CH629507A5 - Process for the polymerisation of mono- and di-olefinic compounds - Google Patents

Description

The present invention relates to a process for the polymerization of mono- and diolefinic compounds consisting of bringing the compound or compounds in question into contact with a catalytic, ternary system characterized in that it consists of the combination of:

a) an alkyl aluminum or hydride derivative of formula Al Rs_x Hx in which R is a hydrocarbon radical, and x is a variable number from 0 to 3;

b) a compound of a transition metal;

c) a polyiminoalane.

The polymerization of unsaturated compounds by means of binary catalysts made up of transition metal compounds in combination with aluminum alkyls or hydrides is known: particularly the same applicant is the owner of numerous patents or patent applications relating to the polymerization of the above compounds by means of systems based on transition metal derivatives in combination with polyaminoalanes (PIA).

Among others, systems consisting of TiCl4 and compounds resulting from the repetition of units of the type (H Al NR), in which R is a hydrocarbon radical, compounds characterized by a cage molecular structure, whose steric configuration depends on the number of imminent units.

Now we have surprisingly found that the addition of aluminum alkyl- or hydride-derivatives (A) to the binary system consisting of the compound of the transition metal (B) and polyaminoalane (C) allows to realize ternary catalysts of polymerization of mono- and diolefins much more active than the catalysts constituted by the pairs AB or BC: in particular A is an aluminum compound of formula Al R, .x Hx, in which R is a hydrocarbon radical ex a variable number between 0 and 3.

The same applicant, indeed, holds an Italian patent application, application no. 19094 A / 76 of 1.1.1976, relating to a procedure for modifying the PIA consisting in reacting PIA and alkyl aluminum to molar ratios between the imminent units (H Al NR) and the alkyl aluminum between 1 and 3.

The reaction, according to the said application, can be summarized as follows:

(H Al NR) n + y Al R'3 - * [(R 'Al NR) Z (H Al NR) n.z] + s Al R'3_x Hx (1)

(THE)

wherein n indicates the number of repeated imminic units, R and R 'are hydrocarbon radicals, equal to or different from each other; z is io equal to the product yx, z varies between 1 and n, and x has the values mentioned above. Compounds are obtained deriving from the substitution, partial or total, of hydrogen hydrides of PIA by alkyl groups with retention of the typical cage molecular structure, together with derivatives of Al hydrides of Al-15 position Al R3_x Hx.

As the quantity of alkyl aluminum increases, the reaction leads to the formation of derivatives (I) having a. increasing number of alkyl radicals bound to aluminum until PIA derivatives are obtained in which all the hydro-2nd hydride atoms have been replaced by alkyl radicals. The use of quantities of (H Al NR) n in excess of the alkyl aluminum in the above reaction favors the formation of simple hydruric derivatives of aluminum, Al R2H, Al RH2, Al H3, and, in particular, the species at higher hydrogen con-25 content.

The interaction of the latter, or of the aluminum alkyls themselves, with PIA molecules, is responsible for the formation of species which, in union with the transition metal compound, generate catalysts with a greater catalytic activity. This fact, which responds to the object of the present invention, has been ascertained by us in that:

1. The results obtained in polymerization tests of isoprene with the above ternary systems in comparison with the PIA-Ti Cl4 and Al R3-Ti Cl4 binary systems indicate that the 35 greatest activity of the ternary systems is attributable to particular compounds of PIA interaction with Al R3 or Al R3_x Hx. The results are shown in fig. 1, wherein the solid polymer yield, in ordinate, is reported as a function of the molar ratio Al / Ti in abscissa.

40 In this figure the curves refer respectively to:

A - Ti Cl4 + Al Age

B - (HAIN-iPr) and + TiCl4

C - (H Al N-iPr) 6 + Ti Cl4 + Al Et3

45

The same result was found in the polymerization of ethylene with the Ti Cl3 - PIA - Al R3 ternary systems compared with the Ti Cl3 - PIA and Ti Cl3 - Al R3 binary systems. The results are shown in table 2.

50 2. An activating effect due to the substitution of hydruric hydrogens of PIA with alkyl groups is also to be excluded, since PIA, even partially or totally alkylated, were much less active than the starting PIA or inactive in the polymerization of isoprene in union with Ti Cl4 . 55 3. An increase in activity in the polymerization of isoprene has been observed with respect to PIA, with products (II) obtained by subsequent chlorination of PIA and treatment with Li Al H4. In accordance with reactions 2 and 3, these treatments correspond to the formation of PIA complexes with 60 Al H3

(H Al NR) and + H CI -> [(CI Al NR) (H Al NR) 5] + H2 (2) [(CI Al NR) (H Al NR) S] + Li Al H4 (H Al NR )is. Al H3 + LiCl (3)

65 (II)

Fig. 2 refers to the increase in activity observed for product II compared to the starting PIA; it reports

3

629507

the solid polymer yield, in ordinates, as a function of the Al / Ti ratio on the abscissa.

In this figure the curves refer respectively to:

A - (HAI N-iPr) 6. Al H3 + Ti Cl4 B - (H Al N-iPr) 6 + Ti Cl4

The polymerization processes can be carried out at temperatures ranging from - 50 ° C to + 250 ° C, and preferably in the range of 10-200 ° C and at a variable pressure between the vapor pressure of the monomer, when in the liquid state and 200 atm , the interval 1 20 atm being preferred, optionally in the presence of a solvent selected from the aliphatic, aromatic or cycloaliphatic hydrocarbons.

The molar ratio range Al / Me (in which Al indicates the sum of the aluminum of the imminic units or the aluminum of the simple alkyl or hydruric derivatives and Me = transition metal), which as is known, influences the speed of polymerization and the solid polymer yield, can vary between 0.1 and 500, varying the preferable range by the nature of the monomer to be polymerized.

Examples 1-15

Fig. 1 wherein the solid polymer yield, in ordinate, is reported as a function of the Al / Ti ratio, in abscissa includes the results obtained with the ternary system (H Al N-iso C3H7) 6 - A1 (C2Hs) 3 - Ti CI4 (curve C, examples 1 to 4), corresponding in particular to the molar ratio 1

Al (C2H5) 3 / - (H Al N-iso C3H7) 6 = 0.02 in comparison with the 6

results obtained with binary systems (H Al N-iso C3H7) 6 - Ti Cl4 (curve B, examples 5 to 10) and AI (C2H5) 3 - Ti CI4 (curve A, examples 11 to 15).

The polymerization tests were performed with the following procedure (for all examples):

In a drink bottle, previously heated to 120 ° C and cooled under nitrogen flow, anhydrous n-heptane (90 ml), TiCl4 (0.64 mmoles and then Al (C2H5) are introduced, maintaining the atmosphere of nitrogen ) 3 or PIA, whether or not adding Al (C2H5) 3 in the amount described, corresponding to the desired Al / Ti ratio, a brown precipitate is formed.

The reaction mixture is aged, stirring, 10 minutes at room temperature, and added with 20 g. of isoprene. The bottle is sealed and kept stirring for 2 hours in a thermostatic bath at 30 ° C. At the end the polymerization is stopped by adding 20 cc. of methanol, containing an antioxidant.

The reaction mixture is poured into an excess of methanol and the solid polymer is dried at 50 ° C under vacuum and weighed. The structure of the dry polymer is determined by I.R. and the intrinsic viscosity in toluene at 30 ° C.

Table 1 shows the structure and intrinsic viscosity of polyisoprene obtained with the aforementioned ternary system.

Examples 16-35

Fig. 2 wherein the solid polymer yield, in ordinate, is reported as a function of the Al / Ti ratio on the abscissa includes the results obtained in the polymerization of isoprene with the system (H Al N-iso. C3H7) 6. Al H3 - Ti Cl4 (curve A, examples 16 to 25) in comparison with the system (H Al N-iso C3H7) 6 - Ti Cl4 (curve B, examples 26 to 35). These results confirm the greater activity of species resulting from the complexing of ('H Al N-iso C3H,) 6 with simple alano-derivatives.

The compound was obtained by the following process. you. Operating in a nitrogen atmosphere with a solution of (H

To the N-iso C3H7) 6 (9.5 mmoles) in diethyl ether (ml 60) a solution (ml 13.5) of H Cl (9.5 mmoles) in diethyl ether is slowly added; the reaction corresponds to the average substitution of a hydruric hydrogen atom into a chlorine atom according to the reaction (2) [see S. Cucinella et al. J. Or-ganometal. Chem. 108, 13 (1976). The product thus obtained (57 X 10-3 g aluminum atoms) in diethyl ether (ml 100) was added with a solution of Li Al H4 (9.5 mmoles) in diethyl ether ( mi 12).

According to the reaction (3), II is formed, which was separated by evaporation of the solution after filtration of the Li CI and dried under vacuum (IO-3 mm Hg; 8 h t amb). The chemical analysis indicates for the product obtained Al: N: Hact = 1: 0.87: 1.25.

The polymerization tests were carried out according to the methods of examples 1-15. Also in the case of the II - Ti CI4 system, the polymer obtained has a high content of 1.4 eis and high values of [vj].

For example, the polymer obtained by Al / Ti = 1.15 has the following characteristics: 1.4 cis% = 95.8; 1.4 trans% = 1.3; 1.2% = 0; 3.4% = 2.9; [TJ] So = 5.20.

Examples 36-52 Fig. 3, wherein the solid polymer yield, in ordinate, is reported as a function of the Al / Ti ratio, in abscissa includes the results obtained in the polymerization of isoprene with the ternary system (H Al N-iso C3H,) 6 - Al H (iso C4H9) 2 - Ti Cl4 (curve A, examples 36 to 44) in comparison with the binary system (H Al N-iso C3H,) 6 - Ti Cl4 (curve B, examples 45 to 52). The polymerization tests were carried out according to the methods of examples 1-27. The polysoprene obtained with the ternary system in question has a high 1,4 eis content and high values of [yj]. For example, the polymer obtained by Al / Ti = 1.20 has the following characteristics: 1.4 cis% = 95.6; 1.4 trans% = 0; 1.2% = 0.5; 3.4% = 3.8; Insat. Total 102; [tj] aiuolo = 4.6.

Examples 53-59 In a 5-liter autoclave, equipped with a stirrer, dried and de-aerated by heating under vacuum and filled up to ambient pressure with hydrogen, 1,600 ml of anhydrous n-heptane are charged by phoning. The temperature is brought to 90 ° C, then 300 ml of n-heptane are added, to which Ti Cl3 AA-PIA - Al Et3 in the quantities Ti Cl3 = 5 mmoles have been added in the order; (A1pia + A1ai Et) = 15 mmoles at ratio 3

AIaI Et 3

variable. Finished adding the catalyst

ALPINA

hydrogen is charged up to a manometric pressure of 1.5 kg / cm2 and then ethylene up to a total pressure of 2.5 kg / cm2, which remains constant with an ethylene flow regulated with the pressure switch. The absorption of ethylene was followed over time with a flow meter. After two hours of polymerization, the autoclave is cooled, the gases are vented, the suspension is discharged, centrifuged and the polymer is dried in a stove under vacuum at 60 ° C and then weighed.

The results obtained are collected in table 2 which shows the greatest activity of the species containing Al Et3, in particular with 6-8% molar both with respect to that without Al Et3, and with respect to the species resulting from the complexation of (H Al N-iso Pr) 6 with simple alano derivatives according to reactions 2 and 3 (examples 28 43).

5

10

15

20

25

30

35

40

45

50

55

60

65

629507

TABLE 1

Intrinsic structure and viscosity of polyisoprene obtained with ternary systems (H Al N-iso. C3H7) 6 - Al (C2H5) 3 - Ti Cl4

Molar ratio Al R's

Al * Ti

1.4 eis

%

1.4 trans%

1.2

%

3.4

%

Insat. total

[rjJ 30 ° C toluene

1

- (H Al NR) 6 6

-

1.20

96.2

0

0.3

3.4

104

5.0

0.02

1.20

96.6

0

0.4

3.0

104

4.8

0.02

1.25

96.6

0

0.4

3.0

104

4.4

* Al is inclusive of PIA aluminum and alkyl aluminum.

TABLE 2

20

Example n.

AlpiA% molar

Al Al Et3 i; "" "

Molar% ëVohmexo

53

(H Al NR) 6

100

- 190

25

54

»

96

4 315

55

»

94

6 416

56

»

ninety two

8 460

30

57

»

88

12 421

58

»

-

100 217

59

(H A1NR) 6A1H3 100

- 335

35

v

1 sheet of drawings

Claims (6)

629507 1. Process for the polymerization of mono- and diolefinic compounds consisting of putting the compound or compounds in question in contact with a ternary catalytic system characterized in that it consists of the combination of: a) an alkyl aluminum or hydride derivative of formula Al R3_x Hx in which R is a hydrocarbon radical, and x is a variable number from 0 to 3; b) a compound of a transition metal; c) a polyiminoalane. 2. Process according to claim 1 characterized in that the reaction is carried out at a temperature ranging from -50 to + 250 ° C. 2 3. Process according to claim 2, characterized in that the reaction is preferably carried out at a temperature varying between 10 and 50 ° C for the diolefins and 50 ° -150 ° C for the monoolefins. 4. Process according to claim 1 characterized in that the reaction is carried out at pressures varying between the vapor pressure of the monomer and 100 atmospheres. 5. Process according to claim 1, characterized in that the reaction is preferably carried out at pressures varying between 1 and 50 atmospheres. 6. Process according to claim 1 characterized in that the reaction is carried out in the presence of a solvent selected from among the halitatic, aromatic or cyclo-aliphatic hydrocarbons.