DE1770240B2 - PROCESS FOR THE POLYMERIZATION OF AETHYLENE - Google Patents

Description

AlR ₂ X

where R is a hydrocarbon radical with a carbon number of 2 to 6 and X is a halogen atom, an alkoxy or mercapto group or a hydrogen atom is used has been and that

(2) the concentration of component (A) 0.1 to 25 mg / 1,

(3) the concentration of component (B) 10 to 100 mg / 1 and

(4) the ethylene partial pressure is 3 to 60 kgf / cm ² .

2. The method according to claim 1, characterized in that a catalyst is used at the titanium tetrachloride and / or titanium tetrachloride and / or titanium used to produce the component (A) as a titanium (IV) compound a titanic acid tracer has been used.

3. The method according to claim 1 and 2, characterized in that a catalyst is used in which for the preparation of component (A) as vanadium (V) compound vanadium oxychloride has been used.

It is already known that conversion genes from titanium and vanadium compounds as well as organometallic To use compounds directly for the polymerization of olelines. Isolation of the reaction product and use of the same with a non-organic compound is not provided. The catalyst does not show high activity, large amounts of transition metal compound, approx. mg / kg polyethylene consumed.

It is also known to carry out the polymerization of olefins in the presence of a catalyst system which is obtained from an _{insoluble precipitate obtained by reducing a mixture of TiCl 4} and VOCI _: with an aluminum trialkyl, optionally in BF .. <- Almosphärc, in amounts of 600 to mg / 1 and an organometallic compound of a metal from 1. to III. Group of the periodic table in amounts of at least 100 mg / 1 of the solvent used for the polymerization. The lower limit of the catalyst consumption of organometallic compound is about 6 g / kg of polyethylene.

According to proposals not yet belonging to the state of the art, in the polymerization of Olefins, the catalyst concentrations, in particular the amounts of titanium-vanadium compound to be used, reduced even further.

The polymers produced by this process but still contain an undesirable and not negligible aluminum content, in addition, the difficult-to-handle boron trifluoride is sometimes present in the preparation of the polymers necessary.

ίο It has now surprisingly been found that in the polymerization of olefins using medium pressures, the organometallic component can not only be reduced below 100 mg / l, but also a reduction in catalyst consumption is achieved. When lowering the concentration of the organometallic component of 1000 mg / l to 50 mg / l, the catalyst consumption fell by 45%. It wasn't to be expected with this If the concentration of organometallic components is low, polymerization can still occur.

The invention therefore relates to a process for the polymerization of ethylene, optionally im Mixture with other Λ-olefins, using of catalysts suspended or dissolved in inert diluents from (A) reduction products of mixtures of titanium (IV) and vanadium (V) compounds with organoaluminum compounds and (B) organoaluminum and / or organozinc compounds, characterized in that that

(1) for the preparation of component (A) an organoaluminum compound of the formula AlR ₂ X, where R is a hydrocarbon radical with a carbon number of 2 to 6 and X is a halogen atom, an alkoxy or mercapto group or a hydrogen atom and that

(2) the concentration of component (A) 0.1 to 25 mg / 1,

(3) the concentration of component (B) 10 to 100 mg / 1 and

(4) the ethylene partial pressure is 3 to 60 kgf / cm ² .

As titanium (IV) compounds are in particular tilane tetrachloride and / or titanic acid tetraesler suitable. Of the vanadium (V) compounds, in particular Vanadium oxychloride suitable.

The effect that in reducing the concentration the organometallic component of the catalyst a significant increase in the catalyst activity occurs, is observed to an even greater extent when hydrogen is excluded is being worked on.

According to the method according to the invention with the claimed catalyst concentrations, the result is roughly the following lower catalyst consumption:

approx. 1.5 to 94 mg

Transition metal compound / kg polyethylene, approx. 180 to 870 mg

Metal organic compound / kg polyethylene.

The process according to the invention is advantageous both in terms of the polymerization and in terms of the: Products.
For the polymerization process only

smallest amounts of organometallic compound and der with a hydrogen partial pressure of 4.8 ata

Transition metal compound used. The cat-regulated melt index / ₅ (according to ASTM D 1238) the

Nevertheless, the analyzer shows a high level of activity; the resulting polymer was about 21 in both cases.

Polymers contain only extremely low levels of catalysts. The consumption of heavy metal compounds could

sator residues, a post-treatment to remove the 5, i.e. by reducing the concentration of the metal

Catalysts from the polymer is not required- organic component from 1000 mg / 1 to 50 mg / 1

borrowed. Reduced by 45% if all processing measures are no longer required. The consumption of triethyl

minimal amounts of catalyst residues result. aluminum was only about 3% of in Example 1

When compared to the comparison experiment, the polymerization products show
processing an increased aging resistance as well as io

good color stability. In the processing example 2
machines does not corrode, so common

Additives to prevent corrosion, such as B. CaI- With the catalyst described in Example 1 cium stearate, which often give rise to disturbances, was produced in the same apparatus in the case of partial traps can. 15 pressures of 13.0 ata ethylene and 22 ata hydrogen

Another advantage can be seen in the fact that it polymerizes.

due to lower use of the expensive aluminum alkyl- The catalyst concentration was:
Connections can be worked more economically.

In the process according to the invention, 6 mg / 1 transition metal compounds,

Regulation of the molecular weight for Ziegler polymer 20 30 mg / 1 triethylaluminum.
Salionen usual means are used, such as. B.

Hydrogen or zinc alkyl compounds. There were 1501 / h. Catalyst suspension

The inert liquids known for this purpose with a liquid level of 300 l in the stirred container, such as e.g. B. aliphatic, are used. Thus, in the 15th and 16th hours of the cycloaliphatic and aromatic hydrocarbons experiment, 49.0 kg of polyethylene with a melting substance were used. index / ₅ of 10 (ASTM D 1238) ci-hold.

This corresponds to a catalyst consumption of: Example 1

and comparative experiment _{36 mg} heavy metal compounds and

The catalyst used for the polymerization 30 180 mg of triethylaluminum per kg of polyethylene,
was prepared as follows: 1 mol of n-Propyltiianat and

3 mol of vanadium oxychloride were mixed in 3.5 1 of heptane. The ash content in the polymer was 40 parts each

thinned and then refluxed for 2 hours million parts,

cooks. After the mixture had cooled, 8 moles of Example 3
Diethyl aluminum chloride dissolved in 51 heptane at 35

approx. 30 ⁼ C slowly metered in over 2 hours. The precipitate formed in a reduction process similar to that in Example 2 was filtered from ethylene partial pressure of 18.2 ata and water, washed and resuspended. The partial pressure of 16.8 ata with the suspension retained above was polymerized after the addition of triethyl-written catalyst,
aluminum used for polymerisation. 40 The following catalyst concentrations were used in a jacket-cooled stirring vessel:
continuous 1001 / h of the diluted with hexane

Pumped catalyst mixture. The liquid level 1 mg / 1 transition metal compound,

in a container of 100 1 was 50 mg / 1 triethylaluminum with a Co-60 emitter.
regulated. The polymer leaving the container 45

The suspension was stirred in a downstream stirrer. In the 15th and 16th hours, it was 19.8 kg

relaxed container and from there to a centrifuge made of polyethylene with a melt index Z ₅ of 1.4

given. The centrifuge-moist powder was then put

dried at about 8O ⁰ C in vacuo. This results in a catalyst consumption of:

At a concentration of 17.5 mg / 1 of the above-mentioned 50

wrote transition metal compounds 15 mg transition metal compounds and

and a) 1000 mg / 1 (comparative test) or b) 50 mg / 1 760 mg triethylaluminum per kg of polyethylene.
(Example 1) Triethylaluminum became ethylene at

an ethylene partial pressure of 3.2 ata polymerized. The ash content in the polymer was 100 parts

The yield in the comparative experiment was 10.0 kg 55 per million parts.

Polyethylene / hour and in example 1 18.6kg poly- example 4
ethylene / hour

This corresponds to a catalyst consumption of: To produce the catalyst, 5.6 moles of diiso-

butylaluminum fluoride presented in 14 l of heptane, llicr-

Comparative _{experiment 6o was c} j _n mixture of 1.6MoI titanium cirachloride

175 mg of transition metal compounds per kg of Po and 2.4 mol of vanadium oxychloride at -30 ° C.

Lyäthylcn and dosed. The precipitate precipitated out was

9980 mg of triethylaluminum per kg of polyethylene; filtered off, washed and then resuspended.

This suspension was then used as a catalyst component

Example 1 ",. _{nenle used} .

94 mg of transition metal compounds per kg of poly- For polymerization at a partial pressure of ethyl

ethylene and of 22 ata with the addition of 6% by weight butylene, bc-

270 mg of triethylaluminum per kg of polyethylene. drew on ethylene, and a partial pressure of hydrogen

of 11.5 ata in the apparatus described in Example 1, a concentration ^v on 0.67 mg / 1 was used from the above described catalyst component. Triethylaluminum in a concentration of 50 mg / l was used as the organometallic component. This gave 17.3 kg of polyethylene with a melt index Z ₅ of 2.1 (ASTM D 1238) in the 21st and 22nd hours of the experiment.

This results in a catalyst consumption of:

11.5 mg transition metal compounds and
870.0 mg of aluminum triethyl per kg of polyethylene.

The ash content in the polymer was 70 parts each, if no catalyst washes off Million parts.

Example 5

With the catalyst described in Example 1, ethylene was at an ethylene partial pressure of 35 ata polymerized in the absence of hydrogen. The catalyst concentrations were:

0.2 mg / 1 transition metal compound mixture, 50.0 mg / 1 triethylaluminum.

ίο This was in the 9th and 10th hours of the attempt 39.6 kg / polyethylene received. This corresponds to a catalyst consumption of:

1.5 mg of transition metal compounds and 380 mg of triethylaluminum per kg of polyethylene.

Claims (1)

Patent claims: 1. Process for the polymerization of ethylene, optionally in a mixture with other \ -olefins, using catalysts suspended or dissolved in inert diluents from (A) reduction products of mixtures of titanium (IV) and vanadium (V) compounds with organoaluminum compounds and (B) organoaluminum and / or organozinc compounds, characterized, that (1) for the production of component (A) an organoaluminum Compound of formula