DE1227235B - Process for the preparation of polymers or copolymers by anionic polymerization - Google Patents

Description

5ÄUSLEGES CHRIFT

227235

Number. 1227 235

File number: C 31069IV d / 39 c

Filing date: October 7, 1963

Opened on: October 20, 1966

As catalysts for anionic polymerization are also organometallic compounds, such as. B. Butyllithium, used, where often stereoregular polymers are formed. Isoprene can be z. B. by butyllithium to stereoregular Polymerize 1,4-cis-polydiene. Also primary or Secondary alcoholates of alkali metals have been used as anionic polymerization catalysts used. However, tertiary alkali metal alcoholates have so far only been ineffective as condensation catalysts known in organic synthesis.

Organometals are used as anionic polymerization catalysts often very active and cause various side reactions with the monomers or with impurities that are difficult to remove, e.g. B. with traces of water or oxygen. Particularly monomeric esters of unsaturated acids, in which the olefinic double bond with the Carbonyl group is conjugated easily react with

'Organometals. The inventors have found that ao z. B. methyl methacrylate reacts quickly with butyllithium, reducing the activity of the catalyst will. The catalyst consumption is therefore quite high. In addition, the polymerization with organometallic Connections are difficult to master, and their dielectric and other properties of the polymers are adversely affected by the catalyst residues.

• It has now been found that the anionic stereospecific polymerization can be carried out very advantageously with a new class of catalysts. The process for preparing polymers or copolymers by anionic polymerization of unsaturated monomers in the presence of alkali metal alcoholates is characterized in that the polymerization catalysts used are tertiary alkali metal alcoholates, optionally in combination with lithium alkyls. These catalysts are suitable for the polymerization and copolymerization of all monomers which can be polymerized anionically, in particular of esters, nitriles and other derivatives of acrylic and methacrylic acid, styrene and its derivatives and also of

"Serving the butadiene series such. As isoprene. The catalysts do not cause undesirable side reactions and polymerization is easily controlled. Their activity is sufficiently high to allow Tieftemperaturpolymerisationen. Especially monomeric esters are easily at temperatures below +10 ⁰ C. polymerize, whereby a predominantly stereoregular structure is obtained.
Tertiary alcoholates of lithium, sodium and processes for the preparation of polymers or
Copolymers by anionic polymerization

Applicant:

Ceskoslovenskä academy ved, Prague

Representative:

Dipl.-Phys. Dr. W. Junius, patent attorney,

Hanover, Abbestr. 20th

Named as inventor:
Dr. Drahoslav Lim,
Jifi Trekoval, Prague

Claimed priority:

Czechoslovakia October 8, 1962 (5727)

Potassium polymerize various alkyl or aralkyl acrylates and methacrylates, acrylonitrile and methacrylonitrile into isotactic polymers, as evidenced by infrared spectral analysis and nuclear magnetic resonance analysis; z. B. the polymerization of methyl methacrylate proceeds smoothly and uniformly between -40 and +20 ⁰ C after a short induction period, the length of which is indirectly proportional to the amount of catalyst added. At temperatures above +10 ⁰ C, branching of the main chain is caused by a side reaction of the growing chain with the ester groups of the polymer. Excessive branching leads to the formation of three-dimensional, insoluble polymers.

A great advantage of the tertiary alkali metal alcoholates, especially the lithium tertiary alcoholates, is that that they can easily be represented in a high degree of purity. Lithium tertiary alcoholates can especially easily purified by sublimation under reduced pressure.

Tertiary alkali metal alcoholates can also be obtained by reacting alkyllithium with esters represent those carboxylic acids which have at most one hydrogen atom on the «carbon atom, such as B. with esters of pivalic or isobutyric acid. With another molecule of the alkyllithium arise at the same time the above-mentioned complexes, which can also be obtained by direct displacement of alkyllithium with finished tertiary alcoholates of the alkali metals and recrystallization from a suitable solvent,

: 609 707/408

Claims (20)

3 '4 such as benzene, can be represented. These - ■ · .. ·. ' ■■. ■ /, ·, " ■ . - ■ ·. .; ..:. * ■ . . ·.-....,; new complex compounds have characteristic ", Infrared spectra and are relatively stable. 100 parts of isoprene were in 200 parts of benzene For example, forms the complex of 1 mol tertLithium- dissolved and + 3O ⁰ C in inert gas with butanolät and 1 mole of butyllithium a fairly 5 0.5 parts of the crystalline complex of butyl Resistant, self-igniting lithium and lithium-terLbutanolate polymerize. the Substance. The activity of the complex is lower. Polymerization lasted 5 hours. The thus obtained than that of pure butyllithium, and the Polymerisa- polymer has predominantly the 1,4-cis structure. tion proceeds without any side reactions, so they. easy ' - . ... can be controlled. However, the activity is high io B e i s ρ i e 1 6 enough to allow rapid polymerization not only of 100 parts of anhydrous pure acrylonitrile were in Acrylic and methacrylic esters, but also dissolved from styrene, 200 parts of petroleum ether. This solution was To enable butadiene and isoprene. In combination under inert gas at -20 ° C 0.2 parts lithium tert. tion with butyllithium even have sodium and butanolate added. The precipitated polymer was Potassium tert-alcoholate has sufficiently high activity, filtered off, with a dilute aqueous solution of a provided that the Alcoholateeincn, high pure wetting agents and finally with pure water . have a degree of proficiency. . Washed 50 ⁰ C and dried. The invention is illustrated by the following examples .. · .... _ _ · ....,. explained in more detail, but without being restricted thereby; ·. - Berspiel7 _, will. . . 20th To 100 parts of butyl acrylate, 0.5 parts Ka Example 1 '' - '''lium tert-butoxide in inert gas at 0 ⁰ C conces- · ■■■■■' · .-- - '* - ο;, "'■; · ■" -. ·): ...>:'. sets. As soon as the viscosity began to rise noticeably, lithium terthexanolate was heated by heating the flask from the outside through an ice suspension of metallic lithium cooled in benzene with a common salt mixture.The viscous solution of 1,1-dimethylbutanol is shown; the latter can be used as a prepolymer for further processing, e.g. by reacting ethyl butyrate with methyl. magnesium iodide are produced. The excess. ... ·. . · ■ " Lithium was filtered off and the traces of residual- -.-.- ' ■ Example 8. ^. High tertiary alcohol together with benzene by adding 10 parts of methyl pivalate in 100 parts Distillation removed. The remainder in the flask was gradually reduced by 30 benzene while cooling to 0 ^{0 C} Sublimation purified at 0.01 mm Hg. 15 parts of butyllithium were added to the alcoholate inert gas. A forms a clear on the walls of the flask, part of the solution thus represented became 100 parts vitreous mass, which in aromatic hydrocarbons freshly distilled methyl methacrylate, which substances is easily soluble. Was the durch'Titration certain to -10 ⁰ C cooled, added. After 6 hours Degree of purity reaches 99.9%: · ■ '"■' 35 days of polymerization in the refrigerator turned into a solid 0.5 part of the lithium tert-hexoxide block thus obtained with a completely isotactic structure was dissolved in 10 parts of toluene and at 0 ^° C. As mentioned above, the degree of branching 100 parts of methyl methacrylate under an inert atmosphere depends on the temperature from in the polymerization. sphere added. After 12 hours at 0 ⁰ C high Molecular Weight obtained branched Polymethylmcthacrylat one small one block having an isotactic structure. 100% 4 ° NIIT isotactic structure represented in accordance with the vorKonversion is duich Itägiges standing at underlying invention, with relatively 20 ° C. The polymer is partially insoluble. . '·' ■■; · · the. The plasticized polymers have some '., ■ ··. \ ■ Example 2 '' interesting properties. They are very tough, · ■ - ■ '· ' 4-5 resistant to scratching the surface • A mixture of 0.1 parts sec-butyllithium and and impact-resistant. They can be used for various purposes, 0.12 parts of lithium tert-butoxide was used to lOOTeilen, including for producing methyl methacrylate at -2O ⁰ C in inert gas of clear, flexible films and sheets. Soft added. After 7 hours, a solid block with macher, including the low-boiling ones, isotactic structure. ■ 50 firmly absorbed by these polymers. The full _R. 'constant transparency of this stercoregular poly- : · - «'· ^; ■ ■■ "■ - ¹¹⁶¹⁸ P ^1613. Meren can probably through their not quite • A solution of 0.25 parts of butyllithium and linear structure explained.
0.35 parts of lithium tert-hexoxide in 10 parts of toluene ... was at -20 ⁰ C to 100 parts of methyl methacrylate 55 ■ Claim: added under inert gas. After 5 hours a solid block of isotactic polymer formed. ■ Process for the production of polymers or Copolymers by anionic polymerization - - B bis ρ ie 1 4 ^of unsaturated monomers in the presence of • ■ * 60 alkali metal alcoholates, thus identifiable • 100 parts of isoprene were ζ eich η et in 200 parts of benzene that you dissolved as a Polymcrisationskataly, and the solution was a mixture of tertiary alkali metal alcoholates, 0.5 part of butyllithium and 0.7 part of lithium tert. optionally used in combination with lithium hexanolate in 10 parts of toluene at + 3O ⁰ C under alkylene. added inert gas. After 2 hours, the 65th Polymerization ended. Infrared analysis proves the publications under consideration: that the product has a high proportion of 1,4-cis U.S. Patent No. 2,856,391; Contains polymers. . · / Ngewandte Chemie, 70, p. 744 (1958). ■■. . 609 707/408 10.65 © Bundesdruckerei Berlin