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1. CA2098739 - PROCEDE D'OBTENTION D'HALOGENURES D'ALKOXYMAGNESIUM

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[ EN ]
The present invention concerns a simple method of preparing alkoxy-magnesium halides in just one step by 4 stoichiometrically converting magnesium that has been preliminarily activated with a magnesium-alkyl compound with 6 an equimolar mixture of an alkyl halide and an alkanol, 7 preferably a ~-branched alkanol.
9 Alkoxy-magnesium chlorides of general formula RMgCl are employed for among other purposes preparing modified-support 11 Ziegler-Natta catalysts, especially those based on titanium, 12 for the polyolefin industry. They are superior to 13 conventional Ziegler-Natta systems particularly because of 14 their higher activity and higher stereospecificity in the polymerization of olefins.
17 The first potential educts that come to mind for preparing 18 compounds of the ROMEX type are Grignard compounds of general 19 formula RMgX in ether. This route, however, seems to be not generally accessible because of the problems involved in 21 quantitatively removing the ether, which often disrupts 22 polymerization. The literature describes many methods of 23 preparing catalyst supports that include magnesium and a 24 halide, especially chlorine. The first simple organometallic route to low melting-point products with or without 26 hydrocarbon, however, is disclosed in European A 0 242 801, 27 which describes preparing an alkyl-magnesium halide from t magnesium and an alkyl halide in anhydrous hydrocarbons with 2 oxygen compounds (alcohols, aldehydes, and ketones with 1 to 3 20 carbon atoms) in an inert-gas atmosphere at normal 4 pressure and at a temperature of 40 to 200 ~C. Preferred are alcohols with 1 to 18 carbon atoms. Treatment with ~-alkyl 6 alkanols with 5 to 18 carbon atoms results in products that 7 dissolve in hydrocarbons when 1.1 to 2.0 moles of alkanol are 8 ' employed in terms of the magnesium. An essential 9 characteristic of this process is that the reaction occurs in two steps. The Grignard compound is prepared in the first 11 step and treated in the second step with the appropriate 12 oxygen compound. When the alkyl halide and the alkanol were 13 added simultaneously in just one step for comparison on the 14 other hand (EPA 0 242 801, Examples A & B), the main products were magnesium dialkoxides.
17 It has surprisingly now been discovered that alkoxy-magnesium 18 halides can also be synthesized in hydrocarbons in just one 19 step if the magnesium is pret; m; n~rily activated with small amounts (approximately 5 % molar) of magnesium alkyl.
22 The present invention accordingly addresses a method of 23 preparing alkoxy-magnesium halides of general formula ROMEX 24 characterized in that magnesium pret;m;n~rily activated with small amounts of a magnesium-alkyl compound is 26 stoichiometrically reacted in just one step with an equimolar 27 mixture o~ an alkyl halide (AlX), especially an alkyl l chloride, and an alkanol (R2OH) in an inert hydrocarbon and n inert-gas atmosphere, whereby Rl is a linear, branched, or 3 cyclic hydrocarbon group with 1 to 8 carbon atoms and R2 is a linear, branched, or cyclic hydrocarbon group with 1 to 20 carbon atoms.
7 Treatment with the 1:1 mixture of alkyl halide and alkanol, 8 preferably an alkanol that branches at the B position and has 9 5 to 18 carbon atoms, occurs in inert hydrocarbons at a 18 temperature 50 to 150 ~C and preferably 80 to 100 ~C. Adding 11 another 0.1 to 1.0 moles of alkanol to improve the flow of 12 the solutions, which are viscous when the alkanols are 213 substituted, and improve stability is practical 14 (EPA 0 242 801). Yields are approximately 90 % and the
RO/Mg/X ratio is precisely or approximately 1 17 Since the space-time yield of the process in accordance with 18 the present invention is higher than that of the two-step 19 process disclosed in EPA 0 242 801, the former is a more economical way to prepare alkoxy-magnesium halides, 21 especially those that branch at position B. Furthermore, 22 the direct, moderate, and continuous off-reaction of the "in 23 situ" occurring Grignard compounds prevents too high a 24 concentration of highly reactive organometallic compound, which obviously renders the process more reliable.
27 The method in accordance with the invention will now be 1 specified with reference to exalnples.
Overall method of preparing ROMEX 4 Mixture I is heated to 100 ~C in a flask of dry oxygen.
Mixture II is added drop by drop for 45 minutes. The batch 6 is preferably allowed to stand for 2 hours and Mixture III 7 added (followed by 30 minutes of agitation at 100 ~ C3 to 8 reduce the viscosity and improve the stability of the 9 solutions. The batch is then filtered. 11 The whole reaction takes approximately 3 hours.
13 Example 1. Preparing 2-ethylhexoxymagnesium chloride 14 I: 6.25 g (0.257 moles~ of powdered magnesium (BOMAG) 10.77 (O.013 moles) of BOMAG-A (20% butyloctyl 16 magllesium in heptane) 17 0.55 of tributylaluminum 18 35.00 of heptane III: 17.85 g (0.193 moles) of butyl chloride 219.55 (0.064 moles) of octyl chloride 2235.20 (0.270 moles) of 2-ethylhexanol 23112.00 of heptane 25III: 35.20 g ~0.270 moles) of 2-ethylhexanol 26190.00 of heptane 1 Yield Eron 420 g of filtrate: 2 Magnesium: 1.46 % (93 % of theoretical) 3 Chlorine: 2.02 4 alkal. M~: 0.73 6 RO/Mg/Cl - 1:1:0.95 9 Example 2. Preparing 2-hexyldecoxymagnesium chloride 10I: 6.25 g (0.257 moles) of powdered magnesium 11 10.00 (0.012 moles Mg) of BOMAG-A 12 0.51 of tributylaluminum 14IT: 17.85 g (0.193 moles) of butyl chloride 55 (0.064 moles) of octyl chloride 16 G5.40 (0.~70 moles) of 2-hexyldecanol 17112.00 of heptane 19III: 65.40 g (0.270 moles) of 2-hexyldecanol 20176.00 of heptane 22 Yield from 445 g of filtrate: 23Magnesium: 1.36 % (92 % of theoretical) 24Chlorine: 2.03 25Alkal. Mg: 0.64 27RO/Mg/Cl = 0.94:1:1