DE1215935B - Process for the polymerization of ethylene and other alpha-olefins that are gaseous at normal pressure - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

C08f

German class: 39 c -25/01

Number: 1215 935

File number: F 31093 IV d / 3-9 G

Filing date: April 27, 1960

Opening day: May 5, 1966

Processes are known which allow ethylene and other -olefins and mixtures of these monomers under comparatively mild conditions in terms of reaction temperature and pressure too high molecular weight, usable as plastic Polymerize polyolefins.

These low pressure processes are usually carried out in hydrocarbons using heavy metal salts the IV. to VI. Subgroups of the Periodi 'see systems with ordinal numbers from 22 to 92 and organometallic compounds of groups I to IIL of the periodic table carried out as catalysts.

They are particularly suitable for such Polymerizations Mixed catalysts made from titanium chlorides and organoaluminum compounds proven.

These low-pressure processes are also known as the »Ziegler process« and are at R a f f - Allison, "Polyäthylene", pp. 72 to 81, described.

To carry out the reaction, it is particularly advantageous that after the reaction with organoaluminum To separate the titanium chloride present in reduced form from the reaction mixture before use, well with inert To wash the dispersant and only then to use it for the polymerization.

In the polymerization itself, the washed catalyst thus obtained is z. B. by adding fresh Activated aluminum diethyl monochlorides.

The advantage of this procedure is based on the removal or partial removal of at halogen-rich aluminum compounds formed during the production of the catalyst, which cause the polymerization inhibit or completely prevent as well as the stereospecificity of the catalyst in the olefin polymerization reduce.

The polymers produced with the catalysts mentioned generally have a very high level Molecular weight, for the usual purposes, however, are polymers with low Molecular weight required.

There are z. B. in the case of the polyethylene for processing by injection molding and the manufacture of hollow bodies polymers best suited to their reduced viscosity _(η η α) - measured at 135 ⁰ C in decahydronaphthalene in ö, l ^d / _o iget solution - having · 1:30 to 3 lie. However, the catalyst system described above gives polymers with η red values> 5 under the customary polymerization conditions.

It is already known by modifying the catalyst system or by adding regulating

Process for the polymerization of ethylene and other olefins which are gaseous at normal pressure

Applicant:

Farbwerke Hoechst Aktiengesellschaft formerly Master Lucius & Brüning, Frankfurt / M.

Named as inventor:

Dipl.-Chem. Dr. Joachim Rasper, Schannenbach via Bensheim (a. D. Bergstrasse); Df. Werner Bartsch, Eppenhäin (Taunus); Tue. Siegfried Sommer,

Frankfurt / M.- Unterliederbach; Dr. Gerhard Bier, Troisdorf (District Cologne)

substances that act during the polymerization To lower the molecular weight of the polymer formed =

• For example, processes are known in which the catalyst system, in addition to titanium trichloride and aluminum * organic compound additionally contains compounds of tetravalent titanium, also Vef * drive to be expected in which the catalyst before and / and during the polymerization by adding * dosing small amounts of oxygen is partially oxidized.

However, to produce such methods, the polymers having reduced molecular weight allow _ä provide polyethylene of relatively low density (<0.95) and not on the polymerization of a-olefins having more than 2 carbon atoms to crystalline polymers because of the low stereospecificity of the catalyst system applicable.

Regulatory additives which are suitable for reducing the molecular weight of the polymer in the polymerization with titanium trichloride and organoaluminum compounds are, for. B ₁ also known compounds with active hydrogen and also organic halogen compounds. Since such compounds mostly not only break off the polymer chain, but also "irreversibly change and inactivate the catalyst, especially in higher concentrations, it is usually difficult when using them to reproducibly create the optimal conditions for the desired molecular weight-lowering effect while at the same time maintaining sufficient catalyst activity to be observed.

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According to processes which are also already known, damage to the catalyst is observed. In this respect, the low solubility of polyolefins with high density and crystallinity is possible if hydrogen is used as a regulator of the carbon dioxide in hydrocarbons,
will. In the technical implementation of this The stereospecificity of the catalysts for the method are due to the high diffusion rate 5 "-olefin polymerization is retained when using hydrogen and the danger of CO ₂ as a regulator; Likewise, a polyethylene obtained with a mixture of hydrogen and air in a large _{amount of CO 2} has a high density, mixing range, and particularly high requirements (> 0.96).

the tightness of the equipment used to a technical advantage offers the fact that as well as special precautionary measures when handling the charcoal added to the polymerization batch the polymer suspension necessary. Dioxide after completion of the polymerization as un-so must z. B. after the end of the polymerization, flammable protective gas for the polymer suspension before emptying the polymerization kettle which can serve.

Hydrogen contained in it by a non-ignitable The regulation of the molecular weight with carbon dioxide

protective gas must be replaced. 15 can be done so that before the start of the polymerization

In patents (e.g. in the French, a certain partial pressure in the polymerization kettle

Patent documents 1173 535 and 1177262), the Ver is adjusted to carbon dioxide and then through

drive for the polymerization of olefins with mixed addition of the catalyst and addition of the monomer

Catalysts made from reducing metal- initiated the polymerization and over the desired

compounds (e.g. aluminum triethyl) and reducing 20 duration is continued.

heavy metal compounds (e.g. titanium tetra- One can also over the entire duration of the

chloride), is implied, polymerization at the same time as the monomer

that the monomer introduce small amounts (about 0.01%) of carbon dioxide, the molar weight

Water, oxygen, carbon dioxide and other acid-regulating effects through the choice of the ethylene

may contain substance-containing compounds. The for 25 carbon dioxide ratio in the gaseous

such a monomer required amounts of catalyst feed (gas) can be varied within wide limits

are specified. However, these are the special can. It is useful in this case to use a small one

Properties of the carbon dioxide, in particular its amount of exhaust gas to be removed during the polymerization

molar weight lowering effect that take it away from the others.

on carried out impurities of the monomer under 30 By varying the ethylene-carbon dioxide ratio

separates, not mentioned. ratio can be the molecular weight of the polymer

"In contrast, in the invention it is precisely the values that are varied during the polymerization, so

the patents cited not recognized mol- that in this way polymers with narrower

Weight-reducing effect of carbon dioxide as well as with a wider molecular weight distribution

utilized. Let the "process of the invention 35" be produced.

The quantities of carbon dioxide to be used are also advantageous, and the fact that patent specifications in ethylene can be used in quantities that are significantly higher than those in the above-mentioned process can also be advantageous. The invention relates to a process for regulating the rate of polymerization by adding.
Polymerization of ethylene and others at normal 40 One can therefore proceed in such a way that, at constant pressure, gaseous oc-olefins and mixtures of moderate ethylene supply, the amount of carbon dioxide of the monomers mentioned in hydrocarbons is set in such a way that the polymerization medium is mixed catalysts, which by reaction of speed over the entire polymerization aluminum-organic compounds and titanium duration is kept constant. In this case, tetrachloride, washing out and optionally heating 45 can have different molecular weights produced by diluting the titanium trichloride obtained and activating the change in the polymerization time or the catalyst titanium trichloride with diethylaluminum monochloride or the polymerization pressure, which are characterized by this.

is that the monomer carbon dioxide in amounts Example 1

from 0.05 to 20 percent by volume, especially 0.1 to 50 ^p

8 percent by volume, based on the gaseous total In a 2-1 glass flask with stirrer, gas inlet charge, is added. pipe and exhaust pipe are under nitrogen 11

Since, according to older investigations, carbon dioxide of a mixture of aliphatic hydrocarbons with organoaluminum compounds of the general boiling range from 180 to 200 ⁰ C, lOmMol of one of my formula R ₂ AlX (X = halogen), as they focussed on 55 titanium tetrachloride and aluminum sesquichloride as the above-mentioned polymerization processes leached titanium trichloride suspension metal-organic catalyst component used and 20mMoI diethylaluminum monochloride, not reacting, was a regulating effect of the dissolved. Not to be expected after heating the mixture to about 8O ⁰ C Kohlendioxydes will readily ^χ stirring _2/2 hours an ethylene (H. Z ei ss, Organometallic Chemistry [Reinhold introduced stream 60, so much carbon dioxide dry Publishing Corp. , New York]; Chapter 5 is added that with about 10% exhaust gas (based on K. Ziegler, Organoaluminium compounds, on the input gas amount) the ethylene uptake at about p. 241, furthermore V. Grignard and R. J e η ki η s, 35 l / h. The carbon dioxide content in the gas is Comptes rend., 179 [1924], p. 89). initially high (10 to 15 percent by volume) and

A premature inactivation of the catalyst 65 decreases in the course of the polymerization (to about 2 to

by temporarily overdosing with carbon dioxide 5 percent by volume at the end). Polymerization time

is not to be feared, as unexpectedly 150 minutes. After the catalytic converter has been destroyed

even at high carbon dioxide partial pressures none through. Butanol addition, filtering off, washing out and

Claims (1)

5 6 Drying of the polymer is 100 g of poly
Ethylene obtained with the reduced viscosity 1.9. Under otherwise in the same manner, but using 11 In a boiling at 60 to 8O ⁰ C hydrocarbons of nitrogen instead of carbon dioxide, 10 mmol of the fraction in Example 3 are obtained guided polymerization is found with almost 5 used TiCl ₃ suspended and 20 mmol of diethyl the same polymerization yield a reduced vis-aluminum monochloride dissolved. While stirring is viscosity of 6 now at 50 ° C for 5 hours a mixture of ethylene Example 2 ^unc * P ^ro Pyl ^s i ^m volume ratio 90:10 initiated the 0.5 percent by volume of carbon dioxide, based on In a 10-1 polymerization apparatus, the total gas is mixed in. The total of 61 methylcyclohexane 60 mmol TiCl ₃ (prepared as the input gas quantity is regulated so that about 5 l / h as described in Example 1) is suspended after the exhaust gas has escaped. After termination of the polymerization, 120 mmol of diethylaluminum monochloride dissolved in the usual way and the auxiliary liquids were removed. It is then at 85 ° C with stirring for 5 hours by steam distillation 150 g of long ethylene at a rate of 15 of a copolymer of ethylene and propylene 240 l / h are introduced. In addition, one derives 4 volume with the reduced viscosity of 3.5 obtained,
percent carbon dioxide, based on the total. Proceed in the same way without carbon dioxide gas. After working up, as in Example 1, additive, a polymer is obtained with the reduction described, 1400 g of polyethylene having a viscosity of 7.5.
reduced viscosity 3 obtained. 20th Example 3 claim: As used in the example 1 apparatus are in process for the polymerization of ethylene and 11 a saturated aliphatic hydrocarbon other gaseous at normal pressure "olefins fraction having a boiling range of 100 to 14O ⁰ C 10 mmol of 25, as well as mixtures of said monomers of a as in Example 1 produced, but additionally suspended in hydrocarbons by means of mixed catalysts, subjected to a heat treatment, _{TiCl 3,} which is dissolved by the reaction of organoaluminum compounds and 20 mmol of diethylaluminum monochloride compounds and titanium tetrachloride, washing out. Now at 5O ⁰ C for 6 hours is long titanium stirring initiated propylene with various amounts of 30 trichloride and activation of titanium trichloride under carbon dioxide and optionally heating the resulting. According to the usual work-up made with diethylaluminum monochloride, about 100 g of polypropylene each have been made with, characterized by the carbon dioxide content of the gas, that the monomers contain carbon dioxide in dependent reduced viscosities: amounts from 0.05 to 20 percent by volume, especially Volume percent CO ₂ 35 0.1 to 8 volume percent, based on the gas Reduced Vis-shaped total charge, added, in the total single gas viscosity 0.0 (comparative test) 10 Publications considered: 0.1 8.6 German Patent No. 878 560; 0.5 4.5 40 French Patent Specification No. 1173 535,1177262; 1.0 2.1 laid out documents of Belgian patents 1.3 1.7 No. 539 302, 540 459. 609 567/584 4.66 © Bundesdruckerei Berlin