Synthesis Of Order Mesoporous Solid Sulfonic Acid And Study On Acid Catalytic Properties

Acid catalytic reactions are important chemical reactions. Compared with the traditional liquid acids, solid acids have many advantages, such as low corrosive, separated from product and activated for reusing easily. Highly ordered hexagonal mesoporous sieve SBA-15 has uniform mesopores together with high surface area, a number of disordered microporous throughout the main porous channels and stable mesostructure. Introducing-SO3H into SBA-15, the solid acid can be used in the acid catalytic reactions.In this thesis, we employed SBA-15 as the carrier, sugar and furfuryl alcohol as the carbon precursors, and prepared sulfonated mesoporous solid acids through a vapor-phase transfer sulfonation procedure. We also had studied the acid catalytic properties of the materials. The main contents are as follows:1. CMK-3-SO3H was used in the acetylation. We employed SBA-15 as the template and sucrose as the carbon precursor. Sucrose carbonized at 550℃for 6 h. Using HF solution to remove SBA-15, we got CMK-3. We made mesoporous carbon sulfonic acid (CMK-3-SO3H) through a vapor-phase transfer sulfonation procedure (at 80℃for 12 h). The catalyst was characterized by means of XRD, SEM, N2 adsorption-desorption, FT-IR, TG-DTA, 13C NMR and acid-base titration, which indicated that it had uniform mesopores together with an amount of acid sites as high as 1.07 mmol g-1. At room temperature (25℃), a relatively short period of time, the catalyst can catalyze the acetylation of many alcohols (phenols/aldehydes) with acetic anhydride respectively, with high yields and selectivity larger than 99%. But the catalyst catalyzed fatty aldehydes with lower yields and poor selectivity. When preparing the material, we found that the load of carbon and the carbonization were difficultly to be controlled. If SBA-15 was removed, the structure of the materials were easily to collapse. If SBA-15 was reserved, this problem can be avoid.2. SBA-15-C-SO3H (sucrose as the carbon precursor) was used in the acetalization and ketalization. We employed SBA-15 as the carrier and sucrose as the carbon precursor. Sucrose carbonized in the channels of SBA-15 incompletedly and generated polycyclic aromatic carbon. We made mesoporous carbon-silica solid acid (SBA-15-C-SO3H) through a vapor-phase transfer sulfonation procedure (at 80℃for 12 h). In the same content of carbon (29%), we investigated the relationship between the intensity of diffraction peak, the acid value and the carbonization temperature. The optimized carbonization temperature was 773 K. The catalyst was characterized, which indicated that it had uniform mesopores together with an amount of acid sites as high as 0.58 mmol g-1. The catalyst could catalyze the condensation of aldehydes (ketones) with glycol reaction effectively. The polycyclic aromatic carbon was filled in the channels of SBA-15 disorderly, so the materials had lower carbon loading. If using furfuryl alcohol as the carbon source, we may get the carbon silicon solid sulfonic acid with the higher carbon loading.3. SBA-15-C-SO3H (furfuryl alcohol as the carbon precursor) was used in the Michael addition reaction. We employed furfuryl alcohol as the carbon precursor and modulated the amount of furfuryl alcohol (0.5 g-5.0 g) inside the channels of AlSBA-15 by the incipient-wetness technique. The mixture was heated at 80℃for 2 h, and then at 150℃for 6 h, the remaining furfuryl alcohol was removed by heating the sample at 150℃with evacuation for 3 h. The polymerized furfuryl alcohol was converted to carbon inside AlSBA-15 by pyrolysis at 500℃for 6 h, producing a series of carbon-silica composites (AlSBA-15-C). We got a series of AlSBA-15-C-SO3H with different carbon loading and acid value, through a vapor-phase transfer sulfonation procedure (at 80℃for 12 h). Using HF solution to remove SBA-15, we got CMK-5. Comparing the series of AlSBA-15-C-SO3H with the series of SBA-15-C-SO3H which were prepared using sucrose as the carbon precursor, we found that AlSBA-15-C-SO3H catalyzed the condensation of cyclopentanone with ethylene glycol more efficiently. When oxalic acid was used as catalyst, there was no need of introducing Al into SBA-15. Optimized SBA-15-C-51%-SO3H from the series of SBA-15-C-SO3H, which was used in the Michael addition reaction, showing a fine catalytic activity. The catalyst and CMK-5 were characterized. We found that the nitrogen adsorption desorption isotherms of the carbon silicon solid sulfonic acid changed from the typeⅣto the typeⅠgradually, the hysteresis loop type changed from H1 to H2 gradually, specific surface area and pore diameter decreased gradually with the increase of the carbon loading.