The photoreduction of hexaaquoiron(III) perchlorate in the presence of tertiary aliphatic alcohols. The effect of added copper

1977 ◽  
Vol 55 (7) ◽  
pp. 1207-1212 ◽  
Author(s):  
John H. Carey ◽  
Barry G. Oliver ◽  
Cooper H. Langford
Keyword(s):  
Quantum Yield ◽  
Outer Sphere ◽  
Butyl Alcohol ◽  
Amyl Alcohol ◽  
Quantum Yields ◽  
Direct Reaction ◽  
Tertiary Butyl ◽  
Tert Butyl Alcohol ◽  
Hydroxyalkyl Radicals ◽  
Good Agreement

The irradiation of ferric perchlorate in the presence of tert-amyl alcohol produces Fe(II) with a quantum yield of 0.110 ± 0.002, 12% lower than the yield obtained when tert-butyl alcohol was used as scavenger. Other tertiary alcohols studied, 3-methyl-2-pentanol and 3-ethyl-3-pentanol, exhibited similar lower yields. It is shown that this reduction is due to the formation of γ-hydroxyalkyl radicals which do not reduce ferric ion to ferrous. The addition of copper causes these radicals to be oxidized. The Fe(II) quantum yield for the irradiation with tertiary amyl alcohol as scavenger in the presence of copper is in good agreement with the tertiary butyl alcohol results in the absence of copper (0.124 ± 0.003).Quantum yields are observed which are independent of scavenger concentration indicating outer sphere photooxidations are not taking place. This result supports the suggestion that an H on the carbon bearing oxygen is necessary for direct reaction between scavenger and the ferric charge transfer excited state.

Photobehavior of aqueous uranyl ion and photo-oxygenation of isobutane using light from the visible region

2003 ◽  
Vol 81 (3) ◽  
pp. 219-229 ◽  
Author(s):  
Trevor M Bergfeldt ◽  
William L Waltz ◽  
Xiangrong Xu ◽  
Petr Sedlák ◽  
Uwe Dreyer ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Perchloric Acid ◽  
Rate Constants ◽  
Butyl Alcohol ◽  
Uranyl Ion ◽  
Quantum Yields ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Butyl Radical ◽  
Electronically Excited

The photochemical and photophysical behavior of the aqueous uranyl ion [UO2(H2O)5]2+ has been studied under the influence of visible light and with added perchloric acid over the range of 0.01–4 M. In the presence of 2-methylpropane (isobutane), photo-oxygenation of isobutane occurs to yield, as the major product, 2-methyl-2-propanol (tert-butyl alcohol) along with lesser amounts of 2-methyl-2-propene (isobutene) and other C1–C8 products. The quantum yield for formation of tert-butyl alcohol is independent of light intensity at the irradiation wavelength of 415 nm and of uranyl concentration, but it increases from 0.016 ± 0.001 at 0.01 M HClO4 (pH 2) to 0.13 ± 0.01 at 4 M HClO4. The emission spectrum from the electronically excited uranyl ion and the associated quantum yields have been measured in the presence and absence of isobutane, as a function of added perchloric acid. While in both cases the shape of the spectrum remains invariant, the quantum yields increase with increasing perchloric acid concentration. The strong dependence on added perchloric acid is interpreted within the context of the presence and interconversion of two electronically excited species, an acid form, *[UO2(H2O)5]2+, and a base form, *[UO2(H2O)n(OH)]+. It is proposed that both forms react with isobutane to give a tert-butyl radical, and that oxidation of coordinated aqua ligands occur, the latter generating a hydroxyl radical whose reaction with isobutane rapidly leads also to a tert-butyl radical. The reaction of this alkyl radical with ground-state [UO2(H2O)5]2+ then gives rise to the stable tert-butyl alcohol product and reduced forms of uranyl ion. Based upon the values of the quantum yields and of excited-state lifetime measurements reported in the literature, a comprehensive mechanism has been developed in a quantitative manner to provide calculated values of the rate constants for the individual mechanistic steps. The calculated rate constants provide a basis to calculate the values of quantum yields for emission and chemical reaction, as well as for lifetimes, that agree very satisfactorily with the experimental values over a 400-fold concentration change in added perchloric acid.Key words: photo-oxidation, photo-oxygenation, uranyl ion, isobutane, tert-butyl alcohol, lifetime, quantum yield, acid–base dissociation.

The Charge Transfer Photochemistry of the Hexaaquoiron(III) Ion, the Chloropentaaquoiron(III) Ion, and the µ-Dihydroxo Dimer Explored with tert-Butyl Alcohol Scavenging

1975 ◽  
Vol 53 (16) ◽  
pp. 2430-2435 ◽  
Author(s):  
Cooper H. Langford ◽  
John H. Carey
Keyword(s):  
Charge Transfer ◽  
Quantum Yield ◽  
Butyl Alcohol ◽  
Extinction Coefficients ◽  
Photochemical Processes ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Radical Yield

There have been several studies of the charge transfer photochemistry of aqueous Fe3+ but the complexity of hydrolytic equilibria and the requirement for scavengers to render the primary photochemical processes observable has left several issues moot as recent reports show. Using tert-butyl alcohol as a scavenger, it is shown that (at 35 °C), charge transfer irradiation at 254 nm of Fe(OH2)63+ gives free •OH with a quantum yield of 0.065, charge transfer irradiation of Fe(OH2)5Cl2+ at 350 nm gives free Cl• with a quantum yield of 0.093, and that as a result of the combined patterns of extinction coefficients and hydrolytic equilibria it is difficult to make Fe(OH2)5OH + the main absorbing species at either wavelength. The dihydroxo-bridged dimer gives only a small radical yield. The scavenger, tert-butyl alcohol, appears to react with •OH or Cl• to give •CH2—C(CH3)2OH which, on reaction with a second Fe(OH2)63+ gives HOCH2C(CH3)2OH.

Outer Sphere Oxidations of Alcohols and Formic Acid by Charge Transfer Excited States of Iron(III) Species

1975 ◽  
Vol 53 (16) ◽  
pp. 2436-2440 ◽  
Author(s):  
John H. Carey ◽  
Cooper H. Langford
Keyword(s):  
Charge Transfer ◽  
Formic Acid ◽  
Excited States ◽  
Outer Sphere ◽  
Butyl Alcohol ◽  
Experimental Conditions ◽  
Tert Butyl Alcohol ◽  
Long Lifetime ◽  
Resonance Relaxation ◽  
Metal Charge Transfer

When methanol, 2-propanol, and formic acid are used as scavengers in the ligand to metal charge transfer (l.m.c.t.) photolysis of Fe(OH2)63+, Fe(OH2)5CI2+, Fe2(OH2)8(OH)24+, or FeEDTA, there is a linear relationship between quantum yield for Fe(II) production and scavenger concentration, [S], at higher [S] values. Extrapolation of the linear portions to [S] = 0 gives an intercept corresponding to the limiting yields observed for scavenging with tert-butyl alcohol. Butanol scavenging at the limit has been shown to give the primary free radical yields from photolysis of aquo iron(III) species. Nuclear magnetic resonance relaxation time studies show that alcohols do not coordinate to Fe(III) and calculations from known stability constants indicate that formic acid does not coordinate under the experimental conditions. The increase of Fe(II) yields with [S] is attributed to an outer sphere oxidation of noncoordinated organic species by the charge transfer excited states of Fe(III) species. There is no discrimination among the organic reductants. The results may be understood without postulating a long lifetime for the Fe(III) l.m.c.t. states if the reaction is assumed to occur only with organic molecules in encounter with the Fe(III) complex at the time of excitation. Organic products were formaldehyde from methanol oxidation and acetone from 2-propanol oxidation. The Fe(II): formaldehyde stoichiometry was 2:1.

scholarly journals III. Researches on the hydrocarbons of the series C n H 2 n +2 .—No. IV

1868 ◽  
Vol 16 ◽  
pp. 367-372 ◽  
Keyword(s):  
Boiling Point ◽  
Chemical Structure ◽  
Butyl Alcohol ◽  
Amyl Alcohol ◽  
Tertiary Butyl Alcohol ◽  
Tertiary Butyl

On the relation between Boiling-point and Chemical Structure . It is from researches published only during last year that we have obtained a more definite knowledge of the chemical structure of some of the hydrocarbons of the above series, so that we are enabled to explain the mode in which the carbon atoms are united. This has been achieved by obtaining these hydrocarbons by synthesis from other compounds, the structure of which is perfectly well known. Thus Friedel and Ladenburg* prepared, by acting upon methylchloracetol, C { CH 3 CH 3 Cl 2 , with zincethyl, the hydrocarbon C 7 H 16 , which they call carbdimethyldiethyl, and which has the structure C {CH 3 CH 3 C 2 H 5 C 2 H 5 . Butlerow replaced in tertiary butyl alcohol the group HO by hydrogen, and obtained an isomer of diethyl to which he gives the name trimethylformen, C { CH 3 CH 3 CH 3 H. In my last communication to the Society I described di-iso-propyl and amylisopropyl, and pointed out their constitution. Further, Erlenmeyer has shown that amyl alcohol and butyl alcohol formed by fermentation have the following structure:

The photochemical decomposition of t -butyl hydroperoxide in solution

1953 ◽  
Vol 220 (1142) ◽  
pp. 322-339 ◽  
Keyword(s):  
Quantum Yield ◽  
Wave Length ◽  
Butyl Alcohol ◽  
Quantum Yields ◽  
Oxidation Reactions ◽  
Butyl Hydroperoxide ◽  
Acetone Water ◽  
Photochemical Decomposition ◽  
Solvent Molecules ◽  
A Chain

The photochemical decomposition of t -butyl hydroperoxide by light of wave-length 3130 Å has been investigated in three solvents. Reaction mechanisms are elucidated by consideration of the products and the quantum yields of decomposition. In carbon tetrachloride a chain reaction occurs in which the quantum yield of 3.2 at 20° C increases to 5.3 at 50° C. The main products are t -butyl alcohol and oxygen with smaller amounts of acetone, water and compounds arising from the oxidation of methyl radicals. The same series of reactions takes place in n -hexane, but superimposed are oxidation reactions involving solvent molecules which ultimately lead to the formation of alcohols. The quantum yield in this solvent is 3.9 and independent of temperature. When the peroxide is irradiated in dioxan solution immediate hydrogenation of the radicals produced in the primary photo-chemical act prevents the formation of reaction chains and the quantum yield is unity. The interaction of the radicals with solvent molecules is such that some of the etheric oxygen of the dioxan is transformed into alcoholic hydroxyl during the course of the reaction, and the fragmentation of dioxan gives formaldehyde Experiments with a dioxan solution using light of wave-length 2450 to 2800 Å show no fundamental change in the mode of decomposition of the peroxide, but an increase in concentration of the products of dioxan decomposition indicates a more vigorous attack by the radicals on the solvent.

Synthesis, spectroscopic, and magnetic studies of new alkoxy and allied bimetallic derivatives of nickel(II) with aluminium

1984 ◽  
Vol 62 (6) ◽  
pp. 1003-1007 ◽  
Author(s):  
R. C. Mehrotra ◽  
Jagvir Singh
Keyword(s):  
Butyl Alcohol ◽  
Amyl Alcohol ◽  
Octahedral Geometry ◽  
Tertiary Butyl Alcohol ◽  
Magnetic Studies ◽  
Tertiary Butyl ◽  
Magnetic Susceptibilities ◽  
Molecular Weights ◽  
Visible Reflectance ◽  
Derivatives Of

Nickel(II) tetraisopropoxyaluminate undergoes alcoholysis reactions with various alcohols and acetylacetone to yield products with the composition: Ni[Al(OR)4]2 (when ROH = methanol, ethanol, 2,2,2-trifluoroethanol, 2,2,2-trichloroethanol, n-butanol, and 1,3-dichloro-2-propanol); Ni[Al(O-i-Pr)(O-t-Bu)3]2 (with tertiary butyl alcohol); Ni[Al(O-i-Pr)2(O-t-Am)2]2 (with tertiary amyl alcohol); and Ni[Al(O-i-Pr)2(acac)2] (with acetylacetone). On the basis of their visible reflectance and infrared spectra along with molecular weights and magnetic susceptibilities, and octahedral geometry is tentatively suggested for these complexes in the solid state with indications of an equilibrium between tetrahedral and octahedral forms in solution. The alkoxy ligands have also been fitted into the spectrochemical and nephelauxetic series.

scholarly journals Mechanism of protection of adenosine from tert-butoxyl radicals and repair of adenosine radicals by α-tocopherol in aqueous solution

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
G. Vijayalakshmmi ◽  
M. Adinarayanna ◽  
P. Jayaprrakash Rao
Keyword(s):  
Aqueous Solution ◽  
Rate Constant ◽  
Butyl Alcohol ◽  
Quantum Yields ◽  
Oh Radicals ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Tert Butyl Hydroperoxide ◽  
Tert Butyl Alcohol

The rates of oxidation of adenosine and α-tocopherol by tert-butoxyl radicals (t-BuO•) were studied spectrophotometrically. Radicals (t-BuO•) were generated by the photolysis of tert-butyl hydroperoxide (t-BuOOH) in presence of tert-butyl alcohol to scavenge •OH radicals. The rates and the quantum yields () of oxidation of α-tocopherol by t-BuO• radicals were determined in the absence and presence of varying concentrations of adenosine. An increase in the concentration of adenosine was found to decrease the rate of oxidation of α-tocopherol, suggesting that adenosine and α-tocopherol competed for t-BuO• radicals. From competition kinetics, the rate constant of α-tocopherol reaction with t-BuO• was calculated to be 7.29 x 108 dm3 mol-1 s-1. The quantum yields expt and cal values suggested that α-tocopherol not only protected adenosine from t-BuO• radicals, but also repaired adenosine radicals, formed by the reaction of adenosine with t-BuO• radicals.

scholarly journals The construction of thermodynamic expressions needed in the physicochemical mathematical model required for the rational quantitative evaluation of the freeze drying process of pharmaceutical solutions employing tertiary butyl alcohol as a co-solvent

2018 ◽  
Author(s):  
Athanasios I Liapis ◽  
Jee-Ching Wang ◽  
Roberto Bruttini
Keyword(s):  
Mass Transfer ◽  
Freeze Drying ◽  
Knudsen Diffusion ◽  
Butyl Alcohol ◽  
Gas Mixture ◽  
Vapor Pressures ◽  
Tertiary Butyl ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Binary Gas Mixture

A thermodynamic model employing the UNIFAC (Dortmund) method was developed to determine the currently unavailable partial vapor pressures of the binary gas mixture of water and tert-butyl alcohol (TBA) in equilibrium with their frozen solid mixtures. The results agree satisfactorily with the experimental data and indicate that TBA has higher vapor pressures which lead to higher total pressures at the moving interface that could result in larger total pressure gradients and convective mass transfer rates in the dried layer during primary drying. But the higher total pressures reduce the magnitude of the bulk diffusivity of the gas mixture and combined with the smaller Knudsen diffusivity of TBA could significantly impact the competing mass transfer mechanisms during freeze drying.   Keywords: Freeze drying; Water and tert-butyl alcohol (TBA); UNIFAC (Dortmund); Partial vapor pressures; Convective flow and bulk and Knudsen diffusion

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