Low-viscosity concentrated solutions of alkaline earth metal alkoxides in aprotic solvents and processes for preparation thereof

Abstract

A solution of a mixed alkaline earth alkoxide compound with an aluminum compound in an aprotic solvent, and methods of making and using them.

Claims

1. A solution comprising a mixed alkaline earth alkoxide compound of formula M(OCH.sub.2R.sup.6).sub.2-a-b(OR.sup.7).sub.a[(CHR.sup.8).sub.nOR.sup.9].sub.b in a mixture with an aluminum compound of formula Al(OCH.sub.2R.sup.6).sub.3-c-d(OR.sup.7).sub.c[O(CHR.sup.8)—OR.sup.9].sub.d in an aprotic solvent, wherein M is an alkaline earth metal selected from Mg, Ca, Ba, and Sr; OCH.sub.2R.sup.6 is an alkoxide radical composed of at least 3 and a maximum of 40 C atoms having a branch in the 2-position, relative to O; R.sup.7 is an alkyl radical containing 2-15 C atoms which is either linear or has a branch at the 3- or higher position relative to O; O(CHR.sup.8).sub.nOR.sup.9 is an alkoxide radical in which R.sup.8 is an alkyl radical containing 1-6 C atoms which is either linear or has a branch at the 3- or higher position relative to O; R.sup.9 is an alkyl radical containing 2-15 C atoms which is either linear or has a branch; n is an integer between 1 and 4; a+b≦2; c+d≦3; a and c are from 0.01 to 0.8; and b and d each range from 0.1 to 1.99; and wherein the solution has a content of aluminum relative to the alkaline earth metal in the range between 0.2 and about 20 mol %.

2. The solution according to claim 1, characterized in that the alkaline earth metal has a concentration in the range of 0.4 to 1.6 mmol/g.

3. The solution according to claim 1, characterized in that the solution has a viscosity of ≦300 cP at room temperature.

4. The solution according to claim 1, characterized in that the solution has a content of protic impurities relative to the alkaline earth metal between 0.1 and 40 mol %.

5. The solution according to claim 1, wherein O(CHR.sup.8).sub.nOR.sup.9 is derived from a C.sub.2-C.sub.4 glycol monoether.

6. The solution according to claim 1, wherein O(CHR.sup.8).sub.nOR.sup.9 is derived from an alcohol selected from the group consisting of 2 ethoxyethanol, 3-ethoxy-1-propanol, 3-ethoxy-1-butanol, 2-(2-ethylhexoxy) ethanol, 2-butoxyethanol, 2-hexyloxyethanol and 1,3-propylene glycol monobutyl ether.

7. The solution according to claim 1, characterized by containing 0.1 to 80 mol % free alcohol relative to the alkaline earth metal.

8. A method comprising preparing Ziegler-Natta polymerization catalysts with a solution of claim 1.

9. A method comprising performing an organic synthesis, wherein a solution of claim 1 is used in the organic synthesis.

10. The solution according to claim 1, characterized in that in the alkoxide radical OCH.sub.2R.sup.6, R.sup.6 is —CHR.sup.10R.sup.11 where R.sup.10 and R.sup.11 independently stand for alkyl radicals having 1 to 18 carbon atoms.

11. The solution according to claim 1, characterized in that in the aprotic solvent is an aliphatic hydrocarbon or an aromatic hydrocarbon selected from the group consisting of cyclohexane, methylcyclohexane, hexane, heptane, octane, nonane, decane, dodecane, decalin, and commercially available benzene fractions, benzene, toluene, ethylbenzene, xylenes, and cumene.

Description

EXAMPLES

(1) All reactions were carried out in dry glass equipment rendered inert with argon. Commercially available magnesium shavings were used. The concentrations of Mg and Al were measured by inductively coupled plasma (ICP). The content of protic impurities was determined gasometrically by reaction with an approximately 1% LiAlH.sub.4 solution in THF under ice cooling.

(2) The gas quantities measured in the synthesis typically exceed the anticipated value, because the reaction hydrogen is solvent vapor-saturated, and because gaseous hydrocarbons are released from the trialkyl aluminum compound that is used (e.g., ethane from triethylaluminum).

Example 1: Preparation of Magnesium Bis(2-Butoxyethanolate) in Mixed Toluene/Heptane with the Addition of 3.5 Mol % Ethanol (Relative to the Total Alcohol Content)

(3) 13.5 g of magnesium shavings, 216 g of toluene, and 90 g of heptane were placed in a 0.5-L double-jacketed glass reactor equipped with a reflux condenser and a dropping funnel. 7.6 g of a 25% solution of triethylaluminum in toluene was then injected, and the mixture was heated to the boiling point. 2.3 g of ethanol and 163 g of 2-butoxyethanol were added dropwise over a period of 120 minutes. 15.1 L of gas was evolved (107% of theoretical yield). After the dosing, the reactor contents were refluxed for an additional 90 minutes, resulting in further evolution of 0.3 L of gas.

(4) After cooling to approximately 80° C., the light gray suspension was siphoned off and filtered. 425 g of a non-viscous liquid was obtained which had a magnesium content of 1.26 mmol/g (corresponding to a conversion of 102% of theoretical yield). The product solution also contained 0.035 mmol/g of aluminum and had a protic impurity content of 0.23 mmol/g.

(5) Yield: 96% of theoretical

(6) Viscosity (Brookfield): 10 cP

Comparative Example 1: Preparation of Magnesium Bis (2-Butoxyethanolate) in Mixed Toluene/Heptane without Addition of a Primary Alcohol which is Unbranched or which has a Branch at the 3- or Higher Position and Contains 2-15 C Atoms HOR7

(7) 14.7 g of magnesium shavings, 215 g of toluene, and 90 g of heptane were placed in a 0.5-L double-jacketed glass reactor equipped with a reflux condenser and a dropping funnel. 7.6 g of a 25% solution of triethylaluminum in toluene was then injected, and the mixture was heated to the boiling point. At internal temperatures of around 104° C., 16.3 g of 2-butoxyethanol (ethylene glycol monobutyl ether) was added dropwise over a period of 90 minutes. 3.4 L of gas (24% of theoretical yield) was evolved, and the solution became increasingly viscous and dark (almost black). After the dosing, the reactor contents were refluxed for an additional four hours, resulting in further evolution of 0.6 L of gas.

(8) After cooling to approximately 80° C., the dark gray suspension was siphoned off and filtered. 411 g of a viscous fluid having a magnesium content of 0.27 mmol/g (corresponding to a conversion of 22% of theoretical) was obtained. The product solution also contained 0.034 mmol/g of aluminum and had a protic impurity content of 2.30 mmol/g.

(9) Yield: 18% of theoretical

Example 2: Preparation of Magnesium Bis(2-2-Ethylhexoxy)Ethanolate) in Toluene with the Addition of 1.5 Mol % Ethanol (Relative to the Total Alcohol Use)

(10) 14.7 g of magnesium shavings and 304 g of toluene were placed in a 0.5-L double-jacketed glass reactor equipped with a reflux condenser and a dropping funnel. 7.6 g of a 25% solution of triethylaluminum in toluene was then injected, and the mixture was heated to the boiling point. 0.97 g of ethanol and 236 g of 2-2(-ethylhexoxy)ethanol were added dropwise over a period of 120 minutes. 12.5 L of gas was evolved (86% of theoretical yield). After the dosing, the reactor contents were refluxed for an additional four hours, resulting in further evolution of 2.4 L of gas.

(11) After cooling to approximately 80° C., the light gray suspension was filtered. 539 g of an almost clear liquid was obtained which had a magnesium content of 1.11 mmol/g (corresponding to a conversion of 103% of theoretical yield). The product solution also contained 0.032 mmol/g of aluminum and had a protic impurity content of 0.030 mmol/g.

(12) Yield: 99% of theoretical

(13) Viscosity (Brookfield): 10 cP

Comparative Example 2: Attempted Preparation of Magnesium Bis(2-(2-Ethylhexoxy)Ethanolate) in Toluene without Addition of a Primary Alcohol which is Unbranched or which has a Branch at the 3- or Higher Position and Contains 2-15 C Atoms HOR7

(14) 14.7 g of magnesium shavings and 305 g of toluene were placed in a 0.5-L double-jacketed glass reactor equipped with a reflux condenser and a dropping funnel. 7.6 g of a 25% solution of triethylaluminum in toluene was then injected, and the mixture was heated to the boiling point. 240 g of 2-2(-ethylhexoxy)ethanol was added dropwise over a period of 120 minutes. 1.2 L of gas was evolved (8% of theoretical yield). After the dosing, the reactor contents were refluxed for an additional four hours, resulting in no further evolution of any gas.

(15) After cooling to approximately 80° C., the light gray suspension was filtered. 545 g of an almost clear liquid was obtained which had a magnesium content of <0.01 mmol/g (corresponding to a conversion of 0% of theoretical yield). The product solution also contained 0.032 mmol/g of aluminum and had a protic impurity content of 2.50 mmol/g.

(16) Yield: 0% of theoretical

Comparative Example 3: Preparation of Magnesium Bis(2-Ethylhexanolate) in Toluene/Heptane with the Addition of 4 Mol % Ethanol in the Absence of an Alcohol Containing an Alkoxy Function HO(CHR8)nOR9

(17) 18.9 g of magnesium shavings, 443 g of toluene, and 40 g of heptane were placed in a 0.5-L double-jacketed glass reactor equipped with a reflux condenser and a dropping funnel. 9.6 g of a 25% solution of triethylaluminum in toluene was then injected, and the mixture was heated to the boiling point. 3.11 g of ethanol and 215 g of 2-ethylhexanole were added dropwise over a period of two hours. 14.7 L of gas was evolved (79% of theoretical yield). After the dosing, the reactor contents were refluxed for an additional 270 minutes, resulting in further evolution of 2.9 L of gas without foaming (in total, 17.6 L, or 95% of theoretical yield).

(18) After cooling to approximately 80° C., the reaction mixture was siphoned off and filtered. 615 g of a light gray, clear liquid was obtained which had a magnesium content of 1.24 mmol/g (corresponding to a conversion of 103% of theoretical yield). The product solution also contained 0.033 mmol/g of aluminum and had a protic impurity content of 0.25 mmol/g.

(19) Yield: 98% of theoretical

(20) Viscosity (Brookfield): 3,700 cP

Example 3: Preparation of Mixed Magnesium Bis(2-Ethylhexanolate)/Magnesium Bis(2-Butoxyethanolate) Solution in Toluene/Heptane with the Addition of 4 Mol % Ethanol (Relative to the Total Alcohol Use)

(21) 18.4 g of magnesium shavings, 443 g of toluene, and 40 g of heptane were placed in a 0.5-L double-jacketed glass reactor equipped with a reflux condenser and a dropping funnel. 9.6 g of a 25% solution of triethylaluminum in toluene was then injected, and the mixture was heated to the boiling point. 3.0 g of ethanol and a mixture of 108 g of 2-ethylhexanol and 97.5 g of 2-butoxyethanol were added dropwise over a period of two hours. 17.2 L of gas was evolved (93% of theoretical yield). After the dosing, the reactor contents were refluxed for an additional 120 minutes, resulting in further evolution of 1.8 L of gas (in total, 19.0 L, or 103% of theoretical yield).

(22) After cooling to approximately 80° C., the reaction mixture was siphoned off and filtered. 602 g of a light gray, clear liquid was obtained which had a magnesium content of 1.26 mmol/g (corresponding to a conversion of 104% of theoretical yield). The product solution also contained 0.035 mmol/g of aluminum and had a protic impurity content of 0.23 mmol/g.

(23) Yield: 98% of theoretical

(24) Viscosity (Brookfield): 80 cP

(25) Comparative examples 1 and 2 were carried out according to the technical teaching of WO 2007/026016 A1; i.e., the magnesium was activated with trialkylaluminum solutions, and the reactions with the branched alcohol HO(CHR.sup.8).sub.nOR.sup.9 were carried out at the boiling point.

(26) When 2-butoxyethanol was used in toluene/heptane in the absence of a primary alcohol HOR.sup.7 which is unbranched or which has a branch at the 3- or higher position and contains 2-15 C atoms for a six-hour reaction time, a conversion of approximately only 18% of the theoretical yield of the desired magnesium alcoholate was obtained (comparative example 1). A strong increase in viscosity was observed. The method product also had an extremely high content of protic impurities: 2.30 mmol/g, corresponding to 370 mol % relative to dissolved magnesium. In the presence of 3.5 mol % ethanol, over a shortened reaction time of 3.5 hours, the target product was reached with 96% yield (example 1). Consequently, the content of protic impurities was very markedly decreased to only 18%. The product viscosity was extremely low (10 cP) despite the very high product concentrations.

(27) Example 2 and comparative example show the results upon usage of a long-chain alkoxy-substituted alcohol, the 2-(2-ethylhexoxy)ethanol. In this case, it was impossible to initiate any reaction at all without the use of a primary alcohol which is unbranched or which has a branch at the 3- or higher position and contains 2-15 C atoms HOR.sup.7, whereas a highly concentrated, low-viscosity solution of magnesium bis(2-(2-ethylhexoxy)ethanolate) was obtained at 99% yield when 1.5 mol % ethanol was used.

(28) Comparative example 3 was worked in accordance with the teachings of WO2010/146122, without the use of an alcohol containing an alkoxy function HO(CHR.sup.8).sub.nOR.sup.9, and a highly concentrated solution of magnesium bis(2-ethylhexanolate) in toluene/heptane was prepared. The yield and the content of protic impurities were indeed in the desired ranges, but the viscosity was extremely high, at 3,700 cP.

(29) In the last example 3, a mixture of three different alcohols was used. In this case, equal molar amounts of 2-ethylhexanol and the alcohol containing an alkoxy function, 2-butoxyethanol, were used. When 4 mol % ethanol was used, a solution containing the desired mixture of magnesium bis(2-ethylhexanolate) and magnesium bis(2-butoxyethanolate) was obtained at a very favorable yield. The viscosity was comparatively very low, at 80 cP.