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1.
The kinetics of the ozone reaction with isomeric acetoxytoluenes in acetic anhydride in the presence of sulfuric acid and
mixed manganese bromide catalyst was studied. Under these conditions it is possible to stop the oxidation process at the stage
of formation of hydroxybenzaldehydes in the form of the respective acetoxybenzylidendiacetates (63–70%). The reaction products
contain also acetoxybenzyl acetate (16–18%) and a small amount of acetoxybenzyl bromide (2%). The mechanism of oxidation-reduction
catalysis with manganese bromide complex explaining the experimental data was considered. 相似文献
2.
Liquid-phase oxidation of 2,4-dinitrotoluene with ozone in the presence of acetic anhydride as stop reagent and manganese(II) acetate as catalyst was studied. The major products of oxidation with ozone in acetic anhydride are 2,4-dinitrobenzyl alcohol (65.8%) and 2,4-dinitrobenzaldehyde (18.8%) in the form of the corresponding acetates. A reaction scheme accounting for the results obtained is considered. 相似文献
3.
V. F. Traven I. V. Voevodina A. V. Manaev N. Ya. Podkhalyuzina 《Chemistry of Heterocyclic Compounds》2007,43(4):416-420
New derivatives of coumarin, containing annulated α-pyrone rings, were obtained by reaction of the borate complexes of three
isomeric acyl(hydroxy)coumarins with acid anhydrides. It was shown that the borate complex of 3-acetyl-4-hydroxy-2-pyrone
also condenses with acetic anhydride to form a derivative containing a new annulated α-pyrone ring.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 513–517, April, 2007. 相似文献
4.
The kinetics of acetamidotoluene oxidation in glacial acetic acid in the presence of cobalt acetate is reported. At 95°C and
atmospheric pressure, acetamidotoluenes are oxidized by molecular oxygen very slowly: oxidation is complete in 10–12 h, and
the major reaction products are acetamidobenzoic acids (27–36% yield). The introduction of ozone into the reactive gas increases
the reaction rate by one order of magnitude. The main role of ozone is to generate the active form of the catalyst. 相似文献
5.
Kinetics and products of the reactions of ozone with toluene and its derivatives in acetic anhydride
The reactions of ozone with toluene and its derivatives in acetic anhydride were studied. It was found that competing parallel
reactions of ozone with the aromatic ring and substituents occurred in the ozone-arene-acetic anhydride system. The ratio
between these reaction paths depended on the arene structure and reaction conditions. The selectivity of the oxidation of
toluene and its derivatives at the methyl group varied from 0 to 40%. The fraction of aromatic products decreased as the number
of methyl groups at the ring was increased. Tri- and tetramethylbenzenes were oxidized only at the aromatic ring. The stability
of an aromatic system increased upon the introduction of electron-acceptor substituents into the benzene ring. Aminotoluenes
and hydroxytoluenes were oxidized with ozone mainly at the NH2 and HO groups; however, as in the case of toluene, the aromatic ring and methyl group became the main directions upon their
acylation. The oxidation of the methyl group in acetic anhydride in the presence of sulfuric acid was finished at the step
of the formation of the acylated derivatives of benzyl alcohols and benzaldehydes, which are resistant to the action of ozone. 相似文献
6.
Zhao RS Cheng CG Yuan JP Jiang T Wang X Lin JM 《Analytical and bioanalytical chemistry》2007,387(2):687-694
A novel purge-and-trap method coupled with gas chromatography-mass spectrometry (GC-MS) is developed for the analysis of trace
and ultratrace phenols based on their derivatization with acetic anhydride. Parameters affecting the extraction efficiency,
such as purge temperature, concentration of sodium chloride, purge time, and volume of derivatization reagent, were investigated.
The optimized conditions were addition of 150 μL acetic anhydride, purge time of 25 min at the purge temperature of 60 °C
with 30% NaCl. The linear range was 0.2–100 μg L−1 for phenols. The limits of detection (LODs) ranged from 0.08 to 0.15 μg L−1 and the relative standard deviations (RSDs) for most of the phenols at the 10 μg L−1level were below 10%. Natural water samples collected from a pool were successfully analyzed using the proposed method. The
recovery of spiked water samples was 72.9–84.2%. 相似文献
7.
Potapenko E. V. Galstyan G. A. Galstyan A. G. Kudyukov Yu. P. 《Kinetics and Catalysis》2001,42(6):796-799
The reaction of 4-nitrotoluene oxidation with ozone in acetic anhydride in the presence of MnSO4and sulfuric acid was studied. The main reaction product is 4-nitrobenzyl acetate, the yield of which is 63.2%. Based on an analysis of the experimental data, a mechanism of the catalytic ozonation of 4-nitrotoluene in acetic anhydride was proposed. 相似文献
8.
Preparation of aromatic alcohols and aldehydes by oxidation of p-cresol with ozone in acetic anhydride in the presence of sulfuric acid, manganese acetate, and potassium bromide was studied. The optimal oxidation conditions were determined. 相似文献
9.
Eleven structurally different α, β-unsaturated ketones were subjected to the Clemmensen reduction under anhydrous conditions using amalgamated zinc, hydrogen chloride in a solution of ethyl ether, and acetic anhydride. In all cases but one the formation of cyclopropyl acetates was observed. 4-Methyl-3-penten-2-one, methyl vinyl ketone, 2-isopropylidene-1-cyclopentanone, and 2-cyclohepten-1-one led to substituted cyclopropyl acetates. Stereospecific reactions were found with 2-ethylidene-1-cyclopentanone, 2-benzylidene-1-cyclohexanone, and methyl 1-cyclohexenyl ketone, whereas 3-penten-2-one, 3-methyl-3-buten-2-one, and 2-methyl-2-cyclohexen-1-one afforded mixtures of the isomeric cyclopropyl acetates. These results are interpreted in terms of the intital formation of an allylic anion which undergoes electrocyclic closure. A stereospecific course is followed when geometric constraints permitted. Exceptions are discussed. 相似文献
10.
E. V. Tatarnikova V. V. Sizov A. V. Aleksandrov I. V. Tselinskii 《Russian Journal of Organic Chemistry》2009,45(10):1523-1527
N-Nitrobenzimidazol-2-ones readily undergo rearrangement to C-nitro derivatives on heating in various solvents (ethyl acetate, butyl acetate, acetonitrile, acetone, dioxane, o-dichlorobenzene, anisole, acetic acid). This rearrangement was used to develop a procedure for the synthesis of 4,5,6,7-tetranitro-1,3-dihydrobenzimidazol-2-one
in high yield (90–96%) by nitration of 1,3-dihydrobenzimidazol-2-one, as well as of 5,6-dinitro- and 4,5,6-trinitro-1,3-dihydrobenzimidazol-2-ones,
with a small excess of concentrated nitric acid in a mixture with acetic anhydride and acetic acid at 50–60°C. 相似文献
11.
Summary The bicyclic acetate obtained in the reaction of 2-pinene oxide with acetic anhydride is a mixture of (–)-and (±)-trans-pinocarveol acetates; one of the monocyclic acetates obtained is a mixture of (+) and (±)-trans-carveol acetates.Translated from Izvestiya Akademii Nauk SSSR, Khimicheskaya, No. 12, pp. 2144–2152, December, 1965 相似文献
12.
The kinetics and the mechanism of the liquid-phase oxidation of 2,4-dinitrotoluene with ozone in the presence of manganese(II) acetate have been investigated. The major products of 2,4-dinitrotoluene oxidation with ozone in acetic anhydride are 2,4-dinitrobenzyl acetate (65.8%) and 2,4-dinitrobenzylidene diacetate (18.8%). The effect of the manganese(II) acetate concentration on the selectivity of substrate oxidation at the methyl group is reported. A redox catalysis mechanism providing an explanation to experimental data is considered. 相似文献
13.
Contamination by Brettanomyces is a frequent problem in many wineries that has a dramatic effect on wine aroma and hence its quality. The yeast Brettanomyces/Dekkera is involved in the formation of three important volatile ethylphenols—4-ethylphenol, 4-ethylguaiacol and 4-ethylcatechol—that
transmit an unpleasant aroma to wine that has often been described as ‘medicinal’, ‘stable’ or ‘leather’. This study proposes
an in situ derivatisation and headspace solid-phase microextraction– gas chromatography coupled to mass spectrometry method
to determine the three ethylphenols in red Brettanomyces-tainted wines. The most important variables involved in the derivatisation (acetic anhydride and base concentration) and
the extraction (extraction temperature and salt addition) processes were optimised by experimental design. The optimal conditions
using 4 mL of wine in 20-mL sealed vials were 35 μL of acetic anhydride per millilitre of wine, 1 mL of 5.5% potassium carbonate
solution and 0.9 g of sodium chloride and the extraction was performed with a divinylbenzene–carboxen–poly(dimethylsiloxane)
fibre at 70 °C for 70 min. Then, the performance characteristics were established using wine samples spiked with the ethylphenols.
For all compounds, the detection limits were below the odour threshold reported in the literature and they were between 2
and 17 μg L−1 for 4-ethylguaiacol and 4-ethylphenol, respectively. Intermediate precision (as relative standard deviation) was acceptable,
with values ranging from 0.3 to 12.1%. Finally, the method was applied in the analysis of aged Brettanomyces-tainted wines. 相似文献
14.
E. Rafiee Sh. Tangestaninejad M. H. Habibi I. Mohammadpoor-Baltork V. Mirkhani 《Russian Journal of Organic Chemistry》2005,41(3):393-395
Tetrahydropyranyl ethers derived from primary alcohols were directly and efficiently converted into the corresponding acetates and formates by the action of ethyl acetate, acetic acid, acetic anhydride, and ethyl formate in the presence of a catalytic amount of potassium dodecatungstocobaltate K5CoW12O40 · 3H2O. Tetrahydropyranyl ethers derived from secondary alcohols and phenols can also be transformed into the corresponding acetates with the use of acetic anhydride, but K5CoW12O40 · 3H2O was ineffective for esterification with ethyl acetate, acetic acid, and ethyl formate.__________From Zhurnal Organicheskoi Khimii, Vol. 41, No. 3, 2005, pp. 403–405.Original English Text Copyright © 2005 by Rafiee, Tangestaninejad, Habibi, Mohammadpoor-Baltork, Mirkhani.The original article was submitted in English. 相似文献
15.
J.S. Yadav B.V. Subba Reddy P. Vishnumurthy Ch. Janardhana Chary 《Tetrahedron letters》2007,48(33):5915-5918
Lithium tetrafluoroborate is found to be an efficient catalyst for allylation and cyanation of aldehydes with allyltrimethylsilane and trimethylsilyl cyanide in the presence of acetic anhydride at room temperature to produce homoallylic acetates and α-cyano acetates in excellent yields. A solution of 10 mol % of LiBF4 in acetonitrile provides a convenient reaction medium to carry out allylation and cyanation reactions under very mild and neutral conditions. 相似文献
16.
I. V. Gruzdev I. M. Kuzivanov I. G. Zenkevich B. M. Kondratenok 《Journal of Analytical Chemistry》2013,68(2):161-169
A procedure is developed for determining phenol; 2-, 3-, and 4-methylphenols, and 2,4- and 2,6-dimethylphenols in aqueous media, which consists in the synthesis of iodine derivatives, their extraction with toluene, and determination by gas chromatography with electron-capture detection. The optimal conditions for the iodination of phenols in water are found; also the extraction and gas chromatography behavior of methylphenols and their iododerivatives are investigated. To make the identification of iododerivatives of methylphenols more reliable, they are subjected to acylation with acetic anhydride in the extract. The analytical range of phenols in water is 0.01–10 μg/L, the relative standard deviation is 2–6%, and the duration of analysis is up to 40 min. 相似文献
17.
O. V. Drygina V. B. Panov O. Yu. Okhlobystin 《Chemistry of Heterocyclic Compounds》1980,16(2):130-133
The corresponding o-carboranylpyrylium perchlorates were obtained from 4H-pyrans of the o-carborane series under the influence
of 70% HClO4 in acetic anhydride or 2,2′,4,4′-tetramethoxydiphenylammonium perchlorate. The carboranylpyranyl free radicals were studied
by EPR spectroscopy, and it was shown that the unpaired electron is localized in the carborane ring.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 185–188, February, 1980. 相似文献
18.
Viktoria S. Moskvina Olexander V. Turov Volodymyr P. Khilya Myroslav M. Garazd Ulrich M. Groth 《Monatshefte für Chemie / Chemical Monthly》2008,43(4):1391-1396
New functionalized derivatives of 8,8,10-trimethyl-4-phenyl-7,8-dihydro-2H,6H-pyrano[3,2-g]-chromene-2,6-dione – analogues of the natural compound graveolone – possessing hydrazine, hydroxylamine, and thiosemicarbazide
residues were synthesized and their reactions with acetic anhydride were studied. The structure of the obtained compounds
was confirmed by NMR spectroscopy. 相似文献
19.
Passive sampling and stir bar sorptive extraction for the determination of endocrine-disrupting compounds in water by GC-MS 总被引:1,自引:0,他引:1
Emanuele Magi Marina Di Carro Camilla Liscio 《Analytical and bioanalytical chemistry》2010,397(3):1335-1345
A new method using the extraction and preconcentration capabilities of stir bar sorptive extraction, combined with high-resolution
gas chromatography and mass spectrometry, was developed for the determination of five selected endocrine-disrupting compounds
(4-n-nonylphenol, bisphenol A, estrone, 17β-estradiol, and 17α-ethinylestradiol) in water. In situ derivatization to transform
the phenolic compounds into lipophilic and volatile analytes was carried out with acetic anhydride. Two different methods
of headspace derivatization to further improve the chromatographic properties of 17β-estradiol and 17α-ethinylestradiol were
developed and compared. The optimized method provided good sensitivity (limits of quantitation 1.2–2.6 ng), repeatability
(relative standard deviation 2–9%), and reproducibility (relative standard deviation 10–17%). Passive sampling by means of
polar organic chemical integrative samplers was applied to monitor river waters used as supply sources for drinking water
treatment plants in the Liguria region of Italy. The analytes showed a different distribution at the three sites considered;
bisphenol A proved to be the most abundant, ranging from 185 to 459 ng per sampler. 相似文献
20.
A. G. Galstyan S. G. Galstyan N. F. Tyupalo 《Russian Journal of Applied Chemistry》2010,83(2):267-270
Reaction of toluene with ozone in acetic anhydride was studied. The dependence of the direction, selectivity, and extent of
oxidation on the reaction temperature, solvent nature, and catalyst composition was examined. 相似文献