CS223252B1 - Method of solution polymerization of conjugated diens - Google Patents

Description

The invention relates to solution polymerization of conjugated. dienes in the presence of organolithium initiators.

It is generally known that "organolithium initiated potymenzam ienů ^d. also called anion: oic "living" ^p otymerizace can be performed only in aprotic solvents, from which then the solvent to or otherwise well jeopardize the stability of the growth centers, i.e., the C-Li bonds. Commonly used solvents are hydrocarbons, therefore, whether al ^and Fatic ^{to E,} I ^to about napřfclad ^hexane cyHoadfatické such as cyclohexane, or aromatics, such as benzene or toluene. However, the synthesis of an organolithium initiator often requires the use of a more polar solvent than the hydrocarbons, with the result that the diene polymerization itself takes place in the hydrocarbon / polar solvent mixture, since the initiator is metered into the reaction mixture regularly as a solution. Polar extended Oust ^{d p} ro l ^{YP or} rave tafotótoru are ethers such as diethyl ether, tetrahydrofuran or methylterc.butyléter, tertiary amines such as triethylamine, or mixtures thereof to hydrocarbons.

Přftomnos: after these extended árnějmch ^ ^p ou ^{te d} EL polymerising system results solvation growth centers, which leads to increase the proportion of 1,2, respectively. 3,4- in polydiene at the expense of 1,4-trans and 1,4-cis addition. For example, in the polymerisation of butadiene in a net angular ^thanks u forms ^a pre-8 to ^2% l ^ ^^ ruktu but the presence of several percent tetrahydrofuran already leads to an increased proportion of 1,2-ssruktur to about ^80%. Diethyl ether and trietylannn maj ^In this sense somewhat less pronounced effect of other substances are even more effective than tetrahydrofuran. Besides changing the microstructure has ^pres omnos ^t pol ^and rrnC slotóenin ^h for n ^a sledek and increase the polymerization rate and ^{to change} nu o ^p of ^poly mer ^and under ^N N ^U C ^hp Parameter ^of the copolymerization of dienes with vinylaromatic monomers, for example. They suppress the formation of homo sequences, i.e. the formation of block copolymers in the polymerization of the monomer mixture

S ^y ntéza telechelic polymers whose chains are capped reactive functional sku-nam ^ and in them ^the terýc ^{H or} and ^d all I Synthesis of block copolymers in which the middle part of the polymer chain is formed homosekvencí repeating units of another type than the end of the string, it requires the use Initiators having two active centers in the molecule, i.e. two active carbon-alkali metal bonds, which are generally lithium. Such compounds, if their structure and molecular weight of not suitably Suited ^ n ^ ^b ývají insoluble in ^p mo ^é uteovodících and need to be synthesized and dosed in a polar solvent.

Although the polar solvent is diethyl ether or tetrahydrofuran, it is also introduced with the initiator into the polymerization batch and makes it impossible to synthesize high-l-structured polystyrene. In addition, mixed solvents of ^dl-it-Umov / ETE-Toer is recycled in the process, has complications. resulting from the need to separate the components before reuse.

Nor is it negligible that conventional ethers, such as diethyl ether and tetrahydrofuran, form dangerous peroxides upon contact with air oxygen. This fact, together with exira ^é mn ^of írízkým tem vznl · appreciates ether necessitates special precautions during handling and use of these substances. The danger of these two substances in terms of the possibility of fire and explosion · is also associated nepřízínivými characteristics in terms of hygiene and protection životníiho ^y ^ .. ^ oSre

From the viewpoint of mixing, transport, heat transfer and other processing of the concentration of a solution ^{of p} ol ^y mer ^of at. n ^{t he} b ^s "Hvmg" ^p olymerizaci limited by their viscosity. This, in addition to the polymer concentration and temperature, depends on the number of lithium atoms in the polymer molecule, the type of monomer and the type of solvent. A higher number of lithium atoms in the polymer molecule as well as the use of an aromatic solvent leads to high solution viscosity. Normally, the final polymer concentrations in the solution are about 20 masses, why. ITovádí When polymerization mostly in ovo ^says metal ^hl m ^é ^ ostřefe apply this ^purpose Daj both vytokoI'no.l · eklálární polymers and varnish precursors for nízkomolekuiární liquid telechelic polymers.

The above disadvantages are overcome by the method according to the invention. According to the invention, a solution polymerization of conjugated dienes in the presence of organolithium initiators MTBE performed in an environment, wherein the polymerization initiator is added to the ^poly Psylla ^N N ^U a mixture ^of the ^f orm ^of flowable in MTBE.

Solvating solvent herein means a solvent which is polar enough to ensure the necessary solubility of all t ^h e ^f number ^for the system potymerizujmmo in stages ^with EC ^H ^ REA ^to CE. Dienem ^{means a} hydrocarbon with a conjugated double bond system, ie a compound with a backbone of the C = C-C-C molecule, in particular butadiene or isoprene.

The organolithium compound is then a substance containing at least one carbon-lithium bond in the molecule such that it is capable of initiating anionic livrng polymerization. ^d ienů. Examples are n-butyllithium, 1,4-dilithiobutane, alpha, omega-dilithiooligobutadiene or alpha, omega-diithiooligoisoprene.

^P oužitím MEIT ^y ^ t-Bu ^yl ERU E ^t j and ^k a span? T ^ED la ^p ro amontevou "living" pol ^y isomerisation dienes is reflected so that at the temperatures required for this type of polymerization normal, ie. 20-50 ° C, the content of 1,2 - ^^^ ^ ene in polyWa equal to approximately ⁵ 0 pncíemž with increasing polymerization temperature decreases slightly.

The content of ^1, 2-a ^{to t} ru tare znaшená ^that the ^{Tg of} the obtained polybutadiene is about -70 ° C which is the optimum value of for example rubber on the tire treads for cars and definitely keeps polybutadiene elastomer properties.

The 1,2-structure content of the polybutadiene remains unchanged, although a substantial portion of the methyl tert-butyl ether is replaced by an aliphatic or aromatic hydrocarbon. Due to the complications in recovering the mixed solvent, it does not therefore seem useful to replace part of the ether with a hydrocarbon, as necessary when tetrahydrofuran or other active agent is used as the solvating solvent.

The high ignition point of methyl tert-butyl ether, together with its inability to produce hazardous peroxides and relatively favorable health characteristics, predetermine this ether for the proposed use. In addition, it has been shown that low molecular weight polybutadienes with two lithium atoms at the chain ends provide solutions of lower viscosity in methyl tert-butyl ether than in hydrocarbons or mixed solvents in which the hydrocarbon predominates. This makes it possible to process polymer solutions with a much higher concentration, which is an indisputable advantage. Under such conditions, the rate of polymerization is also considerable and the length of the technological cycle is essentially limited by the construction of the polymerization apparatus, respectively. its ability to rapidly dissipate the heat of polymerization. This ability should be matched to the monomer feed rate.

The advantages of the above invention can be illustrated by the following examples.

Example 1

A glass dilatometer of approximately 120 ml was filled with an anhydrous solution of 10% by weight of butadiene in toluene under inert conditions and allowed to reach 50 ° C. A 10% solution of n-butyl lithium in hexane in an amount of 1 mole of n-Buli / 46 moles of butadiene was metered into the stirred contents of the dilatometer via a syringe valve. The rate of polymerization was calculated from the rate of movement of the meniscus in the specific capillary of the dilatometer, and after reaching 100% conversion, the polybutadiene formed after isolation of organometallic with methanol was isolated from the solution and the 1,2-structure content was determined by infrared spectroscopy. The results, together with the evaluation of the other examples and the basic data on the polymerization conditions, are given in Table I.

Example 2

The procedure of Example 1 was repeated except that a solution of 1,4-dilithiobutane in diethyl ether at a concentration of 35 g / l in an amount of 1 mol of dilithiobutane per 46 moles of butadiene was used to initiate butadiene polymerization. The evaluation results are again shown in Table I.

Example 3

The procedure of Example 1 was repeated except that a solution of 1,4-dilithiobutane in methyl tert-butyl ether at a concentration of 7.75% by weight was used to initiate the polymerization; the butadiene concentration in the solution was 14% by weight and the polymerization temperature was 30 ° C. Dilithiobutane was dosed in an amount of 1 mol per 38 moles of butadiene. The evaluation results are shown in Table I.

Example 4

The procedure of Example 3 was repeated except that a 10% by weight solution of butadiene in methyl tert-butyl ether was introduced into the dilatometer; the evaluation results are given in Table I.

Example 5

The procedure of Example 4 was repeated except that the polymerization temperature was maintained at 50 ° C; the evaluation results are given in Table I.

Table I

Polymerization in dilatometers

Example No. Initiator solvent concentration-temperature rate 1.2-content calculated for polymerization of butymerization polymerization structures diene molecularization in ° C (mole% (%) in mass solution / s.10) ³ ) capacity (% by weight)

1 n-Buli / hexane 1,4-DLB / DEE toluene 10 50 0.12 14 2480 2 1,4-DLB / MTBE toluene 10 50 0.21 48 2480 3 1,4-DLB / MTBE toluene 14 30 0.17 45 2050 4 1,4-DLB / MTBE MTBE 10 30 0.06 51 2060 5 1,4-DLB / MTBE MTBE 10 50 0.28 46 2060

Example '6

To a stainless steel reactor of 4.5 1 equipped šnetovým mícMdlem in tempered diffuser those temperacrnm ^jacket was charged with 355 wt. Parts of toluene and 42 wt. Parts. polymerization initiator, which in this case, alpha, omega-dilithiooligoizopren dissolved in a mixed maiden ^p ou le ^STED toluene / tetra ^{hyd ro-furan 80/20} wt. parts. The initiator concentration was 0.95 mmol / g and ^{kz t} EC ^h o s ^p natóvtovOm ^would lo ^d 2 of ^{9.5 h} the reactor mot duo toluene and ^7.3 wt. Parts of tetrahydrofuran. After the mixture was allowed to warm to 30 ° C, the mixture was stirred for 90 min. charged with 100 parts by weight, 'parts butadiene, which corresponds ^to a molecular weight ignites ^eh l o ^p ol ^y butyl and ^di ene ^{(1% to} onverze °°) 2550th Te ^p lota during the polymerization was kept at 30 ° C viscosity of the resulting mites ^k u "livin ^g 'and ^{f al,} omega-di ithiopol ^{y i} of butadiene was 50 mPa. s at 30 ° C and the concentration ^of the ^poly mer roztolw ²⁰ wt. %. Isolated Polybutadiene was analyzed by infrared spectroscopy and was found to contain 8% ² 1 ² -strulktur.

Example 1 a d 7 ‘...........

Procedure after ^comm la le ^{d d 6 was} in the ^P and ^K incorporated with the гoz ^part EM. that extended ou ^p em ^Inhalants Poly ^e aturisation was MTB and initiator V-dilithiobuta extended ^p ^ u ^s t ^currency tattéž Met ^y lterc.but ^yl ester and ^Star. NASA and ^d with ^examples from ⁷ 6 wt. Parts of methyl ^{y y} lterc.but methyl ether and 4.3 wt. Parts of 1,4-dilithiobutane; 'This was for 75 minutes to ^be in ^the L ov ^and NO limot ^{parts 00 b} uta п ^ ^ ^Pr' routine or rea ^{CZK nus b} YLA temperature maintained at 50 ° C. Viscosity of Solutions of the prepared "livin ^g 'and ^g-alfa.ome diiithiopo ^LYB utadienu (calculated molecular weight ²⁰ 00) ^to one of ^the oncentraci ^C No. 54% by weight was 120 mPa. s at -30 ° C; in the isolated ^poly huta ^d ienu ^would lo ^f m račervenou spelítrostopn zjmtěno 48% ^1, 2-SSRUs ^to tur.

Example 8

The procedure of Example 6 was repeated with the exception that the initiator used elkvivalentního amount of a solution of 1,4-dihthlobutanu Met ^y tert. ^b ut ^{s yl} ester and about 0 ^to oncentraci-mmol ^{/ g.} V ^ l ^to ignite Ozitech ^eh of mites in ^the "livin ^g" alte.omega-diiithte ^^ utadienu was 60 MPa. s at 30 ° C and the product isolated contained in the solution by an infra ^red warning SPE ^for TROS opte ^{4 to} 8% ^12-kt brief ur.

Example 1 9

Into a 1 1 four-necked flask was filled with spherical ¹⁴ wt ^says l ^{U k} ovového nthrn rouhaného on ^the chip 2 by weight, and 51 parts of naphthalene, ⁵ parts by mass, metyíterc.butytéteru. The mixture was - thermostated at 24 ° C - and ^stirred vigorously on a knife mfcha ^ em. B During ^the 5 'ho ^d in B ^to the REA ^{yl CZK} the mixture ^of a' ^p s ^{p STE} no ¹³⁶ parts by weight of isoprene. To the resulting solution, freed from the unreacted lithium forcing over to another flask with stirring and heating to 30 ° C was added over 1.5 hr gave a ^SI No. ^H 544 wt iso dM ^p Reno. ^{P 1} of methanol dezalktivac b ^y l in ^{98.2% and} chop zolován polyisoprene which, according to infrared spelttroskopie content of 3 ^{to 4} STRETCH tur 46 percentages. Comparative experiment where instead meth lterc.biit ^{y y} b LETERME ^{yl U} sing (Лг ^ ¹ ^^ ^dl in ^p ol ^y mer obsaliu about 61% steulktur-S.A.

Claims (1)

A method of solution polymerization conjugated dienes ^.gamma.CH reactant feed for p ^ ^ ^ organodlhiový Ш ^ ^ ог ^{characterized} in tm ^brand Eny that - after COUNTERS ^ly performed in an environment of MTBE, the initiator is added as a solution in MTBE.