- Solvent-Jump Relaxation Kinetic and Equilibrium Studies of the Reaction of NOCl with n-BuOH
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The kinetics and mechanism of the reaction between NOCl and n-BuOH is investigated at 5 and 22 deg C in CCl4-HOAc mixtures, ranging from pure CCl4 to 75percent v/v HOAc.In the solvent mixtures, the use of the solvent-jump relaxation method is demonstrated on this reaction which is insensitive to concentration-jump but is perturbable by a sudden change of the reaction medium.The experimental relaxation amplitudes are in agreement with the ones calculated theoretically, and the ratios of the rate constants k1/k-1 agree with the equilibrium constants K determined photometrically.The variation of the thermodynamic and activation parameters is discussed as a function of solvent composition.
- Napoleone, V.,Schelly, Z. A.
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Read Online
- Synthesis and evaluation of 4-(3-methyl-2-butenoxy) isonitrosoacetophenone, a radiation-induced stress metabolite in Citrus
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The time- and dose-dependent occurrence of 4-(3-methyl-2- butenoxy)isonitrosoacetophenone, a γ-irradiation-induced stress metabolite was investigated. The chemical synthesis of the compound is reported. The compound exhibits antifungal activity, as well as antioxidant activity, as indicated by its ability to scavenge reactive oxygen radicals in a chemiluminescence assay.
- Dubery, Ian A.,Louw, Anna E.,Van Heerden, Fanie R.
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Read Online
- Method for recycling byproducts in synthesis of diphenyl sulfide compound
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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.
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Paragraph 0058-0063; 0074-0079
(2021/03/30)
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- Preparation method of furanone acid
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The invention belongs to the technical field of medical chemical industry, and particularly relates to a preparation method of furanone acid. The method comprises the following steps of: adding dropwisely a sodium nitrite aqueous solution into a concentrated sulfuric acid and long-chain alcohol aqueous solution, separating an ester layer to obtain nitrite after the dropwise addition is finished; dissolving 2-acetyl furan in a dilute hydrochloric acid solution, adding concentrated sulfuric acid and a catalyst, controlling temperature, adding dropwisely the nitrite, continuously stirring to react after the dropwise addition is finished, adjusting pH after the reaction is finished, filtering to recover the catalyst, and adding an extracting agent into filtrate to extract long-chain alcohol generated by the reaction and unreacted acetyl furan, wherein a water phase is a furanone acid aqueous solution. By the adoption of the preparation method of the furanone acid, an adopted oxidant only needs to slightly exceed the amount of a substrate, so that generation of toxic gas nitrogen oxide is reduced compared with oxidation of sodium nitrite; and the reaction condition is mild, the use of the catalyst accelerates a hydrolysis process, the side reaction is reduced, the yield is improved and more than 82.5%, and a conversion rate of the 2-acetyl furan reaches more than 95%.
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Paragraph 0036-0038
(2019/07/29)
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- An efficient synthesis of 2-(2,2-difluoroethoxy)-6-trifluoromethyl-n-(5,8- dimethoxy-1,2,4-triazolo[1,5-c]pyrimidine-2-yl) benzenesulfonamide: Penoxsulam
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An efficient nine-step synthesis of 2-(2,2-difluoroethoxy)-6- trifluoromethyl-N-(5,8-dimethoxy-1,2,4-triazolo[1,5-c] - pyrimidine-2-yl) benzenesulfonamide has been developed. The starting material 4-nitro-2-(trifluoromethyl)aniline starting material was converted via 2-bromo-4-amino-6-trifluoromethylaniline and 2-bromo-4-acetamido-6- trifluoromethylbenzenesulfonic acid to 2-bromo-6-trilfuoromethylbenzenesulfonic acid. This was then combined with 2-amino-5,8-dimethoxy-1,2,4-triazolo[1.5-c] pyrimidine to give the target molecule. Compared with the reported method, this approach has advantages in its shorter reaction time, milder reaction conditions and easier purifiction. Moreover, the overall yield has been improved to 22.9% which is twice of that of the reported method.
- Wu, Feifei,Gao, Shiguang,Chen, Zhiyin,Su, Jinyue,Zhang, Dayong
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p. 197 - 200
(2013/07/05)
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- Process for Producing Cl-C4 Alkyl Nitrite
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The present invention relates to a process for producing C1-C4 alkyl nitrite, comprising loading a resin catalyst layer and/or a porous filler layer into a reactor, passing nitrogen oxide, oxygen and C1-C4 alkanol as raw materials through the resin catalyst layer and/or porous filler layer in a counter current, parallel current or cross current manner, reacting under the conditions including a reaction temperature of from 0 to 150° C., a reaction pressure of from ?0.09 to 1.5 MPa, a molar ratio of C1-C4 alkanol/nitrogen oxide of 1-100:1, a molar ratio of nitrogen oxide/oxygen of 4-50:1, to obtain an effluent containing C1-C4 alkyl nitrite, wherein said nitrogen oxide is NO, or a mixed gas containing NO and one or more selected from N2O3 and NO2.
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Page/Page column 4
(2011/10/31)
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- Spectrokinetic study of the reaction system of 2NO2?N 2O4 with butanols between 320-358 K in the gas phase
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Spectrokinetic studies of the gas-phase equilibrium between nitrogen tetroxide and butanols in the reaction system 2NO2?N 2O4 (1,2), N2O4+ROH? RONO+HNO3 (3,4) have been undertaken in the temperature range 298-358 K. The products - RONO (n-butyl-ONO, sec-butyl-ONO, iso-butyl-ONO and tert-butyl-ONO) - were identified by their UV spectra and the values of the maxima UV absorption cross sections were determined in the range 320-420 nm at 298 K. The temperature dependences of both the forward and reverse rate constants, k3 and k4, were obtained. The extrapolated values of the forward rate constants are 10-18 k3 av/cm3 molec-1 s-1 3.9±1.0; 1.7±0.3; 4.2±0.8; 5.7±1.1 and the reverse rate constants are 10-20 k4av/cm3 molec -1 s-1 0.3±0.1; 2.3±0.6; 0.4±0.1; 2.3±0.6 at 298 K for the reaction of NO2/N2O 4 with n-butanol, sec-butanol, iso-butanol and tert-butanol, respectively. The activation energy for the forward E3 and for the reverse E4 reaction were derived.
- Wojcik-Pastuszka,Jodkowski
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experimental part
p. 131 - 143
(2009/09/25)
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- Dispersed fluorescence spectroscopy of primary and secondary alkoxy radicals
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Dispersed fluorescence (DF) spectra of 1-propoxy, 1-butoxy, 2-propoxy, and 2-butoxy radicals have been observed under supersonic jet cooling conditions by pumping different vibronic bands of the B-X laser induced fluorescence excitation spectrum. The DF spectra were recorded for both conformers of 1-propoxy, three conformers of the possible five of 1-butoxy, the one possible conformer of 2-propoxy, and two conformers of the possible three of 2-butoxy. Analysis of the spectra yields the energy separations of the vibrationless levels of the ground X and low-lying A electronic state as well as their vibrational frequencies. In all cases, the vibrational structure of the DF spectra is dominated by a CO stretch progression yielding the vco stretching frequency for the X state and in most cases for the A state. In addition to the experimental work, quantum chemical calculations were carried out to aid the assignment of the vibrational levels of the X state and for some conformers the A state as well. Geometry optimizations of the different conformers of the isomers were performed and their energy differences in the ground states were determined. The results of the calculation of the energy separations of the close-lying X and A states of the different conformations are provided for comparison with the experimental observations.
- Jin, Jin,Sioutis, Ilias,Tarczay, Gyoergy,Gopalakrishnan, Sandhya,Bezant, Andrew,Miller, Terry A.
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p. 11780 - 11797
(2008/01/27)
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- Method for preparing alkyl nitrites
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The invention concerns a method for preparing alkyl nitrites of formula (I) R ONO (I) ONO wherein R represents a C1-C20, advantageously C2-C10 linear or branched alkyl group. The invention is characterised in that it consists in gradually and continuously adding in an aqueous medium, an alcohol of formula (II) R OH, R being as defined above, a nitrite of formula (III) M NO2, wherein M represents a metal cation, and a strong acid, so as to form continuously said alkyl nitrite, and in continuously drawing off said alkyl nitrite thus formed from the reaction medium.
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- Cyclodextrin catalysis in the basic hydrolysis of alkyl nitrites
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The influence of β-cyclodextrin (β-CD) on the hydrolysis reaction of a variety of structural types of alkyl nitrites (RONO) is studied in acid and in basic aqueous solutions.Acid-catalysed hydrolysis of alkyl nitrites is inhibited by the presence of β-cyclodextrin.The results are accounted for by assuming the formation of host-guest complexes between β-cyclodextrin and alkyl nitrite, which are unreactive or much less reactive than the uncomplexed RONO.We propose that the result is a concenquence of the orientation of alkyl nitrite in the cavity of CD.The degree of inhibition increases with the greater inclusion of the alkyl nitrite in the CD cavity.The kinetic data are quantitatively analyzed to afford the stability constants of the host-guest complexes.On the contrary, the presence of β-cyclodextrin strongly increases the rate of hydrolysis of alkyl nitrites in a basic medium, that is at a pH value higher than the pKa of β-cyclodextrin.This feature suggests the formation of a reactive complex between the alkyl nitrite and β-cyclodextrin, whose ionized CD hydroxy group promotes a nucleophilic attack in the rate-limiting step.This behaviour is consistent with a higher reactivity towards alkyl nitrites of an ionized CD hydroxy groups as compared with the OH-; the contrary occurs in the case of esters, whose cleavage by cyclodextrin in basic aqueous media has been studied extensively over the last several years.
- Iglesias, Emilia,Fernandez, Aurora
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p. 1691 - 1700
(2007/10/03)
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- Oxidative Cleavage of Ethers by Metallic Nitrates Supported on Silica Gel
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Metallic nitrates supported on silica gel efficiently cleave and oxidize ethers to the corresponding aldehydes or ketones under mild conditions.Silica gel is essential for the efficient oxidation, and Cu(NO3)2 and Zn(NO3)2 are suitable for practical use.Overoxidation of the product aldehydes is not observed.In some cases alkyl nitrites are isolated in addition to the carbonyl compounds, and the decomposition of alkyl nitrites to the corresponding carbonyl compounds is promoted by the presence of metallic nitrates supported on silica gel.Mechanistic study suggests nitrogen dioxide is an active species.
- Nishiguchi, Takeshi,Bougauchi, Masahiro
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p. 5606 - 5609
(2007/10/02)
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- Tetraphenylphosphonium Nitrites
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Three different forms of tetraphenylphosphonium nitrite have been found to exist: an ionic nitrite, a co-ordinated nitrite, and a molecular species.
- Clark, James H.,Macquarrie, Duncan J.
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p. 229 - 230
(2007/10/02)
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- Reaction of alcohol with NO2 on a Cleaned Glass Surface
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Formation of alkyl nitrite from alcohol and NO2 was very fast on a Pyrex glass surface cleaned with chromic acid mixture.The reaction was practically zero order with respect to NO2.The rate constant was (1.7 +/- 0.08)*10E-18 cm3*molecule-1*s-1 for methyl nitrile formation and the apparent activation energy was -53.5 kJ*mol-1.
- Maeda, Yasuaki,Fujio, Yoshifumi,Munemori, Makoto
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p. 2127 - 2130
(2007/10/02)
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- Disproportionation to Combination Ratios of Alkoxy Radicals with Nitric Oxide
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The disproportionation to combination ratios were measured at 175 deg C for the reactions RO + 15NO -> RO15NO (2a) and RO + 15NO -> RCHO + H15NO (2b), with the following alkoxy radicals: C2H5O, n-C3H7O, n-C4H9O, and i-C4H9O.The alkoxy radical was generated by the termal decomposition of the corresponding alkyl nitrite in the presence of 15NO.The rate of the corresponding isotopically enriched alkyl nitrite was measured by mass spectrometry while the aldehyde rate was determined by gas chromatography.The results obtained for k2b/k2 were 0.22 +/= 0.02, 0.26 +/= 0.03, 0.29 +/= 005, and 033 +/= 0.03, respectively, for C2H5O, n-C3H7O, n-C4H9O, and i-C4H9O.With these values of k2b/k2 we were able to determine the primary quantum yield of the photolysis of the corresponding alkyl nitrites at 366 nm to be, respectively, 0.32 +/= 0.04, 0.44 +/= 0.06, 0.19 +/= 0.04, and 0.19 +/= 0.02.
- Morabito, Paul,Heicklen, Julian
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p. 2914 - 2916
(2007/10/02)
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- Formation of Organic Nitro-compounds in Flowing H2O2+NO2+N2+Organic Vapour Systems. Part 2.-H2O2+NO2+N2+Alkane System
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The principal products from the surface-initiated reactions in flowing mixtures of H2O2, NO2,N2 and RH, where RH=ethane, propane, n-butane and n-pentane, have been identified as the nitroalkane, alkyl nitrite and alkyl nitrate.The product yields have been measured; in the case of propane the variation of the yields with total gas pressure has also been studied.Values have been obtained for the relative rates of primary and secondary H-atom abstraction from each alkane by OH and for the rate-constant ratios k3/k4 and k5/k6 at 298 K:.The trends in the product yields with the variation of pressure and change of R indicate that RO radicals are produced via reactions (4)-(6) rather than by a single-step reaction of R with NO2.
- Baulch, Donald L.,Campbell, Ian M.,Chappel, Jonathan M.
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p. 609 - 616
(2007/10/02)
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- Hydrolysis, Nitrosyl Exchange, and Synthesis of Alkyl Nitrites
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Alkyl nitrites undergo relatively slow hydrolysis in phosphate-buffered aqueous media under neutral conditions with small but significant dependence of reactivity on structure.However, rapid nitrosyl exchange with alcohols is observed, and equilibrium constants for this transformation exhibit remarkable correlation with equilibrium constants for nitrosyl exchange of alcohols with nitrosyl chloride and with nitrous acid. tert-Butyl nitrite has the greatest driving force for nitrosyl transfer among the 12 alkyl nitrites examined, and this capability is used for the synthesis of alkyl nitrites derived from steroidal alcohols and of alkyl thionitrites.
- Doyle, Michael P.,Terpstra, Jan W.,Pickering, Ruth A.,LePoire, Diane M.
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p. 3379 - 3382
(2007/10/02)
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- Gas-phase Reaction of Hydroxyl Radicals with Alkyl Nitrite Vapors in H2O2+NO2+CO Mixtures
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The yields of CO2 from the chain reaction in H2O2+NO2+CO+alkyl nitrite mixtures, in wich OH is the chain carrier and alkyl nitrites induce a chain termination step, have been used to deduce rate constants (ks) for OH attack on alkyl nitrites (RONO) in the vapour phase at ambient temperatures.Values of ks/E9 dm3 mol-1 s-1 as a function of R were determined as follows: 0.71 +/-0.12 (CH3), 1.15+/-0.23 (C2H5), 1.56+/-0.32 (n-C3H7), 3.41+/-1.48 (n-C4H9), 3.89+/-0.58 (sec-C4H9), 3.47+/-0.52 (i-C4H9), 0.91+/-0.15 (t-C4H9), all based on ks=(1.63+/-0.16)E9 dm3 mol-1 s-1 for OH +n-butane.The small increase in ks from R=CH3 to t-4H9 is considered to support a recent postulate that both H-abstraction and NO-abstraction pathways are operative, at least for R=CH3.Under typical, sunlit urban atmosphere conditions it is deduced that OH attack on alkyl nitrites is a minor removal process compared to their photodissociative destruction.
- Audley, Gary J.,Baulch, Donald L.,Campbell, Ian M.,Waters, Des J.,Watling, Gillian
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p. 611 - 618
(2007/10/02)
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