CA1042009A - Nickel bis-diorgano-orthophosphate catalyst compositions - Google Patents

Abstract

Abstract This invention comprises use of nickel bis-diorgano orthophosphates as catalysts. When used in conjunction with alkyl aluminum halides, controlled oligomerization of ethylene, propylene and other olefins is achieved with the formation of polymers with low degrees of polymerization,e.g. 2 to 10, pre-ferably no more than about 6.

Description

lO~Z009 The object of this invention is to provide new catal- ~-yst combinations for controlled oligomerization both alone and during high polymerization of olefins with other catalysts.

One class of these compounds employed are of the gen-eral formula Ni[OP(O) (OR)2~2 =
in which each R is a non-aromatic hydrocarbon group free of aliphatic unsaturation, i.e. an alkyl or cycloalkyl group, con-taining one to eight, preferably two to four, carbon atoms or a non-aromatic hydrocarbon ether group free of aliphatic unsatur-ation, i.e. an alkoxyalkyl group, containing three to six -;
carbon atoms or a chlorinated or brominated derivative of any of such groups. These compounds are disclosed in the Parent Application, Canada Patent Application 213,706.

A combination catalyst for controlled olefin oli-gomerization employed in this invention consists essentially of the reaction product of (A) a nickel bis-diorgano-ortho-phosphate of the general formula Ni COP (O) (OR)2]2 in which each R is as defined above and (B) an alkyl aluminum halide of the general formula R'cAl Xd in which each R' is an alkyl group of one to six carbon atoms, each X is a halogen atom, preferably chlorine or bromine, each of c and d is 1 or 2 and the total of c and d is 3. The mol ratio of (A) to (B) can range from 1:1 to 1:20 but is preferably in the range of 1:8 to 1:12. -This invention further comprises the use of the above-described catalysts combinations in a method for olefin aligomerization or polymerization consisting essentially of (1) mixing the appropriate catalyst combination described above with (D) a mono- or di-olefin which can be any aliphatic, 30 cycloaliphatic or aromatic hydrocarbon containing no more than about 8 carbon atoms, preferably an aliphatic hydrocarbon containing no more than about 4 carbon atoms and/or a styrene, . .:' '~' `:

oo9 either alone or with (E) a hydrocarbon solvent free of aliphat-ic unsaturation, i.e., an alkyl, cycloalkyl or aromatic hydro-carbon containing up to 14 carbon atoms, any aromatic hydro-carbon being optionally substituted with up to about four lower - alkyl groups or other non-interfering substituents such as, for example, amines, oxygen-free anions of non-metallic inorganic acids such as chlorine atoms and bromine atoms and nitrile groups, at a temperature and pressure and for a time sufficient - to cause reaction of (D) and (2) separating the resulting products. The total amount of catalyst combination is present in an amount of from about 0.0001 to 0.01 total mol per mol of (D). This system operates spontaneously as an exothermic reac-tion as soon as the components are mixed. Generally, the system temperature can range from 0 to 250C., preferably 50 ;~ to 150C., and the system pressure can range from 1 to 500 psig., preferably 10 to 100 psig. The desired reaction can take up to 24 hours, but for the aliphatic olefins the reaction is generally almost instantaneous and is maintained by a continuous addition of monomer or monomers with or without additional catalyst.

Examples of desired products include:
Nickel bis (dipropyl orthophosphate), nickel bis (di-n-octyl orthophosphate), nickel bis (di-4,4-dimethylhexyl - orthophosphate), nickel bis (di-2-ethylhexyl orthophosphate), nickel bis (diethyl orthophosphate), nickel bis (diisobutyl or-- thophosphate), nickel bis (monobutyl mono-tert-butyl orthopho-sphate), nickel bis (monopentyl mono-2-methylpentyl orthophos-phate), nickel bis (di-3-methylhexyl orthophosphate), nickel bis (mono-2-ethyl-hexyl mono-3-methylhexyl orthophosphate), nickel bis (di-2,3-dimethylhexyl orthophosphate), nickel bis -; (dicyclohexyl orthophosphate), nickel bis (dibutyl orthophosphate), nickel mono(diethyl orthophosphate) mono (di-' '

2 -. :.

.: . : - . :: ~

: ~,,)4200g ` isohexyl orthophosphate), nickel bis (di-3,3-dimethylpentyl . orthophosphate), nickel mono (monoheptyl monohexyl orthophos-phate) mono(monoheptyl monooctyl orthophosphate), nickel bis (di-2,2,4-trimethylpentyl orthophosphate), nickel bis (di-2-- ethosyethyl orthophosphate), nickel bis (dicyclopentyl orthophosphate), nickel bis (di-2,2-dimethylbutyl orthophosphate), nickel mono(monopropyl monobutyl orthophosphate) mono(monoamyl monohexyl orthophosphate), nick-el bis (dicyclohexyl orthophosphate), nickel bis (dicyclobutyl orthophosphate), nickel bis (di-3-chloropropyl orthophosphate), nickel bis(bis-2,3-dibromopropyl orthophosphate~ and nickel bis (di-2-chloroethyl `~ orthophosphate).
The nickel bis-diorgano-orthophosphates employed in this invention are particularly useful in combination with alkyl aluminum halides as a catalyst system for controlled ole-fin oligomerization. More specifically, this catalyst system consists essentially of the reaction product of (A) one or more nickel bis-diorgano-orthophosphates of the formula NiCOP (0) (OR)2~2 as described above and (B) one or more alkyl aluminum halides of the general formula R'cAl Xd in which each R' is an alkyl group of one to about six carbon atoms, each X is a halogen atom, preferably chlorine or bromine, each of c and d is 1 or 2 and the total of c and d is 3, the mol ratio of (A) to (B) being in the range of 1:1 to 1:20, preferably 1:8 to 1:12.
Generally, as the mol ratio of (A) to (B) increases, the average degree of polymerization of the resulting oligomer ncreases.
The alkyl aluminum halides are primarily the com-~ 30 pounds R' Al X2, R'2 Al X and mixtures thereof including the mixtures of the formula R'3A12X3 usually referred to as the sesquihalides. Each R' can be, for example, a methyl, ethyl,

- 3 -4200~
propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, pentyl or hexyl group. Each X can be fluorine, chlorine, bromine or iodine. Examples of suitable alkyl aluminum halides include diethylaluminum chloride, n-butylaluminum dibrornide, ethyl - aluminum sesquichloride, methyl aluminum sesquichloride, ethyl aluminum sesquibromide, ethyl aluminum sesquifluoride and the like.
The catalyst compositions of (A) and (B) ars simply prepared by mixing the components. The components can be mixed prior to addition to the polymerization reaction system or can be added simultaneously or separately to such reaction system.
The desired reaction generally takes place immediately, but in any case it is known that the desired reaction takes place in no more than two hours.
The combination catalyst system is used in the method comprising ~1) mixing the appropriate combination catalyst described above with (D) one or more mono- or di-olefins which can be any aliphatic, cycloaliphatic or aromatic hydrocarbons containing no more than about 8 carbon atoms, preferably styrene, and/or one or more aliphatic hydrocarbons containing no more than about 4 carbon atoms, alone or with (E) a hydrocarbon solvent free of aliphatic unsaturation selected from the class aromatic hydrocarbon being optionally substitut-ed with up to about four lower alkyl groups or other non-inter-fering substituents such as amines, anions of non-metallic inorganic acids and nitrile groups, at a temperature and pressure and for a time sufficient to cause the reaction of (D) and (2) separating the resulting product.
Examples of suitable olefins (D) include ethylene, propylene, isobutylene, butene-l, cis-butene-2, trans-butene-; 2, pentene-l, hexene-l, cyclopentene, cyclohexene, cyclo-heptene, 4-methylcyclooctene, 2-methylbutene-1, styrene, buta-: 1()420~
diene, isoprene, 3-vinylcyclohexene and the acyclic and cyclic terpenes. Substitution or inclusion of non-inter~ering groups as in acrylonitrile, methyl vinyl ether, vinyl chloride and chloroprene is not intended to put such olefins outside the scope of suitable olefins (D). The preferred olefins are styrene and aliphatic olefins of 2 to 4 carbon atoms.

, For these polymerization reactions the reacting mono-mer or monomers may act as a solvent for the system.
Alternatively, an inert solvent (E) can be employed. While simple paraffin oils, cycloaliphatic hydrocarbons and aromatic hydrocarbons can be used, the halogeno-alkanes are preferred, particularly methylene chloride, chloroform, carbon tetrachlo-ride and ethylene chloride.
The mol ratio of total catalysts to (D) can be as little as 0.0001:1 as taught in the prior art but preferably ranges from 0.001:1 to 0.01 to 1.
For the polymerization of olefins (D) no solvent com-:..................................................................... , ` ponent (E) need be present, but a small amount of component (E) ; may accelerate the polymerization reaction. In such cases the mol ratio of (E) to (D) should be less than 0.01:1, preferably no more than about 0.001:1.
: The temperatures required for the oligomerization and ` polymerization reactions with the catalyst combinations of this ; invention are not particularly critical with the catalyst - combinations of this invention. Some heat may be necessary to initiate reaction such as heating to at least 30C. The maximum temperature which can be employed is dependent on the melting points, boiling points and decomposition points of the catalytic components, the reacting component (D) and the ~ 30 products as well as the desired control over rate of reaction.
For practical purposes, the maximum temperature is about 200C.
and the preferred temperature range is 40C. to 100C.

~ 04~00~ :
Ambient pressures are satisfactory generally ranging from atmospheric pressure to no more than about 50 atmospheres, preferably no more than 100 psig.
Under these conditions of temperature and pressure the oligomerization and polymerization reactions can be oper-ated batchwise for from five minutes to four hours or more or these reactions can be run continually. The separation of the desired product is well within the skill of the art being prim-arily a problem of fractional distillation.
Typically, for either oligomerization or polymeri-zation a reaction vessel is purged with some monomer (D) if gaseous or an inert gas such as nitrogen. Then enough of the alkyl aluminum halide (B) is added to dry the vessel. An inert solvent such as heptane may be added. The desired amount of components (A) and (B) are added, preferably in (A) to (B) mol ratios of 1:8 to 1:12 with monomer (D) at ambient pressure at a - sufficient rate to allow continuous reaction but not at such an ; excessive rate as to kill the reaction. The product is then distilled off if oligomer or extracted if high polymer.
Although prior addition of cocatalyst (B) favors rapid initiation and more rapid reaction of monomer (D) in the presence of the initial excess of this component (B), ; . -, .
concurrent addition of (B) with (A), favors formation of higher ; molecular weight oligomer products.
The following examples are illustrative of the best presently-known methods of practising this invention and are not intended to limit this invention the scope of which is ;. ..
- delineated in the appended claims. Unless otherwise stated, all quantitative measurements are by weight.

3 Example I

Oligomerization of Ethylene To a two liter stirred autoclave, after having been ` ~04Z()Og : ~
purged with ethylene, was added 500 ml. of benzene, 2.0 grams of ethyl aluminum sesquichloride EASC (0.0162 mole calculated as one aluminum atom per mole) and sufficient ethylene on a continuous basis to maintain a pressure of 50 psig in the auto-clave. To this system was immediately added 5 ml. of a catalyst solution of 0.75 gram of nickel bis-dibutylorthophosphate in 15 ml. of benzene, and the reaction temperature in the autoclave rose from 26C. to 42C. Additional 5 ml. portions of the catalyst solution were added 30 and 60 minutes respectively after the first catalyst addition to give a total of 0.00157 mole of the nickel catalyst. The flow of ethylene was increas-ed to maintain the system pressure at 100 psig. The reaction was allowed to proceed for 3 hours at ambient temperature (about 50C.) after which the autoclave was vented. The total ethylene added amounted to 30.4 moles.
The 1293 grams of remaining liquid was fractionally distilled to separate three fractions in addition to the ` benzene solvent. The first fraction was 550 grams of a liquid boiling in the range of 40 to 70C., having a refractive index of 1.4190 and being made up of oligomers of which a major constituent was cis-2-butene as identified by infrared spectrum. The second fraction was 125 grams of a liquid boiling in the range of 92 to 130C., having a refractive index of 1.4315 and being made up of oligomers having degrees of polymerization primarily in the range of 3 to 6. The third fraction was 75 grams of a liquid boiling above 130C. and having a refractive index of 1.4338. Thus, of the 750 grams of fractionated product 90 percent was made up of oligomers as described above instead of high polymers.
Similar polymerizations have been run using nickel bis-diethylorthosphosphate instead of the nickel bis-dibutyl-orthophosphate resulting in products having in one case 86%

` 1~4Z~9 oligomers having degrees of polymerization of 3 to 4, in anoth-er case 95% oligomers having degrees of polymerization of 3 to

- 4, over 87% being trimers, and in a third case 97% being trimers and the remainder being tetramers. No basis for this variation has been proven.
Example II
Oligomerization of Ethylene to Heavier Products The reaction of Example I was repeated, except without the initial addition of ethyl aluminum sesquichloride ; 10 to the autoclave. The same nickel catalyst and aluminum cocat-; alyst amounts were added uniformly and concurrently during the first 45 minutes of reaction. The reaction temperature in the autoclave rose from 24C. to 50C. within 5 minutes after the initial catalyst and cocatalyst additions, and the reaction was ; maintained at 50C. by cooling for the remainder of the ~
~` reaction period. The flow of ethylene was adjusted to maintain 100 psig. After 1 hour about 80 grams of ethylene (2.8 moles) had been consumed by the reaction, and the autoclave was vented.
The product was distilled to recover 74 grams of high boiling liquid, which gas chromatography analyzed to consist more than 90% of hexamers to decamers of ethylene. Refractive index of this fraction at 25C. was 1.4720.
Example III
Oligomerization of Propylene The catalyst and cocatalyst for this run were pre-pared by dissolving 0.75 gram of nickel bis-dibutylorthophos-phate in 15 ml. of chloroform and 1.5 grams of ethyl aluminum sesquichloride in 15 ml. of heptane to give 0.00157 mole of the nickel catalyst and 0.0121 mole of the EASC calculated as one aluminum atom per mole.
A two liter stirred autoclave was purged with pro-.- . . . ~

~ 4ZOO9 -pylene and pressurized to 20 psig after which 550 ml. of n-heptane was introduced. Then 5 ml. each of the catalyst and cocatalyst solutions were added followed by 200 ml. of propylene monomer. The resulting reaction raised the ambient temperature to 40C. The reaction was maintained continuously for a period of two hours at 50 psig and 40C. by regularly adding catalyst, cocatalyst and propylene monomer until all of the catalyst and cocatalyst solutions and 2000 ml. of additional propylene monomer had been added to give a total of 28.8 moles of monomer. The autoclave was then vented to atmos-pheric pressure.
The product was fractionally distilled to give three distinct fractions in addition to the solvent. The first frac-tion was 760 grams of a liquid boiling in the range of 61 to 91C., having a refractive index of 1.3900 and being made up of oligomers of which a major portion was a combination of methyl pentenes and methyl cyclopentenes as identified by infrared spectra. The second fraction was 170 grams of a liquid boiling in the range of 130 to 140C., having a refractive index of 1.4165 and being made up of oligomers having degrees of polymerization primarily in the range of 3 to 6. The third fraction was 125 grams of a liquid boiling above 140C. and having a refractive index of 1.4397. Thus, of the 1055 grams of fractionated product over 88 percent was made up of oligomers as described above.
A similar polymerization using nickel bis-diethyl-orthophosphate instead of nickel bis-dibutylorthophosphate re-sulted in a product containing 49.4% dimers and 30.6% trimers, but no basis has been proven for this variation.
Example IV
Oligomerization of Isobutylene - A stirred two liter autoclave with cooling controlled ' -_ g _ :
~ 042Q~5 to maintain below 50C. was purged and then pressurized to 30 psig. with isobutylene gas. Subsequently 500 ml. dry, pure benzene solvent was added, and a reservoir o~ isobutylene was connected to the autoclave to maintain 30 psig. throughout the ; reaction.
Catalyst containing 0.50 grams nickel bis-dibutyl orthophosphate (0.00105 mole) and cocatalyst containing 2.0 grams ethyl aluminum sesquichloride (0.0162 mole) in separate solvents (80 cc. total) were metered uniformly and concurrently into the autoclave over a period of two hours. Heat evolved by the oligomerization raised the reaction temperature ~rom 25C.
to 50C. after the initial addition of catalyst and maintained the reaction temperature at 50C. for three hours. The total monomer consumed was 9.0 moles. The vented product weighed 1013 grams. The product was distilled to recover 150 grams of liquid boiling in the range 210-213C. with refractive index 1.4447 and density 0.78 grams per cc. at 25C. This product was made up of oligomers of three to five mers.

. . .

': .
': '.'. ' ...

;, 10

Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A combination catalyst for controlled olefin oli-gomerization consisting essentially of the reaction product of (A) a nickel bis-diorgano-orthophosphate of the general formula Ni[OP (O) (OR)2]2 in which each R is selected from the class consisting of non-aromatic hydrocarbon groups free of aliphatic unsaturation and containing one to eight carbon atoms, non-aromatic hydrocarbon ether groups free of aliphatic unsaturation and containing three to six carbon atoms, and chlorinated and brominated derivatives thereof and (B) an alkyl aluminum halide of the general formula R'cAl Xd in which each R' is an alkyl group of one to six carbon atoms, each X is a halogen atom, each of c and d is 1 or 2 and the total of c and d is 3, the mol ratio of (A) to (B) ranging from 1:1 to 1:20.

2. A composition in accordance with claim 1 wherein each X is chlorine or bromine and each R is an alkyl group of two to four carbon atoms.

3. A method for olefin oligomerization consisting essentially of (1) mixing the catalyst of claim 1 with (D) an olefinic hydrocarbon containing no more than about 8 carbon atoms and, optionally, (E) a hydrocarbon solvent free of aliphatic unsaturation and containing up to 14 carbon atoms, any aromatic hydrocarbon being optionally substituted with up to about four non-interfering substituents, the mol ratio of total catalyst to component (D) ranging from 0.0001:1 to 0.01:1, at a temperature and pressure and for a time sufficient to cause reaction of (D) and (2) separating the resulting prod-ucts.

4. A method in accordance with claim 3 wherein component (D) is selected from the class consisting of ali-phatic hydrocarbons containing two to four carbon atoms and styrene.