19847-12-2Relevant articles and documents
Tuning the surface composition of novel metal vanadates and its effect on the catalytic performance
Dhachapally, Naresh,Kalevaru, V. Narayana,Radnik, Joerg,Martin, Andreas
, p. 8394 - 8396 (2011)
Tuning the surface composition of metal vanadates using different cations leads to the development of a new class of highly effective catalysts tested in the ammoxidation of 2-methylpyrazine. Especially, an enrichment of V in the near-surface region is beneficial for improved selectivity. With this approach, a knowledge based optimisation of the catalysts was possible for the first time, which indeed led to highly efficient novel LaVOx catalysts with a high yield of 2-cyanopyrazine (≥85%) and extremely high space-time-yields (ca. 525 g-1CP kg-1cat h-1).
Ammoxidation of 2-Methylpyrazine. Characterisation of Catalyst
Forni, Lucio,Oliva, Cesare,Rebuscini, Claudio
, p. 2397 - 2408 (1988)
The effect of changing the relative ratios of the active components in Sb-V-Mn mixed oxides, their concentration on the support and the nature of the latter has been analysed by employing several techniques, such as X-ray diffraction, scanning electron microscopy, electron probe microanalysis and electron spin resonance spectroscopy, together with chemical analysis, a titration of the surface acidity, and determinations of both the B.E.T. surface area and the porosity.A close dependence of activity and selectivity on the nature of the support was observed, connected with the ability of the latter to supress the formation of microporosity.The catalytic activity is due to Sb4+ species.V and Mn both act as a structural promoter, conferring electrical conductivity on the solid and so improving the rapid electron transfer from the bulk to the surface, and vice versa.
Metal vanadate catalysts for the ammoxidation of 2-methylpyrazine to 2-cyanopyrazine
Dhachapally, Naresh,Kalevaru, Venkata N.,Brückner, Angelika,Martin, Andreas
, p. 111 - 118 (2012)
The ammoxidation of 2-methylpyrazine to 2-cyanopyrazine was carried out in a fixed bed metal reactor in the temperature range of 320-460 °C using a series of metal vanadate-containing solids (MV) as catalysts. These solids named as AlVO4, FeVO4, CrVO4, NbVO5, LaVO4 and BiVO4 were prepared with a nominal V/M ratio = 1 always using the same synthesis procedure. Fresh and spent solids were characterized by X-ray diffraction, UV-vis DRS, XPS and pyridine-FTIR & ESR spectroscopy. The results revealed that the phase composition, near-surface-region behaviour and catalytic properties strongly depend on the nature of the metal used in MV solids. XRD showed the formation of crystalline MV phases in case of LaVO4 and BiVO4; whereas FeVO 4 and CrVO4 exhibited poor crystallinity only. AlVO 4 sample revealed the clear formation of crystalline V 2O5 whereas in NbVO5 only a small proportion of V2O5 was detected. XPS depicted that the enrichment of vanadium in the near-surface-region is clearly dependent on the type of MV. It can be concluded that high near-surface-region V/M molar ratios promote the selectivity to cyanopyrazine but reduce the catalytic activity and vice versa. NbVO5 showed the best catalytic performance compared to all other MVs. Almost 69% yield of 2-cyanopyrazine at total conversion could be successfully obtained.
Preparation process of pyrazinamide
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Paragraph 0023; 0025; 0028-0029; 0032; 0034; 0037; 0039;, (2020/07/24)
A preparation process of pyrazinamide comprises the following steps: (1) synthesis of 2-methylpyrazine: putting a catalyst I into a reactor I, and performing reducing for 4 hours; adding 2-methylpyrazine into the reactor I, then adding ethylenediamine and 1, 2-propylene glycol, carrying out gas-solid phase contact catalytic reaction in the reactor I, cooling a mixture generated by the reaction through a condenser, feeding the mixture into a receiver, taking tail gas, and performing absorbing, emptying and separating to obtain 2-methylpyrazine, (2) chemical base catalysis; putting the catalystII into a reactor II, introducing an aqueous solution of 2-methylpyrazine in a mass ratio of (1:10)-(1:20) into the reactor II through a metering pump, introducing ammonia gas and air, controlling thetemperature of the reaction system to be 3-6 DEG C, maintaining the pH value to be 9-10, performing reacting for 1-2 hours, and performing heating to 20-30 DEG C to obtain 2-cyanopyrazine; and (3) synthesis of pyrazinamide. The preparation process of pyrazinamide has the advantages of the simple process, the high conversion rate, no generation of by-product pyrazinic acid, the good economic benefits and the wide application prospect.
METHOD FOR PRODUCING AROMATIC NITRILE COMPOUND AND METHOD FOR PRODUCING CARBONATE ESTER
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Paragraph 0099; 0101; 0102, (2019/07/03)
Provided is a method for regenerating an aromatic amide compound into a corresponding aromatic nitrile compound, the method realizing a dehydration reaction of providing a target compound selectively at a high yield with generation of a by-product being suppressed. Also provided is a method for producing an aromatic nitrile compound that decreases the number of steps of dehydration reaction and significantly improves the reaction speed at a pressure close to normal pressure. Furthermore, the above-described production method is applied to a carbonate ester production method to provide a method for producing carbonate ester efficiently. The above-described objects are achieved by a method for producing an aromatic nitrile compound including a dehydration reaction of dehydrating an aromatic amide compound, in which the dehydration reaction uses diphenylether.
