固体碱KF/MgAl-LDO催化苯酚与碳酸二甲酯合成苯甲醚  

Synthesis of anisole from phenol and dimethyl carbonate catalyzed by solid base KF/MgAl-LDO

作　　者：王玉斌 陈彤[1] 王公应[1] WANG Yubin;CHEN Tong;WANG Gongying(Chengdu Institute of Organic Chemistry,Chinese Academy of Sciences,Chengdu 610041,Sichuan,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院成都有机化学研究所,四川成都610041 [2]中国科学院大学,北京100049

出　　处：《精细化工》2021年第8期1590-1596,1620,共8页Fine Chemicals

基　　金：四川省重点研发项目(2021YFG0109)。

摘　　要：以Mg(NO_(3))_(2)·6H2O和Al(NO_(3))_(3)·9H_(2)O为原料,共沉淀法制备了镁铝水滑石(MgAl-LDHs),以MgAl-LDHs为前驱体,高温焙烧得到类水滑石MgAl-LDO和不同碱金属卤化物(MX)掺杂的固体碱催化剂MX/MgAl-LDO。对其进行XRD表征和Hammett法碱性滴定,并考察了其催化苯酚与碳酸二甲酯(DMC)合成苯甲醚的活性。结果显示,前驱体MgAl-LDHs的Mg/Al物质的量比、沉淀pH及焙烧温度均影响KF/MgAl-LDO的结构和碱性;KF的掺杂大幅增加了催化剂的碱量,且碱强度(H0)在11.0~15.0区间强碱的碱量提升更为显著,KF/MgAl-LDO增加的强碱性位主要是由KMgF_(3)和K2CO_(3)提供。当KF掺杂量为KF/MgAl-LDO质量的33%时,KF/MgAl-LDO具有最好的催化性能。在DMC/苯酚物质的量比为2∶1,KF/MgAl-LDO用量为苯酚质量1%,200℃下反应4 h,苯甲醚收率为95.2%。对催化剂催化活性与碱性关系分析发现,催化剂的活性与总碱量正相关,而碱强度在11.0~15.0区间的强碱性位具有最高的催化效率。Magnalium hydrotalcites(MgAl-LDHs)were prepared using Mg(NO_(3))_(2)·6H_(2)O and Al(NO_(3))_(3)·9H_(2)O as raw materials by co-precipitation method.Then,hydrotalcite like MgAl-LDO and solid base catalyst MX/MgAl-LDO doped by different alkali metal halides(MX)were prepared by calcination at high temperature using MgAl-LDHs as precursor.The samples were characterized by XRD and Hammett indicator,and the catalytic activity for the synthesis of anisole from phenol and dimethyl carbonate(DMC)was investigated.The results showed that the Mg/Al molar ratio,precipitation pH and calcination temperature of the precursor MgAl-LDHs all affected the structure and alkalinity of KF/MgAl-LDO.The doping of KF greatly increased the base amount in the catalyst,and the strong base amount increased more significantly when the base strength(H0)was in the range of 11.0~15.0,which was mainly provided by KMgF_(3) and K_(2)CO_(3).When the doping dosage of KF was 33% of the mass of KF/MgAl-LDO,the prepared KF/Mg Al-LDO catalyst exhibited the best catalytic properties.Under the conditions of the molar ratio of DMC to phenol of 2∶1,catalyst dosage being only 1% of the mass of phenol,reaction temperature of 200℃ and reaction time of 4 h,the yield of anisole was 95.2%.The analysis of the relationship between catalytic activity and alkalinity of the catalyst indicated that the activity of the catalyst was positively correlated with the total base amount,and the highest catalytic efficiency was obtained when the base strength was in the range of 11~15.

关 键 词：固体碱 镁铝水滑石 氟化钾 碳酸二甲酯 苯甲醚 催化技术 

分 类 号：TQ426[化学工程] TQ241