst comprises an alkyl aluminum compound; and
(c) the molar ratio of Al in the cocatalyst to Fe in the ethylene oligomerization catalyst is about 2000 or less.
This invention further concerns an improved continous process for the production of a linear &agr;-olefin product, the process comprising the step of contacting, in a continuous reactor, process ingredients comprising an ethylene oligomerization catalyst composition, ethylene and a cocatalyst, wherein:
(a) the ethylene oligomerization catalyst composition comprises an iron complex of a compound of the formula
wherein:
R
1
, R
2
and R
3
are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group, provided that any two of R
1
, R
2
and R
3
vicinal to one another taken together may form a ring;
R
4
and R
5
are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group;
R
6
and R
7
are each independently a substituted aryl having a first ring atom bound to the imino nitrogen, provided that
in R
6
, a second ring atom adjacent to said first ring atom is bound to a halogen, a primary carbon group, a secondary carbon group or a tertiary carbon group; and further provided that
in R
6
, when said second ring atom is bound to a halogen or a primary carbon group, none, one or two of the other ring atoms in R
6
and R
7
adjacent to said first ring atom are bound to a halogen or a primary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom; or
in R
6
, when said second ring atom is bound to a secondary carbon group, none, one or two of the other ring atoms in R
6
and R
7
adjacent to said first ring atom are bound to a halogen, a primary carbon group or a secondary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom; or
in R
6
, when said second ring atom is bound to a tertiary carbon group, none or one of the other ring atoms in R
6
and R
7
adjacent to said first ring atom are bound to a tertiary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom; and
(b) the cocatalyst comprises an alkyl aluminum compound;
wherein the improvement comprises reducing the formation of polyethylene waxes and polymers in the linear &agr;-olefin product by contacting the process ingredients at a molar ratio of Al in the cocatalyst to Fe in the ethylene oligomerization catalyst of less than about 2000.
This invention also concerns a method for reducing the formation of polyethylene waxes and polymers in a continous process for the production of a linear &agr;-olefin product, said continuous process comprising the step of contacting, in a continuous reactor, process ingredients comprising an ethylene oligomerization catalyst composition, ethylene and a cocatalyst, wherein:
(a) the ethylene oligomerization catalyst composition comprises an iron complex of a compound of the formula
wherein:
R
1
, R
2
and R
3
are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group, provided that any two of R
1
, R
2
and R
3
vicinal to one another taken together may form a ring;
R
4
and R
5
are each independently hydrogen, hydrocarbyl, substituted hydrocarbyl or an inert functional group;
R
6
and R
7
are each independently a substituted aryl having a first ring atom bound to the imino nitrogen, provided that:
in R
6
, a second ring atom adjacent to said first ring atom is bound to a halogen, a primary carbon group, a secondary carbon group or a tertiary carbon group; and further provided that
in R
6
, when said second ring atom is bound to a halogen or a primary carbon group, none, one or two of the other ring atoms in R
6
and R
7
adjacent to said first ring atom are bound to a halogen or a primary carbon group, with the remainder of the ring atoms adjacent to said first ring atom being bound to a hydrogen atom; or
in R
6
, when said second ring atom is bound to a secondary carbon group, none, one or two of the other ring atoms in R
6
and R
7
adjacent to said first ring atom are bound to a haloge
Dang Thuan D.
E. I. du Pont de Nemours and Company
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