Solid material comminution or disintegration – Processes – With heating or cooling of material
Reexamination Certificate
1999-03-08
2001-10-23
Rosenbaum, Mark (Department: 3723)
Solid material comminution or disintegration
Processes
With heating or cooling of material
Reexamination Certificate
active
06305622
ABSTRACT:
TECHNICAL FIELD PERTINENT TO THE INVENTION
The present invention relates to a process for producing a trihydrocarbyl aluminum which is an important co-catalyst for olefin polymerization.
PRIOR ART
The process for synthesizing a trialkyl aluminum from an aluminum-magnesium alloy and a halogenated alkyl is known and is described in, for example, U.S. Pat. No. 2,744,127 of K. Ziegler.
In this U.S. Patent use of an aluminum-magnesium alloy composed of 35 to 43% aluminum and 57 to 65% magnesium is described. It is also described that trimethyl aluminum can be synthesized at a yield of 60 to 75% from methyl bromide and the above aluminum-magnesium alloy. The literature, however, makes no mention of whether or not trimethyl aluminum can be synthesized from methyl chloride and an aluminum-magnesium alloy.
It is also described that triethyl aluminum can be synthesized from ethyl bromide and an aluminum-magnesium alloy at a yield of 75 to 85%. The literature gives an Example wherein triethyl aluminum can be synthesized from ethyl chloride and an aluminum-magnesium alloy, but makes no mention on the yield.
In the synthesis of trimethyl aluminum, there has been an industrially and economically serious drawback in that particularly when methyl chloride of low cost and easy availability is used in volume, the reaction does no proceed favorably.
The primary object of the present invention is to provide a process which can produce trimethyl aluminum using methyl chloride of low cost and easy availability in volume, at a yield at least equal to that obtained using iodide or bromide.
Another object of the present invention is to provide a process wherein the reaction proceeds easily and the yield is high when compared with conventional processes, even when an iodinated hydrocarbon or a brominated hydrocarbon is used as a raw material.
MEANS FOR ACHIEVING THE TASK
The present inventors conducted a study in order to solve the above problems and, as a result, have completed the present invention. The present invention comprises the following invention and embodiments.
(1) A process for producing a trihydrocarbyl aluminum by reacting an aluminum-magnesium alloy containing 20 to 80% by weight aluminum and 80 to 20% by weight magnesium, with a halogenated hydrocarbon, in which process
the aluminum-magnesium alloy has been subjected to a grinding treatment in the presence of an abrasive medium by the use of a ball mill or a vibration ball mill, and/or,
in the reaction, agitation is conducted in the presence of an abrasive medium or there is used a homogenizer rotating at a high speed of 5,000 to 20,000 rpm.
(2) A process for producing a trihydrocarbyl aluminum by reacting an aluminum-magnesium alloy with a halogenated hydrocarbon according to the above (1), in which process,
in the reaction, agitation is conducted in the presence of an abrasive medium.
(3) A process for producing a trihydrocarbyl aluminum by reacting an aluminum-magnesium alloy with a halogenated hydrocarbon according to the above (1), in which process,
in the reaction, there is used a homogenizer rotating at a high speed of 5,000 to 20,000 rpm.
(4) A process for producing a trihydrocarbyl aluminum by reacting an aluminum-magnesium alloy with a halogenated hydrocarbon according to the above (1), in which process
the aluminum-magnesium alloy has been subjected to a grinding treatment in the presence of an abrasive medium by the use of a ball mill or vibration ball mill, and
in the reaction, agitation is conducted in the presence of an abrasive medium.
(5) A process for producing a trihydrocarbyl aluminum according to any of the above (1) to (4), wherein the aluminum-magnesium alloy contains 35 to 45% by weight of aluminum and 55 to 65% by weight of magnesium.
(6) A process for producing a trihydrocarbyl aluminum according to any of the above (1) to (5), wherein the halogenated hydrocarbon is used in an amount of 2.0 to 10.0 moles per mole of the aluminum in the aluminum-magnesium alloy.
(7) A process for producing a trihydrocarbyl aluminum according to any of the above (1) to (6), wherein the halogenated hydrocarbon is a methyl halide.
(8) A process for producing a trihydrocarbyl aluminum according to the above (7), wherein the halogenated hydrocarbon is methyl chloride.
MODE FOR CARRYING OUT THE INVENTION
The present invention is hereinafter described in more detail.
The reaction of the present invention is represented by the following reaction formula when the aluminum-magnesium alloy used is Al
2
Mg
3
.
Al
2
Mg
3
+6RX→2AlR
3
+3MgX
2
(1)
In the above formula, R is a chain or cyclic hydrocarbon residue having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and specific examples thereof are methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, n-hexyl group, n-octyl group, cyclohexyl group, phenyl group and benzyl group; X is chlorine, bromine or iodine.
In the present invention, particularly remarkable effects can be obtained when RX is methyl chloride.
In the aluminum-magnesium alloy used in the reaction, the atomic composition is such that the aluminum content is 20 to 80% by weight, preferably 30 to 60% by weight, particularly preferably 35 to 45% by weight and the magnesium content is 80 to 20% by weight, preferably 40 to 70% by weight, particularly preferably 55 to 65% by weight.
There is no particular restriction as to the atomic composition of the aluminum-magnesium alloy as long as the composition is in the above range.
However, an atomic composition consisting of 35 to 45% by weight of aluminum and 55 to 65% by weight magnesium is particularly preferred.
The aluminum-magnesium alloy having the above atomic composition is preferred because the amounts of the two components in the alloy are close to stoichiometric amounts and moreover the alloy is very brittle and can be easily made into a fine powder by the grinding treatment described later. Since the aluminum-magnesium alloy of the above atomic composition, i.e. a composition close to Al
2
Mg
3
leaves little reside in the reaction and is preferred economically and industrially, the most preferred atomic composition is a composition close to Al
2
Mg
3
(Al: 42.6% by weight, Mg: 57.4% by weight). When a commercially available alloy is out of this compositional range, magnesium or aluminum is added thereto and, as necessary, grinding is conducted, whereby a particularly preferred compositional range can be obtained.
It is generally known that aluminum-magnesium alloy consists of various kinds of crystals, each of which is different in atomic composition. In order to carry out the reaction smoothly, it is preferable that the aluminum-magnesium alloy used in the present invention be as uniform as possible in crystal structure and atomic composition throughout the alloy portion. Moreover, it is desirable that the crystal structure be as amorphous as possible.
An aluminum-magnesium alloy uniform in crystal structure and in atomic composition throughout the alloy portion, such as mentioned above, can be obtained by melting aluminum and magnesium and then cooling the melt rapidly.
As a method for rapidly cooling the melt of aluminum and magnesium, there can be employed, for example, a well-known method used in production of amorphous alloy, such as the atomization method, liquid rapid cooling method or the like.
The above-mentioned aluminum-magnesium alloy is used in the state of a fine powder. When the fine powder is obtained by a grinding treatment in the presence of an abrasive medium by the use of a ball mill or a vibration ball mill (Vibratom), a good result can be obtained. However, the present invention process is applicable also to a case of using a fine powder of aluminum-magnesium alloy produced by the known atomization or stamp mill method.
Grinding by ball mill is conducted by feeding an abrasive medium (balls) and a material to be ground, into a container and grinding the material to be ground, into a fine powder by collision with moving balls. It is generally carried o
Iwao Tetsuya
Kawanishi Kaoru
Koga Seijiro
Nishida Tadao
Knobbe Martens Olson & Bear LLP
Nippon Aluminum Alkyls, Ltd.
Rosenbaum Mark
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