含磺酸基介孔分子筛SBA-15-SO_3H催化合成油酸乙酯

采用水热法直接合成含磺酸基的介孔分子筛SBA-15-SO3H。以油酸和乙醇为原料催化合成油酸乙酯,进行了不同催化剂的对比实验以及催化剂组成、反应温度、酸醇物质的量比和催化剂用量等反应条件的考察。得到最佳反应条件:温度130℃,n(酸)∶n(醇)=1∶2.5,反应时间4 h,催化剂质量分数为10%。

新型疏水性固体酸SBA-15-SO_3H催化剂制备及其催化性能

采用水热法直接合成表面含丙磺酸基和不同烷基（如甲基、辛基和十六烷基）的疏水性介孔分子筛固体酸SBA-15-SO3H.实验表明，固体酸的硫质量分数为3．53％～4．255％，酸含量为（0．84～1．08）mmol·g^-1，相对润湿接触角θr（SBA-15SO3H）〈θr（CH3-SBA-15-SO3H）〈θr（C8H17-SBA-15-SO3H）〈θr（C16H33-SBA-15-SO3H）.催化剂对冰醋酸和正丁醇的酯化反应转化率可达75.5％，转化率随相对润湿角的增大而增大。

Preparation, Characterization and Catalytic Performance of La-SO_4^(2-)/SBA-15 in Esterification of Acetic Acid with n-Butanol

La-SO42-/SBA-15 was synthesized with various amounts of lanthanum via incipient-wetness impregnation. Characterization was done by X-ray diffraction（XRD）, transmission electron micrographs（TEM）, nitrogen adsorption, FTIR spectroscopic analysis, thermogravimetric analysis, and the total amount of acidity of catalyst was estimated by TPD of NH3. The results indicate that lanthanum has been incorporated into SBA-15 molecular sieve. The prepared materials（La-SO42-/SBA-15） keep the highly ordered mesoporous two-dimensional hexagonal structure and do not change the mesoporous channel structure of the support SBA-15. The catalyst showed best catalytic activity in the synthesis of n-butyl acetate. The optimum conditions of the esterification by orthogonal experiments were studied： the molar ratio of n-butanol to acetic acid 1：1.2, the amount of catalyst 7.5%, reaction time 80 min. The yield of n-butyl acetate could reach 93.2% under the optimum conditions. The catalyst was recyclable, cost effective and environmental friendly.

Carbon dioxide reforming of methane over Ni/Mo/SBA-15-La_2O_3 catalyst:Its characterization and catalytic performance

The Ni/Mo/SBA-15 catalyst was modified by La2O3 in order to improve its thermal stability and carbon deposition resistance during the CO2 reforming of methane to syngas. The catalytic performance, thermal stability, structure, dispersion of nickel and carbon deposition of the modified and unmodified catalysts were comparatively investigated by many characterization techniques such as N2 adsorption, H2-TPR, CO2-TPD, XRD, FT-IR and SEM. It was found that the major role of La2O3 additive was to improve the pore structure and inhibit carbon deposition on the catalyst surface. The La2O3 modified Ni/Mo/SBA-15 catalyst possessed a mesoporous structure and high surface area. The high surface area of the La2O3 modified catalysts resulted in strong interaction between Ni and Mo-La, which improved the dispersion of Ni, and retarded the sintering of Ni during the CO2 reforming process. The reaction evaluation results also showed that the La2O3 modified Ni/Mo/SBA-15 catalysts exhibited high stability.

Immobilization of acetylcholinesterase on functionalized SBA-15 mesoporous molecular sieve for detection of organophosphorus and carbamate pesticide

The immobilization of acetylcholinesterase （ACHE） on amino functionalized SBA-15 mesoporous sieves （NH2-SBA-15） was explored for detection of organophosphorus and carhamate pesticides. Several methods have been studied and the ＂adsorption-crosslinking＂ is found to be the best one. Firstly, AChE and bovine serum albumin （BSA） were adsorbed in turn on the surface of NH2-SBA-15 by electrostatic adsorption, and then glutaraldehyde was added for cross-linking the amino group of AChE. The NH2-SBA- 15 showed around 95% immobilization efficiency and the specific activity of immobilized AChE （ACHE- NH2-SBA-15） reached 130% relative to free AChE under optimal immobilization conditions. It was found AChE-NH2-SBA-15 retained 94.0% and 82.8% of its initial activity after 60days at 4℃ and 25℃, respectively. It remained 55.0% of its initial activity after 6 times recycling. During the detection of pesticide, the AChE-NH2-SBA-15 showed wider linear range and much lower limit of detection compared with free ACHE. The current method showed good recovery （93.8%-109.3%） and low RSD （〈5%） for both standard solution and real vegetable samples of Carbaryl and Trichlorfon. It was believed that AChE-NH2- SBA- 15 could be exploited as a fast, sensitive and low-cost biocatalyst towards the detection of pesticides residues which could be stored at room temperature for a long time.

Mesoporous molecular sieve confined phase change materials with high absorption,enhanced thermal conductivity,and cooling energy charging/discharging capacity

The biggest challenge for organic phase change materials(PCMs)used in cold energy storage is to maintain high heat storage capacity while reducing the leakage risk of PCMs during the phase transition process.This is crucial for expanding their applications in the more demanding cold storage field.In this study,novel formstable low-temperature composite PCMs are prepared with mesoporous materials,namely SBA-15 and CMK-3(which are prepared using the template method),as supporting matrices and dodecane as the PCM.Owing to the combined effects of capillary forces within mesoporous materials and interactions among dodecane molecules,both dodecane/SBA-15 and dodecane/CMK-3 exhibit outstanding shape stability and thermal cycling stability even after 200 heating/cooling cycles.In comparison to those of dodecane/SBA-15,dodecane/CMK-3 exhibits superior cold storage performance and higher thermal conductivity.Specifically,the phase transition temperature of dodecane/CMK-3 is-8.81℃ with a latent heat of 122.4 J·g^(-1).Additionally,it has a thermal conductivity of 1.21 W·m^(-1)·K^(-1),which is 9.45 times that of dodecane alone.All these highlight its significant potential for applications in the area of cold energy storage.

Enhanced desulfurization performance of hybrid membranes using embedded hierarchical porous SBA-15

The utilization of materials with a hierarchical porous structure as multi-functional additives is highly attractive in the preparation of hybrid membranes.In this study,novel hybrid membranes are designed by embed-ding hierarchical porous Santa Barbara Amorphous 15(SBA-15)with a dual-pore architecture(micropores and mesopores)for pervaporation desulfurization.The SBA-15 with cylindrical mesopores provides molecular transport expressways to ensure improved permeability,while micropores on the wall have molecular sieving effects that are essential for the enhancement of permselectivity of thiophene molecules.Considering thiophene/n-octane mixture as a model system,the hybrid membrane with embedded 6 wt-%SBA-15 exhibits optimal pervaporation desulfurization performance with a permeation flux of 22.07 kg·m^-2·h^-1 and an enrichment factor of 6.76.Moreover,the detailed structure and properties of hybrid membranes are systematically characterized.This study demonstrates the immense potential of hierarchical porous materials as additives in membranes to simultaneously increase permeability and permselectivity.

Asymmetric transfer hydrogenation of prochiral ketone catalyzed over Fe-CS/SBA-15 catalyst

A heterogeneous chiral catalyst Fe(III)-CS(chitosan)complex/mesoporous molecular sieve SBA-15(Santa Barbara Amorphous)was prepared.The asymmetric transfer hydrogenations of prochiral acetophenone and 4-methyl-2-pentanone to corresponding chiral alcohols were carried out on Fe-CS/SBA-15 at atmosphere pressure using 2-propanol as hydrogen donor.Effects of Fe content in cata-lyst,reaction temperature,reaction time and promoter KOH concentration on the conversion of substrates and enantio-selectivity were investigated.Fe-CS/SBA-15 with 2.2%mass fraction Fe exhibits considerable enantioselectivity and cata-lytic activity for the asymmetric transfer hydrogenations of aromatic ketone and aliphatic ketone.Under optimal reaction conditions:KOH concentration 0.03 mol/L,reaction tem-perature 70℃ and reaction time 4 h,enantiomer excess(ee)of(R)-1-phenylethanol and conversion of acetophenone can reach 87.4%and 27.7%,respectively.Under the above KOH concentration and reaction temperature and reaction time of 8 h,the ee of(R)-4-methyl-2-pentanol and conversion 4-methyl-2-pentanone amounted to 50.2%and 25.5%,respectively.