DE1188283B - Process for the polymerisation of olefins or olefin-containing gases - Google Patents

Description

Process for the polymerization of olefins or olefin-containing gases The polymerization according to Ziegler proceeds in such a way that you first have one produces active catalyst complex from individual components. About these components include organometallic compounds such. B. triethyl aluminum or monochlorodiethyl aluminum, and on the other hand z. B. Titanium tetrachloride (see documents laid out by the Luxembourg Patents 33,201 and 33,306).

The formation of the active catalyst complex is a chemical process, which takes place with considerable heat release, no physical mixing process Sense. The active catalyst complex is no longer liquid and colorless like the ones used Catalyst components but solid and colored. Usually the active one Catalyst complex prepared outside the reaction vessel by adding the catalyst components combined in a solvent to form the catalyst complex.

According to an older proposal, dry polymerization is used, which does not yet belong to the state of the art, if one considers the polymerization in one low-boiling solvent in the usual way in the presence of an active catalyst complex begins and uses the heat of reaction to remove the solvent during the polymerization to remove. The polymerization continues without a solvent until the Catalyst complex is consumed. Then this must be added.

So here is a small part of the polymer in a first stage produced in an inert organic auxiliary liquid and in the second stage further polymerized after reduction of the auxiliary liquid.

When polymerizing in the presence of a solvent, it is As described, it is customary to make the addition in such a way that one initially forms the active catalyst complex and then some way into the reaction vessel introduces. You could z. B. also the addition of the catalyst complex in the carry out the second stage of dry polymerization.

One prepares the active catalyst complex in a solution and gives this solution is applied to a polymer, the result is a paste. Such a mush could enter into a running dry polymerization. But it is disadvantageous to do so.

Namely, it is of crucial importance that the catalyst complex is evenly and finely distributed on the dry polymer.

This is not straightforward in the aforementioned way possible. Is the Rate at which the solvent under the influence of the heat of polymerization distilled off, slower than the polymerization rate, clumps can be seen Do not avoid dry polymerization inside the reaction vessel. It It is therefore advantageous to remove the solvent from the slurry beforehand and that dry product for further polymerization in an ongoing dry polymerization to introduce.

When adding to the catalyst complex go the actual Trockenpolymeris ation, so the second stage of the procedure described, still two process steps ahead, namely the preparation of the active catalyst complex in solution as well as evaporation of the solvent.

By two process steps before the actual dry polymerization to avoid, it would be basically conceivable initially to use the catalyst components to combine outside the reaction vessel without solvent in any form, to form the active complex.

You would then only have one procedural step before the actual one Dry polymerization.

However, it is difficult to find an active catalyst complex, the z. B. is formed directly from the liquid components into the reaction chamber to introduce. Because a prerequisite for the smooth implementation of a continuously working dry polymerization is that the addition of the catalyst complex takes place evenly and that for its even distribution within the reaction space Care is taken.

These conditions are particularly difficult to meet when you want to work with very small amounts of the catalyst complex. The same Difficulties arise when dealing with the catalyst components individually without solvents in the ongoing dry polymerization.

It therefore suggests itself to put the catalyst components outside to vaporize, gas or atomize the reaction vessel in this state to combine to form an active catalyst complex and then put it in the reaction vessel to introduce. It also stands to reason that the catalyst components are present in this way to combine the olefin to be polymerized. The catalyst complex falls in the process as smoke. However, the smoke cannot be prevented from coagulating. In order to but then the fineness is lost, which is an essential prerequisite for the further polymerization is.

The invention relates to a process for the polymerization of Olefins of the olefin-containing gases with the aid of organometallic compounds Catalyst combinations according to Ziegleer, with the exception of the homopolymerization of ethylene, the polymerization from beginning to end either in the presence or in Absence of solvents or diluents is carried out in the invention the volatile catalyst components by themselves or as solutions in steam, gas or mist form with the aid of vapor or gaseous carrier streams into the reaction vessel be introduced, in which a dispersant - in wet polymerization in liquid form, in the case of dry polymerisation in the form of the freshly produced polyolefin with the exception of a polyolefin obtained by the polymerization by means of the above Catalyst combinations in an inert, low-boiling organic liquid or in a mixture of such liquids and by evaporation of this liquid according to the first stage of the process according to patent application G 16931 IVdI39c (cf. German Auslegeschrift 1099168) has been produced - is submitted.

The introduction of the catalyst components into the reaction chamber The way over the vapor phase is therefore particularly easy, because one is aware of the facts can serve that the catalyst components have relatively low boiling points and the vapor pressure of the liquid catalyst components with the temperature increases. For example, you send a through the liquid catalyst components Gas flow that is charged with vapor as it passes through the liquid, namely the more the higher the temperature is.

The catalyst transport is also greater, the greater the amount of gas that is sent through the liquid. One must use inert carrier gases, such as nitrogen or gaseous hydrocarbons, e.g. B. cH4. But you can too use gaseous olefins.

It is also possible to use the catalyst components in dissolved form to be introduced into the reaction space according to the invention by gasifying, evaporating or atomizing.

An advantage of the method according to the invention is that the no additional process steps upstream of the actual polymerization must be, in order to an active catalyst complex or to an active, for Polymerization enabled mass to come. Another benefit is the steady and uniform formation and replenishment of the active catalyst complex in the reaction space compared to the uneven and periodic supply of what has already been formed Catalyst complex. Another advantage is the even distribution of the active catalyst complex to the entire polymer present in the reaction space. Another advantage is the ability to do so without the slightest difficulty an active contact complex throughout the course of a dry polymerization to produce consistent composition.

All of these characteristics are critical to the production of a polymerization product consistent quality.

Example 1 1000 ml of pure heptane were poured into a reaction vessel from 3 1 contents filled and rinsed and stirred while passing pure nitrogen through. After about an hour, aluminum triethyl and titanium tetrachloride were steam or mist-shaped and initiated separately.

The titanium tetrachloride was in a wash bottle with a Frit, the temperature of which was kept at 800 C. Were through the wash bottle about 11 nitrogen passed per hour. Another wash bottle with frit was filled with aluminum triethyl. At about 1300 C, 3 liters of nitrogen per hour were generated passed through. The two nitrogen streams loaded with the catalyst vapors were combined in the submitted heptane.

After about an hour after getting a small amount of active catalyst complex propylene was also introduced through a separate inlet pipe, without the supply of the catalyst components being interrupted. The reaction temperature was kept at 40-450.

With a molar ratio of triethylaluminum to titanium tetrachloride of about 2.5: 1 the yield was 80 g.

Example 2 In the apparatus according to Example 1 were under inert Conditions entered 180 g of freshly produced polypropylene. The not active, however inert product was made according to the arrangement described in Example 1 with the contact components Triethylaluminum and titanium tetrachloride steamed.

To evaporate the triethylaluminum in the submitted polymer twice as much nitrogen was used as for evaporating titanium tetrachloride. The molar ratio of triethylaluminum to titanium tetrachloride was 1.4: 1. The reaction temperature gradually rose to 600 C and was kept at this temperature. After yourself 139 g of polypropylene had newly formed, the test was interrupted.

Claims (1)

Claim: Process for the polymerization of olefins or olefin-containing ones Gases with the aid of catalyst combinations containing organometallic compounds according to Z i e g 1 e r, with the exception of the homopolymerization of ethylene, the polymerization from start to finish either in the presence or absence of solution or diluents is carried out, characterized in that the volatile Catalyst components for or as solutions in steam, gas or mist form with the aid of vapor or gaseous carrier streams into the reaction vessel be introduced, in which a dispersant - in wet polymerization in liquid form, in the case of dry polymerisation in the form of the freshly produced polyolefin with the exception of a polyolefin, which is polymerized by means of the mentioned above Catalyst combinations in an inert, low-boiling organic liquid or in a mixture of such liquids and by evaporation of this liquid according to the first stage of the process according to patent application G 16931 IVd / 39 c (cf. German Auslegeschrift 1099168) has been produced - is presented.