Monomer-isomerization polymerization. XIX. Monomer-isomerization copolymerizations of methylbutenes and 2-butene with Ziegler-Natta catalyst

The copolymerization of 3-methyl-1-butene (3M1B), 2-methyl-2-butene (2M2B), or 2-methyl-1-butene (2M1B) with trans-2-butene (2B) was attempted in the presence of a Ziegler-Natta catalyst. It was found the 3M1B underwent monomer-isomerization copolymerization with 2B to give a copolymer consisting of both 3M1B and 1-butene (1B) units, with an infrared (IR) spectrum in good agreement with that obtained from the copolymerization of 3M1B with 1B under similar conditions. When the apparent copolymerization parameters obtained by a TiCl₃–(C₂H₅)₃Al catalyst were compared, the apparent reactivity of 3M1B observed in the 3M1B-2B system was much higher than that in the 3M1B-1B system. However, 2M2B and 2M1B did not undergo monomer-isomerization copolymerization with 2B, and only the homopolymer of 1B was obtained under similar conditions.     

Monomer-isomerization polymerization. XVI. Monomer-isomerization polymerization of methylpentenes with Ziegler-Natta catalyst

The polymerizations of 4-methyl-1-pentene(4M1P), 4-methyl-2-pentene (4M2P), 2-methyl-2-pentene (2M2P), and 2-methyl-1-pentene (2M1P) with Ziegler-Natta catalyst have been investigated. Both 4M1P and 4M2P were found to polymerize with TiCl₃–(C₂H₅)Al catalyst to give high molecular weight poly(4M1P), while 2M2P and 2M1P did not give polymers with 4M1P units. However, when the polymerizations of 2M1P and 2M2P were carried out with ternary catalyst systems, TiCl₃–(C₂H₅)AlCl–(PPh₃)₂PdCl₂ and TiCl₃–(C₂H₅)AlCl–Ni(SCN)₂ polymers with 4M1P units were obtained in low yield. It was concluded that these four methylpentenes could polymerize with the monomer-isomerization polymerization mechanism to poly(4M1P). The results of the observed isomer distribution of methylpentenes recovered, and the rate of polymerization of four methylpentenes suggest that the isomerization from 2M1P to 4M1P with the above ternary catalyst systems might proceed via a direct one-step isomerization mechanism.     

Monomer-isomerization polymerization. XVII. Monomer-isomerizations copolymerizations of 2-butene with 3-heptenes and 4-methyl-2-pentenes with Ziegler-Natta catalyst

2-Butene(2B) copolymerizes with 3-heptene(3H) and 4-methyl-2-pentene(4M2P) by a monomer-isomerization copolymerization mechanism in the presence of TiCl₃–(C₂H₅)₃Al catalyst at 80°C to yield the copolymers of 1-olefin units. By comparison, the copolymerization of 1-butene(1B) with 4-methyl-1-pentene(4M1P) was also carried out under similar conditions. The composition of the copolymers obtained from these copolymerizations was determined from the ratios of optical densities D₇₂₃/D₁₃₈₀ and D₁₁₇₀/D₁₃₈₀ in their infrared (IR) spectra. The apparent monomer reactivity ratios for the monomer-isomerization copolymerization of 2B with 3H and 4M2P, in which the concentration of olefin monomer in the feed was used as 2-olefin, were determined as follows: cis-2B(M₁)/3H(M₂); r₁ = 4.00, r₂ = 0.20: trans-2B(M₁)/3H; r₁ = 3.50, r₂ = 0.20; 4M2P(M₁)-trans-2B(M₂): r₁ = 0.05, r₂ = 9.0. These results indicate that the isomerization of 2-olefins to 1-olefins was important to monomer-isomerization copolymerization.     

Monomer-isomerization polymerization. XVIII. Monomer-isomerization copolymerizations of 4-phenyl-2-butene with 4-methyl-2-pentene and 3-heptene with Ziegler-Natta catalyst

4-Phenyl-2-butene (4Ph2B) undergoes monomer-isomerization copolymerization with 4-methyl-2-pentene (4M2P) and 2-and 3-heptene (2H and 3H) with TiCl₃–(C₂H₅)₃Al catalyst at 80°C to produce copolymer consisting exclusively of 1-olefin units. For comparison the copolymerization of 4-phenyl-1-butene (4Ph1B) with 4-methyl-1-pentene (4M1P) and 1-heptene (1H) was carried out under similar conditions. The composition of the copolymers obtained from these copolymerizations was determined from the ratios of optical densities D₁₃₈₀ and D₁₆₀₀ of infrared (IR) spectra of their thin films. The apparent monomer reactivity ratios for the monomer-isomerization copolymerization of 4Ph2B with 4M2P, 2H, and 3H in which the concentration of olefin monomer in the feed was used as internal olefin and those for the copolymerization of 4Ph1B with 4M1P and 1H were determined as follows: 4Ph2B(M₁)-4M2P(M₂); r₁ = 0.90, r₂ = 0.20, 4Ph1B(M₁)-4M1P (M₂); r₁ = 0.40, r₂ = 0.70, 4Ph2B(M₁)-2H(M₂); r₁, = 0.45, r₂ = 1.85, 4Ph2B(M₁)-3H(M₂); r₁ = 0.50, r₂ = 1.20, 4Ph1B(M₁)-1H(M₂); r₁ = 0.55, r₂ = 0.75. The difference in monomer reactivity ratios seemed to originate from the rate of isomerization from 2- or 3-olefins to 1-oletins in these monomer-isomerization copolymerizations.     

Monomer-isomerization polymerization. XXXVIII. Monomer-isomerization copolymerizations of styrene and 2-Butene with Ziegler–Natta catalyst

Monomer-isomerization copolymerizations of styrene (St) and cis-2-butene (c2B) with TiCl₃-(C₂H₅)₃Al catalyst were studied. St and c2B were found to undergo a new type of monomer-isomerization copolymerization, i.e., only isomerization of 2B to 1-butene ( 1B ) took place to give a copolymer consisting of St and 1B units. The apparent copolymerization parameters were determined to be r_st = 16.0 and r_c2b = 0.003. The parameters were changed by the addition of NiCl₂ (r_St = 8.4, r_c2b = 0.05). The copolymers containing the major amount of St units were produced easily through monomer-isomerization copolymerization of St and 2B. © 1995 John Wiley & Sons, Inc.     

Monomer-isomerization polymerization. XXIII.. Monomer-isomerization polymerization of 5-phenyl-2-pentene with ziegler–natta catalysts

5-Phenyl-2-pentene (5Ph2P) was found to undergo monomer-isomerization polymerization with TiCl₃–R₃Al (R = C₂H₅ or i-C₄H₉, Al/Ti > 2) catalysts to give a polymer consisting of exclusively 5-phenyl-1-pentene (5Ph1P) unit. The geometric and positional isomerizations of 5Ph2P to its terminal and other internal isomers were observed to occur during polymerization. The catalyst activity of alkylaluminum examined to TiCl₃ was in the following order: (C₂H₅)₃Al > (i-C₄H₉)₃Al > (C₂H₅)₂AlCl. The rate of monomer-isomerization polymerization of 5Ph2P with TiCl₃–(C₂H₅)₃Al catalyst was influenced by both the Al/Ti molar ratio and the addition of nickel acetylacetonate [Ni(acac)₂], and the maximum rate was observed at Al/Ti = 2.0 and Ni/Ti = 0.4 in molar ratios.     

Monomer-isomerization polymerization. XX. Monomer-isomerization polymerization of 2-, 3-, and 4-octenes with Ziegler–Natta catalyst

A study of the monomer isomerization polymerization of 2-, 3-, and 4-octenes has been made with TiCl₃–(C₂H₅)₃Al catalyst at 80°C in comparison with the ordinary polymerization of 1-octene. It was found that all these octenes underwent monomer-isomerization polymerization to give high-molecular-weight homopolymer consisting exclusively of the 1-octene unit. The addition of an isomerization catalyst such as nickel acetylacetonate accelerated this polymerization. The rates of polymerization were found to decrease in the following order: 1-octene > 2-octene > 3-octene > 4-octene. These results indicate that the isomerization proceeded by a stepwise double-bond migration. It was also found that the monomer-isomerization copolymerization of 2-octene and 2-butene occurred under similar conditions and produced copolymers of both 1-olefin units.     

Monomer-isomerization polymerization. XI. Monomer-isomerization copolymerizations of 2-butene with 2-pentene and 2-hexene with Ziegler-Natta catalyst

2-Pentene and 2-hexene were found to undergo monomer-isomerization copolymerizations with 2-butene by Al(C₂H₅)₃–VCl₃ and Al(C₂H₅)₃–TiCl₃ catalysts in the presence of nickel dimethylglyoxime or transition metal acetylacetonates to yield copolymers consisting of the respective 1-olefin units. For comparison, the copolymerizations of 1-pentene with 1-butene and 1-hexene with 1-butene by Al(C₂H₅)₃–VCl₃ catalyst were also attempted. The compositions of the copolymers obtained from these copolymerizations were determined by using the calibration curves between the compositions of the respective homopolymer mixtures and the values of D₇₆₆/D₁₃₈₀ in the infrared spectra. The monomer reactivity ratios for the monomer-isomerization copolymerizations of 2-butene (M₁) with 2-pentene and 2-hexene, in which the concentrations of both 1-olefins calculated from the observed isomer distribution were used as those in the monomer feed mixture, and for the ordinary copolymerizations of 1-butene (M₁) with 1-pentene and 1-hexene by Al(C₂H₅)₃-VCl₃ catalyst were determined as follows: 2-butene (M₁)/2-pentene (M₂): r₁ = 0.14, r₂ = 0.99; 1-butene (M₁)/1-pentene (M₂): r₁ = 0.30, r₂ = 0.74; 2-butene (M₁)/2-hexene (M₂): r₁ = 0.11, r₂ = 0.62; 1-butene (M₁)/1-hexene (M₂): r₁ = 0.13, r₂ = 0.90.     

Monomer-isomerization polymerization. XXVI. Formation of polyallylcyclohexane from propenylcyclohexane through monomer-isomerization polymerization with Ziegler–Natta catalysts

Monomer-isomerization polymerization of propenycyclohexane (PCH) with TiCl₃ and R_3-xAICI_x (R = C₂H₅ or i-C₄H₉, x = 1–3) catalysts was studied. It was found that PCH underwent monomer-isomerization polymerization to give a high molecular weight polymer consisting of an allylcyclohexane (ACH) repeat unit. Among the alkyaluminum cocatalysts examined, (C₂H₅)₃Al was the most effective cocatalyst for the monomer-isomerization polymerization of PCH, and a maximum for the polymerization was observed at a molar ratio of Al/Ti of about 2.0. The addition of isomerization catalysts such as nickel acetylacetonate [Ni(acac)₂] to the TiCl₃–(C₂H₅)₃Al catalyst accelerated the monomer-isomerization polymerization of PCH and gave a maximum for the polymerization at a Ni/Ti molar ratio of 0.5. PCH also undergoes monomer-isomerization copolymerization with 2-butene (2B).     

Monomer-isomerization polymerization. XIII. Monomer-isomerization polymerization of 1,4-cyclohexadiene with Ziegler-Natta catalyst

1,4-Cyclohexadiene underwent monomer-isomerization polymerization to yield poly(1,3-cyclohexadiene) with a Ziegler-Natta catalyst comprising TiCl₄–Al(C₂H₅)₃ catalyst with Al/Ti molar ratios of 0.5–3.0 at 60°C for 96 hr. Good yields of polymer were obtained (49.5% yield at Al/Ti = 3.0; [η] = 0.04 dl/g). The infrared and NMR spectra of the polymer were identical to those of poly-(1,3-cyclohexadiene), confirming that 1,4-cyclohexadiene first isomerizes to 1,3-cyclohexadiene and then homopolymerizes to give poly-1,3-cyclohexadiene. 1,3-Cyclohexadiene polymerized without isomerization easily in the presence of TiCl₃–Al(C₂H₅)₃ catalyst at Al/Ti molar ratios of 0.5–3.0 at 60°C for 3 hr (76.3% yield at Al/Ti = 3.0; [η] = 0.06 dl/g).     

Monomer-isomerization polymerization. V. Effects of transition metal compounds on monomer-isomerization polymerizations of butene-2 and pentene-2

In order to clarify the correlation between polymerization and monomer isomerization in the monomer-isomerization polymerization of β-olefins, the effects of some transition metal compounds which have been known to catalyze olefin isomerizations on the polymerizations of butene-2 and pentene-2 with Al(C₂H₅)₃–TiCl₃ or Al(C₂H₅)₃–VCl₃ catalyst have been investigated. It was found that some transition metal compounds such as acetylacetonates of Fe(III), Co(II), and Cr(III) or nickel dimethylglyoxime remarkably accelerate these polymerizations with Al(C₂H₅)₃–TiCl₃ catalyst at 80°C. All the polymers from butene-2 were high molecular weight polybutene-1. With Al(C₂H₅)₃–VCl₃ catalyst, which polymerizes α-olefins but does not catalyze polymerization of β-olefins, no monomer-isomerization polymerizations of butene-2 and pentene-2 were observed. When Fe(III) acetylacetonate was added to this catalyst system, however, polymerization occurred. These results strongly indicate that two independent active centers for the olefin isomerization and the polymerizations of α-olefins were necessary for the monomer-isomerization polymerizations of β-olefins.     

Monomer-isomerization polymerization. VI. Isomerizations of butene-2 with TiCl3 or Al(C2H5)3–TiCl3 catalyst

A study of the isomerization of butene-2 with TiCl₃ or Al(C₂H₅)₃–TiCl₃ catalyst in n-heptane has been investigated at 60–80°C to elucidate further the mechanism of monomer-isomerization polymerization. It was found that positional and geometrical isomerizations in the presence of these catalysts occurred concurrently with activation energies of 14–16 kcal/mole. The presence of Al(C₂H₅)₃ with TiCl₃ catalyst could accelerate the initial rates of these isomerizations and initiate the monomer-isomerization polymerization of butene-2. From the results obtained, it was concluded that the isomerization of butene-2 proceeds via an intermediate σ-complex between the transition metal hydride and butene isomers.     

Monomer-isomerization polymerization. XXII.. Isomerization and polymerization of propenylbenzene with various ziegler–natta catalysts

The isomerization and polymerization of propenylbenzene (PB) with various Ziegler–Natta catalyst systems have been investigated. With the TiCl₃–(C₂H₅)₃Al (Al/Ti > 2.0) catalyst at 80°C, PB polymerized to give a polymer exclusively consisting of allylbenzene (AB) unit. During the polymerization, AB, which polymerized readily with the catalyst, was produced through isomerization of PB, indicating that PB underwent monomer-isomerization polymerization. PB also polymerized with isomerization to AB in the presence of TiCl₃?(C₂H₅)₂AlCl?NiCl₂ catalyst system, and a copolymer with PB and AB units was obtained. With TiCl₃?C₂H₅AlCl₂ catalyst, poly(PB) was formed via ordinary vinylene polymerization without isomerization. From these facts, it was concluded that the structure of the polymers produced from PB widely changed, depending on the catalyst systems used, which determine the rate of isomerization to AB and the polymerization reactivity of the PB and AB isomers formed.     

Monomer-isomerization oligomerization of 2-ethyl-1,3-butadiene by acid catalysts

The cationic oligomerization of 2-ethyl-1,3-butadiene (2EBD) by a superacid (CF₃SO₃H) and a superacid derivative (CH₃COClO₄) accompanied monomer isomerization to 3-methyl-1,3-pentadiene (3MPD) before propagation to yield oligomers of the isomerized monomer as main products in benzene at 50°C. Detection of 3MPD in the reaction mixture and ¹H-NMR structural analysis of the produced oligomers confirmed the occurrence of this “monomer-isomerization oligomerization.” On the other hand, in the presence of a metal halide catalyst (BF₃OEt₂) 2EBD reacted without isomerization and yielded oligomers that were different from those produced by the foregoing superacid catalysts. Monomer isomerization was suppressed in a polar solvent [(CH₂Cl)₂] or at lower temperatures. The mechanism of the oligomerization with monomer isomerization was discussed.     

Copolymerization of propylene with 1-butene and 1-pentene with the isospecific catalytic system rac-Me2Si(4-Ph-2-MeInd)2ZrCl2-MAO

The copolymerization of propylene with 1-butene and 1-pentene at 60°C in the propylene bulk in the presence of the homogeneous isospecific metallocene catalyst of the C₂ symmetry rac-Me₂Si(4-Ph-2-MeInd)₂ZrCl₂ activated by polymethylaluminoxane is studied. Copolymers containing up to 30 mol % 1-butene and up to 10 mol % 1-pentene are synthesized. For the copolymerization of the above monomers, reactivity ratios are estimated to be equal to unity, thereby indicating the azeotropic character of the process. It is found that the distribution of comonomer units in the copolymers is close to statistical. For both comonomers, the comonomer effect is observed: an increase in the rate of propylene polymerization after addition of a small amount of a less reactive comonomer. The addition of 1-butene and 1-pentene to polypropylene shows a weak effect on the stereoregularity of chains but causes a marked reduction in the molecular mass of the polymer and changes its thermophysical characteristics and mechanical properties. An X-ray diffraction study of the copolymers is performed.     

THE MECHANISM OF THE COPOLYMERIZATION OF BF_3-COMPLEXED ETHYL ACRYLATE WITH PROPYLENE

The copolymerization of BF_2-omplexed ethyl acrylate with propylene in the presence ofAIBN at 25℃was investigated. It was found that the rate of the copolymerization was propor-tional to the square root of the initiator concentration. The chain transfer agent CCl_4 greatly af-fects the inherent viscosity of the resulting copolymer. The smaller the dielectric constant of thesolvent, the greater the rate of copolymerization is. The equal concentration of the two monomersgive the maximum copolymerization rate. The ~1H-NMR and ~(13)C-NMR analysis indicated, when[EA.BF_2]/[EA.BF_2]+[P]>0.5, the resulting copolymer was the acrylate-rich random copoly-mer. Through the kinetic experiments we suggest that copolymerization follows the mechanismof the random copolymerization of the ternary complex with binary complex. When [EA.BF_3]/[EA.BF_2]+[P]<0.5, the resulting copolymer is always strictly alternating, and the alternatingcopolymerization follows the mechanism of the ternary complex homopolymerization. Usingthe homolog of the propylene, 1-pentene, we found that BF_3-complexed ethyl acrylate can forma ternary complex with 1-pentene identified by UV spectroscopy. This is a strong evidence forthe mechanism of ternary complex homopolymerizetion.     

The features of syndiotactic polypropylene

The mechanism of stereoselectivity of propylene insertion in propylene-ethylene copolymerization on a C_S symmetrical zirconium complex i-Pr(Cp) (Flu) ZrCl₂ catalyst is discussed. Calculation results indicate that not only the β-carbon in the growing chain end of the polymer but also the substituent of the β-carbon play an important role in the selectivity of the prochiral face of the next-coming propylene monomer. The stereoregularity of propylene units connected to an ethylene unit (PPE) in propylene-ethylene copolymer was observed to be lower than that in propylene sequences (PPP) in the ¹³C NMR spectrum, which supports the calculation results. Furthermore, the structure and properties of propylene-olefin (ethylene, 1-butene, 1-pentene, 1-hexene, and 4-methyl-1-pentene) copolymers prepared with the i-Pr(Cp) (Flu) ZrCl₂ catalyst system were studied. Propylene-1-butene copolymer exhibits peculiarly lower melting point depression because 1-butene units enter into the unit cell of the crystal structure of syndiotactic polypropylene.     

Effect of para-Substituents in Ethylene Copolymerizations with 1-Decene, 1-Dodecene,and with 2-Methyl-1-Pentene Using Phenoxide Modified Half-Titanocenes-MAO Catalyst Systems

Effect of para-substituents in the ethylene (E) copolymerization with 1-decene (DC), 1-dodecene (DD), and with 2-methyl-1-pentene (2M1P) using a series of Cp*TiCl₂(O-2,6-ⁱPr₂-4-R-C₆H₂) [R=H ( 1 ), ^tBu ( 2 ), Ph ( 3 ), CHPh₂ ( 4 ), CPh₃ ( 5 ), SiMe₃ ( 6 ), SiEt₃ ( 7 ), and newly prepared 4-^tBuC₆H₄ ( 8 ) and 3,5-Me₂C₆H₃ ( 9 )]-MAO catalyst systems has been studied. The activities in these copolymerization reactions were affected by the para-substituent, and the SiMe₃ ( 6 ), SiEt₃ ( 7 ) and 3,5-Me₂C₆H₃ ( 9 ) analogues showed the higher activities at 50 °C in the E copolymerization reactions with DC (1.06–1.44×10⁶ kg-polymer/mol-Ti⋅h), DD (1.04–1.88×10⁶ kg-polymer/mol-Ti⋅h) than the others, whereas no significant differences were observed in the comonomer incorporations. Complexes 6 and 7 also showed the higher activities at 50 °C in the E/2M1P copolymerization, and the 2M1P incorporation was affected by the para-substituent and the polymerization temperature; complex 9 showed better 2M1P incorporation at 25 °C.     

Monomer-lsomerization Polymerization of Some Branched Internal Olefins with a Ziegler-Natta Catalyst

New examples for the monomer-isomerization polymerizations of some branched internal olefins, 4-methyl-2-pentene and 4-phenyl-2-butene, are presented. When these olefins are polymerized with A1(C₂ H₅)₃-TiCl₃ ([TiCl₃] = 120 mmole/liter, A1/Ti = 3.0) catalyst at 80°C, considerable amounts of high polymers [27.5%/60 hr ([η] = 0.68 d1/g) and 35.6%/100hr, respectively] were obtained. From the additional fact that the isomerization from these 2-olefins to the mixture of their positional isomers including 1-olefins was observed during the polymerization, it is assumed that the polymerizations from these 2-olefins are performed with the 1-olefins which isomerized from the starting 2-olefins.     

Targeted synthesis of homo-and copolymers of propylene in liquid propylene initiated by highly efficient homogenous metallocene catalysts

Studies devoted to the homo-and copolymerization of propylene with ethylene and higher olefins (1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene) in liquid propylene under the action of homogeneous metallocene catalysts of various types are surveyed in brief. The main kinetic features of the processes and the properties of the polymers are discussed. The optimal conditions for the highly efficient syntheses of isotactic, syndiotactic, hemiisotactic, and stereoblock PPs are described. It is shown that the combined cocatalyst—polymethylaluminoxane coupled with (i-Bu)₃Al—shows promise for the processes under consideration. Depending on the type of catalyst used, the copolymerization of propylene with ethylene yields copolymers with a block, random, or close to alternating distribution of comonomer units in a polymer chain. The copolymerization of propylene with higher olefins in the monomer bulk initiated by highly active sterically hindered isospecific catalytic systems shows an ideal character, and the reactivity ratios are r ₁ ≈ r ₂ ≈ 1; that is, the composition of the copolymer is equal to the composition of the monomer mixture at all comonomer ratios. It is demonstrated that the synthesis of homo-and copolymers of propylene in the monomer bulk in the presence of modern homogeneous catalysts is promising for highly efficient production of both traditional and new polymer materials with a unique combination of mechanical and thermal properties.