DE1020186B - Process for polymerizing olefins - Google Patents

Description

GERMAN

It is known that one can mono- and diolefins with suitable fixed contacts at elevated pressure and can polymerize at elevated temperature to solid waxy or liquid hydrocarbons. as Catalysts are activated metal oxides of VI. Subgroup of the periodic table with aluminum oxide or aluminum silicates are used as carrier material. Difficulties arise with these procedures because the solid contact is covered with high molecular weight products during the reaction, their residue Removal with liquid hydrocarbons does not succeed. The catalyst is thereby at continuous Operation inactive relatively quickly, tears open and contaminates the polymer with contact sludge.

It has now been found that olefins can advantageously be polymerized with the aid of a solid contact can, if the polymerization in the presence of a chromium oxide catalyst coated on aluminum ortho-phosphate undertakes. Such a fixed contact can easily be separated from the polymer formed, since it is soluble in both alkalis and acids. Another benefit of this process is it can be seen that the catalyst is obtained from the aqueous solution of alkalis or acids by neutralization can be recovered again.

The fixed contact to be used according to this invention can be made by impregnating aluminum phosphate with aqueous chromic acid solutions. Finely divided aluminum orthophosphate, such as grains, granules or compacts of this phosphate with particle sizes between 0.5 and 10 mm, with 0.1 to Treat 1 molar aqueous solutions of chromium (VI) oxide. The one separated from the impregnation solution Fixed contact is immediately in the moist state or after a pre-drying for activation to a higher level Temperatures warmed. If you do this heating in the air stream, temperatures are between 350 and 600 ° C and heating times of 5 to 12 hours are advantageous. In the hydrogen stream, the Catalyst also at a lower temperature, preferably at temperatures between 150 and 300 ° C, activate.

The heat treatment partially reduces the hexavalent chromium to trivalent chromium. The chromium content of the catalyst is expediently adjusted so that it is 2 to 6 ⁰ I ₀ , based on the total weight of the solid contact.

Olefins that can be polymerized by this process are, for. B. ethylene, propylene and other short-chain mono- or diolefins. Cheap polymerization temperatures are from 40 to 150 ° C, but preferably 65-100 ⁰ C. The working at pressures between 10 and 120 at and the addition of inert diluents to the reaction system by methods of polymerizing
of olefins

Applicant:

Aniline & Soda Factory in Baden
Aktiengesellschaft, Ludwigshafen / Rhein

Dr. Horst Kerber, Ludwigshafen / Rhine,

and Dr. Rolf Platz, Mannheim,
have been named as inventors

Advantage. Suitable diluents are, in particular, inert solvents which are liquid at room temperature, such as liquid saturated aliphatic hydrocarbons, e.g. B. cyclohexane, heptane or octane, useful. The relationship between catalyst and diluent can be varied widely and should preferably be between 1: 5 and 1:15.

The process can be carried out batchwise or continuously. In discontinuous operation expediently, the catalyst and the diluent are placed in a pressure vessel and this is carried out olefin to be polymerized as it is consumed to the reaction vessel. With continuous One can process the monomer and an inert solvent together with the contact Pump in cocurrent or countercurrent one or more times through a reaction chamber. Let good sales can also be achieved if the monomers dissolved in an inert diluent are solidified arranged catalyst in the trickle or sump process brings to the polymerization.

To separate the solid contact, the polymer can be mixed with dilute alkalis or acids, expediently at temperatures between 100 and 150 ° C, treat. For example caustic soda, Caustic soda, hydrochloric acid or sulfuric acid in question, the concentration of which is adjusted so that it is about 1 to 12 is normal, but preferably 1 to 5 is normal. It is also expedient to add an inert liquid Solvent such as an aliphatic or cycloaliphatic hydrocarbon, e.g. B. isooctane, n-octane, Heptane or cyclohexane.

The polymers produced by this process are practically ash-free.

709 807/297

Claims (1)

3 4 The parts given in the example below Relax can be the autoclave a solid block, are parts by weight. consisting of isooctane-containing polyethylene and solid example contact. The crushed reaction mass is in a pressure To prepare the contact, use a powder vessel with 500 parts of 2N sodium hydroxide solution and 1000 parts shaved aluminum orthophosphate, which is added to 4 mm diameter parts isooctane and stirred for 18 hours diameter strands formed and then heated 5 hours 13O ⁰ C. After cooling down, it separates is dried at 200 ° C. 500 parts of the so pre-treated polyethylene as a soft, easy to crush Delten phosphate compacts become 1000 ecm of a mass on the surface. It is severed with 0.8 molar aqueous chromic acid solution added and there io methanolic hydrochloric acid and then with hot methanol Leave at room temperature for 12 hours. After washing until the filtrate reacts neutrally. You get separation of the liquid phase one fills the now 250 parts of a white, solid and! yellow-colored solid in a reaction tube, and ethylene, at temperatures between 125-133 ⁰ C. activated by 8 hours of heating to 500 ³ C. The softens, The green colored contact is direct for the polymer 15 _. sation can be used. Patent claims: In a stainless steel shaking autoclave 1. Process for polymerizing olefins in 35 parts of the present in the manner described are applied to a carrier provided aluminum phosphate-chromium oxide contact and chromium oxide catalyst, characterized in that 250 parts of isooctane filled. The autoclave is equipped with stick 20 that aluminum orthophosphate is used as a carrier. The fabric is rinsed and then turned under a pressure of ethylene. 40 set at. Now the autoclave is slowly increased to 85 ° C. 2. Method according to claim 1, characterized in that heated. At 57 ° C., the pressure in the autoclave is 62 atm, so that the formed can be separated off gone up. From 78 ⁰ C is a significant pressure drop on polymer, the catalyst and the aluminum 22 at detectable. The consumed ethylene is replaced. 25 Phosphate dissolves in alkalis or acids. and maintain a pressure of 85 atm in the autoclave. The polymerization proceeds rapidly. Publications considered after 4 ^x / _{2 hours:} interrupt the reaction. After cooling and French patent specification No. 1 110 260. © 709 807 / 2OT 1t. 57