CS196266B2 - Method of preparing the transition metal component of acatalytic system - Google Patents

Description

The present invention relates to processes for the preparation of a transition metal component of an ethylene polymerization catalyst system comprising the titanium tetrachloride reaction with a manganese carboxylic compound. This component may be used as such or may be finely dispersed on a material with a high specific surface area.

It is known that catalytically active titanium halides are generally used in the low pressure polymerization of α-olefins and are prepared by the reduction of titanium halides with alkylaluminum or alkyl halides. The reaction is generally carried out under an inert atmosphere and in the presence of an inert solvent. The catalyst thus prepared is then used together with the alkyl metal compounds to polymerize α-olefins in an organic solvent suspension at low monomer pressures.

However, these titanium halides are contaminated with aluminum compounds and do not exhibit too high catalytic activity, so that the final polymer requires expensive washing operations to remove catalyst residues.

Recently, a method has been proposed in which polymerization catalysts with improved efficiency are obtained by applying titanium halides to inorganic substances.

As carriers, for example, magnesium oxide or hydroxychloride, silica or alumina were used; all of these carriers have a high specific surface area, however, it should be noted that the catalytic activity of the titanium compounds on the above-mentioned materials as catalytic supports is highly dependent on the chemical nature of their surface, so that these carriers often have to undergo hydrogen to improve their own efficiency.

The catalyst system with a transition metal component prepared by the process of the invention has a high activity in ethylene polymerization and requires no pretreatment when used on a support.

SUMMARY OF THE INVENTION The present invention provides a process for preparing a transition metal component of a catalyst system comprising an alkyl halide, alkyl derivative or metal hydride of the first three groups of the Periodic Table of the Elements comprising reducing titanium tetrachloride with a optionally applied to a carrier.

When using a catalytic support, the process according to the invention consists in impregnating the support, previously dried by heat treatment, with a carbonyl compound of low valence manganese, preferably zero valence, dissolved in a hydrocarbon solvent, and then refluxing said carrier in titanium tetrachloride and subsequently. in removing excess of this chloride from the carrier .........

Otherwise, when no carrier is used, the reaction product is obtained by simply reacting the carbonyl compound manganese β titanium tetrachloride at its boiling point until gas evolution ceases. The solid metal thus obtained is filtered off and washed until the titanium tetrachloride is completely removed; in this way a solid solution of manganese chloride in titanium tetrachloride is obtained.

During the process, volatile carbon monoxide is evolved while manganese is oxidized and titanium tetrachloride is reduced to titanium tetrachloride according to the equation

Mn (COj _p + nTiCU - MnCl _n. NTiCl 3 + p CO, where p denotes the number of carbonyl n and the state of valence assumed by manganese during its oxidation from titanium tetrachloride.

The material used as carrier for the reaction is selected from alkali metal or alkaline earth metal halides, the amount of manganese being 0.1 to 10%, preferably 1 to 3% by weight, based on the carrier.

Prior to use, these halides are dried and then milled to increase the specific surface area. They can then also be sieved to select a fraction of predetermined grain size.

. In any case, the polymerization activities are higher than those which can be obtained by means of carriers processed only? with TiCU under the same additional conditions: · .; ; ··.

_; These catalysts are favorable. the hydrogen behavior and, in the case of ethylene polymerization, lead to a narrow molecular weight range.

The following examples serve to illustrate the invention without limiting it in any way. The procedure was carried out under the following operating conditions ("standard polymerization"): The solvent, the organometallic compound (at a concentration of 0.2% by volume) and the above-described transition metal reaction product were fed into an autoclave thermostatized at 85 ° C. The ethylene pressure is kept constant throughout the experiment, which is 6 hours. The polymers obtained are dried under vacuum to constant weight before calculating the yield. The symbol MF denotes a melt flow index of g / 10 min. Example 1 ‘g of NaCl, finely ground and oven dried at 400 ° C, was refluxed in TiCl 2 (50 cc) together with Mn 2 (CO) 10 (0.5 g) for 6 hours. The product was filtered, washed with ligroin and dried under vacuum. The product had the following composition:

Ti = 1.83%

Mn = 1.10%

By using 200 mg of this product in standard polymerization at a polymerization time of 6 hours at p _H / Pch = 1.1 (MPa / psi) 2 4 BY2 lo produced 278g of polymer MF _{2, 1o} = 0.800, MF ₂ and ₆ = 30,784, and MF _{2, 6} / MF _2, and ₆ = 38.48, containing 13.2 ppm of Ti or Ti + 21.5 ppm Mn. Example 2

16.8 g of NaCl, finely ground (same as in Example 1), was refluxed in TiCl 4 (50 mL) together with Mn 2 (CO) 10 (0.5 g) for 4 hours.

The product was filtered, washed repeatedly with hexane and dried. It had the following composition:

Ti 0,97%

Mn = 0.49%

245 mg of this product was used in the polymerization test for 2 hours at relative pressures of H2 and C2H4 equal to 0.8 / 1.2 (MPa / MFa J7). ......

65 g of a polymer with MF ₂ , ₁₆ = = 0.263, MF ₂₁ , ₆ = 8.47, MF ₂ , ₁₆ / MF ₂ , ₁₆ , = 32.2, containing? 36.5 ppm Ti or 55 ppm Ti + + Mn.

Example 3

KCl, finely ground and dried, at 400 ° C (5 grams) was suspended in TiCH and refluxed for 4 hours with Mn 2 (CO) 10 (0.18 g).

The product was filtered, washed with hexane and dried under vacuum; The product had the following _composition; ,?

Ti = 2.29% · · · ·

..... - Mn = 0.68 O / o

158 mg of this product was used in polymerization for 6 hours at H2 / C2H4 relative pressures equal to 0.8 / 1.2 (MPa / MPa). 466 g of a polymer with MF _{2 16} = 0.331 * MF ₂₁ , 6 = 11.55, MF _{2 16} / MF _{2> 16} = 348, containing 7.77 ppm Ti and 10.35 ppm Ti + Mn were obtained. . Example 4

MgCl 2 (10 gj, pre-dried under a stream of HCl at 350 ° C) was refluxed with stirring in 50 ml TlCl 4 together with Mn 2 (CO) 10 (0.45 g) for 6 hours. the following composition:

Ti = 0.90%

Mn = 0.54% ·

Using 290 mg of this product in po196266 lymeration for 2 hours at P _H / P _c h equal to 2 2 4

1 / 0.5 (psi / MPa) was made with 53 g of polymer MF _{2, 16} - 2.96, MF _{21 6} - 110.6, MF _{21 6} / / MF _2, I6 = 37.2, containing 49.2 ppm Ti or 78.6 ppm Mn + Ti.

Example 5

5.9 g of KCI, finely ground and dried, were refluxed with 0.53 g of Mn (CO) sCl and 30 cm ^{3 of} TiCl ³ for 6 hours.

The product was filtered, washed with ligroin and dried under vacuum. It had the following composition:

Ti - .2,60%

Mn = 1.40%

Using 305 mg of this product in the polymerization for 2 hours at a pressure ratio Ph / Pch = 1 / 0.5 (MPa / MPa), 190 g of polymer (M) were produced. F ₂ , i6 = 8.29, MF _2W = = 300.46, MF ₂ i // MF ₂ , i ₆ =; 36.24, containing 45 ppm Ti or 67 ppm Ti + Mn.

Example 6

MnfCO 3 Cl was prepared by passing a weak chlorine stream through a solution of Mna (CO) 10 in CCU at 0 ° C, evaporating the volatiles under vacuum and sublimating at 40 ° C and 13.3 Pa [Abel and Milkinson - J. Chem. Soc. 1501, (1959)]. The desired product containing 14.37% chlorine was obtained

15.21% of the theoretical value.

The product obtained was reacted with an excess of TiCl 4 and kept at reflux until gas evolution ceased (about 16 hours).

A violet solid product was obtained, which was filtered, washed with ligroin to remove excess TiCl4, dried under vacuum and showed the following elemental ana-

lysis: found theory for TiCls and MnCl2 Ti% 19.25 17.11 Mn% 20.20 19.60 Cl% 60.20. 63.27

The product so obtained was used for the polymerization of ethylene under the conditions referred to as "standard polymerization". The results are shown in the following table.

MnTiCls Catalytic Systine (Unbound) - Al (iBut) 3

EXAMPLE cocatalyst P _H / P _c h time MF _{2 16} MF _2L6 MF ₂ and ₆ / MF _2, and ₆ yield ppm ppm (mg) ^{2 2 4} (h) (g) of Ti, Ti + Mn _ (psi / MPa ) __

30/5 0,5 / 0,5 2 Ϊ / 36 49,86 36/7 165 36 73 what about what CM

CO o oo r-I CM CO CO o oo in O) HID ts

cm. xn * © o cm co r-T ’Φ what

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. CO CO CM * rH CM what

CO CM CM CM xn t> co o o o o ΧΌ CO, co * o θ 'θ' θ

WHAT WHAT WHAT WHAT ΗΉ Ή CM

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Claims (3)

A process for the preparation of a transition metal component of a catalyst system comprising an alkyl halide, alkyl derivative or metal hydride of the first three groups of the Periodic Table of the Elements, characterized in that titanium tetrachloride is reduced with a carbonyl compound of manganese of the formula Mn 2 CO 3 or Mn 2 O 2 O 3 Cl, optionally supported on a carrier. 2. A method according to claim 1, characterized by OF THE INVENTION by impregnating the support with a solution of said carbonyl manganese compound in a hydrocarbon solvent and refluxing with titanium tetrachloride, whereupon the excess titanium tetrachloride is removed. 3. The process of claim 1 wherein said carbonyl manganese compound is reacted with titanium chloride. at the boiling point of titanium tetrachloride.