FR2459251A1 - METHOD OF ISOMERIZING DOUBLE ISOLATED LINKS IN DOUBLE BONDS CONNECTED IN HOMOPOLYMERS AND / OR COPOLYMERS OF DIENES (1,3) - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS FOR ISOMERIZING DOUBLE LINKS INSULATED IN DOUBLE CONJUGATE LINKS IN HOMOPOLYMERS AND OR COPOLYMERS OF DIENES- (1,3) USING AN ISOMERIZATION CATALYZER AND POSSIBLY IN THE PRESENCE OF A SOLVENT. DEPENDING ON THE PROCEDURE, AN ALKALINE ALCOHOLATE IS USED AS ISOMERIZATION CATALYST AND ISOMERIZED AT 50-250C OR, IF A STRONGLY POLAR APROTIC COMPOUND IS ADDITIONALLY USED, AT A TEMPERATURE OF 0 TO 150C. THE PROCESS ALLOWS PARTICULARLY INTERESTING CIS-1,4 STRUCTURES TO BE OBTAINED, BY PROVIDING, WITHOUT GELIFICATION, PRODUCTS CONTAINING FEW IONS OF ALKALINE METALS.

Description

The present invention relates to an isomerization process of

  double bonds isolated conjugated double bonds in homopolymers and / or copolymers of dienes- (1,3). In homopolymerization of dienes (1,3), as well as in the copolymerization thereof, with each other or with vinyl-substituted aromatic hydrocarbons,

  polymers having isolated double bonds.

  However, it is known that low molecular weight and high molecular weight compounds containing conjugated double bonds are more reactive and therefore also more attractive than the corresponding isolated double bond compounds. For this reason, processes for the preparation of compounds with conjugated double bonds have already been developed. For example, 1,3-dienes have been copolymerized with acetylene

  / -J. Furukawa and others "Day Polym. Sci., Polym Chem Ed."

  volume 14, 1213-1219 (1976). Another, more economical, option is isomerization of isolated double bonds

  in conjugated double bonds. To practice this isomerization

  The most diverse catalytic systems have been used.

  Thus, DE-AS 1 174 071 discloses a process for the isomerization of butadiene polymerization products in

  which the polymerization products are heated to temperatures

  from 100 to 3000C in the presence of small amounts of metals

  transitions from Groups VI to VIII of the Periodic Classification

  or compounds in which these metals are in the zero-valent state. The disadvantages of this process lie in the fact that on the one hand the isomerization temperature is very high and that gelation can occur and on the other hand, with

  relatively expensive catalysts, an isomer occurs

  cis-trans transformation which leads to a loss of cis-1,4 reactive structures. In addition, according to the process of German Offenlegungsschrift 2,342,885, a system comprising an organic compound of

  alkali metal and a special diamine as isomer catalyst

  homopolymers and copolymers of low molecular weight butadienes. However, given the chelation effect

  diamines introduced, the polymer has a relative content

  alkali metal ions, which has negative effects, for example when used in the field of paints. In addition, the combination of polymerization and isomerization, described as preferential, does not give the high content of cis-1,4 structures which is advantageous for

  the drying properties of low molecular weight polybutadienes

  lar. Finally, DE 1,156,788 and DE-AS 1,156,789 disclose processes for converting esters of fatty acids and mono-alcohols containing isolated double bonds into fatty acid esters containing duplicates. conjugated bonds and in which isomerization catalysts,

alkaline alcoholates.

  The object of the invention is to provide an isomeric process

  isolated double bonds in double bonds

  in homopolymers and / or copolymers of dienes-

  - (1,3), in which we obtain generally technically valuable cis-1,4 structures, without gelling, and which gives products with a low content

in alkali metal ions.

  This problem is solved by the fact that an alkali metal alcoholate is used as the isomerization catalyst and that the isomerization is carried out at temperatures of +50 to

+ 250GC.

  It is surprising that alcohol can be used

  alkaline lains as their use appeared to be

  limited to special compounds. For example, the isomer

  described for esters of fatty acids and mono-alcohols can not be transposed to classes of compounds as related as esters of fatty acids and polyalcohols.

  or fats (see DE-OS 2 155 727, page 2, paragraph 1).

  By homopolymers and copolymers of (1,3) -dienes,

  In the context of the invention, the term "homogenous products"

  polymerization, for example, butadiene- (1,3), isoprene, (2,3-dimethylbutadiene and piperylene, the products of 2459s251 copolymerization of these dienes- (1,3) with each other as well as with vinyl-substituted aromatic compounds such as styrene, c-methylstyrene, vinyltoluene and divinylbenzene The content of vinyl-substituted aromatic compounds in the copolymerization products should not exceed 50 mol%. the process according to the invention, polybutadienes having molecular weights (1n) of from 500 to 20,000, in particular from 600 to 10,000 and most preferably from 800 to 6,000, the microstructure of the dienes contained in the homopolymers and copolymers is generally not critical, but it is advantageous that at least 20% of the double bonds

have a cis-1,4 structure.

  As alkali alkoxides, the alkali compounds of all the compounds of the present invention can be used in the process according to the invention.

  primary, secondary and tertiary monoalcohols and polyalcohols.

  Preferred bodies are the alcoholates of sodium and

  potassium of aliphatic or cycloaliphatic monohydric alcohols

  at most 20 carbon atoms, preferably 3 to 8

carbon atoms.

  Typical alcoholates that can be used are, for example, isopropoxides of sodium and potassium,

  tertiary butoxides of sodium and potassium 2-ethyl-

  hexyloxides of sodium and potassium.

  In general, the alkali metal alkoxide is added to the polymer to be isomerized in a proportion of 0.1 to 10 g, preferably 0.5 to

3 g per 100 g of polymer.

  The polymer to be isomerized can be used both with solvent and without solvent. It is appropriate or necessary to use a solvent when the viscosity of the polymer is so

  higher than the homogeneous distribution of the constituents of

lyser is not assured.

  The solvents, which must be free from disturbing impurities such as water, may be, for example,

  aliphatic, cycloaliphatic and aromatic hydrocarbons.

  Typical representatives of these groups are hexane, octane,

  cyclohexane, toluene and xylene.

4 -24592t5

  The process according to the invention is carried out at temperatures of

  ratures of +50 to + 250C, preferably of +80 to + 150C.

  In general, in carrying out the process according to the invention, the alcoholate is combined with the polymer to be isomerized, optionally dissolved in a solvent and the whole is heated to the desired temperature. If the catalyst is poorly soluble, for example in the case of methoxides, a third solvent is added

  such as hexamethylphosphorotriamide to the possible polymer

  dissolved in a solvent. The reaction time required depends on the nature and amount of the catalyst, the polymer to be isomerized and the temperature. We can easily determine

  the optimal reaction time by some experiments

  tation. The reaction is terminated, for example, by cooling to room temperature (250 ° C.). Until this step, all operations are preferably carried out under an inert gas atmosphere, for example argon. Then, the catalyst is removed as much as possible by washing with water and / or treatment.

  adsorption, for example by means of bleaching earth.

  The homopolymers and / or copolymers of dienes- (1,3) isomerized by the process according to the invention, which are preferably used for the production of coating agents, have a conjugated diene structure to a degree of up to 35% of the number. total of double bonds. It also appears to a small extent, triene structures and tetraenes

conjugates.

  According to one embodiment, in order to be able to conduct the isomerization under less severe temperature conditions, is introduced, in addition to the alkali metal alcoholate, an aprotic compound

strongly polar.

  Thanks to this measure, it is possible to drive

  isomerization at temperatures of 0 to + 1500C, preferably

  from + 20 to + 100 ° C, that is, relatively to the case where an alkali alkoxide is simply used, it is surprisingly possible to lower the reaction temperature to a constant concentration of up to 1000 ° C. of

  catalyst and with a constant degree of isomerization.

  In this case, the alcoholates that can be used are

  these, as mentioned above. However, besides

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  the alcohol function, the alcohols from which alcoholates are derived

  may still carry other functional groups, for example

  ple of the ether or amine groups. Difunctional or polyfunctional alcohols are for example polyethylene glycols, optionally etherified on one side. Highly polar aprotic compounds that

  are, for example, dimethylsulfoxide, dimethyl

  thylformamide, dimethylacetamide 1,2-diethoxyethane

  tetramethylurea, tetramethylenesulfone, N-methylpyrrole

  rolidone, isophorone, acetophenone and ethylene carbonate.

  Dimethylsulfoxide, dimethylformamide and N-methylpyrrolidine

rolidone are preferential.

  The strongly polar aprotic compound is generally

  0.1 to 20 g, preferably 0.5 to

  10 g per 100 g of polymer to be isomerized.

  In general, in carrying out the process according to the invention, the alcoholate and the strongly polar aprotic compound are combined with the polymer to be isomerized, optionally dissolved in a solvent, and the whole is heated to the desired temperature. The reaction time required depends on the nature and amount of the catalyst, the polymer to be isomerized and the temperature. Optimal reaction time can be easily determined by some orientation experiments. The reaction is terminated by adding an active hydrogen compound,

  for example methanol. Until this stage, all the operations

  rations, especially at elevated temperatures, are carried out under a protective gas atmosphere, preferably argon. Then, the catalyst is eliminated as much as possible by washing with water and / or by an adsorption treatment, for example by means of

bleaching earth.

  The homopolymers and / or copolymers of dienes (1,3) isomerized by the process according to the invention, preferably polybutadienes having molecular weights (Mn) of 500 to 000, which are preferably used for the production of stabilizing agents. coating, exhibit conjugated diene structures in

  a measure of up to 70% of the total number of double bonds.

  There are also small amounts of conjugated structures of

triene and tetraene.

6 2459251

  Other characteristics and advantages of the invention will emerge from the following examples intended to illustrate the

  various forms of implementation of the method.

  The indicated conjugate contents were determined by ultraviolet spectroscopy and, in the case of polybutadienes, they are indicated in percentages by weight, calculated for C8H14 (conjugated dienes), C8H12 (conjugated trienes) and C8H14 (conjugated tetraenes). The term "room temperature" means 250C in all the examples. The metal / chain ratio

  in each case, the molar ratio between metal and polymer.

  All percentages are by weight except

otherwise stated.

  The microstructures were determined by spectrophotometric

  infrared light and the figures indicated relate to the

number of double bonds.

Example 1

  4 g of a polybutadiene oil having 76% of cis-1,4 structure and a carbon content of 2000 g are introduced into a 4 liter stirring flask dried by heating and swept with argon.

'

  in conjugated diene structures less than 0.5% (In = 1500).

  With the oil heated at 1200 ° C., 1% by weight of tertiary butoxide is added three times at intervals of 120 minutes.

  of potassium and samples are taken from each

  in which the isomerisation is completed by cooling

  at room temperature. At 1200.C, the oil is colored

  dark red in the presence of tertiary potassium butoxide.

  The product is isolated by diluting with hexane and removed.

  by centrifugation the alkoxide thus precipitated. Table 1 shows the microstructures and conjugate contents as a function of time. All reactions, including those of the following examples, take place under an argon atmosphere, because at high temperature, the presence of oxygen can lead to gelation.

Table 1

  Variation of isomerization by tertiary butoxide

  potassium (KtBO) at 120 ° C, as a function of time.

  The microstructures shown are the relative values (

  100%). Absolute contents are 80 to 95%.

  The product is applied to a sheet with a wet sheet thickness of 50 μm and its drying behavior is determined according to DIN 53 150. Dust-free times and core drying times of less than 1 hour are obtained (comparison: raw material: dust-free and drying at

heart: 9 hours).

  The same test is performed with a freshly sublimed KtBO instead of the commercial product. It gives the same results. It is also possible to add all of the catalyst at once. We get slightly lower grades in

  conjugates (20% conjugated diolefins after 6 hours).

Examples 2 to 6

  The isomerization with KtBO as a catalyst is carried out on polybutadiene oils of different structure and of another molecular weight. In addition, copolymers are used

  formed with styrene as well as oils of other monomers.

  The results are shown in Table 2. Microstructures

  remain approximately constant as in Example 1.

  Time ContentMicrostructure Content in conjugates in KtBO F 7% 7 -% in

  weight 7, / hr trans-1,4 1,2 cis-1,4 Diole-triole tetra--

Fine fine olefins

1 2 22 1 77 12.8 O O

2 4 20 1 79 19 0.06 O

3 6 21 1 78 32 0.08 O

  __ __ _ __ __ _ __ _ __ __ _ __ i _ __ _ __ __ _ __ _ _ __ _ __ __ _ __ __ __ _ __ _ __ _ _ __ __ _ __ _ __ __ _ __ _

Table 2

  Isomerization of oils of other monomers, other structures

  and higher molecular weights.

  N Type X KtB0,% Tempey Time Conjugate content, oil by weight / C_7 / h_7% diolefin / -C-C7 / -h T

2 OPV 10 150 2 9.9

3 P0130 2 120 5 7.5

4 P0160 2 120 5 4,6

St / Bu 5,150 3 7.8

6 PIP - 5,150 5,1,1

  _ _ _ _ _ - - - - - - - - - - _ _ _ _ _ _ _ - - - - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _-__ _ _ _ _ _ _

  X Types of oil: OPV = vinyl polymer oil (prepared according to DEOS 2,361,782)

  P0130 and P0160 = commercial products of Chemische Werke Hils AG.

  St / Bu = styrene / butadiene copolymer oil (prepared according to the patent

DE I 212 302)

  PIP = polyisoprene oil prepared using LiBu.

  In -the experiments, one adds at once

amount of catalyst indicated.

  Characteristics of the initial oils (content

less than 0.5%) -

trans-1,4

8 to 16

51 (3.4)

  Microstructure,% 1,2 cis-1,4 2-4 to 90

41 (1.4)

  Styrene o o o Oil type Mn VPO P0130 P0160 St / Bu 3,000 6,000 PIP 1,600

9 2459251

  Examples 7 and 8 Based on the procedure of Example 1, isomerized with 2-ethylhexyloxide of sodium or potassium (NaOC8

  or KOC8). The results are shown in Table 3.

, Table 3

  Isomerization Using Alkoxides of Na and K To prepare the alkoxides, the alkali metals are finely pulverized in xylene. Then they are reacted with an excess of 2-ethylhexanol. To complete the reaction, we

  heated to 145 ° C. and excess alcohol and xylene are removed.

  Then the polybutadiene oil is added and the mixture is brought to the desired temperature. However, it is also possible to isomerize

with excess alcohol.

  Examples 9 to 13 The procedure of Example 1 is repeated with other alkoxides, the catalyst being added all at once. Potassium or sodium alcoholates derived from methanol (Examples 9 and 10), isopropanol (Example 1t), cyclohexanol (Example 12), benzyl alcohol (Example 14) and propylene glycol (1) are used. 2) (Example 13), prepared as in Examples 7 and 8. The results are shown in FIG.

Table 4.

  Example Alcoholic% by Weight Temp. Time, Diolefins Nature, Conjugated H,% C 7 NaOC 8 5 150 5 6

8 KOC8 5 120 1 13.2

Table 4

  Isomerisation Using Different Alcoholates The comparison of Examples 9 and 10 clearly shows that when it comes to poorly soluble alcoholates such as methoxide,

  it is useful to add a third solvent such as HMPT.

  Examples 15 to 22 Based on the process described in Example 1,

  Different concentrations of KtBO are used at different times.

  tures. The results are summarized in Table 5.

Table 5

  Isomerization using KtBO Example KtBO, Temp-Time Diolefins N% by weight, C / -h 7 conjugates,% 0.1 150 i 1.1

16 0.5 120 3 7.1

17 i 120 3 14.0

18 5 150 0.5 16.7

19 10 120 5 17.6

5 120 3 17.1

21 5 80 5 6.3

22 5 50 5 1.1

  Example Alcoholic% Temp. Time Diolefins NO conjugated weight oC hours 9 NaOCH3 5 120 2 1.1 NaOCH3 / 10% HMPT 5 120 5 3.4 11 KO isopropyl 5 150 3 11.1 12 KO cyclohexyl 5 120 7 11 9

13 KOC30H 5 150 3 11.5

  14 KO benzyl 7 150 7 18 X Hexamethylphosphorotriamide il 2459251

Example 23

  The process of Example 1 is repeated in xylene as a solvent. For this purpose, 200 g of polybutadiene oil in 40 g of xylene are added at room temperature.

  weight of KtBO and then heated to 135 C. After one half

  hour, it is determined by ultraviolet spectroscopy that the

  in conjugated diolefins is 14.20%.

  EXAMPLE 24 A 500 ml stirred flask, previously dried by heating and flushed with argon several times, was charged with 150 g of polybutadiene A oil (tMn 600, double bonds: cis-1.4: 75). %, trans-1,4: 24%, 1,2: 1%), as well as 15 g

  N-methylpyrrolidone and 6 g of tertiary potassium butoxide.

  The conjugate content of the initial oil is less than 0.5%.

  The contents of the balloon, at first clear, turn blue-black when heated to 80 C with stirring. The oil to be isomerized is protected by argon. After various periods of time, samples are taken that volatile fractions are rinsed off for 1 hour at 140 ° C. under an oil pump vacuum. The product can be isolated by filtration or by adsorption methods. The content of conjugated diolefins, calculated as a percentage by weight of C8H14 by ultraviolet spectroscopy, is 12.4% after 5 hours. The conjugated triolefins, calculated as percentage by weight of C8H12, are present at a rate of 1.8%, the conjugated tetraolefins,

  calculated as a percentage by weight of C8H10 at the rate of 0.23%.

  The viscosity increased slightly, from 800 mPa.s to 1350 mPa.s (measured at 20 C), the relative distribution of the microstructure

has remained constant.

  Examples 25 to 41 and Comparative Examples A to E By a method analogous to that of Example 23, experiments are carried out under modified reaction conditions and with other strongly polar aprotic additives. Abbreviations have the following meaning;

12 2459251

  KTBO = tertiary potassium butoxide DMSO = dimethylsulfoxide DMF = dimethylformamide NMP = N-methylpyrrolidone B = polybutadiene oil with the following characteristics: Mn 3,000, cis-1,4 double bonds: 80%, trans-1,4: 19%

1.2: 1%

Table 6

  Exem- KTBO Solvent Additive Oil Temp. Time Diolefins N Polybuty Nature Quantity Nature Quantity conjugated tadiene g / 100 g / 100 μg / - C 7 / -7 77

4 A NMP 10 - 50 3 10.5

  DMSO 0.5 Toluene 100 80 3 18.3 27 1 A DMSO 1.0 Toluene 100 80 3 19, 3 28 1 A DMSO 3.0 Toluene 100 80 5 19.5 29 i A DMSO 5.0 Toluene 100 80 5 21.5 1i A DMSO 10.0 Toluene 100 80 5 25.0 31 1 A DMSO 20.0 Toluene 100 80 0.5 8.5 32 1 A DMSO 5.0 Toluene 100 50 5 12.5 33 1 A DMSO 5.0 Toluene 100 20 1 8.6 6 2 A DMSO 20.0 Toluene 100 80 0.5 14.3 5 A DMSO 20.0 Toluene 100 80 1.0 17.2 36 1 B DMSO 5, 0 Toluene 100 80 3 17.2 37 1 B DMSO 5.0 pxylene 100 120 5 26.8 38 1 A DMF 0.5 Toluene 100 80 5 11.8 39 1 A DMF 3.0 Toluene 100 80 5 14.7 1 A DMF 5.0 Toluene 100 80 3 15.2 41 1 A DMF 10.0 Toluene 100 80 3 16.5

I._. _

1- N N rw ut b

14 2459251

Table 7

  Comparative Examples (Without Addition of Highly Polar Aprotic Compounds) The same degree of conjugation can be obtained without the addition of the strongly polar aprotic compound if the temperature is raised to about 50 ° C and / or if more

  high concentrations of catalyst.

  N KTBO Solvent Oil Temperatures Diolefins% polybuta Nature Amount T, C conjugates, diene g / 100g h% A 1 A Toluene 100 80 5 7.2 B i A i-octane 100 100 5 13.0 C 1 A p -xylen 100 138 5 19.6 D 1 B Toluene 100 80 1 7.8 E 2 B Toluene 100 80 5 17.0

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Claims (4)

  1. Isomerization process of isolated double bonds to conjugated double bonds in homopolymers and / or   copolymers of dienes- (1,3) using an isomene catalyst   and in the presence of a solvent, characterized in that the isomerization catalyst used is an alkali metal alcoholate and the isomerization is carried out at temperatures from + 50 to + 250 C.   2. Process according to Claim 1, characterized in that the alkali metal alcoholate used is sodium salt.   and / or potassium of an aliphatic mono-alcohol or cyclo-aliphatic   tick containing up to 20 carbon atoms.   3. Process according to claims 1 and 2, characterized   terized by the fact that a strongly polar aprotic compound is also used and the isomerisation is carried out between zero and 150 C.   4. Method according to one of claims 1 to 3,   characterized in that dimethylsulfoxide, dimethylformamide is used as the aprotic compound which is highly preferred. or N-methylpyrrolidone.