Trifluoride Ethyl Research Articles

Influence of boron trifluoride complex addition on structure and composition of mesophase pitch from FCC decant oil via two-stage thermotreatment

In order to optimize the molecular structure and composition distribution of mesophase pitch, the two-stage thermotreatment process preparation using boron trifluoride ethyl valerate complex as catalyst was investigated. During the two-stage thermotreatment, the cationic polymerization initiated by catalytic polycondensation made carbonaceous microcrystalline molecules contain more semi-rigid structures, while parts of alkyl side chains and naphthenic structures were retained. Subsequently, the mesophase pitch was rapidly induced to form by removing non-mesogens and enriching sufficient concentrations of mesogens in the vacuum polycondensation stage. The results showed that the two-stage thermotreatment process could change the chemical structure of the aromatic nucleus and obtain a suitable softening point (283 °C) at 100% anisotropic content. The mesophase pitch with 5 wt% catalyst addition (MP-5) had high content of methylene structure (HF = 3.18 wt%), naphthenic structure (HN = 3.45 wt%) and fusible/soluble TI-PS sub-fraction (28.07 wt%). In addition, MP-5 also possessed high aromaticity (fa = 0.90) and stacking order (Lc = 37.48 Å, n = 11.70). Unfortunately, an increase in the oxygen-containing groups was accompanied when the catalyst content reached to 10 wt%, which disrupted the aromatic lamellae parallel stacking structure of the mesophase pitch due to steric hindrance, resulting in more isotropic structures in the product.

Investigation of the Dual Polymerization of Rapid Curing Organophosphorous Modified Epoxy/Amine Resins and Subsequent Flame Retardancy

AbstractIn this work, two rapid curing, low viscosity phosphorous modified epoxy amine resin systems are simultaneously cured via chain growth and step growth mechanisms. Anionic chain growth polymerization is catalyzed by a Lewis base using 2‐ethyl‐4‐methylimidazole (2E4MI), while cationic chain growth polymerization is catalyzed using a Lewis acid boron trifluoride ethyl amine (BF3). The effects of these catalysts and increasing chemical incorporation of 9,10‐dihydro‐9‐oxy‐10‐phosphaphenanthrene‐10‐oxide (DOPO) on the cure reaction, chemorheology, and flame retardancy are investigated. The 2E4MI catalyst accelerates the onset of cure, but retards cure at higher DOPO concentrations. The addition of BF3 also accelerates the onset of reaction further, but does not significantly retard cure with increasing DOPO. Increasing DOPO reduces the glass transition temperature regardless of catalyst but the imidazole displays a larger reduction. These contrasting effects are discussed in terms of the increased concentration of hydroxyl groups from DOPO retarding anionic polymerization, while establishing a secondary propagating reaction mechanism in the case of cationic polymerization. Rheological studies show that these formulations remain ideal for liquid molding fabrication technologies, while the cured resins maintain a V0 fire rating according to the UL‐94 test and are promising candidates for the rapid manufacture of fire resistant composites.

Synthesis and Biological Activities of New 1,2,3,4- Tetrahydroquinoline Derivatives Using Imino Diels-Alder Reaction

This research contains the preparation of some novel derivatives of tetrahydro quinolone. First step, includeprepared new Schiff’s bases compounds (I1-I5) were prepared by the direct condensation between diaminecompounds and aromatic aldehydes substituted by different groups. Tetrahydroquinoline derivativescompounds (I6-I10) were prepared through imino Diels-Alder reaction using the derivatives of Schiff basewith cinnamic acid, and Boron tri fluoride ethyl etherate (BF3.Et2O) as a catalyst. The prepared compoundswere identified by infrared spectra, 1H-NMR, and 13C-NMR. Antibacterial activity of the prepared compoundswas measured by using three pathogenic microorganisms including Staphyloccus haemolyticus, Klebsiellapneumonia,and Candida albicans. Also, a comparative study was achieved to study the biological activityof these prepared compounds using Agar Diffusion method.

Three novel electrochemical electrodes for the fabrication of conducting polymer/SWCNTs layered nanostructures and their thermoelectric performance

Single-walled carbon nanotubes (SWCNTs), PEDOT:PSS/SWCNTs, and SWCNTs/PEDOT:PSS nanofilms were used as working electrodes to electrodeposit polyaniline (PANI) in a mixed alcohol solution of isopropyl alcohol (IPA), boron trifluoride ethyl ether (BFEE), and polyethylene glycol (PEG). The thermoelectric (TE) performances of the resulting nanofilms were systematically investigated. SWCNTs/PEDOT:PSS/PANI nanofilms showed a relatively high electrical conductivity value of 232.0 S cm−1. The Seebeck coefficient was enhanced and exhibited the values of 33.8, 25.6, and 23.0 μV K−1 for the SWCNTs/PANI, PEDOT:PSS/SWCNTs/PANI, and SWCNTs/PEDOT:PSS/PANI films, respectively. The maximum power factor achieved was 12.3 μW m−1 K−2. This technique offers a facile and versatile approach to a class of layered nanostructures, and it may provide a general strategy for fabricating a new generation of conducting polymer/SWCNTs materials for further practical applications.

Study on Preparing Light Colored C<sub>9</sub> Petroleum Resins with High Softening Point

Polymerizable C9 fraction was cut by atmospheric distillation of raw C9 fraction from thermal cracking. The obtained fraction polymerized using boron trifluoride ethyl ether as catalyst and then the polymerized mixture was washed by warm 10%wt Na2CO3 aqueous solution and distilled water and separated by vacuum distillation for producing light colored C9 petroleum resins with high softening point. The suitable conditions for polymerization process, washing process, vacuum distillation process were investigated to improve the C9 petroleum resins production. Under these conditions, the petroleum resins product with Gardner color index of 4-5 and softening point of 102-120°C could be obtained.

A new approach to the Schiff base-substituted oligophenols: The electrochromic application of 2-[3-thienylmethylene]aminophenol based co-polythiophenes

Two new copolymers were synthesized by electrochemical polymerization of 2-[3-thienylmethylene]aminophenol (2,3-TMAP) and poly-2-[3-thienylmethylene]aminophenol (P-2,3-TMAP) with thiophene (Th) and the obtained thiophene copolymers were examined as electrochromic materials. Electro copolymerization reactions of the compounds were performed in acetonitrile (AN)/boron trifluoride ethyl etherate (BF 3EtE) solvent mixture (9:1, v/v) where LiClO 4 utilized as the supporting electrolyte. After electro copolymerization reaction, obtained electrochromic films deposited on ITO glass plates, 2,3-TMAP-co-Th and P-2,3-TMAP-co-Th, were investigated as spectroelectrochemically. The new electrochromic materials derived from Schiff base substituted-phenol/oligophenols are red colored at low potentials and blue colored at high potentials. Electro copolymerization mechanism was identified. Spectroelectrochemical monitoring showed good absorption recovery for P-2,3-TMAP-co-Th, while absorbance decrease was observed for 2,3-TMAP-co-Th during the repeated potential scans. Suitable potential range for operating the device from red to blue was found to be between 0 and +1.4 V. P-2,3-TMAP-co-Th showed 12–13% transmittance changes at applied potentials and the response times were 3.1 and 4.1 s for 476 and 800 nm, respectively. As a result P-2,3-TMAP-co-Th may be good candidate for electrochromic devices and can be thought as a feasible nominee for anodically coloring electrochromic layers in ECDs.

ChemInform Abstract: The Generation of Difluoroenolates from Trifluoroethanol and Reproducible Syntheses of α,α-Difluoro-β-hydroxy Ketones.

Metallated difluoroenol carbamate 1 reacted with aldehydes and ketones in the presence of highly oxophilic Lewis acid boron trifluoride–ethyl ether; the Lewis acid attenuated the transacylation reaction to the corresponding enolates so that allylic alcohols could be isolated. Treatment of the allylic alcohols with strong base afforded difluoroenolates which could be trapped cleanly in aldol reactions.

Synthesis and metal-ion binding properties of new N2S4- and N2S5-donor macrocycles

Synthetic procedures for new N2S4- and N2S5-donor macrocycles (2 and 4) were given. The ligands were prepared by the reaction of NaBH4 with the appropriate macrocyclic diamide in the presence of boron trifluoride ethyl etherate in dry tetrahydrofuran (THF). Solvent extraction method was used to evaluate metal-ion binding properties of the new ligands. The solvent extraction experiments suggested that the reduced macrocycles have Ag+ and Hg2+ selectivities compared to Pb2+, Co2+, Zn2+, Ni2+, Cu2+, Mn2+ and Cd2+ ions. The extraction constants (log K ex) and complex compositions were determined for Ag+ and Hg2+ complex of compound (4).

Electrosynthesis of polyfuran in acetonitrile–boron trifluoride–ethyl ether mixture and its device application

AbstractElectrochemical polymerization of furan was achieved in acetonitrile/boron trifluoride/ethyl ether (CH3CN/BF3/EE) mixture in the presence of tetrabutylammonium tetrafluoroborate via constant potential electrolysis at 1.4 V versus Ag/AgCl. Electrochemical behavior of furan was investigated in the same solvent mixture of varying ratios, utilizing cyclic voltammetry. Free‐standing polyfuran (PFu) films were obtained in CH3CN/BF3/EE mixture (2/4/4; v/v/v) and characterized using FTIR spectroscopic technique. Spectroelectrochemical behavior of the PFu film was investigated by recording the electronic absorption spectra, in situ, in monomer‐free solution. It is observed that PFu film can be reversibly cycled between –0.1 V (gray) and + 0.6 V versus Ag‐wire (gray color); however, this behavior diminishes in the presence of water. Electrochromic device application of PFu film with poly(ethylene dioxythiophene) was also studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 871–876, 2007

One-step axial acetoxylation at C-23. A new method for the functionalization of the side chain of steroid sapogenins

Treatment of steroid sapogenins with diacetoxyiodobenzene (DIB) and boron trifluoride ethyl etherate in acetic acid led to the introduction of an axial acetoxyl group at position C-23 of the side chain.

N—H Insertion Reactions of Rhodium Carbenoids. Part 3. The Development of a Modified Bischler Indole Synthesis and a New Protecting Group Strategy for Indoles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

N–H Insertion reactions of rhodium carbenoids. Part 3.1 The development of a modified Bischler indole synthesis and a new protecting-group strategy for indoles

A modified version of the Bischler indole synthesis has been developed in which the key step is the N–H insertion reaction of rhodium carbene intermediates derived from α-diazo-β-ketoesters with anilines. Thus N-methylanilines 1 react with diazoketoesters 2 in the presence of dirhodium(II) acetate to give (N-arylamino)ketones 3, cyclisation of which using boron trifluoride–ethyl acetate or acidic ion exchange resin gives the indoles 4. In order to extend this method to the synthesis of N-unsubstituted indoles, a new protecting group strategy for indoles was developed. In this, anilines are reacted with α,β-unsaturated-esters or -sulfones to give the conjugate addition products 6 and 9, cyclisation of which gives indoles 8 and 11. The N-(2-ethoxycarbonylethyl)- and -(2-sulfonylethyl)- protecting groups are readily removed from indoles 8 and 11 by treatment with base.

Solvent Extraction of Heavy Metals with a 23-Membered Macrocyclic Ionophore Attached with BF2+-Capped Cobalt(III) Complex

A new (E, E)-dioxime cobalt(III) complex [Co(HL)2pyCl]containing four 23-membered macrocyclic ionophores has beenprepared. The cobalt(III) complex [Co(LBF2)2pyCl]bridged with BF2+ was prepared using the precursorcobalt(III) complex and boron trifluoride ethyl ethercomplex. The solvent extraction of heavy metal cationssuch as Ni2+, Cu2+, Zn2+, Hg2+ and Pb2+ by the BF2+-capped cobalt(III) complex has been investigated. The structure of the complexes is proposedaccording to elemental analyses, 1H and 13C-NMR, IRand mass spectral data.

New diazadi(and tri)thia‐21‐crown‐7 ethers containing 8‐hydroxyquinoline side arms

AbstractA series of macrocyclic diazadi(and tri)thiacrown ethers containing two 5‐substituent‐8‐hydroxyquinoline side arms have been synthesized from the corresponding macrocyclic diazadi(and tri)thiacrown ethers. The crown ethers were obtained by reduction of the proper macrocyclic di(and tri)thiadiamides by borane‐tetrahydrofuran or by sodium borohydride‐boron trifluoride ethyl etherate‐tetrahydrofuran. The yields for the reduction of diamides by sodium borohydride‐boron trifluoride ethyl etherate‐tetrahydrofuran were higher than those by borane‐tetrahydrofuran. The following four methods were used to prepare macrocycles bearing two 8‐hydroxyquinoline side arms: (1) Mannich reaction with 8‐hydroxyquinoline; (2) Reductive animation with 8‐hydroxyquinoline‐2‐carboxaldehyde using sodium triacetoxyborohydride as the reducing agent; (3) Cyclization of N,N'‐bis(8‐hydroxyquinolin‐2‐ylmethyl)‐1,2‐bis(2‐aminoethoxy)ethane (38) with bis(α‐chloroamide) 5; and (4) A step‐by‐step process wherein macrocyclic trithiadiamide 11 was reduced by lithium aluminum hydride‐tetrahydrofuran to the cyclic monoamide 36, which smoothly reacted with 5‐chloro‐8‐hydroxyquinoline to produce monosubstituted‐macrocyclic monoamide 39.

The electrochemical copolymerization of pyrrole and furan in a novel binary solvent system

Electrochemical copolymerization of furan and pyrrole was performed potentiostatically in a binary solvent system consisting of boron trifluoride ethyl ether and additional ethyl ether. The influence of applied polymerization potential and the monomer feed ratio of furan and pyrrole on the synthesis of copolymer was investigated. The higher potential favored the incorporation of furan units into the copolymer, while the amount of pyrrole units incorporated into the film increased with the increasing concentration of pyrrole in the solution. The film obtained was characterized by cyclic voltammetry, infrared and Raman spectroscopies.

Synthesis of high-quality polypyrrole in a binary solvent system consisting of boron trifluoride-ethyl ether and additional ethyl ether

Polypyrrole (PPy) was electrochemically synthesized in boron trifluoride ethyl ether (BTEE) whose acidity was adjusted with additional ethyl ether (EE). A high quality PPy film can be synthesized in a wide mole ratio range of BTEE/EE and under mild conditions. The obtained film showed the highest tensile strength (90MPa) we had ever seen and good anisotropy in electrical conductivity. The structure was investigated using surface enhanced Raman scattering (SERS).

The generation of difluoroenolates from trifluoroethanol and reproducible syntheses of α,α-difluoro-β-hydroxy ketones

Metallated difluoroenol carbamate 1 reacted with aldehydes and ketones in the presence of highly oxophilic Lewis acid boron trifluoride–ethyl ether; the Lewis acid attenuated the transacylation reaction to the corresponding enolates so that allylic alcohols could be isolated. Treatment of the allylic alcohols with strong base afforded difluoroenolates which could be trapped cleanly in aldol reactions.

Synthesis of 4-cyanophenyl 4-azido-4-deoxy-1,5-dithio-β- d-xylopyranoside

l-Arabinose diethyl dithioacetal was converted, via its 4- azido-5-S- benzoyl-4-deoxy-2,3-O- isopropylidene-5-thio- d- xylose diethyl dithioacetal, into 4-azido-4-deoxy-5-thio-α- d-xylopyranose triacetate 29. Glycosidation of 29 with 4-cyanothiophenol in the presence of trimethylsilyl triflate gave the 4-cyanophenyl 2,3-di- O-acetyl-4-azido-4-deoxy-1,2-dithio-α- and -β- d-xylopyranosides 31 and 33 as well as 3-O- acetyl-2,5-anhydro-4-azido-4-deoxy-5-thio- d-lyxose bis(4-cyanophenyl ) dithioacetal 34 in a 8:2:1 respective ratio. Treatment of 29 with hydrogen bromide in acetic acid yielded a 1:4 mixture of 2,3- di-O- acetyl-4-azido-4-deoxy-5-thio- d- xylopyranosyl bromide 38 and 2,3- di-O- acetyl-5-bromo-5-deoxy-4-thio- l- arabinofuranosyl bromide 40. Reaction of the mixture of bromides 38 and 40 with 4-cyanothiophenol in the presence of potassium carbonate afforded the expected 31 and 33 only in traces, while 2-(1 R,2 S,-1,2-di- O-acetyl-1,2-dihydroxy-but-3-en-1-yl)-5-cyano-1,3-benzodithiole and 4-cyanophenyl 2,3- di-O- acetyl-5-S-(4- cyanophenyl)-1,4,5- trithio-α- l- arabinofuranoside ( 42) were isolated in 18% and 20% yield, respectively. The formation of these two derivatives is tentatively explained by involvement of a radical reaction mechanism. When O-(2,3- di-O- acetyl-4-azido-4-deoxy-5-thio-α- d- xylopyranosyl) trichloroacetimidate was used as donor and boron trifluoride ethyl etherate as promoter, 31 and 33 were formed in excellent yield (96%) in a 2:1 ratio. The glycosides, obtained on deacetylation of 33, 34, and 42 showed a significant antithrombotic activity on rats.

Synthesis of O‐glycosylated tuftsins by utilizing threonine derivatives containing an unprotected monosaccharide moiety

Synthesis is described of four tuftsin derivatives containing a D-glucopyranosyl or a D-galactopyranosyl unit covalently linked to the hydroxy side chain function of the threonine residue through either an alpha or beta O-glycosidic linkage. Fmoc-threonine derivatives containing the suitable unprotected sugar were used for incorporating the O-glycosylated amino acid residue. Z-Thr[alpha-Glc(OBzl)4]-OBzl and Z-Thr[alpha-Gal(OBzl)4]-OBzl were prepared from the tetra-O-benzylated sugar and Z-Thr-OBzl by the trichloroacetimidate method in the presence of trimethylsilyl trifluoromethane sulfonate. The alpha glycosylated threonine derivatives were converted into Fmoc-Thr(alpha-Glc)-OH and Fmoc-Thr(alpha-Gal)-OH by catalytic hydrogenation followed by acylation with Fmoc-OSu. beta-Glucosylation and beta-galactosylation of threonine were carried out by reacting the proper per-O-acetylated sugar with Z-Thr-OBzl and boron trifluoride ethyl etherate in dichloromethane. Catalytic hydrogenation of the beta-O-glycosylated threonine derivatives followed by acylation with Fmoc-OSu and deacetylation with methanolic hydrazine yielded Fmoc-Thr(beta-Glc)-OH and Fmoc-Thr(beta-Gal)-OH, respectively. The O-glycosylated threonine derivatives were then reacted with H-Lys(Z)-Pro-Arg(NO2)-OBzl in the presence of DCC and HOBt and the resulting glycosylated tuftsin derivatives were fully deblocked by catalytic hydrogenation, purified by HPLC, and characterized by optical rotation, amino acid analysis, and 1H NMR. The beta-galactosylated tuftsin was also prepared by the continuous flow solid phase procedure.

Electrochemical polymerization of benzene utilizing boron trifluoride ethyl ether complex

Flexible poly-(p-phenylene) films were synthesized by the electrochemical polymerization technique from benzene utilizing boron trifluoride ethyl ether complex on glassy carbon (GC) or In-Sn oxide coated conducting glass (ITO) electrodes. The obtained films exhibit electrochemical oxidation-reduction in propylene carbonate (PC) containing KPF 6. As-grown and doped films indicate high electrical conductivity (>1 S/cm) which is remarkably reduced by undoping (10 −8 S/m), and the band gap of the undoped sample is evaluated to be 2.1 eV from the absorption spectrum.