催化学报
催化學報
최화학보
CHINESE JOURNAL OF CATALYSIS
2009年
12期
1238-1242
,共5页
金国杰%高焕新%杨洪云%陈璐%丁琳%康陈军%谢在库
金國傑%高煥新%楊洪雲%陳璐%丁琳%康陳軍%謝在庫
금국걸%고환신%양홍운%진로%정림%강진군%사재고
钛%HMS分子筛%失活%再生%丙烯%环氧化%环氧丙烷
鈦%HMS分子篩%失活%再生%丙烯%環氧化%環氧丙烷
태%HMS분자사%실활%재생%병희%배양화%배양병완
titanium%HMS molecular sieve%deactivation%regeneration%propylene%epoxidation%propylene oxide
研究了以异丙苯过氧化氢为氧化剂选择氧化内烯制环氧丙烷的Ti/HMS催化剂的失活原因.采用XRD(X射线衍射),FT-IR(傅里叶变换红外光谱),UV-Vis(紫外-可见光谱)和TG(热重分析)等技术表征了催化剂失活前后的结构和化学组成.结果表明,催化剂的失活主要是由于反应过程中所产生的重组分在催化剂表面吸附,覆盖了活性中心所致;并不是由于四配位的活件钛物种转化为六配位、八配位或者锐钛矿TiO_2所致.采用热异丙苯溶剂洗涤的方法可以部分恢复失活催化剂的活性,但不能恢复到新鲜催化剂的水平:采用低温烧炭方法能够使催化剂的活性恢复到新鲜催化剂的水平.因此,Ti/HMS催化剂的失活是可逆的,采用合适的再生方法可以恢复其催化活性.
研究瞭以異丙苯過氧化氫為氧化劑選擇氧化內烯製環氧丙烷的Ti/HMS催化劑的失活原因.採用XRD(X射線衍射),FT-IR(傅裏葉變換紅外光譜),UV-Vis(紫外-可見光譜)和TG(熱重分析)等技術錶徵瞭催化劑失活前後的結構和化學組成.結果錶明,催化劑的失活主要是由于反應過程中所產生的重組分在催化劑錶麵吸附,覆蓋瞭活性中心所緻;併不是由于四配位的活件鈦物種轉化為六配位、八配位或者銳鈦礦TiO_2所緻.採用熱異丙苯溶劑洗滌的方法可以部分恢複失活催化劑的活性,但不能恢複到新鮮催化劑的水平:採用低溫燒炭方法能夠使催化劑的活性恢複到新鮮催化劑的水平.因此,Ti/HMS催化劑的失活是可逆的,採用閤適的再生方法可以恢複其催化活性.
연구료이이병분과양화경위양화제선택양화내희제배양병완적Ti/HMS최화제적실활원인.채용XRD(X사선연사),FT-IR(부리협변환홍외광보),UV-Vis(자외-가견광보)화TG(열중분석)등기술표정료최화제실활전후적결구화화학조성.결과표명,최화제적실활주요시유우반응과정중소산생적중조분재최화제표면흡부,복개료활성중심소치;병불시유우사배위적활건태물충전화위륙배위、팔배위혹자예태광TiO_2소치.채용열이병분용제세조적방법가이부분회복실활최화제적활성,단불능회복도신선최화제적수평:채용저온소탄방법능구사최화제적활성회복도신선최화제적수평.인차,Ti/HMS최화제적실활시가역적,채용합괄적재생방법가이회복기최화활성.
Using cumene hydroperoxide as an oxidant,the deactivation and regeneration of the Ti/HMS(titanium-containing hexagonal mesoporous silica)catalyst were studied for epoxidation of propylene to propylene oxide.The structure and surface species of the fresh and used catalysts were characterized by X-ray diffraction.Fourier transform infrared spectroscopy,ultraviolet-visible spectroscopy,and thermogravimetry analysis.The results indicated that the main reason for catalyst deactivation was that the active sites on the catalyst surface were covered by polymer molecules produced during the reaction.The catalyst deactivation was not due to the transformation of tetra-coordinated Ti species to hexa-coordinated,octa-coordinated,or even anatase species.Hot cumene washing could partly restore the catalyst activity,but the low-temperature carbon-burning could restore the catalyst activity nearly to the level of fresh one.Therefore,the deactivated Ti/HMS catalyst Was renewable and its activity could be restored by a proper regeneration method.