摘要
对二甲苯(PX)高温液相催化氧化过程采用Co-Mn-Br三元催化体系,在一定条件下,反应过程中催化剂Mn会形成氧化物沉淀析出,从而影响反应过程及产品质量.对反应产物中灰黑色沉淀固体用X射线衍射法(XRD)进行了表征,验证该沉淀主要成分是MnO1.88的晶体;用原子吸光光度法(ASS)测定了母液中钴、锰离子浓度,从而定量反应过程中Mn的沉淀量.对水浓度、原料PX浓度、Br浓度和锰浓度4种影响Mn沉淀因素进行了系统的实验考察,并结合PX氧化反应机理认识到Mn的沉淀机理为在有水条件下Mn(III)发生歧化反应生成MnO2.
A process for oxidation of p-xylene(PX) with mol ec ular oxygen at elevated temperature and under liquid phase conditions in the pre sence of catalyst comprised of cobalt, manganese and bromide components, where p recipitation of the manganese catalyst occurred under certain conditions which a ffected the reaction process and the terephthalic acid(TA)quality. The dark gr ay precipitation was characterized by XRD and confirmed as MnO 1.88 crystal lite. Cobalt and manganese concentration in the mother liquor were obtain by AAS . In this study, several factors (such as water?solvent ratio(HAC/PX)?mangan ese and bromide concentration) that can affect the precipitation of manganese we re investigated systematically, After clarifying the catalysis mechanism of the oxidation process, the author brought forward the Mn precipitation mechanism.
出处
《浙江大学学报(工学版)》
EI
CAS
CSCD
北大核心
2003年第4期482-486,共5页
Journal of Zhejiang University:Engineering Science
基金
中国石油化工股份公司资助项目(X500029).