DE1047435B - Process for the polymerization of styrene - Google Patents

Description

GERMAN

In the earlier Belgian patent 538 782 a process for the production of crystalline Polystyrene claimed, styrene containing inter alia in the presence of metal alkyl bonds Catalysts polymerized by reaction of compounds of the metals of the subgroups the IV. to VI. Group of the periodic table with organic compounds of aluminum, Zinc and magnesium were obtained, polymerized. The solid product made after this procedure is obtained, shows in the X-ray diagram diffraction fringes through which usually crystalline Products are displayed. However, the product obtained by this older process is not perfect crystalline, but is made up of a highly crystalline and an amorphous product. The amorphous product can be removed by extraction with suitable solvents.

Especially when working under such conditions that highly crystalline products with a very high Molecular weight are obtained (as in Example 30 of the mentioned Belgian patent), the polymerizes Styrene with a relatively low yield, so that a large part of the monomer remains unchanged. In almost all cases, the yield of crystalline product neither increases with a longer reaction time nor with elevated temperatures or with any other change in the reaction conditions and the composition of the catalytic converters noticeably. The cases in which it was possible to increase the conversion yield, can be attributed to the formation of non-crystalline product.

There has now been a process for the polymerization of styrene to crystallizable, high molecular weight, linear, essentially unbranched head-to-tail polymerization, after which it was possible is to markedly increase the yield of crystalline product. According to the invention, one works in Presence of catalysts containing metal alkyl bonds produced by reaction of compounds the metals of the subgroups IV. to VI. Group of the Periodic Table, including Thorium and Uranium, with organic compounds of aluminum, zinc and magnesium, can be obtained and in the presence of solvents for the low molecular weight styrene polymers that are not compatible with the catalyst react. When using catalysts based on Ti Clg, polymers in particular are obtained with a higher percentage of crystalline polystyrene. It is preferable to work in the presence of Solvents that can swell the entire polymerization product. Suitable solvents are liquid, aromatic hydrocarbons or solvents that contain at least one aromatic group

Process for the polymerization of styrene

Applicant:

Montecatini Societä Generale
per l'Industria Mineraria e Chimica,

Milan (Italy),

and Dr. Dr. e. H. Karl Ziegler,

Mülheim / Ruhr, Kaiser-Wilhelm-Platz 1

Representative:
Dr.-Ing. A. v. Kreisler, Dr.-Ing. K. Schönwald,

Dipl.-Chem. Dr. phil. H. Siebeneicher

and Dr.-Ing. Th. Meyer, patent attorneys,

Cologne 1, Deichmannhaus

Claimed priority:
Italy from March 21, 1955

Giulio Natta, Piero Pino and Giorgio Mazzanti,

Milan (Italy),
have been named as inventors

contain, for example, benzene, toluene, xylenes, ethylbenzene and other benzene homologues. Suitable Solvents are also hydrocarbons that contain aromatic or cycloaliphatic groups, such as B. tetrahydronaphthalene.

Aromatic compounds which have substituents, such as OH, NH ₂ , NO ₂ and the like, which react with the catalysts, e.g. B. phenol, nitrobenzene or aniline are not suitable as solvents. On the other hand, halogenated aromatic compounds in which the halogen is bonded to the nucleus can be used as solvents. Particularly suitable are, for. B. chlorobenzene and the liquid dichlorobenzenes.

Finally, the solvent for the polymer can also be the monomer itself, not just at the beginning the polymerization, but also during the same, if it is ensured that unchanged monomer is present until the end of the polymerization.

According to the invention, a mixture of styrene can be used as the starting material for the polymerization Ethylbenzene from the dehydrogenation of ethylbenzene

809 700/587

3 4

use without the styrene completely from the ethyl J 104 g of a crystalline polystyrene are obtained

to separate benzene, because such a separation: has very cost-similar properties as that in the previous

is playful. The mixture can after removal of the example described product,
the impurities harmful to the catalytic converter (e.g.

Carbonic acid or moisture) as it occurs, 5 Example 3

be used. One can - also one of styrene - One introduces 250 g of mono-

enriched mixture, for example a 40 to 95% meres styrene and a solution of 11.4 g of aluminum

Use a mixture containing styrene. After triethyl in 500 ecm of pure anhydrous tetrahydro-

Polymerization then retains a certain amount of naphthalene in a nitrogen atmosphere. To-

Ethylbenzene, which contains little styrene and which was set in motion in the autoclave,

after any removal of the remaining material, the temperature is increased to 70 ° C. and then injected

the styrene for the production of styrene by De- 6 g TiCl ₄ , dissolved in 30 ecm tetrahydronaphthalene,

hydrogenation is returned to the cycle under nitrogen pressure. The temperature rises spontaneously

can be. tan to 78 ° C in a short time and then sinks again

Example 1 ^{15 to 76} ° ^C

. . Splashes 3 hours after the first addition of _{TiCl 4}

In a 2150 ccm shaking autoclave, 3.50 g of Ti Cl ₄ in 30 · ecm of tetra-640 ecm of anhydrous benzene and 11.4 g of aluminum trihydronaphthalene are introduced into the autoclave. The shaking of the autoclave ethyl and 250 g of freshly distilled anhydrous is continued for a further 7 hours; then you can put styrene in a nitrogen atmosphere. It is heated to find that 65.5% of the styrene polydene autoclave used is heated to 69 ° C. and is heated at this point. The experiment is interrupted, 5.7 g (equal to 0.03 mol) of TiCl _{4 are introduced} , the reaction product dissolved in 30 ecm and treated, as in benzene, under nitrogen pressure. The temperature game 1 described.

rises spontaneously in a short time to 82 ° C. and falls. In this way, 111 g of a crystalline one are obtained

then to 75 ° C. 25 polystyrene. This corresponds to a percentage of

3 hours after the first _{addition of TiCl 4,} 67.8% of the converted styrene splashes.
one more solution of 3.8 g (equal to 0.02 mol) ",. _1st
TiCl ₄ in 30 ecm benzene into the autoclave. The example 4
Shaking of the autoclave is continued for 15 hours at a temperature of 70 to 75.degree. C. in a 2080 ccm autoclave. After this 30 miniumtriethyl and 680 g from the dehydrogenation period, 82% of the imported styrene are poly-ethylbenzene-derived mixture, which is 37.6% merized. Methanol is pumped into the autoclave in order to decompose the organometallic compounds containing styrene, 60.4% ethylbenzene and 2% toluene.

carries out the reaction product that comes out of one after the autoclave is set in motion

Solvent swollen polymer is from. 35, bring the temperature to 75 ° C and inject

The polymer is completely coagulated with alcohol, then 6 g of Ti Cl ₄ , dissolved in 30 ecm of benzene, under nitrogen

lined, grated into a fine powder and rubbed several times with fabric pressure. The temperature rises spontaneously

Acetone and HCl treated in the heat. During 85 ° C and then drops back to 75 ° C.

This treatment dissolves the unchanged mono 3 hours after the first addition of _{Ti Cl 4}

mers and the non-crystalline polymers formed are added to the autoclave with 3.5 g of TiCl ₄ in 30 ecm

sate in the solvent and can then from the benzene a. Shaking the autoclave continues

same to be recovered. 7 hours, and afterwards the reaction

The tion product remaining after these treatments, which represents a percentage of 52.5% of the

solid portion is filtered, washed and corresponds to the monomers used in a vacuum, discharged and

hot dried. The 45 deposited in this way is treated as in Example 1. 77.5 g of one are obtained

Product consists of 105 g of a crystalline polycrystalline polystyrene,

styrols, which on radiographic examination turns out to be _. . . _

turns out to be highly crystalline. This product has a very icep

high molecular weight. It is a white, powdery man feeds 200 g of styrene into a 2150 cc autoclave

solid product that has a very high softening 50 and 9.1 g of aluminum ethyl in a nitrogen atmosphere

point and up to temperatures above 200 ° C sphere. The autoclave is set in motion and

remains crystalline. splashes when the internal temperature has reached 70 ° C,

Beis ■ el 2 5.2 g of TiCl ₄ , dissolved in 20 cm benzene. The temperature rises spontaneously to 80 ° C and in a short time

250 g of mono-55 is passed into a 2080 ccm autoclave and after a short time it falls back to the initial value, meres styrene and a solution of 11.4 g of aluminum 3 hours after the first addition are further triethyl in 500 ecm of anhydrous chlorobenzene in one 2.9 g of Ti Cl _{4 were} added without a temperature nitrogen atmosphere. After you notice the auto change.

After a further 7 hours the temperature is converted to 70 ° C and then 6 g Ti Cl ₄ , dissolved 60 monomers to crystalline polystyrene one percent in 30 ecm chlorobenzene, are injected under nitrogen pressure. The rate of 26.5% is achieved. The temperature is now interrupted and the experiment rises spontaneously to 80 ° C. in a short time. The extracted from the autoclave poly- and then falls back to 75 ° C., 3 hours after is merisat, first as in the previous examples, Ti Cl ₄ -Zusatz is injected into the autoclave described cleaned. 53 g of a crystalline 3.50 g of Ti Cl _{4 are obtained} in 30 ecm of chlorobenzene. The shaking of 65 polystyrene
the autoclave is continued for another 7 hours; For so much 6
after this period it can be determined that 71%

of the applied styrene are polymerized. In a 150 ecm with a thermometer,

interrupts the experiment, leads the reaction product stirrer and dropping funnel-equipped glass flask, the

off and treated as described in Example 1. 70 kept at 70 ° C in a thermostatic bath

Claims (7)

1 g of Ti Cl3 and 40 ecm of benzene are introduced in a nitrogen atmosphere. Then 0.4 g of triethylaluminum in 10ccm benzene and then 18 g of styrene are slowly added with stirring. After 70 hours, the reaction is interrupted by adding an excess of methyl alcohol in order to coagulate the polymer formed, which is washed repeatedly with methyl alcohol. After separation of the solvent and the monomer and after extraction of the residue with benzene, about 1 g of oily polymer is recovered from the methanol solution. The solid polymer is extracted with acetone. A residue of 9.53 g of crystalline polystyrene remains. 0.3 g of amorphous polystyrene are recovered from the acetone solution by precipitation with methyl alcohol. About 90% of the polymerized monomer was converted to crystalline polystyrene. EXAMPLE 7 1 g of TiCl3 and 40 ecm of benzene are introduced into the reaction flask described in Example 6 at 70 ° C. in a nitrogen atmosphere. 0.8 g of triethylaluminum in 10 ecm of benzene and then 18 g of styrene are then slowly added. After 70 hours of reaction, about 1 g of oily polymer and 4.15 g of crystalline polystyrene are obtained by the process described above. No amorphous, acetone-soluble polystyrene is obtained. The crystalline polymer corresponds to a yield of approximately 80%, based on the total polymerized monomer. The conversion yield increases if a more concentrated styrene solution in benzene is used. EXAMPLES 250 g of styrene and a solution of 11.4 g of triethylaluminum in 550 ecm of cumene are introduced into a 2050 ccm shaking autoclave in a nitrogen atmosphere. The mixture is heated to 72 ° C. with stirring and a solution of 6 g of titanium tetrachloride in 30 ecm of cumene is then injected into the autoclave. The temperature rises by itself to 80 ° C. The autoclave is kept with stirring for about 10 hours at a temperature between 70 and 80 ° C. This is followed in the same way as described in the previous examples and a total of 90 g is obtained Polystyrene. About 50% of this remains as a residue after extraction with warm acetone; this residue appears crystalline by X-ray and has an intrinsic viscosity of 2.2 in tetrahydronaphthalene solution at 100.degree. P \ T ti S T Λ Ν PROVERBS: 1. Process for the polymerization of styrene to crystallizable, high molecular weight, linear, im essential unbranched head-tail polymers, characterized in that in The presence of catalysts containing metal alkyl bonds polymerizes by reaction of compounds of the metals of the subgroups of IV. to VI. Group of the periodic table, including thorium and uranium, with organics of aluminum, zinc and magnesium and in the presence of aromatic or cycloaliphatic groups containing Solvents for the low molecular weight styrene polymers that do not work with react with the catalyst. 2. The method according to claim 1, characterized in that catalysts are used which by reaction of titanium trichloride with organic compounds of aluminum, zinc or magnesium. 3. Process according to Claims 1 and 2, characterized in that in the presence of Solvents works that swell the entire polymerization product. 4. Process according to Claims 1 and 3, characterized in that the solvent liquid organic hydrocarbons such as benzene and its higher homologues, in particular Ethylbenzene, halogenated derivatives of benzene, especially chlorobenzene, or tetrahydronaphthalene be used. 5. Process according to Claims 1 and 2, characterized in that the solvent for the Polymer the monomer itself is used. 6. Process according to Claims 1 to 5, characterized in that the starting material for the Polymerization a mixture of the styrene with other hydrocarbons from the dehydrogenation of ethylbenzene is used. 7. The method according to claims 1 to 6, characterized in that the starting material for the Polymerize a mixture enriched in styrene, such as one containing 40 to 95% styrene Mixture, is used. © 809 700/587 12.