N-butyl Vinyl Ether Research Articles

Triblock and pentablock terpolymers by sequential base-assisted living cationic copolymerization of functionalized vinyl ethers

A series of novel, well-defined triblock and pentablock terpolymers of n-butyl vinyl ether (nBVE), 2-chloroethyl vinyl ether (CEVE) and tert-butyldimethylsilyl ethylene glycol vinyl ether (SiEGVE) were synthesized by sequential base-assisted living cationic polymerization.

Theoretical studies on the mechanisms and rate constants for the hydroxylation of n-butyl, iso-butyl and tert-butyl vinyl ethers in atmosphere

The reaction mechanisms for the atmospheric hydroxylation of n-butyl vinyl ether (n-BVE), iso-butyl vinyl ether (i-BVE), and tert-butyl vinyl ether (t-BVE) were investigated by using quantum chemical method in this paper. The geometry optimizations and frequency calculations were carried out at the MPWB1K/6-31+G(d,p) level, and the accurate energetic parameters were obtained by the MPWB1K/6-311++g(3df,2p) method. The reaction mechanisms for the title reactions have been presented. Ten possible reaction channels were discussed for the primary hydroxylation of n-BVE and t-BVE, while fourteen pathways for i-BVE. Three favorable reaction pathways were chosen for each isomer to undergo further investigation. Major products are n-butyl formate, iso-butyl formate, tert-butyl formate, and HCHO. The rate constants of the primary reactions were calculated over the temperature range of 200–400 K and the pressure range of 100–2,000 Torr by employing MESMER program. At 298 K and 760 Torr, the whole rate constants of n-BVE + OH, i-BVE + OH, and t-BVE + OH are 12.3 × 10−11, 9.32 × 10−11 and 5.75 × 10−11 cm3 molecule−1 s−1, respectively. Additionally, the lifetimes of the three isomers with respect to OH radical are $$\tau$$ (n-BVE) = 1.13 h, $$\tau$$ (i-BVE) = 1.49 h, and $$\tau$$ (t-BVE) = 2.41 h.

Synthesis and properties of poly(2-adamantyl vinyl ether)-based optical plastics

Cationic polymerization of 2-adamantyl vinyl ether (2-vinyloxytricyclo[3.3.1.13,7]decane; 2-AdVE) and copolymerization of 2-AdVE with n-butyl vinyl ether (NBVE), 2-methoxyethyl vinyl ether (MOVE), or 2-(2-vinyloxyethoxy)ethyl acrylate (VEEA), vinyl ethers containing a flexible chain or a polymerizable group, were performed to obtain poly(vinyl ether) plastics for optical use. With the living cationic initiating systems such as isobutyl vinyl ether–acetic acid adduct/ethylaluminum sesquichloride (IBEA/Et1.5AlCl1.5) or the hydrogen chloride/zinc chloride (HCl/ZnCl2), all the obtained copolymers had unimodal and relatively narrow molecular weight distributions (polydispersity ratio: M w/M n = ~1.5 at high conversion) throughout the copolymerizations. These results indicate that the copolymerizations of 2-AdVE with the three comonomers led to the statistical copolymers without contamination of homopolymers. With BF3OEt2 as an initiator, homopolymer of 2-AdVE and poly(2-AdVE)-based polymers, poly(2-AdVE-stat-NBVE), poly(2-AdVE-stat-MOVE), and poly(2-AdVE-stat-VEEA), were produced with high-molecular weights (M n = 31,800–116,000) in toluene at −30 °C in quantitative yield within 10 min. They have excellent thermal stability owing to their high glass transition and thermal decomposition temperatures. The transparency (86–91 %) and refractive index (1.52–1.53) of the molded polymers are similar to those of conventional optical plastics such as poly(methyl methacrylate) (PMMA) and polycarbonate (PC), whereas their specific gravity (1.09–1.12) and water absorption (0.06–0.17 %) are significantly lower than those of PMMA and PC. In addition, the Abbe number of poly(2-AdVE), poly(2-AdVE-stat-NBVE), and poly(2-AdVE-stat-MOVE) exceeded 60 and was higher than those of PMMA and PC, indicating that the poly(2-AdVE)-based plastics are very suitable for optical lens.

Mechanistic Insights into the Gold(I)-Catalyzed Activation of Glycosyl ortho-Alkynylbenzoates for Glycosidation

Anomerization, which involves cleavage and formation of the anomeric C-O bond, is of fundamental importance in the carbohydrate chemistry. Herein, the unexpected gold(I)-catalyzed anomerization of glycosyl ortho-alkynylbenzoates has been studied in detail. Especially, crossover experiments in the presence of an exogenous isochromen-4-yl gold(I) complex confirm that the anomerization proceeds via the exocleavage mechanism, involving (surprisingly) the addition of the isochromen-4-yl gold(I) complex onto a sugar oxocarbenium (or dioxolenium) and an elimination of LAu(+) from the vinyl gold(I) complex. The inhibitory effect of the exogenous isochromen-4-yl gold(I) complex when in stoichiometric amount on the anomerization has guided us to disclose an isochromen-4-yl gem-gold(I) complex, which is inactive in catalysis but in equilibrium with the monogold(I) complex and the LAu(+) catalyst. The proposed key intermediate in the anomerization, a transient glycosyloxypyrylium species, is successfully trapped via a cycloaddition reaction with n-butyl vinyl ether as a dienophile. SN2-like substitution of the initially formed glycosyloxypyrylium intermediate has then been achieved to a large extent via charging with acceptors in an excess amount to lead to the corresponding glycosides in a stereoselective manner.

Synthesis of methyl substituted [5,6]- and [7,8]-fused pyridocoumarins via the iodine-catalyzed reaction of aminocoumarins with n-butyl vinyl ether

2-Methyl substituted [5,6]- or [7,8]-fused pyridocoumarins are prepared from the Povarov-type, three-component reactions of 6- or 7-aminocoumarins with n-butyl vinyl ether, catalyzed by iodine in refluxing acetonitrile, through the aza-Diels–Alder reaction of the initially formed N-iminoaminocoumarins with a second equivalent of the vinyl ether.

H(OEt2)2[P(1,2‐O2C6Cl4)3]: Synthesis, Characterization, and Application as a Single‐Component Initiator for the Carbocationic Polymerization of Olefins

The development of novel Brønsted acids featuring the hexacoordinate phosphorus(V) anion [TRISPHAT](-) {[1](-)=[P(1,2-O2C6Cl4)3](-)} are reported. The title compound, H(OEt2)2[1], was synthesized from 1,2-(HO)2C6Cl4 (3 equiv) and PCl5 in the presence of diethyl ether. This compound was fully characterized by (1)H, (31)P and (13)C NMR spectroscopy, X-ray crystallography and elemental microanalysis. Dissolution of H(OEt2)2[1] in acetonitrile results in the slow precipitation of crystalline H(OEt2)(NCMe)[1], which was characterized by X-ray diffraction; however, in CD2Cl2 solution the [TRISPHAT](-) anion protonated and ring-opened. The weighable, solid H(OEt2)2[1] was found to be a competent initiator for the polymerization of n-butyl vinyl ether, α-methylstyrene, styrene and isoprene at a variety of temperatures and monomer-to-initiator ratios. At low temperatures, polymers with M(n) >10(5) were obtained for n-butyl vinyl ether and α-methylstyrene whereas slightly lower molecular weights were obtained with styrene and isoprene (10(4) < M(n) <10(5)). The poly(α-methylstyrene) synthesized at -78 °C is syndiotactic-rich (ca. 87% rr) whereas the polystyrene obtained at -50 °C is atactic. The polyisoprene obtained possessed all possible modes of enchainment as well as branched and/or cyclic structures that are often observed in polyisoprene.

Theoretical investigation on the Pt(ІІ)-catalyzed [3+2] cycloaddition reactions of propargyl ether derivatives with n-butyl vinyl ether

By carrying out density functional theory (DFT) calculations, we have performed a detailed mechanism study on the Pt(II)-catalyzed [3+2] cycloaddition reactions of two propargyl ether derivatives, 2-(3-methoxyprop-1-ynyl) aniline derivative (1A) and phenol derivative (2A), with n-butyl vinyl ether. The calculated results show that the two reactions proceed according to similar elementary step mechanism. For both the two reactions, the elimination of the methoxy group is the rate-determining step. The present results provide a theoretical validation for the mechanism proposed by Iwasawa et al.

Oxidative Heck Reactions using Aryltrifluoroborates and Aryl N-Methyliminodiacetic Acid (MIDA) Boronates.

A microwave-assisted protocol furnished cinnamic acid esters from electron-deficient olefins at 120 °C using 1,3-bis(diphenylphosphino)propane (dppp) as the supporting ligand and para-benzoquinone (p-BQ) as the hydride acceptor. Use of acetone as the solvent and methanol as a co-solvent, the electron-rich olefin, n-butyl vinyl ether, was regioselectively arylated to furnish branched products under the same conditions.

Mechanistic and kinetic study on the ozonolysis of n-butyl vinyl ether, i-butyl vinyl ether and t-butyl vinyl ether

Density functional theory (DFT) and ab initio method are employed to elucidate the mechanisms for O3-initiated oxidation of n-butyl vinyl ether (n-BVE) and its isomers (i-BVE and t-BVE). For each BVE, the reactions proceed via O3 cycloaddition resulting in the formation of primary ozonides (POZs) and then two self-decomposition pathways of POZs are followed. Major products are identified to be formaldehyde and butyl formates (CH3CH2CH2CH2OCHO for n-BVE, (CH3)2CHCH2OCHO for i-BVE and (CH3)3COCHO for t-BVE). The total and individual rate constants for main product channels have been calculated using the modified multichannel Rice–Ramsperger–Kassel–Marcus (RRKM) approach. At 298K and 101kPa, the calculated total rate constants are 2.50×10−16, 3.41×10−16 and 4.17×10−16cm3molecule−1s−1 for n-BVE+O3, i-BVE+O3 and t-BVE+O3, respectively, which are in perfect agreement with experimental results. The total rate coefficients are almost pressure independent in the range of 0.001–101kPa but obviously positive temperature dependent over the whole study temperature range (200–400K). Also, the favorable reaction pathways have been determined through the estimation of branching ratios. Moreover, the influence of alkoxy group structure on the reactivity of vinyl ethers was examined.

Novel degradable polymer networks containing acetal components

A novel copolymer network with acetal structure was prepared using bis[4-(vinyloxy)butyl] (4-methyl-1,3-phenylene)biscarbamate (BECT) as the crosslinking agent. Firstly, a tri-copolymer of maleic anhydride (MAn), n-butyl vinyl ether (BVE) and 4-hydroxybutyl vinyl ether (HBVE) was synthesized via free-radical polymerization with 2,2′-azobisisobutyronitrile as the initiator. The tri-copolymer consisted of two sorts of alternating units, MAn-alt-BVE and MAn-alt-HBVE. The linear copolymer Poly((MAn-alt-BVE)-co-(MAn-alt-HBVE)) with pending hydroxyl groups was then combined with BECT in the presence of pyridinium p-toluenesulfonate, generating a copolymer network comprising acetal components in the crosslinking segment. This polymer network exhibited degradation in acid conditions.

Thioxanthone-ethylcarbazole as a soluble visible light photoinitiator for free radical and free radical promoted cationic polymerizations

Thioxanthone-ethylcarbazole (TX-EC), 7-ethylthiochromeno[2,3-b]carbazol-13(7H)-one, as a novel visible light absorbing one-component Type II photoinitiator with high solubility, was synthesized and characterized. Its ability to initiate free radical photopolymerization of methyl methacrylate (MMA) was demonstrated and compared with that of the parent thioxanthone-carbazole (TX-C) both in the presence and absence of a co-initiator. It is found that TX-EC is a more effective photoinitiator in all cases. The mechanism of initiating radical formation for free radical polymerization in the absence of an added co-initiator involves photoexcitation of TX-EC and hydrogen abstraction of triplet states of TX-EC from the ethyl group attached to the carbazole moiety. In the presence of triethyl amine, the corresponding hydrogen abstraction reaction occurs between a triplet photoinitiator and the amine compound. The possibility of visible light photoinitiation of free radical promoted cationic polymerization of several monomers, namely cyclohexene oxide (CHO), n-butyl vinylether (BVE), N-vinyl carbazole (NVC) and 3,4-epoxycyclohexyl-3′,4′-epoxycyclohexene carboxylate (EEC) using TX-EC and Ph2I+PF6− combination was also demonstrated.

ChemInform Abstract: Efficient and Highly Selective Method for the Synthesis of Benzo(naphtho)quinoline Derivatives Catalyzed by Iodine.

A mild, efficient, and highly selective method for the synthesis of pyranoquinoline and furoquinoline derivatives via a three-component reaction of aromatic aldehyde, naphthalen-2-amine or anthracen-2-amine and 2,3-dihydrofuran, or 3,4-dihydro-2H-pyran catalyzed by iodine is described. It should be noted that exo-isomer was obtained with high selectivity in good yields, which was confirmed by X-ray diffraction analysis. The 3-arylbenzo(naphtha)[f]quinolines were isolated in high yields when the chain n-butylvinyl ether was used as reactant, with the unexpected loss of the butoxy group.

Efficient and Highly Selective Method for the Synthesis of Benzo(naphtho)quinoline Derivatives Catalyzed by Iodine

A mild, efficient, and highly selective method for the synthesis of pyranoquinoline and furoquinoline derivatives via a three-component reaction of aromatic aldehyde, naphthalen-2-amine or anthracen-2-amine and 2,3-dihydrofuran, or 3,4-dihydro-2H-pyran catalyzed by iodine is described. It should be noted that exo-isomer was obtained with high selectivity in good yields, which was confirmed by X-ray diffraction analysis. The 3-arylbenzo(naphtha)[f]quinolines were isolated in high yields when the chain n-butylvinyl ether was used as reactant, with the unexpected loss of the butoxy group.

Highly Conjugated Thiophene Derivatives as New Visible Light Sensitive Photoinitiators for Cationic Polymerization

A visible light sensitive photoinitiator system for the cationic polymerization of typical monomers, e.g. of oxiranes such as cyclohexene oxide, of vinyl ethers such as n-butyl vinyl ether, and of other vinyl monomers such as N-vinylcarbazole, using highly conjugated thiophene derivatives is described. The cationic polymerization of these monomers was initiated at room temperature upon irradiation in the visible region (λinc = 480 nm) in CH2Cl2 solutions with 4,7-di(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)benzo[1,2,5]thiadiazole (DTDT) or 5,8-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2,3-di(thiophen-2-yl)quinoxaline (DTDQ) in the presence of diphenyliodonium hexafluorophosphate (Ph2I+PF6−). A feasible mechanism, as correlated with optical absorption and fluorescence spectroscopic measurements, free energy changes (ΔG), and proton scavenging studies, involves formation of exciplex by the absorption of light in the first step. Subsequent electron transfer from excited DTDT or DTDQ to iodonium ion yield...

Novel addition-fragmentation agent in cationic photopolymerization

The aim of present study is to examine the photo-initiation efficiency of N,N-dimethylacrylamide-based allylic ammonium salt as one component addition-fragmentation agent (cationic photoinitiator cum radical source) in free radical accelerated cationic polymerization. Novel addition-fragmentation agent (AFA), 2-(N,N-dimethylcarboxy-3-propenyl)(phenylcarbonyl-4-phenylene) dimethyl ammonium hexafluoroantimonate (DMPDA) was synthesized as cationic photoinitiator and its initiation efficiency was examined in polymerization of cyclohexene oxide (CHO), isobutyl vinyl ether (IBVE), and n-butyl vinyl ether (n-BVE) in CH2Cl2 solvent at wavelength λ > 290 nm. The rate of polymerization increases with the increase in initiator concentration and reaction time. The results demonstrate that DMPDA acts as an efficient photoinitiator (AFA) without use of radical source in free radical accelerated cationic polymerization.

Synthesis and Modification of Alternating Copolymers Based on Vinyl Ethers, Chlorotrifluoroethylene, and Hexafluoropropylene

Fluorinated copolymers bearing ammonium groups were prepared by radical copolymerization of fluorinated olefins (chlorotrifluoroethylene, hexafluoropropylene) with different vinyl ethers (2-chloroethyl, cyclohexyl, n-butyl, and ethyl vinyl ethers) followed by the cationization of these copolymers with trimethylamine. Copolymers were obtained in high yield (generally >85%), with molecular weights ranging from 8000 to 25 000 g mol−1. From elemental analysis as well as 1H and 19F NMR spectroscopy, the alternating structure of these polymers was confirmed. The chemical modification of these copolymers consisted of a two-step reaction: (i) the replacement of the chlorine atom by an iodine atom followed by (ii) the substitution of the halogen atom by the trimethylamine into a quaternary ammonium. The resulting copolymers were characterized with the usual techniques to assess their compositions and structures. Their thermal analyses, in dynamic mode, under air, showed decomposition temperatures (Td,10%) higher t...

A new procedure for preparing butyl acrylate-vinyl n-butyl ether copolymer as effective thickening additive to oils

The possibility of preparing copolymers by radical copolymerization on adding an active monomer, butyl acrylate, to refluxing inactive vinyl n-butyl ether was examined. The copolymer composition was studied by IR and NMR spectroscopy and by gravimetric analysis. The molecular weight and polydispersity coefficient of the copolymer were determined.

Isospecific polymerization of vinyl ethers with titanium catalysts containing modified tridentate anionic donor ligands

AbstractBACKGROUND: Stereo‐regulated polymerization of vinyl ethers (VEs) assumes significance because of its elegance and the resultant unique polymer properties. Although several Lewis acid catalysts polymerize VEs with good control of molecular weight, achieving stereo‐regularity is quite challenging. There are literature reports of a few catalyst systems capable of producing highly isotactic poly(vinyl ether) (PVE) only at lower temperatures with the polymer becoming atactic with an increase in reaction temperature. Hence innovating new catalyst systems which can produce highly stereo‐regular PVEs with high molecular weight at ambient temperature is quite challenging.RESULTS: We used two different titanium pre‐catalysts (1‐TiCl2 and 2‐TiCl2) for the polymerization of VEs. These pre‐catalysts in combination with methylaluminoxane (MAO)/borate polymerized VEs in higher conversions. Highly isotactic poly(n‐butylvinyl ether) (PBVE; 75% dyad isotactic ratio) was obtained with 1‐TiCl2/MAO at ambient temperature.CONCLUSION: We synthesized unimodal and highly isotactic PBVE with molecular weights of the order of 105 g mol−1 using the non‐metallocene‐type single‐site catalyst system 1‐TiCl2/MAO even at ambient temperature. The symmetry around the metal centre in the pre‐catalyst and the polymerization temperature played a major role in controlling the stereo‐regularization of the olefin inserted. Copyright © 2009 Society of Chemical Industry

Polymerization of vinyl ethers using titanium catalysts containing tridentate triamine ligand of the type N[CH2CH(Ph)(Ts)N]22−

Titanium complexes having tridentate triamine of the type N[CH2CH(Ph)(Ts)N]22− in combination with methylaluminoxane (MAO) was able to polymerize ethyl vinyl ether in good yields. The polymers obtained in general were having molecular weight in the order of 105 with narrow molecular weight distributions. Polymerization conditions had an impact on the molecular weight and the polydispersity index (PDI). Using chlorobenzene as the solvent the polymer had an Mn of 350 000 and PDI of 1.21, where as under neat conditions the Mn was 255 000 with PDI of 1.21. The type of solvent and the temperature dictated the polymerization rate and the polymer stereo regularity. The molecular weight of the polymer is distinctly governed by the polymerization temperature. Temperature ranging between −50 and ambient (30°C) resulted in high molecular weight polymers and vice versa at a temperature of 60–70°C resulted in low molecular weight polymers in moderate yields. The polymers obtained below 30°C are highly stereo-regular compared to that of the ones produced at and above ambient temperature. The polymerization of iso-butyl vinyl ether (IBVE) was faster than that of linearly substituted n-butyl vinyl ether (BVE) and less bulky ethyl vinyl ether (EVE). The order of isotacticities of the polymers obtained are polyIBVE>polyBVE>polyEVE. The use of borate cocatalyst for activation generated narrow molecular weight polymers with a linear increase in the yield and molecular weight over time suggesting the living nature of the catalyst system.

Novel allylic phosphonium salts in free radical accelerated cationic polymerization

In the present study, the synthesis and evaluation of novel allylic phosphonium salts as addition fragmentation agents in combination of conventional (photo-/thermal) free radical source for cationic polymerization are described. The amide based allylic phosphonium salts, namely 2-(N, N-dimethylcaboxy-propenyl) triphenylphosphonium hexafluoroantimonate (DMTPH) and 2-(morpholinocarboxy-propenyl) triphenyl phosphonium hexafluoroantimonate (MTPH) were synthesized and characterized. The thermal and photo-latency of these salts was examined with and without free radical sources in bulk polymerization of cyclohexene oxide (CHO) salts at 70 °C and λ > 290 nm irradiation, respectively. In presence of thermal free radical source, the order of activity was observed as PAT > BPO > AIBN. The order of activity of free radical sources on photopolymerization was found to be benzoin > benzophenone > TMDPO. In addition, photopolymerization of other cationically polymerizable monomers (such as n-butyl vinyl ether, isobutyl vinyl ether, N-vinyl carbazole and glycidyl phenyl ether) was also examined at λ > 290 nm irradiation. It is concluded that the rate of cationic polymerization can be accelerated using novel phosphonium salts with combination of free radical sources, by both thermal and photochemical mode.