鈦硅分子篩擠條成型催化劑熱穩(wěn)定性能的研究

1、 246 分子催化第 18 卷 和雙氧水有效利用率急劇下降. 當焙燒溫度達到 1 100 后, 分子篩骨架完全破壞, 催化劑不再具 有催化活性. 由表 2 可知, 在焙燒溫度為 900 時, T S 21 仍具有很高的催化活性; 當焙燒溫 度 升 至 1 000 時, 催化劑還具有較好的催化活性 . 隨著 焙燒溫度的提高, 由于 T S 21 SiO 2 和 T S 21 的骨架 表 2 在不同溫度下焙燒 TS- 1 所得樣品的丙烯環(huán)氧化性能 T ab le 2 Epox ida tion of p rop ylene w ith d ilu te hyd rogen p erox ide o

2、ver T S 21ca lcined a t d ifferen t tem p era tu res Ca lcina tion tem p era tu re ( 540 700 900 1 000 1 100 1 200 X H 2O 2 S PO S MM E U H 2O 2 97. 78 96. 75 97. 05 68. 64 0 0 91. 75 89. 83 91. 20 98. 71 - 8. 24 10. 17 8. 80 1. 29 91. 42 88. 36 86. 91 68. 17 - - R eaction cond ition: reaction tem p

3、 era tu re 60 , reaction ti m e 60 m in, p rop ylene p ressu re 0. 4 M Pa, the concen tra tion of H 2O 2 0. 53 m o l L , the concen tra tion of ca ta lyst 12 g L. 鈦和分子篩結(jié)構(gòu)的變化不同, 體現(xiàn)在二者催化活性 變化上的巨大差異. 由此可見, 載體的加入降低了 鈦硅分子篩擠條成型催化劑的熱穩(wěn)定性能. ( 4 : 280 286 5 Fejes P, N agy J B , H a lá sz J et a l. A pp l

4、 C a ta l A J , 1998, 175 ( 1 2 : 89 104 6 Guo X W ( 郭新聞 , W ang X SH ( 王祥生 , L i G ( 李 3 結(jié)論 當焙燒溫度在 540 700 之間, T S 21 負載于 上結(jié)構(gòu)穩(wěn)定 , 丙烯環(huán)氧化性能與 Si O2 T S 21 相同; 當焙燒溫度高于 900 , 熱穩(wěn)定性明顯低于 T S 21 本身, 催化氧化性能下降. 在 T S 21 和 SiO 2 之間存 在相互作用 . 在 1 000 焙燒時, 由于受載體 Si O2 作用, 使 T S 21 骨架遭到破壞; 在 1 200 焙燒時, 由于受 T S 21

5、作用, 限制了載體 SiO 2 晶型轉(zhuǎn)變. 參考文獻: 1 W ang L ( 王嵐 , M eng SH H ( 孟霜鶴 , T an ZH CH ( 譚志誠 , et a l. C h in J C a ta l ( 催化學報 J , 2001, 22 ( 5 : 491 493 2 L iu ZH M ( 劉中民 , H uang X Y ( 黃興云 , H e CH Q ( 何長青 , et a l. C h in J C a ta l ( 催化學報 J , 1996, 17 ( 6 : 540 543 3 L i H Y ( 李宏愿 , L iang J ( 梁娟 , L iu B

6、X ( 劉寶祥 , et a l. P etrol C hem T echnol ( 石油化工 J , 1986, 15 鋼 , et a l. A cta P etrol S in ( Petro l P roc ( 石油學報 ( 石油加工 J , 2002, 18 ( 2 : 34 40 7 W ang X SH ( 王祥生 , Zhang Y H ( 張義華 , Guo X W ( 郭新聞 , et a l. ZL 01145256. 0. 2001 8 Ca ra ti A , F lego C , P revide M a ssa ra E, et a l. M icro ( 申請?zhí)?/p>

7、 P , 144 M esop or M a ter J , 1999, 30 ( 1 : 137 圭 , X in Q ( 辛勤 , Zhang H ( 張慧 , 9 Guo W G ( 郭文王 et a l. C h in J C a ta l ( 催化學報 J , 1981, 2 ( 1 : 36 41 10 L i C , X iong G, X in Q , et a l. A ng ew C hem In t E d J , 1999, 38 ( 15 : 2 220 2 222 11 L i C , X iong G, L iu J , et a l. P hy s C hem

8、B J , 2001, 105 ( 15 , 2 993 2 997 ( 7 : 405 410 4 Guo X W ( 郭新聞 , L i G Y ( 李光巖 , W ang G R ( 王 桂茹 , et a l. C h in J C a ta l ( 催化學報 J , 1995, 16 第 4 期成衛(wèi)國等: 鈦硅分子篩擠條成型催化劑熱穩(wěn)定性能的研究 247 Therm ostab il ity of Extruded T itan ium Sil ica l ite Ca ta lyst 1 1, 2 1 1, 2 CH EN G W ei2guo , W AN G X iang 2s

9、heng , L I Gang , GU O X ing 2 w en , 3 3 LI AN Yu 2x iang , L I Can ( 1. D ep a rtm en t of C a ta ly sis C hem istry and E ng ineering , D a lian U n iv ersity of T echnology , D a lian 116012, C h ina; 2. S ta te K ey L abora tory of F ine C hem ica l , D a lian U n iv ersity of T echnology , D a

10、 lian 116012, C h ina ; 3. S ta te K ey L abora tory of C a ta ly sis , D a lian Institu te of C hem ica l P hy sics , C h inese A cad em y of S ciences , D a lian 116023, C h ina Abstract: T itan ium silica lite ( T S 21 w a s successfu lly syn thesized w ith tet rap rop y lamm on ium b rom ide ( T

11、 PAB r a s the tem p la tes, t itan ium tet rach lo ride a s T i sou rce and co llo ida l silica a s Si sou rce. T he ex t ruded t itan ium silica lite w a s p rep a red u sing Si O 2 a s suppo rt. T he therm o stab ility of the ex t ruded t itan ium silica lite w a s invest iga ted and their p erfo

12、 rm ance in p rop y lene epox ida t ion w ere tested. A bove ca ta ly st s w ere cha racterized by XRD , IR , U V R am an and SEM . It ha s been show n tha t am o rp hou s silicon . B u t silicon d iox ide in d iox ide convert s in to t ridym ite22H a t 1 000 and in to t ridym ite 220H a t 1 200 T S

13、 21 Si O 2 rem a in s st ill t ridym ite 22H a t 1 200 becau se it is affected by T S 21. R ela t ive cry sta llin ity of T S 21 Si O 2 decrea ses m o re d ram a t ica lly than tha t of T S 21 w ith the increa se of the ca lcina t ion tem p era tu re. T he fram ew o rk of T S 21 Si O 2 is dest royed

14、 w hen the ca lcina t ion tem p era tu re reaches 1 000 , how ever, the fram ew o rk of T S 21 rem a in s a t the sam e tem p era tu re. A s the ca lcina t ion tem p era tu re rise, the in ten sity - 1 of 960 cm p eak in IR sp ect ra of T S 21 Si O 2 decrea se rap id ly. W hen the ca lcina t ion tem

15、 p era tu re rise up to 1 000 , the band a t 960 cm - 1 in IR changes to 948 cm - 1 and the band a t 1 230 cm 1 and 545 cm 1 - 1 - 1 d isapp ea r. B u t the band s of T S 21 a t 1 230 cm and 545 cm a re qu ite st rong. T he fo rm a t ion of t ridym ite 2 2H resu lt s in t itan ium a tom s sep a ra t

16、 ing from fram ew o rk and the fram ew o rk dest roy ing. Si m ila r conclu sion . In R am an sp ect ra, the in ten sity of the resonance can a lso be d raw n from the U V 2 R am an m ea su rem en t s - 1 enhanced R am an band a t 1 125 cm , w h ich rep resen t s the fram ew o rk site t itan ium sp

17、ecies, decrea se . T h is ind ica tes the dest ruct ion of fram ew o rk t itan ium sp ecies w ith d ram a t ica lly after ca lcined a t 900 tet rahed ra l coo rd ina ted st ructu re in T S 21 Si O 2 after the ca lcina t ion s, w h ile th is change does no t happ en in . T he conversion of hyd rogen p erox ide decrea ses d ra st ica lly ca ta lyzed by T S 21 befo re and after ca lcina t ion s T S 21 Si O 2 ca lcined a t 900 , w h ile