CATALYST COMPOSITION AND PROCESS FOR OLIGOMERIZATION OF ETHYLENE
A catalyst composition including: (a) a chromium compound; (b) a ligand of the general structure R 1 R 2 P—N(R 3 )—P(XR 7 ) 2 , wherein X is O or S, R 1 , R 2 , and R 3 are each independently C 1 -C 10 -alkyl, C 6 -C 20 -cycloalkyl, arylalkyl, alkylaryl, or trialkylsilyl, or any cyclic derivatives of the ligand, wherein at least one of the P or N atoms of the PNP-unit is a member of the ring system, the ring system being formed from one or more constituent compounds of the ligand by substitution, and R 7 is C 1 -C 10- alkyl, C 3 -C 10 -cycloalkyl, arylalkyl, or trialkylsilyl; and (c) an activator or co-catalyst.
1 . A catalyst composition comprising:
(a) a chromium compound;
(b) a ligand of the general structure
R 1 R 2 P—N(R 3 )—P(XR 7 ) 2
wherein
X is O or S,
R 1 , R 2 , and R 3 are each independently C 1 -C 10 -alkyl, C 6 -C 20 -aryl, C 3 -C 10 -cycloalkyl, arylalkyl, alkylaryl, or trialkylsilyl, or any cyclic derivatives of the ligand, wherein at least one of the P or N atoms of the PNP-unit is a member of the ring system, the ring system being formed from one or more constituent compounds of the ligand by substitution, and
R 7 is C 1 -C 10 -alkyl, C 3 -C 10 -cycloalkyl, arylalkyl, or trialkylsilyl; and
(c) an activator or co-catalyst.
2 . The catalyst composition according to claim 1 , wherein the chromium compound is an organic salt, an inorganic salt, a coordination complex, an organometallic complex of Cr(0) or Cr(III), or a combination thereof.
3 . The catalyst composition according to claim 2 , wherein the chromium compound is CrCl 3 (THF) 3 , Cr(III)acetylacetonate, Cr(III)octanoate, chromium hexacarbonyl, Cr(III)-2-ethylhexanoate, (benzene)tricarbonyl-chromium, or a combination thereof.
4 . The catalyst composition according to claim 1 , wherein R 1 , R 2 , R 3 , and R 7 are each independently methyl, ethyl, isopropyl, tert-butyl, cyclohexyl, phenyl, benzyl, tolyl, or xylyl.
5 . The catalyst composition according to claim 1 , wherein the activator or co-catalyst is trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, ethylaluminumsesquichloride, diethylaluminum chloride, ethylaluminumdichloride, methylaluminoxane (MAO), modified methylaluminoxane (MMAO), or a combination thereof.
6 . The catalyst composition according to claim 1 , wherein the ligand is Ph 2 P-N(i-Pr)-P[S(i-Pr)] 2 , Ph 2 P-N(i-Pr)-P(OC 2 H 5 ) 2 , Ph 2 P-N(i-Pr)P(OCH 3 ) 2 , or a combination thereof.
7 . The catalyst composition according to claim 1 , additionally comprising a solvent, wherein the solvent is one of aromatic hydrocarbons, straight-chain aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, straight-chain olefins, ethers, or a combination thereof.
8 . The catalyst composition according to claim 7 , wherein the concentration of the chromium compound is from 0.01 to 100 millimoles per liter.
9 . The catalyst composition according to claim 1 , wherein the ligand/Cr molar ratio is from 0.5 to 50.
10 . The catalyst composition according to claim 5 , wherein the Al/Cr molar ratio is from 1:1 to 1000:1.
11 . A catalyst composition, obtainable by combining at least:
(a) a chromium compound;
(b) a ligand of the general structure
R 1 R 2 P-N(R 3 )-P(XR 7 ) 2
wherein
X is O or S,
R 1 , R 2 , and R 3 are each independently C 1 -C 10 -alkyl, C 6 -C 20 -aryl, C 3 -C 10 -cycloalkyl, arylalkyl, alkylaryl, or trialkylsilyl, or any cyclic derivatives of the ligand, wherein at least one of the P or N atoms of the PNP-unit is a member of the ring system, the ring system being formed from one or more constituent compounds of the ligand by substitution, and
R 7 is C 1 -C 10 -alkyl, C 3 -C 10 -cycloalkyl, arylalkyl, or trialkylsilyl; and
(c) an activator or co-catalyst.
12 . A process for tri- and/or tetramerization of ethylene, comprising subjecting the catalyst composition according to claim 1 to a gas phase of ethylene in a reactor and conducting an oligomerization.
13 . The process according to claim 12 , wherein the oligomerization is carried out at a pressure of 1 to 200 bar.
14 . The process according to claim 13 , wherein the oligomerization is carried out at a temperature of from 10 to 200° C.
15 . The process according to claim 14 , wherein the mean residence time is from 10 minutes to 20 hours.
16 . The process according to claim 13 , wherein the pressure is 10 to 50 bar.
17 . The process according to claim 14 , wherein the temperature is from 20 to 100° C.
18 . The process according to claim 15 , wherein the mean residence time is from 1 to 4 hours.
19 . The catalyst composition according to claim 1 , wherein the solvent is toluene, benzene, ethylbenzene, cumene, xylenes, mesitylene, hexane, octane, cyclohexane, methylcyclohexane, hexene, heptene, octene, diethylether, tetrahydrofuran, chlorobenzene, or a combination thereof.