540-80-7Relevant academic research and scientific papers
Flash Pyrolytic Production of Rotationally Cold Free Radicals in a Supersonic Jet. Resonant Multiphoton Spectrum of the 3p2A2''= X2A2'' Origin Band of CH3
Chen, Peter,Colson, Stephen D.,Chupka, William A.,Berson, Jerome A.
, p. 2319 - 2321 (1986)
Methyl radicals with the rotational temperature of 40 K are produced by flash pyrolysis prior to supersonic expansion.A mass-resolved resonant MPI spectrum of the 3p2A2'' = X2A2'' origin band shows clearly resolved rotational structure, in sharp contrast to the spectrum at room temperature.Flash pyrolysis, coupled with ionization by resonant MPI or vacuum-UV, provides a potentially general method for obtaining spectra of gas-phase free radicals and reactive intermediates.
Nitrosation of Organic Hydroperoxides by Nitrogen Dioxide/Dinitrogen Tetraoxide
Pryor, William A.,Castle, Laurence,Church, Daniel F.
, p. 211 - 217 (1985)
Cumyl and tert-butyl hydroperoxides react rapidly with NO2/N2O4 in organic solvents in the presence of a base to form the organic nitrate (RONO2) as the major product, together with smaller amounts of the corresponding nitrite (RONO), alcohol, and carbonyl compound (acetophenone or acetone from cumyl and tert-butyl hydroperoxide, respectively).The products from tert-butyl hydroperoxide are similar whether a base is present or not but those from cumyl hydroperoxide are more complex.We have formulated the initial reaction as a nitrosation of the hydroperoxide by N2O4 to give the pernitrite ester.This latter species is unstable and either rearrenges to give the nitrate or dissociates to form alkoxyl radicals and nitrogen dioxide that ultimately give the other observed products.The kinetics of the reaction were studied by stopped flow and are complex, but we conclude the kinetics are consistent with the nitrosation mechenism.The rate constants at 30 deg C are 2.4*104 and 8.1*103 M-1 s-1 for tert-butyl and cumyl hydroperoxides, respectively.We suggest that this facile reaction of NO2/N2O4 with hydroperoxides may have important consequences respect to the pulmonary toxicity of NO2 in smoggy air.
S-Nitrosocaptopril formation in aqueous acid and basic medium. A vasodilator and angiotensin converting enzyme inhibitor
Sexto, Alexia,Iglesias, Emilia
, p. 7207 - 7216 (2011)
The reaction of S-nitrosocaptopril (NOcap) formation was studied in both aqueous acid and basic medium. Captopril (cap) reacts rapidly with nitrous acid in strong acid medium to give the stable - in the timescale of the experiments - NOcap. The kinetic study of the reaction involving the use of stopped-flow, shows that at low sodium nitrite (nit) concentration, the reaction is first-order in both [nit], [H+], and is strongly catalysed by Cl - or Br- (= X-): rate = (k3 + k 4[X-])[H+][nit][cap]. In aqueous buffered solution of acetic acid-acetate the reaction rate is much slower and the decomposition of NOcap was observed; however, the rate of NOcap decay is more than 30-fold slower than its formation. In aqueous basic medium of carbonate-hydrogen carbonate buffer, as well as in alkaline medium, the kinetics of the nitroso group (NO) transfer from tert-butyl nitrite (tBN) to cap was studied using either conventional or stopped flow methods. In mild basic medium, the NOcap decomposes. The NOcap formation is first-order in both tBN and cap concentrations, and the reaction rate increases with pH until to, approximately, pH 11.5, above which value it becomes pH independent or even invariable with the [OH-]. Kinetic results show that the thiolate ion of cap is the reactive species. In fact, the presence of anionic micelles of sodium dodecyl sulfate (SDS) inhibits the reaction due to the separation of the reagents; whereas, cationic micelles of tetradecyltrimethylammonium bromide (TTABr) catalyse the reaction at low surfactant concentration due to reagents concentration in the small volume of the micelle. The rate equation is: rate = kf KSH[cap][tBN]/(KSH + [H+]). The rate of NOcap decomposition in mild basic medium is first-order in both [cap] and [NOcap], and decreases on increasing pH; but, in alkaline medium the NOcap is stable within the timescale of the experiments. Based on the results, the NOcap decomposition yields the disulfide compound that is formed in the nucleophilic attack of the -SH group of cap to the sulfur electrophilic center of NOcap, -S-NO. The resulting rate equation is: rate = kd[H +][cap][NOcap]/(KSH + [H+]).
Rate-limiting NO+ Formation in Nitrosation Reaction in Acetonitrile
Crookes, Michael J.,Williams, D. Lyn H.
, p. 571 - 572 (1988)
Acid-catalysed nitrosation of methanol, thioglycolic acid, and water in acetonitrile using alkyl nitrites or nitrous acid (except in the case of water), is kinetically zero order in the substrate, consistent with rate-limiting NO+ formation.
Laser-Induced Fluorescence Excitation Spectra of terf-Butoxy and 2-Butoxy Radicals
Wang, Chuji,Shemesh, Liat G.,Deng, Wei,Lilien, Michael D.,Dibble, Theodore S.
, p. 8207 - 8212 (1999)
Laser-induced fluorescence (LIF) excitation spectra of t-C4H9O (terf-butoxy) and 2-C4H9O (2-butoxy) radicals were investigated in the wavelength range 335-400 nm. The radicals were formed by laser photolysis of the corresponding butyl nitrites at 355 nm. For tert-butoxy, 16 vibronic bands in two progressions were labeled. The dominant progression corresponds to C-O stretching mode with v′c-o = 521 ± 10 cm-1. The transition origin was tentatively assigned at 25 866 cm-1 (386.6 nm). Numerous bands remain unassigned. The LIF excitation spectrum of 2-butoxy, consisting of 15 vibronic bands in four progressions, was observed for the first time. A C-O stretching frequency v′c-o = 567 ± 10 cm-1 was obtained from the dominant progression. The transition origin was tentatively assigned at 26 185 cm-1 (381.9 nm). Three other progressions are evident, which have different vibrational band intervals: 617 ± 10, 590 ± 10, and 552 ± 10 cm-1. Zero-pressure fluorescence lifetimes for numerous vibronic bands of tert-butoxy and 2-butoxy were determined to be about 150 and 85 ns, respectively. These spectra can be used as a convenient spectroscopic tool for kinetic studies of butoxy radicals and should provide a starting point for investigations of their excited states structure and dynamics.
Copper-Catalyzed Four-Component Reaction for the Synthesis of N-Difluoroethyl Imides
Gao, Yu,Peng, Shan-Qing,Liu, De-Yong,Rui, Pei-Xin,Hu, Xiang-Guo
, p. 1715 - 1721 (2019)
A general and efficient method for the synthesis N-difluoroethyl imides has been developed. This copper-catalyzed four-component reaction proceeds via in-situ generated difluorodiazomethane, which does not require prior formation and transferring. The reaction is scalable, tolerant toward a range of functional groups, and also suitable for the late-stage functionalization of drugs and drug-like molecules.
Method for recycling byproducts in synthesis of diphenyl sulfide compound
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Paragraph 0083-0088; 0092-0095; 0099-0102; 0106-0111, (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.
tert-Butyl Nitrite as a Twofold Hydrogen Abstractor for Dehydrogenative Coupling of Aldehydes with N-Hydroxyimides
Dai, Peng-Fei,Wang, Yi-Ping,Qu, Jian-Ping,Kang, Yan-Biao
supporting information, p. 9360 - 9364 (2021/12/09)
A synthetically practical transition metal/catalyst/halogen-free dehydrogenative coupling of aldehydes with N-hydroxyimides promoted solely by tert-butyl nitrite under mild conditions was developed. tert-Butyl nitrite generates two radicals (tBuO and NO) and thus works as a twofold hydrogen abstractor. A diverse array of N-hydroxyimide esters were prepared from either aliphatic or aromatic aldehydes. Benzoyl-substituted aldehydes such as 2-oxo-2-phenylacetaldehyde are also suitable.
Method and device for continuously preparing alkyl nitrite through channelization
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Paragraph 0027-0030, (2019/07/04)
The invention discloses a method and device for continuously preparing alkyl nitrite through channelization. The method comprises the following steps: storing alkyl alcohol and concentrated HCl aqueous solution in a first container and storing sodium nitrite aqueous solution in a second container; continuously conveying the solution in the first container and the second container into a static mixer for mixing by a first metering pump and a second metering pump respectively, enabling mixed solution to continuously enter a tubular reactor for reaction at the temperature of -20 DEG C-5 DEG C for1-250s, enabling feed liquid after reaction to enter a liquid separation tank and performing aftertreatment on the feed liquid in the liquid separation tank, so as to obtain alkyl nitrite. The preparation method disclosed by the invention has the advantages of being good in process safety and easy in control of reaction conditions, achieving continuous production, being high in product yield andachieving large-scale production only through less investment in the industry.
Cleavage of C(aryl)?CH3 Bonds in the Absence of Directing Groups under Transition Metal Free Conditions
Dai, Peng-Fei,Ning, Xiao-Shan,Wang, Hua,Cui, Xian-Chao,Liu, Jie,Qu, Jian-Ping,Kang, Yan-Biao
supporting information, p. 5392 - 5395 (2019/03/29)
Organic chemists now can construct carbon–carbon σ-bonds selectively and sequentially, whereas methods for the selective cleavage of carbon–carbon σ-bonds, especially for unreactive hydrocarbons, remain limited. Activation by ring strain, directing groups, or in the presence of a carbonyl or a cyano group is usually required. In this work, by using a sequential strategy site-selective cleavage and borylation of C(aryl)?CH3 bonds has been developed under directing group free and transition metal free conditions. Methyl groups of various arenes are selectively cleaved and replaced by boryl groups. Mechanistic analysis suggests that it proceeds by a sequential intermolecular oxidation and coupling of a transient aryl radical, generated by radical decarboxylation, involving a pyridine-stabilized persistent boryl radical.
