Boron Trifluoride Etherate Research Articles

Synthesis, thermal stability and kinetic decomposition of triblock copolymer polypropylene glycol–poly glycidyl nitrate–polypropylene glycol (PPG–PGN–PPG)

An energetic triblock copolymer PPG–PGN–PPG (Mn = 1886 g mol−1) was synthesized for the first time by cationic ring-opening polymerization of propylene oxide with low molecular weight poly glycidyl nitrate (PGN) (Mn = 1061 g mol−1) as a macroinitiator, in the presence of boron trifluoride etherate (BF3·OEt2) as the catalyst. The product obtained in high yield was characterized by FTIR, gel permeation chromatography and 1H and 13C NMR spectroscopy. The thermal properties of the triblock copolymer were characterized by differential scanning calorimeter (DSC). The result approved that the glass transition temperature of the triblock copolymer (Tg = − 58 °C) is lower than PGN (Tg = − 35 °C); also, it was more stable than that of PGN. The effect of heating rates (10, 20, 30 and 40 °C min−1) on the decomposition of the copolymer was evaluated. The decomposition temperature of this compound increased as the heating rate increased. The kinetic parameters such as activation energy and frequency factor for the thermal decomposition of the triblock copolymer were obtained from the DSC and DTG data by non-isothermal methods proposed by the ASTM E696, Flynn–Wall–Ozawa (FWO) and Kissinger methods. The values by the FWO method are in good agreement with ASTM and Kissinger methods.

Preparation and electrochemical performance of TEMPO-modified polyterthiophene electrode obtained by electropolymerization

A novel monomer of terthiophene with a side chain TEMPO, 4-(2,5-di(thiophen-2-yl)thiophen-3-yl)acetyl-oxy-2,2,6,6-tetramethylpiperidin-1-yloxy (TT-TEMPO) was successfully synthesized. Its corresponding polymer PTT-TEMPO was prepared via electrochemical polymerization on Pt electrode in boron trifluoride diethyl etherate solution. PTT-TEMPO film showed a uniform network structure. Compared with bare Pt electrode, PTT-TEMPO electrode exhibited high electrocatalytic performance for oxidation of benzyl alcohol in the presence of 2,6-lutidine under similar conditions. Benzyl alcohol was selectively oxidized to benzaldehyde based on in situ FTIR analysis.

Synthesis and cationic ring‐opening polymerization of oxetane monomer containing five‐membered cyclic carbonate moiety via highly chemoselective addition of CO2

ABSTRACTThe bicyclic amidinium iodide effectively catalyzed the reaction of carbon dioxide and the epoxy‐containing oxetane under ordinary pressure and mild conditions with high chemoselectivity to give the corresponding oxetane monomer containing five‐membered cyclic carbonate quantitatively. The cationic ring‐opening polymerization of the obtained monomer by boron trifluoride diethyl ether proceeded to give linear polyoxetane bearing five‐membered cyclic carbonate pendant group in high yield. The molecular weight of the polyoxetane was higher than that of polyepoxide obtained by the cationic ring‐opening polymerization of epoxide monomer containing five‐membered cyclic carbonate. The cyclic carbonate functional crosslinked polyoxetanes were also synthesized by the cationic ring‐opening copolymerization of cyclic carbonate having oxetane and commercially available bisoxetane monomers. Analyses of the resulting polyoxetanes were performed by proton nuclear magnetic resonance, size exclusion chromatography, thermogravimetric analysis, and differential scanning calorimetry. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2606–2615

Three-Component Coupling of Aromatic Aldehydes, 1-Morpholino-2-nitroalkenes, and 3-Aminoazoles via Boron Trifluoride Etherate Catalysis: Reaction Pathway and Features of the Formation of Intermediates.

4,7-Dihydro-6-nitro-7-Ar-5-R-azolo[1,5-a]pyrimidines were obtained by the multicomponent reaction of aminoazoles, morpholino-nitroalkenes, and aromatic aldehydes in the catalysis of boron trifluoride etherate. The optimal reaction conditions were determined, and the formation of the target regioisomer was demonstrated. The pathway for multicomponent transformation, including the formation of azolyl-nitroalkene, was determined. Morpholino-nitroalkenes were assumed to convert into the corresponding nitroalkynes during catalysis of boron trifluoride etherate. For a multicomponent reaction with 4-nitrobenzaldehyde, conditions have been proposed that exclude the formation of a side regioisomer.

A New Alkylation of Aryl Alcohols by Boron Trifluoride Etherate.

The ethylation of aryl alcohols by an ethyl moiety of boron trifluoride etherate is described. The reaction proceeded cleanly and afforded good yields of the corresponding aryl ethyl ethers. It tolerated the presence of functional groups such as aryl, alkyl, halogens, nitro, nitrile, and amino. However, the presence of amino or nitro groups ortho to a hydroxyl group of an aryl compound drastically reduced the yields of the anticipated products due to the chelation of the aforementioned functional groups with boron trifluoride etherate. A nitrogen atom in the aromatic ring system, as exemplified by hydroxypyridine and 8-hydroxyquinoline, completely inhibited the reaction. Resorcinol, hydroquinone, and aryl alcohols with aldehyde functions decomposed under the reaction conditions.

Synthesis of 5-Substituted 2-Pyrrolidinones by Coupling of Organozinc Reagents with Cyclic N-Acyliminium Ions

A coupling reaction between cyclic N-acyliminium ions with organozinc reagents is described. The cyclic N-acyliminium ions, generated in situ from N-substituted-5-hydroxy-2-pyrrolidinones by treatment with boron trifluoride–diethyl ether complex or titanium tetrachloride, are trapped by the organozinc reagent, which is formed from an alkyl bromide in the presence of zinc in the same reaction medium. The N-substituted-5-allyl-2-pyrrolidinones generated using this method serve as versatile intermediates for the synthesis of azabicyclic systems with indolizidine and pyrroloazepinolizidine cores.

The effect of boron trifluoride diethyl etherate on electrochemical polymerization and surface morphology of conjugated porous polymer poly(4,4′,4″-Tris(9-carbazolyl)triphenylamine)

We reported the fabrication of conjugated porous polymer films based on 4,4′,4″-Tris(9-carbazolyl)triphenylamine (TCTA) using electrochemical polymerization in CH2Cl2 containing different ratios of boron trifluoride diethyl etherate (BFEE). The oxidation potential of TCTA in CH2Cl2 with 20 vol % BFEE was measured to be only 0.28 V vs. Ag/AgCl, which was lower than that determined in pure CH2Cl2 (0.72 V vs. Ag/AgCl). Also, PTCTA films obtained from this medium showed better electrochemical behavior. And Fourier Transform Infrared spectra were used for structural analysis of polymers. From Scanning Electron Microscopy for surface morphological analysis, we founded that different percentages of BFEE were important in the control of the resulting surface morphology.

Lewis Acid-Mediated Cyclization of Allenyl Aryl Ketones.

The cyclization of a series of nonheterocyclic allenyl aryl ketones was examined using boron trifluoride etherate and indium triflate to mediate the reaction. Yields with BF3 were low in most instances due mainly to competitive destruction of the substrates. With In(OTf)3, there was less decomposition, and the yields of the cyclized product were much higher, but only for substrates with electron-donating substituents. Cyclization did not occur without those substituents. A computational study using the ωB97X-D/6-311+G(2d,p)//ωB97X-D/6-31+G(d,p) method confirmed better stability of the σ-complexed substrate by indium(III) and that meta-substituents on the phenyl ring of the substrate significantly influenced the activation barrier of the cyclization, whereas the effect of para-substituents was almost negligible. The computational results supported the idea that the cyclization is a 4π-electrocyclization and not a 5-endo-dig ring closure as had been proposed in the literature.

A solution-processable electrochromic polymer designed with Reactive Yellow 160 and 2-hydroxy carbazole

Abstract In this study, we highlight a methodology for obtaining multifunctional, solution-processable super-structured polymeric structures from simple chemical reactions by using ordinary chemicals has been presented. For this purpose, the super-structured multifunctional monomer (CzRY) has been synthesized by combining an electroactive molecule with a commercial dye. In this multifunctional structure, 2-hydroxy carbazole has been chosen as an electroactive polymerizable group while Reactive yellow 160 dye has been chosen as an electrochromic and fluorescent material with the solution-processable property. Electropolymerization of CzRY has been comparatively examined in acetonitrile (ACN) and ACN/BFEE (boron trifluoride diethyl etherate) binary solvent system. PCzRY polymer film prepared in ACN/BFEE solution has been shown excellent electrochemical and electrochromic properties such as good cycling stability (92%), high coloration efficiency (678 cm2/C) and high optical contrast (70%). Moreover, the resultant polymer film has good solubility in THF and DMF. During the redox process, the transparent state of the polymer film was turning into green and aquamarine, respectively. As a result, solution-processable and fluorescent conducting polymer with high electrochromic property has been synthesized and characterized.

Synthesis and structure of novel Si-substituted silylpropyl derivatives of 2-mercaptobenzoxazole and 2-mercaptobenzothiazole

A previously unknown carbofunctional (trimethoxysilyl)propyl derivative of the 2-mercaptobenzoxazole, C6H4NOCS(CH2)3Si(OMe)3, containing a tetracoordinated silicon atom was synthesized by nucleophilic substitution of the chlorine atom in the (3-chloropropyl)-trimethoxysilane with the benzoxazol-2-ylsulfanyl group. The reaction of 2-[(trimethoxysilyl)propylsulfanyl]benzoxazole or –benzothiazole with boron trifluoride etherate led to a previously unknown hydrolytically unstable Si-fluoropropyl derivatives of 2-mercaptobenzoxazole or 2-mercaptobenzothiazole, C6H4N(Y)CS(CH2)3SiF3 (Y = O, S). By transesterification of 2-[(trimethoxysilyl)-propylsulfanyl]benzoxazole by tris(2-hydroxyethyl)amine, a new silatranylpropyl derivative of 2-mercaptobenzoxazole containing an intramolecular coordination bond N→Si and a pentacoordinated silicon atom, C6H4NOCS(CH2)3Si(OCH2CH2)3N, was obtained.

Electrochemical n-doping of polyfluorenone films

The n-doping electrochemistry of polyfluorenone (PFO) films prepared by electrochemical polymerization of fluoren-9-one in boron trifluoride diethyl etherate (BFEE) has been characterized. Cyclic voltammetry in acetonitrile showed rapid and reversible n-doping. The potential dependence of the capacitance, measured by impedance spectroscopy, shows that PFO behaves primarily as a redox polymer during n-doping, with localized, non-interacting redox sites. However the potential dependence of the resistance suggests that there are long range effects of conjugation. Deactivation due to charge (cation) trapping occurred during repeated cycling through the n-doping wave. The n-doping capacity can be partially restored by p-doping. Use of polyethylene glycol as a stabilizer decreased the rate of charge trapping, and increased the recovery of n-doping capacity. Scanning electron microscopy revealed that charge trapping was associated with notable changes in the morphology of the PFO film that are characteristic of an annealing process.

Electropolymerization of Indole and Its 5- Position-Substituted Derivatives in the Mixed Electrolytes of Acetic Acid and Boron Trifluoride Diethyl Etherate

Electropolymerization of Indole and Its 5- Position-Substituted Derivatives in the Mixed Electrolytes of Acetic Acid and Boron Trifluoride Diethyl Etherate

A novel synthetic strategy for styrene-butadiene-styrene tri-block copolymer with high cis-1,4 units via changing catalytic active centres.

A styrene–butadiene–styrene tri-block copolymer (SBS) with a high cis-1,4 unit content (greater than 97%) was synthesized by a novel synthetic strategy based on changing the catalytic active centres using n-butyllithium and a nickel-based catalyst. Firstly, styrene was polymerized via anionic polymerization using butyllithium as the initiator (Li, activity centre Li) at 50°C. The obtained alkylated macroinitiator (PSLi) was aged with nickel naphthenate (Ni) and boron trifluoride etherate (B) to prepare a second reactive centre (Ni-F), which was used to initiate the polymerization of butadiene (Bd). Finally, triphenyl phosphine (PPh3) was added to adjust the electron density of the third active centre (P-Ni-F), and styrene monomer was added again to synthesize the second polystyrene block to obtain SBS. The polymerization technique presented here is simple and has an efficient initiation effect due to the high initiation activities for the different monomers. It also exhibits excellent control over the stereo-structure of the butadiene segments in the prepared copolymers, and the SBS polymers with high cis-1,4 unit content were easily achieved.

Cationic Copolymerization of o-Phthalaldehyde and Functional Aliphatic Aldehydes

There has been a resurgence of research related to poly(phthalaldehyde) (PPHA) in the past several years because of the demonstration of long room-temperature lifetime and its low ceiling temperature facilitating the ability to rapidly depolymerize the polymer at ambient conditions. This rapid depolymerization upon triggering of PPHA mixtures makes them well suited for fabricating transient devices or stimuli-responsive materials. The copolymerization of phthalaldehyde (PHA) with other aldehydes provides a route to incorporate chemical or physical functionality into PHA-based polymers while still maintaining the favorable degradation properties. Although the anionic copolymerization of PHA with benzaldehydes has been described, only a limited number of examples have been reported on the cationic copolymerization of PHA with other aldehydes. In this study, the synthesis and reactivity behavior of PHA copolymers is reported. Aliphatic aldehydes were chosen for their prevalence and favorable degradation properties. Dichloromethane solvent and the boron trifluoride diethyl etherate Lewis acid catalyst showed the best monomer conversions and highest polymer molecular weights. It was found that the aliphatic aldehyde reactivity for copolymerization increased with the electron-withdrawing nature of the aldehyde, which correlates with the aldehyde hydration equilibrium constant. The molecular weight and copolymer yield decrease with an increase in the aliphatic aldehyde feed concentration. Results indicate that the polymerization conditions used in this study (ca. −78 °C) are above the ceiling temperature of the aliphatic aldehyde comonomers, but this does not prevent copolymerization of the comonomer with PHA. Postpolymerization modifications were performed to introduce functional groups into the PHA-based copolymer that are incompatible with the polymerization chemistry. PPHA copolymers were cross-linked using a radiation-induced thiol–ene click chemistry to show that the mechanical properties can be improved even though the copolymer has a lower molecular weight.

Cationic polymerization of waste palm cooking oil under microwave irradiation

Waste palm cooking oil is one of the largest waste types in Indonesia and it is potential as a source of renewable materials. Conversion of the material was carried out by the cationic polymerization of the double bond (C=C) in the triglyceride. The polymerization using boron trifluoride-etherate (BF3-etherate) as the catalyst was performed under microwave irradiation. The irradiation was varied in some power settings and reaction times. The fatty acid components after purification were analysed using gas chromatography (GC). The parameter analysed were iodine number (titrimetric), maximum wavelength absorption (UV-visible spectrometry), functional groups (Fourier transform infrared spectrometry, FTIR) and thermal properties (differential scanning calorimetry, DSC). The treatment using microwave irradiation produced solid polymer form with lower iodine number, meaning that the double bond in the fatty acid has reduced. The small amount of the double bond was also reflected by a hypochromic shift in the UV-vis spectra, as well as decreasing peak intensity at the C=C stretch in the FTIR spectra. The DSC thermogram of the product shows two endothermic transitions, indicating the melting point of the monomer and the polymer product.

Regioselective Alkylation of 5-Substituted Tetrazoles with 3-Chlorobut-2-en-1-ol in Acid Medium

The alkylation of 5-R-tetrazoles (R = H, Me, Ph) with 3-chlorobut-2-en-1-ol was studied in 1,2-dichloroethane, chlorofom, and methylene chloride in the presence of boron trifluoride—diethyl ether complex, as well as in trifluoroacetic acid and in ethyl acetate in the presence of sulfuric acid. The reaction in 1,2-dichloroethane catalyzed by BF3 · Et2O gave 70–80% of the alkylation products containing no less than 99% of the 2-substituted isomer.

Electrochemical capacitive performance of free-standing polyindole film and effect of introducing alkyl chain connecting two indoles

Polyindole (PIn), combining the good properties of polypyrrole and poly(para-phenylene), has been gained significant attention. But the capacitive performances of PIn and its derivatives electropsynthesized in boron trifluoride diethyl etherate (BFEE) were unknown so far. So we first prepared the free-standing PIn film in BFEE and studied its capacitive property. The specific capacitance value of PIn could achieve 270.2 F g−1 at high current density of 10 A g−1. And the capacitance retained of PIn 84.06% after 3000 cycles. For further studying the effect of introducing alkyl chains on the electrochemical properties of PIn, poly1,3-di(1H-indol-1-yl)propane (P(IP-3)), poly1,6-di(1H-indol-1-yl)hexane (P(IH-6)), and poly1,12-di(1H-indol-1-yl)dodecane (P(ID-12)) bridged by alkyl chains with different lengths were electrosynthesized in BFEE. Through a series of experiments, we found that the specific capacitance performances of P(IP-3), P(IH-6), and P(ID-12) were poorer than PIn, indicating the introduction of alkyl chains altered the electrochemical properties of the π-conjugated backbone of PIn and lowered its the properties, which could be proved by scanning electron microscope.

The Different Outcomes of Electrochemical Copolymerisation: 3-Hexylthiophene with Indole, Carbazole or Fluorene.

Electrochemical polymerisation is reported to be a method for readily producing copolymers of various conjugated molecules. We employed this method for mixtures of indole, carbazole or fluorene with 3-hexylthiophene (HT), in order to obtain their soluble copolymers. Although polymer films were obtained, infrared (IR) and Raman investigations showed that instead of the expected linear copolymers, polyindole and polycarbazole N-substituted with HT, as well as a poly(3-hexylthiophene) (PHT)/polyfluorene blend were produced instead. Boron trifluoride diethyl etherate was also used in an attempt to promote copolymerisation, but the produced deposits were found to be highly degraded.

Vinylsilanes in Highly Diastereo- and Regio-Selective Synthesis of Dihydropyrans.

Borontrifluoride etherate (BF3·OEt2) can be efficiently used for the synthesis of dihydropyrans from triethylsilyl homoallylic alcohols and aldehydes in good yields. The reaction is highly diastereo- and regio-selective.

A New Synthesis Strategy on Styrene-Butadiene Di-Block Copolymer Containing High cis-1,4 Unit Via Transfer of Anionic to Coordination Polymerization.

A novel synthesis strategy on styrene-butadiene di-block copolymer (PS-b-PB) with high cis-1,4 unit content was developed, based on a transfer technique from anionic to coordination polymerization. Firstly, the styrene monomer was initiated by n-butyllithium (Li) utilizing anionic polymerization at 50 °C, which resulted in a macromolecular alkylating initiator (PSLi). Secondly, PSLi was aged with nickel naphthenate (Ni) and boron trifluoride etherate (B) for obtaining a complex catalyst system (Ni/PSLi/B). Then, Ni/PSLi/B was applied to initiate the butadiene (Bd) polymerization. Following this new strategy, a series of PS-b-PBs were successfully synthesized. The experimental results indicated that under the molar ratio combination of [Li]/[Ni] = 5 and [B]/[Li] = 1, styrene-butadiene di-block copolymers could be easily achieved with high cis-1,4 unit content (>97%) and controlled molecular weight as well as narrow molecular weight distribution (Mw/Mn < 1.5). Furthermore, the copolymer’s block ratio could also be effectively controlled by controlling the two components’ monomer feed ratio.