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Sample records for 50wx2 nafion-h microsaddles

  1. High octane ethers from synthesis gas-derived alcohols. [Catalyst names: Amberlyst-15, BioRad AG 50WX2, Nafion-H microsaddles, and Purolite 150

    SciTech Connect

    Klier, K.; Herman, R.G.; Johannson, M.; Feeley, O.C.; Bogar, S.; Lawson, E.; Kieke, M.

    1991-11-01

    The objective of the proposed research is to synthesize high octane ethers, primarily methyl isobuty ether (MIBE) and methyl tertiary butyl ether (MTBE), directly from H{sub 2}/CO/CO{sub 2} coal-derived synthesis gas via alcohol mixtures that are rich in methanol and 2-methyl-1-butanol (isobutanol). The overall scheme involves gasification of coal, purification and shifting of the synthesis gas, higher alcohol synthesis, and direct synthesis of ethers.

  2. Simultaneous voltammetric determination of acetaminophen and tramadol using Dowex50wx2 and gold nanoparticles modified glassy carbon paste electrode.

    PubMed

    Sanghavi, Bankim J; Srivastava, Ashwini K

    2011-11-14

    A glassy carbon paste electrode (GCPE) modified with a cation exchanger resin, Dowex50wx2 and gold nanoparticles (D50wx2-GNP-GCPE) has been developed for individual and simultaneous determination of acetaminophen (ACOP) and tramadol (TRA). The electrochemical behavior of both the molecules has been investigated employing cyclic voltammetry (CV), chronocoulometry (CC), electrochemical impedance spectroscopy (EIS) and adsorptive stripping square wave voltammetry (AdSSWV). The studies revealed that the oxidation of ACOP and TRA is facilitated at D50wx2-GNP-GCPE. Using AdSSWV, the method allowed simultaneous determination of ACOP and TRA in the linear working range of 3.34×10(-8) to 4.22×10(-5) M with detection limits of 4.71×10(-9) and 1.12×10(-8) M (S/N=3) for ACOP and TRA respectively. The prepared modified electrode shows several advantages such as simple preparation method, long-time stability, ease of preparation and regeneration of the electrode surface by simple polishing and excellent reproducibility. The high sensitivity and selectivity of D50wx2-GNP-GCPE were demonstrated by its practical application in the determination of both ACOP and TRA in pharmaceutical formulations, urine and blood serum samples.

  3. Reaction calorimetery for coal chemistry and catalysis. Quarterly report, February 1-April 30, 1984. [Dowex-50 and Nafion-H

    SciTech Connect

    Arnett, E.M.

    1984-04-01

    A systematic thermochemical comparison of two quite different sulfonic acid resins (Dowex-50 and Nafion-H) is reported here. Heats of immersion of Nafion have been measured in some selected basic liquids at 30/sup 0/C and are compared with those of Dowex at 80/sup 0/C. Heats of immersion of Dowex and Nafion have also been measured in pyridine over a range of temperature from 30 to 100/sup 0/C and are included in this report. The report also includes the heats of immersion of Dowex and Nafion in n-octylamine (relatively strong base) at fairly high temperature (150/sup 0/C). 2 figures, 3 tables.

  4. Heterogeneous catalysis by solid superacids--14. Perfluorinated resinsulfonic acid (nafion-h) catalyzed Friedel-crafts alkylation of toluene and phenol with alkyl chloroformates and oxalates

    SciTech Connect

    Olah, G.A.; Meidar, D.; Malhotra, R.; Olah, J.A.; Narang, S.C.

    1980-01-01

    Product distributions obtained in the alkylation of toluene with methyl, ethyl, and isopropyl chloroformate and dimethyl oxalate and of phenol with methyl and ethyl chloroformate and dimethyl- and diethyloxalate.

  5. Sulfonic acid resin-catalyzed addition of phenols, carboxylic acids, and water to olefins: Model reactions for catalytic upgrading of bio-oil.

    PubMed

    Zhang, Zhi-Jun; Wang, Qing-Wen; Yang, Xu-Lai; Chatterjee, Sabornie; Pittman, Charles U

    2010-05-01

    Acid-catalyzed 1-octene reactions with phenol and mixtures of phenol with water, acetic acid and 1-butanol were studied as partial bio-oil upgrading models. Bio-oil from fast biomass pyrolysis has poor fuel properties due to the presence of substantial amounts of water, carboxylic acid, phenolic derivatives and other hydroxyl-containing compounds. Additions across olefins offer a route to simultaneously lower water content and acidity while increasing hydrophobicity, stability and heating value. Amberlyst15, Dowex50WX2 and Dowex50WX4 effectively catalyzed phenol O- and C-alkylation from 65 to 120 degrees C, giving high O-alkylation selectivities in the presence of water, acetic acid and 1-butanol. Octanols and dioctyl ethers were formed from water and octyl acetates and phenol acetates from acetic acid. Phenol alkylation slowed in the presence of water. Dowex50WX2 and Dowex50WX4 were more stable in the presence of water than Amberlyst15 and were successfully recycled. Adding 1-butanol to phenol/water/1-octene, gave emulsion-like mixtures which improved phenol conversion and olefin hydration.

  6. Catalytic conversion of bio-oil to oxygen-containing fuels by simultaneous reactions with 1-butanol and 1-octene over solid acids: Model compound studies and reaction pathways.

    PubMed

    Zhang, Zhi-Jun; Sui, Shu-Juan; Tan, Shun; Wang, Qing-Wen; Pittman, Charles U

    2013-02-01

    Upgrading bio-oil by addition reactions across olefins represents a route to refine bio-oil to combustible and stable oxygen-containing fuels. Development and application of highly active strong solid acid catalysts with good hydrothermal stability has become a key determinant for success, because bio-oil's complexity includes large amounts of water. Temperatures of 120°C or more are needed for satisfactory kinetics. Batch upgrading of a model bio-oil (phenol/water/acetic acid/acetaldehyde/hydroxyacetone/d-glucose/2-hydroxymethylfuran) over five water-tolerant solid acid catalysts (Dowex50WX2, Amberlyst15, Amberlyst36, silica sulfuric acid (SSA) and Cs(2.5)H(0.5)PW(12)O(40) supported on K-10 clay (Cs(2.5)/K-10, 30wt.%)) with 1-octene/1-butanol were studied at 120°C/3h. SSA, , exhibited the highest water tolerance and activity. Upgrading using olefin/1-butanol is complex, involving many simultaneous competing esterification, etherification, olefin hydration, phenol alkylation, aldol condensation, sugar dehydration etc. reactions.

  7. CATALYSTS FOR HIGH CETANE ETHERS AS DIESEL FUELS

    SciTech Connect

    Kamil Klier; Richard G. Herman; Heock-Hoi Kwon; James G. C. Shen; Qisheng Ma; Robert A. Hunsicker; Andrew P. Butler; Scott J. Bollinger

    2003-03-01

    A tungstena-zirconia (WZ) catalyst has been investigated for coupling methanol and isobutanol to unsymmetrical ethers, i.e. methyl isobutyl ether (MIBE) and compared with earlier studied sulfated-zirconia (SZ) and Nafion-H catalysts. In all cases, the ether synthesis mechanism is a dual site S{sub N}2 process involving competitive adsorption of reactants on proximal acid sites. At low reaction temperatures, methylisobutylether (MIBE) is the predominant product. However, at temperatures >135 C the WZ catalyst is very good for dehydration of isobutanol to isobutene. The surface acid sites of the WZ catalyst and a Nafion-H catalyst were diagnosed by high resolution X-ray photoelectron spectroscopy (XPS) of N 1s shifts after adsorption of amines. Using pyridine, ethylenediamine, and triethylamine, it is shown that WZ has heterogeneous strong Broensted acid sites. Theoretical study located the transition state of the alcohol coupling reaction on proximal Broensted acid sites and accounted well for XPS core-level shifts upon surface acid-base interactions. While computations have not been carried out with WZ, it is shown that the SZ catalyst is a slightly stronger acid than CF{sub 3}SO{sub 3}H (a model for Nafion-H) by 1.3-1.4 kcal/mol. A novel sulfated zirconia catalyst having proximal strong Broensted acid sites was synthesized and shown to have significantly enhanced activity and high selectivity in producing MIBE or isobutene from methanol/isobutanol mixtures. The catalyst was prepared by anchoring 1,2-ethanediol bis(hydrogen sulfate) salt precursor onto zirconium hydroxide, followed by calcination to remove the -(CH{sub 2}CH{sub 2})- bridging residues.

  8. Mechanistic studies of the pathways leading to ethers via coupling of alcohols

    SciTech Connect

    Sun, Qun; Lietti, L.; Herman, R.G.; Klier, K.

    1995-12-31

    The reaction mechanisms for the solid acid-catalyzed dehydrative coupling of methanol and ethanol with isobutanol and 2-pentanol to form ethers were examined by using isotope labelling and chiral inversion experiments. When the reactions were carried out it 110{degrees}C and 1 MPa with {sup 18}O-ethanol and {sup 16}O-isobutanol over the Amberlyst-35 resin catalyst, 95% of the major product ethyl isobutyl ether (EIBE) contained {sup 16}O, while 96% of the minor product ethyl tertiarybutyl ether (ETBE) contained {sup 18}O. Similar results were obtained with methanol and isobutanol over Nafion-H and Amberlyst-35 catalysts, with methyl isobutyl ether (MIBE) and methyl tertiarybutyl ether (MTBE) as the products. These results indicate that EIBE (MIBE) was produced by a surface-catalyzed S{sub N}2 reaction, while the ETBE (MTBE) product arose via a carbenium intermediate. The analogous reaction carried out over Nafion-H and HZSM-5 catalysts with chiral 2-pentanol verified the surface-mediated S{sub N}2 reaction, wherein chiral inversion of the product ether was observed relative to the S- and R-2-pentanol reactants.

  9. Mechanistic studies of the pathways leading to ethers via coupling of alcohols

    SciTech Connect

    Sun, Qun; Lietti, L.; Herman, R.G.

    1995-12-01

    The reaction mechanisms for the solid acid-catalyzed dehydrative coupling of methanol and ethanol with isobutanol and 2-pentanol to form ethers were examined by using isotope labelling and chiral inversion experiments. When the reactions were carried out at 110{degrees}C and 1 MPa with Et{sup 18}OH and {sup 16}O-isobutanol over Amberlyst-35, 95% of the major product ethyl isobutyl ether (EIBE) contained {sup 16}O, while 96% of the minor product ethyl tertiarybutyl ether (ETBE) contained {sup 18}O. Similar results were obtained with methanol and isobutanol over Nafion-H and Amberlyst-35 catalysts, with MIBE and MTBE as the products. These results indicate that EIBE (MIBE) was produced by a surface-catalyzed S{sub N}2 reaction, while the ETBE (MTBE) product arose via a carbenium intermediate. The analogous reactions carried out over Nafion-H and H-ZSM-5 catalysts with chiral 2-pentanol verified the surface-mediated S{sub N}2 reaction, where in chiral inversion of the product ether was observed relative to the S- and R-2-pentanol reactants. In addition, a remarkable shape selectivity with chiral inversion was observed over the H-ZSM-5 zeolite to selectively form 2-ethoxypentane but not 3-ethoxypentane.

  10. Incorporation of zero valent iron nanoparticles in the matrix of cationic resin beads for the remediation of Cr(VI) contaminated waters.

    PubMed

    Toli, Aikaterini; Chalastara, Konstantina; Mystrioti, Christiana; Xenidis, Anthimos; Papassiopi, Nymphodora

    2016-07-01

    The objective of present study was to obtain the fixation of nano zero valent iron (nZVI) particles on a permeable matrix and evaluate the performance of this composite material for the removal of Cr(VI) from contaminated waters. The experiments were carried out using the cationic resin Dowex 50WX2 as porous support of the iron nanoparticles. The work was carried out in two phases. The first phase involved the fixation of nZVI on the resin matrix. The resin granules were initially mixed with a FeCl3 solution to obtain the adsorption of Fe(III). Then the Fe(III) loaded resin (RFe) was treated with polyphenol solutions to obtain the reduction of Fe(III) to the elemental state. Two polyphenol solutions were tested as reductants, i.e. green tea extract and gallic acid. Green tea was found to be inefficient, probably due to the relatively big size of the contained polyphenol molecules, but gallic acid molecules were able to reach adsorbed Fe(III) and reduce the cations to the elemental state. The second phase was focused on the investigation of Cr(VI) reduction kinetics using the nanoiron loaded resins (R-nFe). It was found that the reduction follows a kinetic law of first order with respect to Cr(VI) and to the embedded nanoiron. Compared to other similar products, this composite material was found to have comparable performance regarding reaction rates and higher degree of iron utilization. Namely the rate constant for the reduction of Cr(VI), in the presence of 1 mM nZVI, was equivalent to 1.4 h of half-life time at pH 3.2 and increased to 24 h at pH 8.5. The degree of iron utilization was as high as 0.8 mol of reduced Cr(VI) per mole of iron. It was also found that this composite material can be easily regenerated and reused for Cr(VI) reduction without significant loss of efficiency.

  11. Nonhumidified intermediate temperature fuel cells using protic ionic liquids.

    PubMed

    Lee, Seung-Yul; Ogawa, Atsushi; Kanno, Michihiro; Nakamoto, Hirofumi; Yasuda, Tomohiro; Watanabe, Masayoshi

    2010-07-21

    In this paper, the characterization of a protic ionic liquid, diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]), as a proton conductor for a fuel cell and the fabrication of a membrane-type fuel cell system using [dema][TfO] under nonhumidified conditions at intermediate temperatures are described in detail. In terms of physicochemical and electrochemical properties, [dema][TfO] exhibits high activity for fuel cell electrode reactions (i.e., the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR)) at a Pt electrode, and the open circuit voltage (OCV) of a liquid fuel cell is 1.03 V at 150 degrees C, as has reported in ref 27. However, diethylmethylammonium bis(trifluoromethane sulfonyl)amide ([dema][NTf(2)]) has relatively low HOR and ORR activity, and thus, the OCV is ca. 0.7 V, although [dema][NTf(2)] and [dema][TfO] have an identical cation ([dema]) and similar thermal and bulk-transport properties. Proton conduction occurs mainly via the vehicle mechanism in [dema][TfO] and the proton transference number (t(+)) is 0.5-0.6. This relatively low t(+) appears to be more disadvantageous for a proton conductor than for other electrolytes such as hydrated sulfonated polymer electrolyte membranes (t(+) = 1.0). However, fast proton-exchange reactions occur between ammonium cations and amines in a model compound. This indicates that the proton-exchange mechanism contributes to the fuel cell system under operation, where deprotonated amines are continuously generated by the cathodic reaction, and that polarization of the cell is avoided. Six-membered sulfonated polyimides in the diethylmethylammonium form exhibit excellent compatibility with [dema][TfO]. The composite membranes can be obtained up to a [dema][TfO] content of 80 wt % and exhibit good thermal stability, high ionic conductivity, and mechanical strength and gas permeation comparable to those of hydrated Nafion. H(2)/O(2) fuel cells prepared using the composite membranes can