F:Flammable;
75-65-0Relevant articles and documents
Electrocatalytic features of a heme protein attached to polymer-functionalized magnetic nanoparticles
Krishnan, Sadagopan,Walgama, Charuksha
, p. 11420 - 11426 (2013)
Direct electron-transfer and electrocatalytic kinetics of covalently attached myoglobin (MB) films on magnetic nanoparticles (MB-MNP covalent), in comparison to the corresponding physisorbed films and individual components, are reported for the first time. MB-MNP covalent ("-" denotes a covalent linkage) was adsorbed onto a cationic poly(ethyleneimine) layer (PEI) coated high-purity graphite (HPG) electrode. Similarly, films of myoglobin physisorbed on magnetic nanoparticles (MB/MNPadsorbed, "/" denotes a noncovalent nature), only MB, or only MNP were constructed on HPG/PEI electrodes for comparison. The observed electron-transfer rate constants (ks, s-1) were in the following order: MB-MNPcovalent (69 ± 6 s -1), MB/MNPadsorbed (37 ± 2 s-1), only MB (27 ± 2 s-1), and only MNP (16 ± 3 s-1). The electrocatalytic properties of these films were investigated with the aid of tert-butylhydroperoxide as a model reactant, and its reduction kinetics were examined. We observed the following order of catalytic current density: MB-MNPcovalent > MB/MNPadsorbed > only MNP > only MB, in agreement with the electron-transfer (ET) rates of MB-MNP covalent and MB/MNPadsorbed films. The crucial function of MNP in favorably altering the direct ET and electrocatalytic properties of both covalently bound MB and physisorbed MB molecules are discussed. In addition, the occurrence of a highly enhanced electron-hopping mechanism in the designed covalent MB-MNPcovalent films over the corresponding physisorbed MB/MNPadsorbed film is proposed. The enhanced electron-transfer rates and catalytic current density suggest the advantages of using metalloenzymes covalently attached to polymer-functionalized magnetic nanoparticles for the development of modern highly efficient miniature biosensors and bioreactors.
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Walling,Heaton
, p. 38,44 (1965)
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Masarwa, Mohamed,Cohen, Haim,Meyerstein, Dan,Hickman, David,Bakac, Andreja,Espenson, James H.
, p. 4293 - 4297 (1988)
Temperature dependence of the rate and activation parameters for tert-butyl chloride solvolysis: Monte Carlo simulation of confidence intervals
Sung, Dae Dong,Kim, Jong-Youl,Lee, Ikchoon,Chung, Sung Sik,Park, Kwon Ha
, p. 378 - 382 (2004)
The solvolysis rate constants (kobs) of tert-butyl chloride are measured in 20%(v/v) 2-PrOH-H2O mixture at 15 temperatures ranging from 0 to 39°C. Examination of the temperature dependence of the rate constants by the weighted least squares fitting to two to four terms equations has led to the three-term form, lnkobs=a1+a 2T-1+a3lnT, as the best expression. The activation parameters, ΔH? and ΔS ?, calculated by using three constants a1, a 2 and a3 revealed the steady decrease of ≈1 kJmol -1 per degree and 3.5 JK-1mol-1 per degree, respectively, as the temperature rises. The sign change of ΔS ? at ≈20.0°C and the large negative heat capacity of activation, ΔCp?=-1020 JK -1mol-1, derived are interpreted to indicate an S N1 mechanism and a net change from water structure breaking to electrostrictive solvation due to the partially ionic transition state. Confidence intervals estimated by the Monte Carlo method are far more precise than those by the conventional method.
Decomposition of tert-butyl hydroperoxide into tert-butyl alcohol and O2 catalyzed by birnessite-type manganese oxides: Kinetics and activity
Qi, Lin,Qi, Xingyi,Wang, Lili,Feng, Lili,Lu, Shupei
, p. 6 - 9 (2014)
Birnessite-type manganese oxides (M-OL-1s, M = K, Mg, Fe, Ni and Cu) are first reported to efficiently catalyze the decomposition of tert-butyl hydroperoxide (TBHP) into tert-butyl alcohol (TBA) and O2 with a 100% selectivity towards TBA under heterogeneous conditions. The same form of overall second-order kinetic equations is fitted out for the M-OL-1s and explained by the proposed mechanism. Life tests and XRD analyses demonstrate no losses in both the activity and the birnessite-type structure after the reaction.
A search for mode-selective chemistry: The unimolecular dissociation of t-butyl hydroperoxide induced by vibrational overtone excitation
Chandler, David W.,Farneth, William E.,Zare, Richard N.
, p. 4447 - 4458 (1982)
The use of optoacoustic spectroscopy permits both the monitoring of the overtone excitation of t-butylhydroperoxide (t-BuOOH) and the in situ detection of the resulting reaction product t-butanol (t-BuOH).The sample is contained in a reaction cell, equippedwith a microphone, in which all surfaces have been specially passivated.The cell is placed inside the cavity of a dye laser tuned to excite the 5-0 O-H stretch of the t-BuOOH at 619.0 nm.The dissociation process yields directly OH and t-BuO, and the latter readily abstracts a hydrogen atom from a parent molecule to form t-butanol (t-BuOH).The appearance rate of t-BuOH is obtained by ratioing the area under the 5-0 O-H stretch of tBuOH to that of a combination band of t-BuOOH.At low pressures, below 40 Torr, a plot of the reciprocal of the t-BuOH appearance rate versus total pressure shows near linear behavior.This linearlity can be well described by a statistical model (RRKM) when careful averaging of the dissociation rate over the thermal energy distribution of the photoactivated molecules is included.At pressures above 40 Torr, a marked deviation from linearity appears.This deviation is fit to a kinetic model in which the dissociation rate of an energy nonrandomized molecule competes with the rate of intramolecular energy relaxation.This places a lower bound of >= 5.0*1011 s-1 on the rate of energy randomization.A discussion of this model in the context of other possible kinetic schemes as well as other photoactivated and chemically activated systems is presented.
Enhanced catalytic performance of porphyrin cobalt(II) in the solvent-free oxidation of cycloalkanes (C5~C8) with molecular oxygen promoted by porphyrin zinc(II)
Shen, Hai-Min,Zhang, Long,Deng, Jin-Hui,Sun, Jing,She, Yuan-Bin
, (2019)
Dual-metalloporphyrins catalytic system based on T(p-Cl)PPCo and T(p-Cl)PPZn was presented to enhance the oxidation of cycloalkanes, especially for cyclohexane, the selectivity towards KA oil increasing from 90.7% to nearly 100.0%, meanwhile the conversion increasing from 3.42% to 4.29%. Enhancement on conversion and selectivity was realized simultaneously. In the dual-metalloporphyrins system, T(p-Cl)PPCo served the role to activate molecular oxygen and promote the decomposition of cyclohexyl hydroperoxide, and T(p-Cl)PPZn catalyzed the decomposition of cyclohexyl hydroperoxide to avoid unselective thermal decomposition. This protocol is also very applicable to other cycloalkanes and will provide a applicable strategy to enhance the oxidation of alkanes.
CHANGE IN THE REACTIVITY OF DI-tert-BUTYL PEROXIDE DURING HOMOLYSIS WITH AN INCREASE IN THE DEGREE OF CONVERSION AND PRESSURE
Zhulin, V. M.,Khueidzha, I.,Koreshkov, Yu. D.
, p. 643 - 649 (1992)
It was found that the differential reactivity (kd') of di-tert-butyl peroxide (DTBP) in a solution of 2-methoxy- (1) and 2-ethoxytetrahydropyran (2) at 130 deg C and pressures p = 20 and 1000 MPa is a periodic function of the degree of conversion, arbitrarily measured by the concentration of tert-butyl alcohol (TBA) formed.The function kd' = F() was calculated with the spline approximation (SA) of the experimental as a function of the reaction time τ, giving a continuous curve of d/dτ as a function of τ.The integral reactivity kd = G() calculated with the kinetic equation for a first-order reaction for decomposition of DTBP in 1, 2, 1+ C6H6 and 2 + C6H6 in three segments of τ in the range of p = 20-1000 MPa changes differently with an increase in the degree of conversion for different p.The volume activation effects (ΔVp) determined by SA of the experimental ln kd as a function of p were calculated for close degrees of conversion, = 0.1-0.14 M.The ΔVp as a function of p obtained were compared with the similarly processed published data on decomposition of DTBP in n-heptane and dicumyl peroxide (DCP) in different aromatic solvents.The results were attributed to the effect of the type of packing of the solvent molecules surrounding the reacting molecule on the reactivity of the peroxide and not to the effect of radical recombination in the primary cage. Keywords: di-tert-butyl peroxide, homolysis, high pressure, role of solvent.
Characterization of co-metabolic biodegradation of methyl: Tert -butyl ether by a Acinetobacter sp. strain
Li, Shanshan,Wang, Dan,Du, Dan,Qian, Keke,Yan, Wei
, p. 38962 - 38972 (2019)
Co-metabolic bioremediation is a promising approach for the elimination of methyl tert-butyl ether (MTBE), which is a common pollutant found worldwide in ground water. In this paper, a bacterial strain able to co-metabolically degrade MTBE was isolated and named as Acinetobacter sp. SL3 based on 16S rRNA gene sequencing analysis. Strain SL3 could grow on n-alkanes (C5-C8) accompanied with the co-metabolic degradation of MTBE. The number of carbons present in the n-alkane substrate significantly influenced the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA), with n-octane resulting in a higher MTBE degradation rate (Vmax = 36.7 nmol min-1 mgprotein-1, Ks = 6.4 mmol L-1) and lower TBA accumulation rate. A degradation experiment in a fed-batch reactor revealed that the efficiency of MTBE degradation by Acinetobacter sp. strain SL3 did not show an obvious decrease after nine rounds of MTBE replenishment ranging from 0.1-0.5 mmol L-1. The results of this paper reveal the preferable properties of Acinetobacter sp. SL3 for the bioremediation of MTBE via co-metabolism and leads towards the development of new MTBE elimination technologies.
Kinetics of a Hydrolysis Reaction in an Oil/Water Microemulsion System Near the Critical Point
Yang, Ya,Jin, Jing,Wang, Jinshou,Shi, Zhen,Zhang, Shenghui
, p. 702 - 711 (2016)
We have constructed the pseudoternary phase diagram of surfynol465?+?n-butanol?+?cyclohexane?+?H2O with km?=?2 (where km is the weight ratio of surfynol465 to n-butanol) by the water titration method. Electrical conductivity measurements were employed to investigate the microstructures of the single-phase region. In the oil/water microemulsion region, we have measured the hydrolysis reaction rate of 2-bromo-2-methylpropane near and far away from the critical point. It was found that the Arrhenius equation was valid for correlating experimental measurements far away from the critical point but a significant acceleration effect exists near the critical point, which is not consistent with thermodynamic interpretation of Griffiths and Wheeler.
Brook,Glazebrook
, (1961)
Solvent Ionizing Power. Comparisons of Solvolyses of 1-Adamantyl Chlorides, Bromides, Iodides and Tosylates in Protic Solvents
Bentley, William T.,Carter, Gillian E.,Roberts, Karl
, p. 5183 - 5189 (1984)
Solvolytic rate constants for 1-adamantyl iodide (1-AdI) in binary aqueous mixtures of ethanol, methanol, acetone, trifluoroethanol, and hexafluoroisopropyl alcohol and in acetic and formic acids are reported.Additional kinetic data for solvolyses of 1-adamantyl halides in 97percent w/w hexafluoroisopropyl alcohol/water were obtained by using a microconductivity cell (volume, ca. 0.4 mL).Kinetic data for iodine-catalyzed solvolyses of 1-AdI in methanol/water mixtures are also reported.A scale of solvent ionizing power for iodides (YI) is defined by log(k/k0)1-AdI=YI, where k is the rate constant for solvolysis of 1-AdI in any solvent at 25 deg C relative to 80percent v/v ethanol/water (k0).Correlations of YI and similarly defined scales for tosylates (YOTs) and bromides (YBr) with data for chlorides (YCl) show variations in slopes attributed to charge delocalization in the leaving group (slopes, Cl>Br>I>OTs); acidic solvents show significant deviations from the correlation lines.The effect of iodine catalysis increases as solvent ionizing power decreases, consistent with formation of the charge delocalized leaving group I3-.YI does not correlate satisfactorily with Kosower's Z values for aqueous and alcohol solvents, and the range of Z values is substantially greater in energy terms than the corresponding range of YI values.Our data provide qualified independent support for a recent proposal by Swain et al. that only two solvent properties correlate the major solvent effect on rates, equilibria and spectra.
Ebert,Lucas
, p. 1230 (1934)
Control of electrochemical and ferryloxy formation kinetics of cyt P450s in polyion films by heme iron spin state and secondary structure
Krishnan, Sadagopan,Abeykoon, Amila,Schenkman, John B.,Rusling, James F.
, p. 16215 - 16224 (2009)
Voltammetry of cytochrome P450 (cyt P450) enzymes in ultrathin films with polyions was related for the first time to electronic and secondary structure. Heterogeneous electron transfer (hET) rate constants for reduction of the cyt P450s depended on heme iron spin state, with low spin cyt P450cam giving a value 40-fold larger than high spin human cyt P450 1A2, with mixed spin human P450 cyt 2E1 at an intermediate value. Asymmetric reduction-oxidation peak separations with increasing scan rates were explained by simulations featuring faster oxidation than reduction. Results are consistent with a square scheme in which oxidized and reduced forms of cyt P450s each participate in rapid conformational equilibria. Rate constants for oxidation of ferric cyt P450s in films by t-butyl hydroperoxide to active ferryloxy cyt P450s from rotating disk voltammetry suggested a weaker dependence on spin state, but in the reverse order of the observed hET reduction rates. Oxidation and reduction rates of cyt P450s in the films are also likely to depend on protein secondary structure around the heme iron.
Selective Functionalization of Hydrocarbons Using a ppm Bioinspired Molecular Tweezer via Proton-Coupled Electron Transfer
Chen, Hongyu,Wang, Lingling,Xu, Sheng,Liu, Xiaohui,He, Qian,Song, Lijuan,Ji, Hongbing
, p. 6810 - 6815 (2021/06/28)
An expanded porphyrin-biscopper hexaphyrin was introduced as a bioinspired molecular tweezer to co-catalyze functionalization of C(sp3)-H bonds. Theoretical and experimental investigations suggested that the biscopper hexaphyrin served as a molecular tweezer to mimic the enzymatic orientation/proximity effect, efficiently activating the N-hydroxyphthalimide (NHPI) via light-free proton-coupled electron transfer (PCET), at an exceptionally low catalyst loading of 10 mol ppm. The resulting N-oxyl radical (PINO) was versatile for chemoselective C-H oxidation and amination of hydrocarbons.
Method for recycling byproducts in synthesis of diphenyl sulfide compound
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Paragraph 0083; 0089-0091, (2021/03/30)
The invention provides a method for recycling byproducts in synthesis of a diphenyl sulfide compound. The byproducts comprise alkyl alcohol and dimethyl disulfide. The method comprises the steps of (1) mixing the byproducts in synthesis of the diphenyl sulfide compound with a sodium nitrite aqueous solution, adding concentrated hydrochloric acid for reaction, and obtaining alkyl nitrite and dimethyl disulfide; and (2) mixing the products obtained in the step (1) with copper powder, adding an aniline compound for reaction, carrying out desolvation treatment on the obtained reaction solution toobtain a diphenyl sulfide compound and byproducts, and returning the byproducts to the step (1). According to the recycling method, the byproducts do not need to be separated, the byproducts serve asraw materials to be directly applied to synthesis of the diphenyl sulfide compound, the process steps are simple and safe, cyclic utilization of the materials is achieved, and the raw material cost ofindustrial production of the diphenyl sulfide compound and the treatment cost of industrial three wastes are remarkably reduced.
