licensing arm. Because of the nature of the catalyst, this process can be tailored to
specific highly selective applications that have been identified by various names
(Chauvel and Lefebvre 1989):
Dimerization of Ethylene to 1-Butene
AlphaButol
™ is utilized for the selective dimerization of ethylene to 1-butene for
use as a comonomer in the production of linear low-density polyethylene (LLDPE).
Though not in the motor fuel range for refinery applications, its mention is included
here for the sake of completeness and continuity with the other Dimersol process
schemes. This type of operation is best suited for locations where LLDPE is being
produced and in which there is no other local source of 1-butene. AlphaButol units
have been reportedly built in Saudi Arabia and Thailand.
Dimerization of Ethylene to n-Butenes
Whereas the IFP AlphaButol process is selective for the production of 1-butene, the
IFP Dimersol E process produces n-butenes and heavier oligomers. The Dimersol E
process also operates at about 50
C in the liquid phase with a Ziegler-type catalyst that
can be a nickel derivative activated by an organometallic reducing agent. Whereas the
AlphaButol process avoids isomerization, the Dimersol E features both dimerization
and isomerization, and it produces a blend of n-butenes and heavier oligomers,
depending on the feed composition, the actual type of catalyst, and the operating
conditions. For polymer-grade ethylene, the Dimersol E process yields 30–70 %
n-butenes with a once-through conversion of 90–100 %, with the rest being in
the C 6 + gasoline fraction. Gasoline production can be further enhanced by adding
propylene to the feed. It is worth noting though that in the Dimersol E process the ratio
of 1-butene to 2-butene in the product is about 1:1, still well above the equilibrium
ratio at 50
C.
Dimerization of Propylene and Butenes, Separately or Combined
The Dimersol process (Fig. 9) uses an organometallic catalyst consisting of a nickel salt
in combination with an alkylaluminum compound. Various modalities are available:
• Dimersol G – for the dimerization of propylene to isohexenes used in gasoline
blending.
• Dimersol E – for the oligomerization of ethylene and propylene olefins
contained in FCC gases and already described above for the nonselective
dimerization and oligomerization of ethylene.
• Dimersol X – for the selective dimerization of propylene and butenes for the
production of heptenes or for the dimerization of n-butenes for the production of
Olefin Condensation
475
specific highly selective applications that have been identified by various names
(Chauvel and Lefebvre 1989):
Dimerization of Ethylene to 1-Butene
AlphaButol
™ is utilized for the selective dimerization of ethylene to 1-butene for
use as a comonomer in the production of linear low-density polyethylene (LLDPE).
Though not in the motor fuel range for refinery applications, its mention is included
here for the sake of completeness and continuity with the other Dimersol process
schemes. This type of operation is best suited for locations where LLDPE is being
produced and in which there is no other local source of 1-butene. AlphaButol units
have been reportedly built in Saudi Arabia and Thailand.
Dimerization of Ethylene to n-Butenes
Whereas the IFP AlphaButol process is selective for the production of 1-butene, the
IFP Dimersol E process produces n-butenes and heavier oligomers. The Dimersol E
process also operates at about 50
C in the liquid phase with a Ziegler-type catalyst that
can be a nickel derivative activated by an organometallic reducing agent. Whereas the
AlphaButol process avoids isomerization, the Dimersol E features both dimerization
and isomerization, and it produces a blend of n-butenes and heavier oligomers,
depending on the feed composition, the actual type of catalyst, and the operating
conditions. For polymer-grade ethylene, the Dimersol E process yields 30–70 %
n-butenes with a once-through conversion of 90–100 %, with the rest being in
the C 6 + gasoline fraction. Gasoline production can be further enhanced by adding
propylene to the feed. It is worth noting though that in the Dimersol E process the ratio
of 1-butene to 2-butene in the product is about 1:1, still well above the equilibrium
ratio at 50
C.
Dimerization of Propylene and Butenes, Separately or Combined
The Dimersol process (Fig. 9) uses an organometallic catalyst consisting of a nickel salt
in combination with an alkylaluminum compound. Various modalities are available:
• Dimersol G – for the dimerization of propylene to isohexenes used in gasoline
blending.
• Dimersol E – for the oligomerization of ethylene and propylene olefins
contained in FCC gases and already described above for the nonselective
dimerization and oligomerization of ethylene.
• Dimersol X – for the selective dimerization of propylene and butenes for the
production of heptenes or for the dimerization of n-butenes for the production of
Olefin Condensation
475