应用化学
應用化學
응용화학
CHINESE JOURNAL OF APPLIED CHEMISTRY
2001年
1期
16-20
,共5页
异丁烷%选择氧化%激光促进表面反应%钒钼复合氧化物%甲基丙烯酸
異丁烷%選擇氧化%激光促進錶麵反應%釩鉬複閤氧化物%甲基丙烯痠
이정완%선택양화%격광촉진표면반응%범목복합양화물%갑기병희산
用共沉淀法制备了V和Mo的复合氧化物.运用XRD、IR、TPD和LSSR技术研究了其晶体结构、表面构造、化学吸附特性和激光促进异丁烷选择氧化反应性能.结果表明:V—Mo—O的主体物相为Mo4V6O24,它具有MoO3和V2O4交替排列的层状结构;其表面上存在着Lewis碱位Mo=O和Mo—O—V键中的O2-及Lewis酸位V4+;异丁烷的2个甲基H分别吸附在2个相邻的Lewis碱位Mo=O上形成双位分子吸附态;在常压和200℃条件下,用一定频率的激光激发Mo=O键1000次,异丁烷的转化率为6.5%,其反应产物是异丁烯、甲基丙烯醛和甲基丙烯酸,其中甲基丙烯酸的选择性为78%.根据实验结果,探讨了激光促进异丁烷选择氧化为甲基丙烯酸的表面反应机理.
用共沉澱法製備瞭V和Mo的複閤氧化物.運用XRD、IR、TPD和LSSR技術研究瞭其晶體結構、錶麵構造、化學吸附特性和激光促進異丁烷選擇氧化反應性能.結果錶明:V—Mo—O的主體物相為Mo4V6O24,它具有MoO3和V2O4交替排列的層狀結構;其錶麵上存在著Lewis堿位Mo=O和Mo—O—V鍵中的O2-及Lewis痠位V4+;異丁烷的2箇甲基H分彆吸附在2箇相鄰的Lewis堿位Mo=O上形成雙位分子吸附態;在常壓和200℃條件下,用一定頻率的激光激髮Mo=O鍵1000次,異丁烷的轉化率為6.5%,其反應產物是異丁烯、甲基丙烯醛和甲基丙烯痠,其中甲基丙烯痠的選擇性為78%.根據實驗結果,探討瞭激光促進異丁烷選擇氧化為甲基丙烯痠的錶麵反應機理.
용공침정법제비료V화Mo적복합양화물.운용XRD、IR、TPD화LSSR기술연구료기정체결구、표면구조、화학흡부특성화격광촉진이정완선택양화반응성능.결과표명:V—Mo—O적주체물상위Mo4V6O24,타구유MoO3화V2O4교체배렬적층상결구;기표면상존재착Lewis감위Mo=O화Mo—O—V건중적O2-급Lewis산위V4+;이정완적2개갑기H분별흡부재2개상린적Lewis감위Mo=O상형성쌍위분자흡부태;재상압화200℃조건하,용일정빈솔적격광격발Mo=O건1000차,이정완적전화솔위6.5%,기반응산물시이정희、갑기병희철화갑기병희산,기중갑기병희산적선택성위78%.근거실험결과,탐토료격광촉진이정완선택양화위갑기병희산적표면반응궤리.
A Mo/V complex oxide was prepared from (NH4)6Mo7O26.4H2O andNH4VO3 by a coprecipitation method. The surface composition, structure, chemsorption and behavior of laser stimulated selective oxidation of isobutane have been investigated by XRD, IR, TPD and microreactor. The results showed that the main phase of the complex oxide is Mo4V6O24, which has a storeyed structure composed of MoO3 and V2O4. There are both Lewis base sites, O2- in the surface Mo=O or Mo—O—V bonds, and Lewis acid site, V4+ appeared on the surface of complex oxide. Two methyl hydrogens in isobutane molecule can be chemisorbed on the terminal oxygen of the neibouring Mo=O bonds on the surface of the complex oxide. Under the conditions of 0.1 MPa, 200 ℃ and 1000 times of laser excitation with 972 cm-1on the MoObonds, about 6.5% isobutane were converted to isobutene, methyl propenal and methacrylic aicd, among them 78% were the latter. A mechanism is proposed for isobutane selective oxidation.