SU820877A1 - Method of preparing catalyst for polymerisation of ethylene - Google Patents

Description

The invention rgnosigs. to a method for preparing a catalyst for the polymerization of ethylene and can be applied in petrochemical industry.

A known method for the preparation of a catalyzer for the polymerization of ethylene is ij according to which the preparation of a catalyst of the complex Tt C & Ixx LESE jti where F is alkyl C - C, x 1-3, is produced in the presence of a complex-forming additive, as which is used aromatic carbohydrates. ) and picyleo kie ethers. According to another known method, homopolymers and copolymers of o-oviches are obtained under the action of a catalyst consisting of the products of the interaction of J-i CB with organomagnesium compounds of the formula TlMgCE, where alkyl, Cj-Cg in the presence of ethers (tetrahydrofuran, disvssane, etc.)

The closest in technical quality and sufficiency and the achieved effect to the proposed method is the preparation method (Yulen in a catalyst for the polymerization of

by mixing the megalachic psychophase magnesium, halovalkyl, taking 3-10 fold molar excess with respect to magnesium, and titanium tetrachloride to heat the mixture to the boiling point of haloalkyl, boiling it while mixing for 1-8 h, removing the excess haloalkvl from ; of the solid precipitate formed, followed by the introduction of trialkylalumin {g.

The disadvantage of the known method is the relatively low activity noJi of the radiated catalyst; hook, the yield of popethylene (PE) in the presence of a catalyst obtained in a known manner, 7O-. 84 kg PE / g Ti h; atm.

In order to produce a catalyst with increased activity, the present method has been proposed {as described in a catalyst for the polymerization of ethylene by mixing. neither metal powdery magnesium, haloalkyl, in this case in a 3-10 fold molar excess with respect to magnesium, and tetrachloride titanium. heating the mixture to boiling point. haloalkyl, boiling it with stirring for 1-8 hours, removing from the excess haloalkyl from the solid precipitate, adding to the precipitate a complexing additive: benzene or tetrahydrofuran, taken in a molar ratio of the additive: magnesium - 0, extract of the complex at 20–25 ° C for 0.5–1.0 h and at a temperature of 354 ° C for 0.5–1.0 h, followed by the introduction of aluminum trialkyl. The distinctive features of the process are the addition to the precipitate of a complexing additive: benzene or tetrahydrofuran, taken in a molar ratio of additive: magnesium — 0.01–10.0 and holding the complex at 2 –25 ° C for 0.5–1.0 and a temperature of 35-40 ° C for 0.51, 0 h. The catalyst obtained by this method has an increased activity as compared to the catalyst obtained by a known method. Thus, the yield of polyethylene in the presence of a catalyst obtained by the present method is 218260 kg of PE Tg h-atm. The essence of the method is as follows. The mixture of metallic (powdered) magnesium with haloalkyl and titanium halogen is heated at the boiling point of the haloalkyl for under constant stirring. 1I p, the course of the reaction is complete and full. the growth of metallic magnesium haloalkyl (iR). taken in excess relative to metallic magnesium (Me), - It is the ratio Me / R 3-1О. An excess of the halo of the residue is distilled at 9 0 -1 0 With under vacuum or in a stream of dry purified nitrogen. To the obtained precipitate is added a complex-forming addition of an aromatic hydrocarbon or cyclic ether, for example, a dried and purified benzene or a 25% solution of tetrahydrofuran in a dried exanol fraction, and an alkaline aluminum dichloride solution in hexane 4. The molar ratio of the additive: Mg 0.01-10.0. The resulting complex is kept for 0.5-1.0 h at 20 asb and O, 5-1.6 h at 40 ° C. In this case, a highly active catalytic complex is formed, in which TiCede is reduced to an oxidation state of less than 4 (Tit), and which is diluted with a saturated and dried liquid hydrocarbon, for example, a hexane fraction. The catalyst prepared according to the present method was tested in a polymerization reaction of tylen. The polymerization of ethylene is carried out in a stainless steel autoclave with a capacity of 0.5 liters. The autoclave is equipped with a baffle and a heating device for maintaining the polymerization temperature constant. As a diluent, 2 5 O ml of the purified and dried hexane fraction with boiling temperatures of 68-73 C are poured into the autoclave. Ethylene of the polymerization frequency is used for polymerization. The pressure in the reactor is kept constant by continuously feeding ethylene. In all the examples, 1 ml of 3.6 U M triethylaluminum solution is used as a cocatalyst. Polymerization temperature 85s, reaction time 30 minutes, pressure 4 atm. Example 1. A mixture containing 0.5 g of powdered metallic magnesium 0.2 g of TV C 64 and 1 O ml (butyl chloride) is heated to the boiling point of butyl chloride and boiled for 1 hour. Then, at a residual pressure of 1 mm Hg .st. and a temperature of 90 ° C for 1 hour while continuously stirring, the excess butyl chloride is distilled off. Under continuous stirring, 0.01 mol of dried purified beng ash and 1.0 ml of a 0.3 M solution of ethyl aluminum dichloride in the hexane fraction are added to the resulting precipitate. The complex is kept for 0.5 h at 2 ° 25 ° C and 0.5 hour at 4 ° C, then diluted with a purified and dried hexane fraction to a concentration of 1.0 mmol Ta. For the polymerization, 10 ml of the catalyzed complex of the indicated concentration is used. The polymerization is carried out for about 5 hours. 250 ml of the hexane fraction, ifO ml of the catalyst complex, 1.0 ml of 3.6 10 M triethylaluminum solution are poured into the autoclave, heated to 85 ° C and ethylene is given to a pressure of 4, atm. Polymerization time is 0.5 hours. 16 g of polyethylene is obtained with an average speed of 166 kg of PE / g Ti Chatm. PREMIUME 2. A mixture containing 0 g ps of osh-shaped metallic magnesium, 0.1 g of TiCE and 10 ml is heated to the boiling point of butyl chloride and boiled for 1 hour. Then, at a residual pressure of 1 mmt .st. and a temperature of 90 ° C for 1 h with continuous stirring is distilled from

Claims (1)

Claim A method of preparing a catalyst for the polymerization of ethylene by mixing metal powder of magnesium, haloalkyl taken in a 3-10-fold molar excess with respect to magnesium and four-chloride chloride, heating the mixture to the boiling point of haloalkyl, boiling it with stirring in the gene; 1-8 hours of removing the excess halogenated from the formed solid precipitate with the subsequent introduction of trialkylaluminium, characterized in that, in order to obtain a catalyst with increased activity, after removing the excess halogenated, a complexing additive is added to the precipitate: benzene or heterohydrofuran in a molar ratio additive: magnesium— 0.01-10.0 and the complex is maintained at a temperature of 2O-25 ° C for 0.5-1.0 hours and at 35-4O ⁰ C for 0.51.0 hours