DE1645489C - Process for the polymerization of butadiene (1,3) - Google Patents

Description

The invention relates to a process for the polymerization of butadiene ^ 1,3) in the presence of one of one ether-free organomagnesium compound and one Titanium tetrahalide formed catalyst in an inert liquid hydrocarbon solvent, wherein the catalyst components are added to the reaction mixture without prior mixing. This process is characterized in that the liquid hydrocarbon solvent is a Mixture of aromatic hydrocarbons with monoolennes containing 3 to 6 carbon atoms, used, the volume concentration of the monoolefin being about 5 times the volume concentration of the butadiene monomer does not exceed.

According to the invention, an additional solvent, namely a monoolefin having 3 to 6 carbon atoms, is used as a component of the solvent mixture for the butadiene polymerization. The use of these monoolefins, which have a large heat capacity, as an additional solvent to an aromatic hydrocarbon advantageously leads to a reduction in viscosity. As a result, better heat conduction is achieved during the polymerization and the polymerization can be continued with a higher solids content in the solution. The use of a monoolefin having 3 to 6 carbon atoms as an additional solvent also leads to the formation of cis-1,4-polybutadiene with a lower tendency to flow on storage and a narrow molecular weight range: the additional solvents also make the catalyst more effective. The use of these monoolefins as an additional solvent to an organic hydrocarbon enables _{the amount of catalyst to be reduced by V 3} to ¹ Z ₂ compared to the amount which would be required if the process according to the invention were carried out in a solvent consisting only of aromatic hydrocarbons. It is not possible to use alkanes instead of the monoolefins with 3 to 6 carbon atoms, since this results in the decomposition of the organomagnesium compound. The active catalyst produced by titanium tetrahalide and butadiene would become practically insoluble and therefore a reduction in the effectiveness of the catalyst would occur.

From British Patent Specification '' ^ O 222 it is known to polymerize 1,3-butadiene in the presence of a catalyst comprising an organomagnesium compound and a titanium tetrahalide, wherein an aromatic hydrocarbon is used as solvent, and the individual _{Katalysatorkompo-:} -ontn _n separated in the Reaktionskesscl are given (icii Γ- r, compared to, as already mentioned, invention .-, £.: r! iäß a mixture of aromatic hydrocarbons with monoolefins containing 3 to 6 carbon atoms is used. This measure brings about a mere use aromatic hydrocarbons according to the aforementioned British patent 950 222 have the advantage that this can reduce the viscosity of the solution, fo

The consequence of this is that better heat transfer takes place during the polymerization, and the polymerization can be continued until the solution has a higher solid content. The use of a monoolefin having from 3 to 6 carbon atoms as ^{<> l} <additional solvent, ie as part of the LöBungsmittelgemischcs further leads / ur formation of ice-1,4-polybutadiene with a lower I lieüneigunji during storage and a narrow molecular weight range. Finally, the addition of a monoolefin having 3 to 6 carbon atoms to an aromatic hydrocarbon solvent increases the effectiveness of the particular catalyst used. In this way it is possible to reduce the amount of catalyst required when carrying out the process described in the presence of a solvent consisting only of aromatic hydrocarbons by 1/3 to _1/2.

Isobutylene is used as a preferred monoolefinic, additional solvent, it can but also other monoolefins, such as propylene, butene (2), pentene (1), pentene (2), 2-methy! butene (2), Hexene (1), 3-methylpentene (2), 2-ethylbutene (2) and their mixtures together with the aromatic Hydrocarbons are used. The amount of additional monoolefinic solvent is used at a concentration of 0.2 to 1.0 volume per volume aromatic hydrocarbon solvent applied. To prevent the formation of cis-polybutadiene-olefin copolymers, the concentration should of the monoolefinic solvent about five times the concentration of the butadiene monomer not exceed.

According to the invention, benzene, toluene, Xylene and mixtures thereof are used.

In the “in situ” process according to the invention, the organomagnesium compound and titanium tetrahalide are formed brought together in a hydrocarbon mixture containing the butadiene to be polymerized. Usually the organomagnesium compound is dispersed in a mixture of butadiene and hydrocarbon solvents and / or dissolved and a solution of titanium tetrahalide in a hydrocarbon to this mixture admitted. The reactant mixture consisting of organomagnesium compound, titanium tetrahalide and butadiene contains at least 300 mol and preferably at least 50 (1 mol of butadiene per viol Titanium tetrahalide. Such a high molar excess of butadiene ensures the formation of the active catalyst and prevents the reduction of the titanium tetrahalide through the organomagnesium compound to an inactive, solid polymer Trihalide with essentially trivalent titanium

This method is characterized by great effectiveness of the catalyst, excellent repeatability and insensitivity to dilution, TcmpcratiP'cin effect or signs of aging a js. The "in situ" method for the production of the active catalyst also enables easier handling of the catalyst and a better regulation of the polymerization rate and the molecular weight locking of the polybutadiene.

The following examples serve to explain the invention in more detail.

Example I.

This example explains the "in situ" preparation of the C ₄ II _n TiXi radical catalyst by using an organomagnesium compound, itanetetraiodide and butadiene, with isobutylene and benzene used as a solvent in the reaction.

38 liter stainless steel Rcaktor was made by Distillation of benzene dried and flushed with dry argon and successively with ISJ kg of benzene (thiophene-free and freed from moisture by azeotropic distillation), 5.44 kg over molecular sieves dried butadiene and 9.4! kg of isobutylene passed through alumina and dried. The reactor charge was brought to a temperature of 5 ° C. and the stirrer switched on and a suspension of 150 mmol of ether-free -i-naphthylinagnesium bromide in I 1 of xylene under argon pressure transferred to the reactor. After stirring for 5 minutes, a solution of 27 g (4S, 6 mmol) in 3 liters of dry benzene dissolved titanium tetraiodide were transferred into the reactor under argon pressure. The reaction mixture was then brought to a temperature of 13 C, whereupon polymerization occurred immediately.

The total reaction time was 63 minutes, the percentage solids content after the end of the reaction was 8.5, and the viscosity at 13 ° C. was 2000 cP. The polymer consisted of 98% cis-1,4, 0.5% trans and 1.3% vinyl polymer. The polymerization was terminated after .63 minutes by pouring the charge into a vessel flushed with argon with 400 ml of ethanol, 400 ml of a 10% strength dimethylamine solution in benzene and 30 g of N-phenyl-N'-cyclohexyl-p-phenylenediamine. A sample of the polymer adhesive was coagulated and had an i M L-4 of 54 at 1 (X) C.

B cisfic 1 2 ^J °

This example explains the "in situ" position <les catalyst, with a slightly larger molar ratio of organomagnesium compound to titanium iodide is applied. In this example, which also uses isobutylene as an additional solvent a polymer is obtained with properties very similar to that of Example 1 produced polymer.

A dry 38-1 Rcaktor previously flushed with argon was mixed with 18.1 kg of benzene. 5.44 kg of butadiene and 9.07 kg of isobutylene charged and this Bctchickung cooled to 5 C. Then there was a suspension of 160 mmol </ - naphthylmagnesiumbiumide in I I a 30 to 70% xylene-benzene / .ol mixture below Ί5 Argon pressure introduced into the reactor. The reactor contents was then stirred for 5 minutes and 27 g (48.6 mmol) of titanium tetraiodide dissolved in 2 l of benzene, Line argon pressure was introduced into the reactor, the temperature being set to 10 ° C. The history the polymerization reaction was similar to that of Bcitpiel I. The reaction was bcfnilci after 60 minutes and the charge is placed in an argon-filled vessel with 900 ml of 1% benzene-iimelhylfimine solution, SOOMI ethanol and 60 g of N-phenyl-N-cyclohexyl-p-phenylenediamine poured.

The following physical properties were determined: Solids content: 10.4%; viscosity (cP) at 10 C: 3592. The polymer consisted of 97% ice, 0.8% trans and 2.0% f » Vinyl polymer. A test sample of the coagulated polymer adhesive had an Ml -4 at KX) C from 60.

B ice ρ ie 1 3 ₍

(Comparison search)

This example explains the "in situ" implementation ties catalyst and its application in a system in which no isobutylene as an additional Solvent is used. In the absence of isobutylene, the reaction mixture becomes very viscous, and as a result of the low heat conduction, the conversion temperature rises considerably

Lin 19-1 stainless steel reactor dried by distillation of xylene and flushed with argon Steel was charged with 15.9 kg of dried benzene and 2.72 kg of butadiene.

The charge was brought to a temperature of 10 ° C. and 71 mmol of ether-free α-naphthylmagnesium bromide in 900 ml of a 30 to 70% xylene-benzene mixture was introduced into the reactor under argon pressure. The contents of the reactor were stirred for 10 minutes and then a solution of 22.9 mmol (12.75 g) of titanium tetraiodide in 1 liter of benzene was introduced into the reactor. Immediately after the addition of the tetraiodide solution, the exothermic reaction began and the reaction temperature rose within 10 minutes (with full cooling by 40 C. Within 15 minutes the conversion had progressed to a 50% conversion (Brookfield viscosity 194 cP) Minutes reaction time, the conversion rose to 86%. (Brookfield viscosity 15 25OcP at 15 C.)

The polymerization was started after 30 minutes by placing the charge in an argon purge Vessel with 400 ml of ethanol, 400 ml of a lO'l'oigen benzene-dimethylamine solution and 15 g N-phenyl-N ^ cyclohexyl-p-phenylenediamine terminated. The polybutadiene became a Ji.ni solvent obtained by flocculation using steam.

It had the following properties: Mooncy viscosity at 100 ° C: 64; 97% cis-1,4 content; 0.6%, trans-1.4 content: 7.0% vinyl content; Viscosity of the diluted solution: 2.73; Ash content: 0.2%.

B e i s ρ i e 1 c 4 to S

These examples illustrate the implementation of dihydrocarbon magnesium compounds, excess Butadiene monomer cream and titanium tetrahalide. These directly from alkyl or aryl halide and Magnesium in the absence of compounds produced are soluble in hydrocarbons. A high efficiency of the catalyst is observed when the dihydrocarbon magnesium compounds with T'tantctrahalogenid and monomcreni Butadiene are implemented. If one puts dihydrocarbon magnesium with the Tilantclrahalogenid in dilute solution, d. H. in the absence of butadiene, um is formed on subsequent addition butadiene is not a polymer.

Table I lists the results that occurred in Use of 5 different dihydrocarbon magnesium compounds were achieved.

100 ml of benzene dried over clay was flushed with 20 ml (12 g) of butadiene in a nitrogen-flushed, treated with a cap closure provided pressure bottle. To the butadicn-benzene solution were 0.225 mmol (1.5 ml of a 0.15 molar Solution in benzene) Dikohydrosiloffmagnesium added. With the subsequent addition of O.ISmMol of a titanium rayodilution (7.5 ml of a (), 2 molar benzene solution), rapid exothermic polymerization occurred with a temperature increase of about 35 (a. The data listed in Table I. show the results of the polymerizations started at 27 (, the one hour before working up

were left long advancing. The polymers were made from the benzene du.ch coagulating with Alcohol obtained in the presence of an antioxidant.

Table I.

Dicohydrocarbon-magnesium prebonding-Bulädier.-Titaniumetrahalogenid-System as a star substance

for butadicn polymerisation

Conversion. %

ice-1.4. %

water-1.4,% ....
Vinyl. %

Di-n-decyl

100

1.2
1.8

example

S j ft I 7

DikohlcnwussurMofTniagncsiuni connection

liL'iivl Di-mL-latol. Vl Di-ivlDlyl 99 93 98 96.3 96.0 96.5 1.4 1.2 1.3 2.3 3.0 2.2

Di-ii-naphthyl

99 96.0

1.2

3.0

Example 9
(Attempted comparison)

This example illustrates the ineffectiveness of a Reaction products * from dihydrocarbyl magnesium compound and titanium tetraiodide in a dilute Hydrocarbon solution containing about 1 percent by weight of reactants.

A reaction mixture was prepared from 0.225 mmol of diphenyl magnesium and 0.168 mmol of titanium tetraiodide in 10.3 ml of benzene. This mixture, which contained about 1 percent by weight of diphenylmagnesium Ti.l ₄ , was placed in a nitrogen-flushed, capped pressure bottle with 24 g of butadiene and 200 ml of benzene. No visible conversion occurred after shaking for 24 hours. suggesting that diphenylmagnesium and the titanium tetraiodide reacted in the dilute benzene solution to form titanium trihalide, the titanium of which is essentially less than four in valence.

Add the same amount, namely 0.225 mmol of diphenylmagnesium to a mixture of 24 g of butadiene and 200 ml of benzene and add 0.168 mmol of IiJ _{4 to this} . thus a rapid exothermic reaction occurs, with results essentially similar to those in Example 5 being obtained. 100% conversion of the butadiene into a polymer with a content of 97 "η cis-1,4-isomer, 1% Iran and 2" II vinyl polymer took place.

Example 10

This example illustrates the effect of the concentrate in ether-free-ni dihydric hydrogen magnesium and titanium tetrahalide on the molecular weight or the Mooncy viscosity of cis-1,4-polybutadine, which was prepared with a catalyst containing essentially tetravalent titanium. Table II shows the results obtained with a JIR-I reactor; in these experiments <m was that of diphenylmagnesium. Butadiene and titanium tetraiodide produced catalyst used.

Kin 38-liter reactor made of stainless steel with device for reading coolant through the reactor jacket <μιμΙι · by distillation of benzene <<s and subsequent flushing with nitrogen gelrock net and then only Ikn / ul. d, is through 1> n! "eiil '-' itt-n dm eh 1 (HiLT (Ic iii-iiiK. k Hi ¹ I weiden win. and mil butadiene (polymerization quality, dried and freed from inhibitor by passing through clay) The charges are shown in Table II The reactor was maintained under positive nitrogen pressure and diphenylmagnesium (prepared under low-temperature conditions) in benzene solution was transferred to the butadiene-benzene solution by means of a nitrogen pressurized stainless steel bomb The stirrer was switched on, the Rcaktortempcralur brought to 25 ¹ C and a 0.2 molar titanium tetraiodide solution with the help of a pressurized stainless steel bomb was added could not be kept constant even with full cooling (10-Λ). A simple control of the implementation and keeping the temperature constant succeeded, however, with the addition of tetraiodide (K) -B) in portions. The polymers listed in Table ü were treated with an antioxidant and then flocculated with steam.

"Table Il

Influence of the diphenylmagnesium and tilantraiodide content on the molecular weight

approach

Benzene (g)

Butadiene (g)

Diphenylmagnesium Millimole (g)

Tilanlctraiodide

Millimoles

temperature

/ eit. Minutes

1 'mwandl.mg, "■«..

(rounded molars
Viskosila'ts / ahl
(Intrinsic, I SA)

M noney viscosity
at KW) (

(is I I (loh.ili. ""

Hans I I (u'hali. ".,

HA

26 601

3632

55 (9.S g)

36.7 (20.4) 25 to -7SC 60
100

2.05 26

M)

10-B

26 604

3632

42 (7.5 g)

24 (13.3)

10 to 50 C.

40

K) O

3.39

ι.ν

continuation

Vinyl,% 2.6 2.1 ML-4 of the mixture 54 300% module after 90 minutes , .. 1180 1350 Tensile strength according to 90 minutes 2220 1800 Stretching after 90 minutes 470 460 / 1T after 90 minutes 46 40

Influence of diphenyl magnesia and titanium tetraiodide content on molecular weight

Recipe *): (Banbury mixer, for vulcanization)

cis-butadiene rubber 100

Soot highly abrasion resistant 50

Zinc oxide 3.0

Stearic acid 2.0 Anti-aging agent 1.0 Abietic acid resin 5.0 Aromatic extender oil 5.0

Sulfur 1.75

Accelerator benzthiazole-2-sulfenamide 0.91

·) Vulcanized at 145 ° C for 90 minutes.

The polymerization was completed after 50 to 100% conversion of butadiene to polymer Addition of a mixture which inactivates the catalyst is complete. Such a mixture is for example a benzene solution containing 0.5 to 2 percent by weight of antioxidant, based on the weight of the polymer, and 0.2 to 1.5 percent by weight of secondary Contains amines, such as dimethylamine, to stabilize the polymer.

Claims (2)

Patent claims: 1. Process for the polymerization of buta- ■ 5 diene (l, 3) in the presence of an ether-free one Organomagnesium compound and a titanium tetrahalide formed catalyst in one inert liquid hydrocarbon solvent, with the catalyst components without prior ίο Mixing added to the reaction mixture are, characterized in that the liquid hydrocarbon solvent is a mixture of aromatic hydrocarbons with monoolefins containing 3 to 6 carbon containing substance atoms, the volume concentration of the monoolefin being about 5 times Volume concentration of the butadiene monomer does not exceed. 2. The method according to claim 1, characterized in that at least 300 moles of butadiene used per mole of titanium tetrahalide. 109 650/20