Surface-initiated ring-opening metathesis polymerization in the vapor phase: an efficient method for grafting cyclic olefins with low strain energies

Surface grafting of cyclic olefins with low strain energies, including cyclopentene (CP), 1,4-cyclohexadiene (CHD), cycloheptene (CHP), cis-cyclooctene (CO), cis,cis-1,5-cyclooctadiene (COD), 1,3,5,7-cyclooctatetraene (COT), cyclododecene (CD), and trans,trans,cis-1,5,9-cyclododecatriene (CDT), was explored using ring-opening metathesis polymerization in the vapor phase. These monomers do not polymerize when SiROMP is carried out in solution because of pronounced chain transfer on surfaces where chains are in close proximity to one another. In the vapor phase, however, chain transfer is suppressed at the solid-vapor interfaces, which permits the polymerization of most of these monomers. A minimal required strain energy of 2.2 kcal/mol was determined in this study, which is significantly lower than the estimated 13.3 kcal/mol for SiROMP carried out in solution, indicating that the enhancement in monomer polymerizability is significant using the vapor-phase approach. A series of polyalkenamers with a controlled fraction of unsaturation from 8 to 50% along the polymer backbone were grafted to solid substrates. It was observed that the logarithm of the largest grafted layer thickness obtained before the removal of chain-transfer products, which correlates with the extent of polymerization, scales with the monomer strain energy. This confirms that the release of ring strain is the thermodynamic driving force for SiROMP. It was also found that although chain transfer is suppressed in the vapor phase it is important in monomer/polymer systems where the fraction of unsaturated bonds is high. In these cases, the grafted polymer thickness is dominated by chain transfer rather than the monomer strain energy. A quantitative relationship is established for estimating the graft thickness of a particular monomer using its strain energy and fraction of unsaturated bonds in the monomer.     

Cyclic homo- and cooligomerization of 2-cyclopropylbutadiene with 1,3-dienes

Conclusions We were the first to study the cyclic homo- and cooligomerization of 2-cyclopropyl-1,3-butadiene with butadiene and isoprene in the presence of catalysts based on nickel. The conditions were found for obtaining 1,5-dicyclopropyl-1,5-cyclooctadiene, 1-cyclopropyl-1,5-cyclooctadiene, 1-cyclopropyl-5-methyl-1,5-cyclooctadiene, and 1-cyclopropyl-5,9 (8)-dimethyl-1,5,9-cyclododecatriene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2634–2636, November, 1979.     

Cyclooligomerization of 1-vinyl-1-cyclopentene catalyzed by nickel complexes

Conclusions The cyclooligomerization of 1-vinylcyclopentene catalyzed by nickel complexes forms a tricyclic dimer and tetracyclic trimer - 1,5-cyclooctene and 1,5,9-cyclododecatriene derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 115–117, January, 1979.     

Synthesis of cyclic polybutadiene via ring-opening metathesis polymerization: the importance of removing trace linear contaminants

The synthesis of cyclic polybutadienes using ring-opening metathesis polymerization (ROMP) was accomplished. A cyclic Ru alkylidene catalyst, where a terminal ligand was covalently linked to the Ru alkylidene, was used to polymerize either 1,5-cyclooctadiene (COD) or 1,5,9-trans-cis-trans-cyclododecatriene (CDT). Trace amounts of an acyclic impurity, 4-vinylcyclohexene, found in the COD led to samples which were contaminated with linear polymer. In contrast, CDT, which was free of the impurity, afforded pure cyclic polymer. These results provide a convenient method for discerning samples of pure cyclic polymer from those which contain trace to large amounts of linear polymer. Furthermore, they emphasize the need to use monomers that are free of acyclic impurities when preparing cyclic polymers using ROMP.     

Photoactivated Cationic Frontal Polymerization

Photoactivated cationic ring-opening polymerizations of certain oxirane and oxetane monomers take place in a frontal manner. The study of the frontal behavior of those monomers was conducted using a new analytical technique involving optical pyrometry that provides insight into the mechanism of these polymerizations.     

Hydrogenation of 1,5,9-Cyclododecatriene in a Three-Phase System in the Presence of Nickel Nanoparticles Supported on NаX Zeolite

Russian Journal of Applied Chemistry - Hydrogenation of 1,5,9-cyclododecatriene in the presence of nanostructured nickel catalysts in a flow-through reactor at atmospheric hydrogen pressure was...     

1,5,9-环十二碳三烯的阳离子型跨环齐聚合反应

本文研究1,5,9-环十二碳三烯在阳离子型引发剂AlCl3和BF3.OEt2催化下进行的跨环聚合反应, 考察各种反应条件对跨环聚合反应的影响, 产物为白色粉末, 分子量均在1096-1431之间对其溶解性, 核磁共振和红外光谱的分析, 确认了它的结构。     

Polymerization reactivity of unsaturated end group generated during the disproportionation in termination reaction of methyl methacrylate polymerization: A study using model compounds

Polymerizations of some vinyl monomers were carried out with 2,2′-azobisisobutyronitrile at 60°C in the presence of a methyl methacrylate (MMA) dimer ( I ) or a MMA polymer ( II ) with a double bond at their ends to confirm the polymerization reactivity of unsaturated end group generated during the disproportionation in termination reaction of MMA polymerization. It was found that the polymerizations of α-monosubstituted monomers have been much retarded than those of α,α-disubstituted monomers by the addition of I . Kinetic study on MMA and methyl acrylate polymerizations showed that the rate constant for the reaction of a propagating radical with I was 5.4 and 29.2 L/mol s in their polymerizations, respectively. ESR study using I and II suggested that an addition reaction was a predominant mechanism for the reaction of an unsaturated end group with a radical rather than a hydrogen abstraction.     

含氮聚合物负载钯络合物的合成及其催化加氢性能的研究

合成了一系列含氮聚合物金属络合物,考察了它们对1,5,9-环十二碳三烯选择性催化加氢的活性及选择性。研究了同种聚合物中单原子配体与双原子配体对催化剂活性的影响。对不同金属物种、孔结构、温度及压力对加氢活性及选择性的影响也进行了系统的比较。     

Simultaneous hydrosilation and ring-opening polymerization as a route to novel polymer architectures

Typical platinum, rhodium and cobalt hydrosilation catalysts have been found to catalyze the ring-opening polymerization of many different types of heterocyclic monomers. In particular, epoxide monomers undergo especially rapid polymerization with these catalysts. Investigations have shown that in the case of platinum and rhodium catalysts these polymerizations proceed at the surface of the metal colloids by means of a novel cationic mechanism. In contrast, polymerizations with octacarbonyldicobalt take place by a homogeneous cationic mechanism. In all cases, polymerization appears to proceed by the formal attack of a positively charged silicon species on the heteroatom with the formation of a silicon-oxygen bond. Interesting comb, graft, block and network polymers can be prepared by carrying out simultaneous epoxide ring-opening and hydrosilation reactions using these catalysts.     

Salen complexes of zirconium and hafnium: synthesis, structural characterization, controlled hydrolysis, and solvent-free ring-opening polymerization of cyclic esters and lactides

Dinuclear salen compounds of zirconium and hafnium are efficient initiators for the solvent-free ring-opening polymerization of cyclic ester monomers and lactides. There is a correlation between the theoretical and experimental number-average molecular weights (M(n)'s) in these polymerizations. Polymerization of β-butyrolactone gives poly(3-hydroxybutyrate) with a good M(n) and molecular weight distribution.     

Polymerizability of unsaturated monomers capable of forming stable radicals

Some unsaturated monomers bearing hindered phenol and arylamine groups capable of forming stable radicals were prepared. Radical polymerizations of vinyl monomers having such groups were investigated with the use of azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, and tetraethylthiuram disulfide as initiator. Polymerizations of these monomers went normally only when azobisisobutyronitrile was used as initiator. The other initiators inhibited polymerizations remarkably or completely. The results suggest that radicals resulting from benzoyl peroxide and cumene hydroperoxide or tetraethylthiuram disulfide abstract hydrogen of the phenol or the amine to produce the stable radicals, thereby inhibiting the polymerization. Meanwhile, carbon radicals resulting from azobisisobutyronitrile add selectively to the vinyl double bonds of the monomers to initiate the polymerizations. The vinyl derivatives as well as allyl derivatives and cinnamic acid derivatives copolymerize easily with conventional monomers such as styrene, maleic anhydride, and butadiene, again, only when azobisisobutyronitrile was used as initiator. Antioxidative properties for styrene copolymers and butadiene-styrene copolymers incorporating the hindered phenol monomers were investigated.     

Kinetics of homogeneous acetoxylation of cyclododecene and 1,5,9-cyclododecatriene catalyzed by Pd(OAc)2

The kinetics of acetoxylation of cyclododecene and (E,E,E)-1,5,9-cyclododecatriene catalyzed by Pd(OAc)₂ has been studied in glacial acetic acid solutions at 323–343 K and atmospheric pressure. The experimental data were described by kinetic equations of the Michaelis-Menten type.     

Capillary gas chromatography of hydrogenation products of 1,5,9-cyclododecatriene stereoisomers

Summary The separation of the products obtained by the hydrogenation of 1,5,9-cyclododecatriene stereoisomers on fused-silica capillary columns coated with dimethylsilicone and cyanopropylmethylsilicone stationary phases was investigated. Retention indices of cyclododecatrienes, cyclododecadienes, cyclododecenes and cyclododecane were determined at three temperatures. The respective standard deviations were 0.3 and 0.6 i.u. The influence of the polarity of the stationary phases on the chromatographic retention of these cyclic hydrocarbones is discussed.     

Rhodium‐Catalyzed Stitching Polymerization of 1,5‐Hexadiynes and Related Oligoalkynes

A new mode of polymerization, rhodium‐catalyzed stitching polymerization, has been developed for the synthesis of π‐conjugated polymers with bridged repeating units from nonconjugated 1,5‐hexadiynes containing both terminal and internal alkyne moieties as monomers. The polymerization proceeded smoothly with a high degree of stitching efficiency under mild conditions, and 1,5,9‐decatriyne and 1,5,9,13‐tetradecatetrayne monomers could also be employed. The present polymerization strategy would be particularly beneficial for the synthesis of polymers consisting of a repeating unit that is difficult to prepare as a stable monomer because it does not require the use of a preformed bridged π‐conjugated monomer.     

Ketene acetal monomers: Cationic photopolymerization

A study of the photoinduced cationic polymerization of a novel series of cyclic and acyclic ketene acetal monomers was carried out. It was observed that the cyclic monomers underwent facile cationic polymerization to give high molecular weight polymers while the acyclic ketene acetals did not. Thermally induced polymerization was also observed on standing catalyzed by glass surfaces. Photoinduced cationic polymerizations employing both diaryliodonium and triarylsulfonium salt photoinitiators were studied. It was observed that the position and type of substitutents in the cyclic ketene acetals was the major factor in determining the proportion of vinyl and ring-opening polymerizations that take place. © 1996 John Wiley & Sons, Inc.     

Reactivity of alicyclic 1,5,9-triketones toward five-, six-, and seven-membered rings in acidic medium. Stereochemistry of intramolecular cyclization products

Chemistry of Heterocyclic Compounds - Among nine alicyclic 1,5,9-triketones with differently fused 5-, 6-, and 7-membered rings in the molecule, existing as mixtures of 3–6 diastereomers,...     

Methoxymercuration of two isomeric 1,5,9-cyclododecatrienes

Conclusions Trans,trans,trans- and cis,trans,trans-1,5,9-cyclododecatriene add mercury acetate in methanol at one double bond without participation of the others.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1913–1914, August, 1968.     

Free-Radical Ring-Opening Polymerization

Although the ionic ring-opening polymerization of heterocyclic compounds, such as ethylene oxide, tetrahydrofuran, ethylen-imine, β-propiolactone, and caprolactam, as well as the Ziegler-Natta ring-opening of cyclic olefins, such as cyclopentene and norbornene, are well known, free radical ring-opening polymerizations are rather rare. The few examples that are reported in the literature involve cyclopropane derivatives or highly strained bi-cyclic olefins. For example, Takahashi [l] studied the free radical polymerization of vinylcyclopropane and reported that the cyclopropane ring opened to give a polymer containing about 80% 1,5-units and about 20% of undetermined structural units.     

An extensive study of bromination of cis,trans,trans-1,5,9-cyclododecatriene: product structures and conformations

Bromine has been added to cis,trans,trans-1,5,9-cyclododecatriene under various reaction conditions. All expected direct addition products have been isolated, and their structures have been determined by microanalysis, NMR and X-ray crystallography. Advanced NMR techniques were used to determine solution conformations of several of the compounds, enabling comparison with the solid-state conformations obtained by crystallography.