Ammoxidation of methylpyrazine over phosphorus-modified vanadium-titanium catalysts

Vanadium-titanium catalysts modified with phosphorus additives (1-15 wt.% of P₂O₅) have been studied in methylpyrazine ammoxidation. Introduction of high amounts of the additive (≥ 10 wt.% of P₂O₅) results in a decrease in activity and selectivity of the catalysts due to formation of low active phase - a ternary compound with the component ratio V : P : Ti ≈ 1 : 1 : 1 with only one type of slightly distorted tetrahedral vanadium (5+) bound via oxygen to phosphorus (5+). The nature of the active sites of the samples modified with 1-5 wt.% of P₂O₅, similarly to that in the V-Ti-O catalyst, was found to include the V⁵⁺ cations strongly bound with TiO₂ and located in the significantly distorted octahedral oxygen environment. This revised version was published online in June 2006 with corrections to the Cover Date.     

A New Synthetic Route for 2,4-Dibromo-5-fluorobenzoic Acid

Fluoroquinolonesareeffectivemedicinesagainstbacteria,evenagainsttumor.Overtenexcellentfluoroquinol0nemedicineshavebeen0nthemarket.Duet0thehigherselectivity,yieldatbrondnationof3-flu0rotoluenethanchlorination,and0theradvantages'-',2,4-dibromo-5-flu0r0benzoicacidhasreplaced2,4-dichloro-5-fluor0-benzoicacidandbecomethekeystartingmaterialofpreparingfluoroquinoIonemedicines'.S0itisofgreatsignificancetofindaneffectivesyntheticpathfor2,4-dibromo-5-fluor0benz0icacid.Therehavebeenproposedtwomethodsf0r…     

Selective catalysts for the production of nitrogen-containing compounds

Herewith are the two processes developed by Nitto, which produce N-containing compounds such as hydrogen cyanide and methylamines. These processes are characterized by unique selective catalysts: an Fe–Sb–O based fluid-bed catalyst for ammoxidation of methanol and a shape-selective zeolite catalyst for ammonolysis of methanol.     

2,4-二氯甲苯氨氧化法制备2,4-二氯苯腈研究

对２,４－二氯甲苯经氨氧化法,一步制备有机中间体２,４－二氯苯腈进行了研究．在“微反－色谱”联用装置上完成催化剂的评比和筛选后,在内径３０ｍｍ的石英管固定床反应器上印证并进行工艺条件实验．考察了反应温度、氨比、空气比和空速对反应的转化率、摩尔收率和选择性的影响．所确定的工艺简捷,在合适的条件下使用ＤＴ１２４号催化剂,转化率高达９８．１％、摩尔收率８９．５％,生成２,４－二氯苯腈为白色针状或片状结晶,纯度高于９９％．同时,结合２,６－二氯甲苯氨氧化反应研究工作,对二氯甲苯的２、４位和２、６位的两个氯原子对反应的影响进行了初步的讨论     

丙烯氨氧化Mo-Bi-Fe-P/海泡石负载型催化剂的研究

丙烯氨氧化Mo-Bi-Fe-P/海泡石负载型催化剂的研究     

对氯甲苯氨氧化法制备对氯苯腈研究

在“微反-色谱”联用装置上完成对氯甲苯氨氧化制备对氯苯腈的催化剂评比和筛选后,在内径30mm的石英管固定床反应器上印证并进行工艺条件实验．考察了反应温度、氨比、空气比和空间速度对反应的转化率、摩尔产率和选择性的影响．所确定的工艺简捷,在合适的条件下使用PC97催化剂,对氯甲苯转化率高达100％,对氯苯腈摩尔产率90．9％,生成的对氯苯腈为白色针状结晶,纯度高于99％．     

基于Monte Carlo模拟的化学反应动力学参数估算

提出并采用基于MonteCarlo模拟与动力学实验相结合的化学反应动力学参数估算方法,由基元反应确定MonteCarlo模拟具体做法,将MonteCarlo模拟结果与动力学实验结果相比较,根据比较结果自动调整和优化动力学参数,从而无需事先确定动力学方程即可有效估算各种化学反应的动力学参数值.采用该方法估算了丙烯氨氧化反应动力学参数,并对估算结果进行了分析与讨论.     

Effect of the surface vanadium valence state on activity and selectivity properties of (VO)2P2O7 used as catalyst in the ammoxidation of toluene

The effect of the surface vanadium valence state of a (VO)₂P₂O₇ catalyst, which was changed by reductive as well as oxidative pretreatment, on its catalytic properties in toluene ammoxidation to benzonitrile is reported.