- A process for the preparation of nitrobenzene derivative
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The invention provides a preparation method of nitrobenzene derivatives, which comprises the following steps: mixing aromatic amino-compound with sodium perborate, a titanic acid catalyst and glacial acetic acid, and reacting to obtain nitrobenzene derivatives, wherein the titanic acid catalyst is prepared by reacting isopropyl titanate and oxydol, and the aromatic amino-compound is a compound with an electrophilic substitution group in the ortho-position of the amino group. By using the sodium perborate as the oxidizer and the titanic acid catalyst as the cocatalyst, the reaction yield is up to 80-85%, and the product purity is up to 99% above.
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Paragraph 0049; 0050; 0051
(2016/10/10)
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- An "ortho effect" in electrophilic aromatic nitrations: Theoretical analysis and experimental validation
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Usually, a π-donor substituent acts as an ortho/para directing group in an electrophilic aromatic substitution reaction, and a π-acceptor substituent acts as a meta directing group. Interestingly, when a π-acceptor substituent is meta to a π-donor substituent, certain electrophilic aromatic nitration occurs ortho to the π-acceptor substituent rather than para . The "ortho effect", highlighted in various textbooks, has been tentatively analyzed here based on ab initio calculations. The reliability of the calculations was verified by the corresponding experimental data, including a newly-designed electrophilic aromatic nitration that also gave reasonable product distributions.
- Li, Hui-Jing,Wu, Yan-Chao,Dai, Jian-Hong,Song, Yan,Cheng, Runjiao,Qiao, Yuanyuan
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p. 1307 - 1312
(2015/02/05)
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- Competition between electron-donor and electron-acceptor substituents in nitrotoluene isomers: A photoelectron spectroscopy and ab initio investigation
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We present an investigation of the close relationship between chemical structure, physical properties and reactivity of the three nitrotoluene isomers: a joint experimental and theoretical study, based on X-ray photoelectron spectroscopy (XPS) measurements and ab initio calculations, addressing the complex interplay between the competing electron-donor and electron-acceptor effects of the nitro- and methyl-substituents on the chemical properties of the nitrotoluene isomers. As the main results of the investigation we: (i) point out that accurate ab initio calculations play a key role in the complete assignment of photoemission measurements, as well as in the estimate of proton affinities in the case of all the eligible sites; (ii) revisit, at a more quantitative level, textbook models based on inductive and resonant effects of different substituents of the aromatic ring, as well as on the hyper-conjugative connection of the methyl group to the π-conjugated system; (iii) provide an accurate analysis of correlation patterns between calculated proton affinities and core-ionization energies, which represent a powerful tool, capable of predicting site-specific reactivities of polysubstituted molecules in the case of electrophilic aromatic substitution reactions.
- Rondino, Flaminia,Catone, Daniele,Mattioli, Giuseppe,Bonapasta, Aldo Amore,Bolognesi, Paola,Casavola, Anna Rita,Coreno, Marcello,O'Keeffe, Patrick,Avaldi, Lorenzo
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p. 5272 - 5282
(2014/01/23)
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- Method for extracting nitrocresols from waste water produced in the manufacture of mononitrotoluene and use of said extract
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The invention provides a process for removing nitrocresols from wastewater of mononitrotoluene preparation, which comprises acidifying the alkaline wastewater of mononitrotoluene preparation with acids to a pH of at most 3 and treating the nitrocresols with an extractant. The invention further provides the preparation of dinitrotoluene by use of the nitrocresol-containing extracts as a feedstock.
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- PRODUCTION OF ISOCYANATE USING CHLORINE RECYCLE
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A process and a system produces isocyanate and converts anhydrous hydrogen chloride, which is a by-product of isocyanate production, to chlorine gas in an electrochemical cell. The chlorine is recycled to the isocyanate process. Any unreacted anhydrous hydrogen chloride may be recycled to the electrochemical cell. By recycling the anhydrous hydrogen chloride and the chlorine, the process and system are able to reduce the cost of producing isocyanate. In addition, this process and system process eliminate or at least substantially minimize the problems associated with disposal of anhydrous hydrogen chloride by turning it into a useful starting material in the isocyanate process.
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- Weak acid process for producing dinitrotoluene
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This invention relates to an improved process for the production of dinitrotoluene wherein one is able to effectively employ a feed sulfuric acid, which is referred to as "weak acid" as the feed sulfuric acid for the nitration facility. The weak acid concentration, as feed, ranges from 86-91%, preferably 87-89% sulfuric acid by weight, to meet the total sulfuric acid requirements for the facility. This is accomplished by utilizing cocurrent processing in a mononitration zone and countercurrent nitration with respect to sulfuric acid in the dinitration zone.
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- Catalytic reduction of nitro aromatic compounds with hydrogen sulfide and carbon monoxide
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In the reduction of di- or polynitro aromatic compounds by gaseous H2 S over a solid catalyst, addition of CO gas promotes formation of amino groups from all nitro groups in the molecule. A preferred embodiment is reduction of 2,4- and/or 2,6-dinitrotoluene in vapor phase at 325° C. over a supported iron or supported cobalt catalyst on a support comprising alumina. The amino products are useful for production of polyurethane resins.
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- SUBSTITUTION OF NITRO GROUPS IN 2,3-DINITROTOLUENE
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The reaction of 2,3-dinitrotoluene with piperidine gives a mixture of 2-piperidino-3-nitrotoluene and 3-piperidino-2-nitrotoluene in a ratio of 3:7.
- Piotrovskii, L.B.,Poznyakova, L.N.
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p. 1691 - 1695
(2007/10/02)
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- Process for the production of nitro derivatives of aromatic compounds
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Nitroderivates of aromatic compounds which are difficult to nitrate, can readily be obtained by nitration providing that the aromatic compound is treated with nitric acid or another nitrating agent in the presence of aliphatic or cycloaliphatic hydrocarbons monosubstituted or polysubstituted by halogen, the nitro group or an alkyl sulphonyl group, and the nitro derivative formed subsequently isolated.
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- Aromatic compound nitration catalyzed by aromatic sulfonic acid supported on solid carrier
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In nitrating an aromatic compound having at least one of ortho-para orientation substituents, a process which is characterized in that nitration is carried out in the presence of an aromatic sulfonic acid supported on a solid carrier in a weight ratio of 1 : 1 to 1 : 20.
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- Sulfonation of aromatic compounds in the presence of solvents
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A process for the sulfonation of aromatic compounds wherein an aromatic substance consisting of one or more aromatic compounds susceptible to the action of sulfur trioxide is formed into a reactant by admixture with one or more organic liquids, substantially inert to sulfur trioxide under the conditions of the process, which reactant is brought to boiling at a temperature not greater than 100° C under a pressure of from 0.1 mm Hg to atmospheric pressure, gaseous sulfur trioxide is introduced thereinto thereby causing it to continue to boil, the component or components of the reactant thus volatilized is or are reconverted to liquid in a heat-exchanger and recycled to the reaction chamber, and the pressure in the reaction chamber and the rate at which the gaseous sulfur trioxide is introduced into the reactant are controlled so as to ensure that there is always present in the reaction chamber an amount of volatilizable matter exceeding that amount volatilizable by the heat of reaction of the aromatic substance present in the reaction chamber with the gaseous sulfur trioxide in contact with said aromatic substance and that the temperature of the reaction mixture is a temperature of 100° C or below.
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- Process for the manufacture of urethanes
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A process for the manufacture of urethanes and the optional co-production of amines by reacting at elevated temperatures and pressures an organic compound containing at least one hydroxyl group with carbon monoxide and a nitrogenous organic compound containing at least one non-cyclic group, in which a nitrogen atom is directly attached to a single carbon atom and is also attached through a double bond to an oxygen or another nitrogen atom, in the presence of an active amount of a catalyst selected from the group consisting of selenium, sulfur, selenium compounds, tellurium compounds, sulfur compounds and mixtures thereof and a base and/or water.
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