Nghiên cứu tổng hợp xúc tác cacbon oxit mang trên vật liệu mao quản trung bình Ia3d, x% CoO/SiO2 (ia3d) (x = 1; 1,5; 3; 5) dùng cho phản ứng oxi hóa Benzylancol

Large-pore three-dimensional (3D) mesoporous silicas are among the most interesting mesoporous materials discovered in recent years, and they have attracted much attention for potential applications requiring easily accessible, uniform and large pores. Examples of these are SBA-15 (p6 mm) and SBA-16 (Im3m), which have cylindrical- and cage-type structures, respectively. It has been reported that hexagonally ordered large-pore mesoporous SBA-15 silica made by using a block copolymer contains complementary pores, while such pores were not found in MCM-41 with the same 2D hexagonal p6 mm symmetry [1 - 4]. These complementary pores are arranged in a disordered way between the hexagonally ordered large pore channels. The mesoporous silica with a bicontinuous cubic structure of Ia3d symmetry is composed of an enantiomeric pair of 3D mesoporous networks that are interwoven, as observed in the MCM-48 structure [4]. In this report, we have successfully synthesized silicas Ia3d as supportant material for catalyst CoO and estimated it’s catalytic activity in the oxygenation reaction of benzylalchhol.
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Nghiên cứu tổng hợp xúc tác cacbon oxit mang trên vật liệu mao quản trung bình Ia3d, x% CoO/SiO2 (ia3d) (x = 1; 1,5; 3; 5) dùng cho phản ứng oxi hóa BenzylancolT¹p chÝ Hãa häc, T. 44 (6), Tr. 730 -733, 2006 NGHI£N CøU TæNG HîP XóC T¸C COBAN OXIT MANG TR£N VËT LIÖU MAO QU¶N TRUNG B×NH Ia3d, x% CoO/SiO2 (ia3d) (x = 1; 1,5; 3; 5) DïNG CHO PH¶N øNG OXI Hãa BENZYLANCOL §Õn Tßa so¹n 9-2-2006 Hoa H÷u Thu , Lª Thanh S¬n1, Lª Kim Anh2, Tr ¬ng §×nh §øc2 1 1 Khoa Hãa häc, Tr êng §HKHTN, §¹i häc Quèc gia H( Néi 2 Bé m«n CNTT, Tr êng §¹i häc Kinh tÕ Quèc d©n Summary Large-pore three-dimensional (3D) mesoporous silicas are among the most interesting mesoporous materials discovered in recent years, and they have attracted much attention for potential applications requiring easily accessible, uniform and large pores. Examples of these are SBA-15 (p6 mm) and SBA-16 (Im3m), which have cylindrical- and cage-type structures, respectively. It has been reported that hexagonally ordered large-pore mesoporous SBA-15 silica made by using a block copolymer contains complementary pores, while such pores were not found in MCM-41 with the same 2D hexagonal p6 mm symmetry [1 - 4]. These complementary pores are arranged in a disordered way between the hexagonally ordered large pore channels. The mesoporous silica with a bicontinuous cubic structure of Ia3d symmetry is composed of an enantiomeric pair of 3D mesoporous networks that are interwoven, as observed in the MCM-48 structure [4]. In this report, we have successfully synthesized silicas Ia3d as supportant material for catalyst CoO and estimated it’s catalytic activity in the oxygenation reaction of benzylalchhol. I - Më §ÇU liÖu M41S. Mét ®iÒu ®Æc biÖt l3 ®é d3i mao qu¶n ng¾n nªn thuËn lîi cho qu¸ tr×nh khuÕch §Çu nh÷ng n¨m 90 cña thÕ kû tr íc, mét sè t¸n.vËt liÖu mao qu¶n trung b×nh (VLMQTB) ®0 Silica lç trung b×nh thuéc hÖ tinh thÓ cÊu® îc c¸c nh3 nghiªn cøu cña h0ng Mobil Oil tróc 3 chiÒu v3 hÖ ®èi xøng cña vËt liÖu silicat×m ra nh hä M41S. Hä VLMQTB n3y bao Ia3d l3 lo¹i VLMQTB thó vÞ nhÊt míi ® îc ph¸tgåm c¸c vËt liÖu MCM-41 (cã cÊu tróc lôc hiÖn trong nh÷ng n¨m gÇn ®©y [4]. Lo¹i vËt liÖul¨ng), MCM-48 (cÊu tróc lËp ph ¬ng), MCM-50 n3y ®0 thu hót sù chó ý cña c¸c nh3 khoa häc v×(cÊu tróc líp).... Mét hä vËt liÖu mao qu¶n trung kh¶ n¨ng øng dông cña nã. VËt liÖu silica Ia3db×nh kh¸c, ® îc chÕ t¹o tõ nguån silic víi c¸c cã lç réng, ®ång ®Òu rÊt thÝch hîp cho c¸c ph©nchÊt t¹o cÊu tróc kh«ng ion nh hexadexyl tö h÷u c¬ cã kÝch th íc ph©n tö lín cã thÓamin, polyetylen oxit. C¸c VLMQTB n3y kh«ng khuÕch t¸n v3o trong c¸c lç cña vËt liÖu. Silicamang ®iÖn tÝch, cã d¹ng lôc l¨ng, ®é trËt tù kÐm Ia3d cã hÖ ®èi xøng kh¸c víi MCM-41 (p6h¬n. Cã cÊu tróc mao qu¶n d¹ng “s©u ®ôc”. mm), SBA-15 (p6 mm) v3 SBA-16 (Im3m). HÖSong ® êng kÝnh mao qu¶n ®ång ®Òu, th3nh ®èi xøng n3y bao gåm mét cÆp ®ång ph©n lËpmao qu¶n d3y h¬n nªn bÒn nhiÖt h¬n so víi vËt thÓ m¹ng l íi cÊu tróc 3 chiÒu ®an xen v3o730nhau. C¸c cÊu tróc cña lo¹i vËt liÖu n3y rÊt khã CoO/SiO2. §iÒu chÕ CoO/SiO2 b»ng c¸ch tÈmx¸c ®Þnh chØ b»ng nhiÔu x¹ tia X v× cã mét sè ít, sau ®ã nung kh«. Pha dung dÞch Co(NO3)3ph¶n x¹ ë c¸c gãc nhiÔu x¹ thÊp t¹o nªn c¸c pic 10% (víi tû lÖ ® îc tÝnh to¸n tr íc) råi cho tõ tõréng v3 trïng chËp lªn nhau. C¸c ph ¬ng ph¸p l îng SiO2 (Ia3d) v3o ®ã, khuÊy ®Òu hçn hîpkÝnh hiÓn vi ®iÖn tö nh SEM, TEM, HR-TEM qua ®ªm b»ng m¸y khuÊy tõ, sau ®ã cho hçnl3 ph ¬ng tiÖn chÝnh ®Ó ®Æc tr ng cÊu tróc cña hîp v3o tñ sÊy ë 100 - 110oC v3 ®Ó qua ®ªm.lo¹i silica Ia3d n3y. TiÕp theo nung chÊt r¾n thu ® îc ë 550oC trong VËt liÖu silica Ia3d ® îc tæng hîp b»ng c¸ch 4 h. Cuèi cïng thu ® îc c¸c mÉu xóc t¸c cã h3mdïng hÖ copolyme ba khèi EO20PO70EO20 v3 l îng CoO kh¸c nhau mang trªn SiO2 (Ia3d).butanol-1, ®Ó ®Þnh h íng cÊu tróc trong m«itr êng n íc axit m¹nh. V3 ®Ó tæng hîp lo¹i vËt III - KÕT QU¶ V, TH¶O LUËNliÖu n3y, ng êi ta th êng dïng c¸c nguyªn liÖu®Çu sau: Chóng t«i ®0 ghi gi¶n ®å nhiÔu x¹ tia X nÒn silica Ia3d v3 cña mÉu 3% CoO/SiO2, c¸c kÕt - Copolyme Pluronic P123 (EO20PO70EO20), qu¶ thu ® îc ® îc tr×nh b3y ë h×nh 1. Tõ gi¶nM = 5800; ...