- Solvothermal synthesis of carbon nanotube-B2O3 nanocomposite using tributyl borate as boron oxide source
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Single-walled carbon nanotube-B2O3 nanocomposite has been prepared using solvothermal technique. Tributyl borate was explored as the boron oxide reagent using toluene and water as the solvent, respectively. Characterization of the reaction products using Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction and thermogravimetric analysis confirmed the formation of the CNT-B2O3 nanocomposite. The solvothermal approach may serve as a facile strategy for synthesis of nanocomposites of metal oxides and carbon nanotubes especially when metal alkoxides is utilized as precursor for the metal oxides.
- Oki, Aderemi,Adams, Luqman,Luo, Zhipping
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Read Online
- A method for the production of sulfate or sulfonate esters
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The present invention relates to method for the production of sulfate or sulfonate esters essentially comprising the steps of adding sulfuric acid or sulfonic acid to boron acid in a medium with or without solvent (121), stirring the prepared mixture 8122), removing the precipitated boric acid (123), removing the solvent in case the solvent is used (124), producing dialkyl sulfate esters, mono alkyl sulfate esters and sulfonate esters of alkali metal salts (125), and based on the acidolysis of boron esters obtained from alcohol and boric acid with sulfuric acid or sulfonic acid.
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Paragraph 0034; 0038
(2015/03/31)
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- Study of the radical chemistry promoted by tributylborane
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The structures of radicals generated in the oxidation process of trialkylborane were detected based on ultra-high performance liquid chromatographyquadrupole-time-of-flight mass spectrometry (UPLC/Q-ToF MS) combined with the spin trapping method. Structur
- Liu, Shujuan,Zheng, Zhen,Li, Minrui,Wang, Xinling
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p. 1893 - 1907
(2013/02/23)
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- A spirocyclic borate and a dihydroborate derived from the 1,2-diselenolato-1,2-dicarba-closo-dodecaborane(12) dianion [1,2-(1,2-C 2B10H10)Se2]2-: Structures, NMR spectroscopy, and DFT calculations
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The reaction of the diselenolato-1,2-dicarba-closo-dodecaborane(12) dianion with BF3-OEt2 affords selectively a spirocyclic bis(1,2-dicarba-closo-dodecaborane-1,2-diselena)borate, whereas the analogous reaction with boron trichloride leads mainly to 1,2-bis(ethylseleno)-1,2- dicarba-closo-dodecaborane(12) through ether cleavage. The spirocyclic borate reacts with methanol by cleavage of both Se-B and Se-C bonds. With borane in THF (BH3/THF) and also with LiBH4 exchange reactions take place, which afford the 1,2-dicarba-closo-dodecaborane-1,2- diselenadihydroborate. The molecular structures of both borates as tetrabutylammonium salts were determined by X-ray analysis. In solution, the borates were characterized by multinuclear magnetic resonance spectroscopy (1H, 11B, 13C, 77Se). The gas-phase geometries of the borate anions were optimized [RB3LYP/6-3111+G(d,p) level of theory], and the NMR spectroscopic parameters (chemical shifts and coupling constants) were calculated.
- Wrackmeyer, Bernd,Klimkina, Elena V.,Milius, Wolfgang
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p. 2164 - 2171
(2011/06/26)
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- Triorganyl- and diorganyloxozirconium hydridoborates - Synthesis and structures
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The reactions of Zr(OBu)4 and Zr(OEt)4 with H 3B·THF in THF led to HB(OR)2 and B(OR)3, but no zirconium tetrahydroborate [(RO)4-nZr(BH4) n] could be isolated. On the contrary, the reactions of [tBu 3CO]4-nZrCln and [tBu3SiO] 4-nZrCln with LiBH4 generated the tetrahydroborates [(RO)3Zr(BH4)] and [(RO) 2Zr(BH4)2]. These can be used to produce by hydroborate exchange dihydridodiorganyl borates [(RO)4-nZr(H 2BC8H14)n] and byproducts. The structures of the new zirconium hydridoborates have been determined by X-ray crystallography. Compound [(tBu3CO)3Zr(H 2BC8H14)] shows site-disordered dihydroborate units with agostic Zr-H-C interactions, while [(tBu3SiO) 2Zr(H2BC8H14)2] is quite symmetric (C2/c). The corresponding tetrahydridoborates possess in most cases μ31-bonded ZrH3BH groups. Compounds of the type [(RO)4-nZr(BH4)n] were obtained from the reaction of(RO)4Zr (R = Bu, Et) with H 3B·THF or that of (RO)4-nZrCln(n = 1, 2; R = tBu3C, tBu3Si) with LiBH4. Boryl group exchange with H2BC8H14- leads to (RO)4Zr(H2BC8H14)n with agostic Zr-H-B bonding when n = 1, whereas a symmetric ZrH2B compound results when n = 2. Copyright
- Knizek, Joerg,Noeth, Heinrich,Schmidt-Amelunxen, Martin
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p. 5548 - 5557
(2012/02/04)
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- Synthesis and antioxidant characteristics of borate esters used in lubricating oil
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In the present studies, the preparation of esters of boric acid with hindered phenols is reported, wherein the alkyl groups are branched on the α-carbon atoms. The products were evaluated in terms of their oxidative stability. In most cases, improvements in oxidative stability in ahydrocarbon media (cumene) were observed.
- Shekarriz,Ghanbari,Taghipoor,Khalili,Hajialiakbari,Adibi,Soleymani
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experimental part
p. 3646 - 3652
(2010/11/04)
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- Aliphatic thioethers by s-alkylation of thiols via trialkyl borates
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A simple and convenient one-pot procedure is described for the synthesis of thioethers via boron esters. This procedure involves in-situ generation of alkyl sulfates by reaction of trialkyl borates with concentrated sulfuric acid and subsequent reaction with thiols in the presence of pyridine. The reactions with boron esters of primary or secondary alcohols proceed cleanly at 100C and afford aliphatic thioethers in reasonable yields (59-93%) within 24 h. Interestingly, the 1H NMR spectra of the products showed no sign of positional isomerisms. The method fails however with thiophenol and does not yield aromatic thioethers, due to electrophilic substitution at the phenyl ring. Copyright Taylor & Francis Group, LLC.
- Gunes, Deniz,Sirkecioglu, Okan,Bicak, Niyazi
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body text
p. 1685 - 1690
(2010/09/17)
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- Preparation and application of SBA-15-supported palladium catalyst for Suzuki reaction in supercritical carbon dioxide
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The external and internal surfaces of SBA-15 were modified by (MeO) 3SiPh and a phosphine ligand, (MeO)3SiCH 2CH2CH2SCH2C6H 4PPh2, before and after the template Pluronic P123 copolymer was removed, respectively. Palladium was then tethered within the cavity of the mesoporous material Ph-SBA-15-PPh3via a ligand-exchange reaction to provide a new supported palladium catalyst Ph-SBA-15-PPh 3-Pd. This catalyst was demonstrated to be a robust and active catalyst in Suzuki reaction of a wide range of aryl bromides with arylboronic acids in supercritical carbon dioxide. After the reaction mixtures were treated at 90 °C for 24 h, the crude coupling products were obtained as crystalline solids when the reaction temperature was lowered to room temperature and the carbon dioxide was then slowly released. The pure products can be obtained by simple recrystallization in good to excellent yields. The Ph-SBA-15-PPh 3-Pd catalyst has low leaching loss and can be reused at least 7 times without loss of activity.
- Feng, Xiujuan,Yan, Mei,Zhang, Tao,Liu, Ying,Bao, Ming
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scheme or table
p. 1758 - 1766
(2011/01/12)
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- Method of production of B10H102? ammonium salts and methods of production of B18H22
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The invention provides new methods for synthesis of B9H9?, B10H102?, B11H14?, and B12H122? salts, particularly alkylammonium salts of B9H9?, B10H102?, B11H14?, and B12H122?. More particularly, the invention provides methods of preparing tetraalkylamronium salts of B9H9?, B10H102?, B11H14?, and B12H122? by pyrolysis of tetraalkylammonium borohydrides under controlled conditions. The invention additionally provides methods of preparing, in an atom efficient process, octadecaborane from the tetraalkylammonium salts of the invention. Preferred methods of the invention are suitable for preparation of isotopically enriched boranes, particularly isotopically enriched 10B18H22 and 11B18H22.
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- Recycle of discharged sodium borate fuel
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The present invention relates to an improvement in the recovery of boron values from a mixture of alkali metal borate and alkali metal hydroxide representing discharged fuel from a hydrogen generator apparatus. The mixture is reacted with carbon dioxide and a lower alcohol to form trialkyl borate, alkali bicarbonate and water. A porous water-absorbing material is added to the reaction mixture to absorb water as it forms thereby improving the yield of trialkyl borate. The trialkyl borate is converted to alkali borohydride that is used in the fuel.
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Page column 6
(2008/06/13)
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- Synthesis of t-butylated diphenylanthracene derivatives as blue host materials for OLED applications
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This paper describes the cost-effective synthesis and the photoluminescence of diphenylanthracene derivatives, which are found to be potential blue host materials for organic light emitting diode (OLED) technology.
- Balaganesan, Banumathy,Shen, Wen-Jian,Chen, Chin H.
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p. 5747 - 5750
(2007/10/03)
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- Practical and efficient procedure for the in situ preparation of B-alkoxyoxazaborolidines. Enantioselective reduction of prochiral ketones
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A new method for the in situ elaboration of B-alkoxyoxazaborolidines is presented. Their use in the enantioselective reduction of prochiral aromatic ketones provides excellent chemical and optical yields of chiral alcohols.
- Ponzo, Viviana L.,Kaufman, Teodoro S.
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p. 495 - 496
(2007/10/03)
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- Convergent synthesis of alpha -aryl- beta -ketonitriles
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The present invention relates to processes for the production of alpha -aryl- beta -ketonitriles, which serve as synthetic intermediates in the preparation of a series of biologically important molecules such as corticotropin releasing factor (CRF) receptor antagonists.
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- Molecular addition compounds. 15. Synthesis, hydroboration, and reduction studies of new, highly reactive tert-butyldialkylamine-borane adducts
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Two series of tert-butyldialkylamines have been prepared and examined for borane complexation. The complexing ability of each amine in the two series examined decreases in the order shown. First series: t- BuN(CH2CH2)2O 1a > t-BuNEt2 1b > t-BuNPr(n)21c > t-BuN(CH2CH2OMe)2 1d >> t-BuNBu(i)2 1e. Second series: t-BuNBu(i)Me 2a > t-BuNPr(i)Me 2b > t- BuNBu(i)Et 2c > t-BuNBu(i)Pr(n) 2d >>t-BuNPr(i)Et 2e. The reactivity of the corresponding borane adducts toward 1-octene increases in the reverse order. The following amines form highly reactive liquid borane adducts hydroborating 1-octene in tetrahydrofuran at room temperature in less than 1 h: t- BuN(CH2CH2OMe)2, t-BuNBu(i)Et, and t-BuNPr(i)Me. The limit of borane complexation among the amines examined is reached for t-BuNBu(i)2 exchanging borane neither with BMS nor with BH3-THF. Among the various borane adducts prepared, the more promising borane adducts, t-Bu(CH3OCH2CH2)2N-BH3 (7), t-BuMePr(i)N-BH3 (8), and t-BuEtBu(i)N-BH3 (9), were selected for complete hydroboration and reduction studies. Hydroboration studies with the new, highly reactive trialkylamine-borane adducts 7-9 and representative olefins, such as 1-hexene, styrene, β-pinene, cyclopentene, norbornene, cyclohexene, 2-methyl-2-butene, α-pinene, and 2,3-dimethyl-2-butene, in tetrahydrofuran, dioxane, tert-butyl methyl ether, n-pentane, and dichloromethane, at room temperature (22 ± 3°C) were carried out. The reactions are faster in dioxane, requiring 1-2 h for the hydroboration of simple, unhindered olefins to the trialkylborane stage. Moderately hindered olefins, such as cyclohexene and 2-methyl-2-butene, give the corresponding dialkylboranes rapidly, with further slow hydroboration. However, the more hindered olefins, α-pinene and 2,3-dimethyl-2-butene, give stable monoalkylboranes very rapidly, with further hydroboration proceeding relatively slowly. The hydroborations can also be carried out conveniently in other solvents, such as THF, tert-butyl methyl ether, and n-pentane. A significant rate retardation is observed in dichloromethane. Regioselectivity studies of 1-hexene and styrene using these amine-borane adducts show selectivities similar to that of BH3-THF. The rates and stoichiometry of the reaction of t-BuMePr(i)N-BH3 in tetrahydrofuran with selected organic compounds containing representative functional groups were also examined at room temperature. The reductions of esters, amides, and nitriles, which exhibit a sluggish reaction at room temperature, proceed readily under reflux conditions in tetrahydrofuran and dioxane and without solvent (at 85-90°C). The carrier amines can be recovered by simple acid-base manipulations in good yield and readily recycled to make the borane adducts.
- Brown, Herbert C.,Kanth, Josyula V. B.,Dalvi, Pramod V.,Zaidlewicz, Marek
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p. 6263 - 6274
(2007/10/03)
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- Ready Preparation of Trialkoxyboranes and Dialkoxyboranes by LiBEt3H-Promoted Reaction of BH3 in Tetrahydrofuran with Alcohols
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A catalytic amount of LiBEt3H (1percent) promoted markedly the reactions of BH3 in tetrahydrofuran (THF) with stoichiometric amounts of alcohols (1:2 and 1:3) to provide corresponding trialkoxyboranes and dialkoxyboranes quantitatively under mild reaction conditions.
- Masuda, Yuzuru,Nunokawa, Yutaka,Hoshi, Masayuki,Arase, Akira
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p. 349 - 352
(2007/10/02)
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