Siliceous mesoporous material templated with hexadecyltrimethylammonium bromide–sodium dehydrocholate mixed micelles

A mixture of sodium dehydrocholate (NaDHC) and hexadecyltrimethylammonium bromide (HDTAB) was employed as a template to produce mesoporous silica. The obtained material shows the same structure as common MCM-41 sieves, but the pore radius distribution is narrower than that of the material produced with the same concentration of pure HDTAB. The average pore radius is also larger than that of the pure HDTAB-templated material.     

立方介孔分子筛Zr-SBA-1的合成及表征

在强酸性条件下以十六烷基三甲基溴化铵为模板剂,TEOS为硅源,沿S X-I 途径合成了Zr含量为0.85~2.42%的介孔分子筛Zr-SBA-1.采用XRD、SEM、BET、DR UV-V is等技术对所合成的Zr-SBA-1的表征结果表明,所合成的Zr-SBA-1分子筛具有典型的立方相介孔结构SBA-1分子筛的特征,锆物种被成功引入分子筛骨架中.     

C5烷烃分子在AlPO4-5分子筛中吸附的分子模拟研究

采用分子水平计算机模拟方法研究了环戊烷、正戊烷和2－甲基丁烷在AlPO4-5分子筛中的吸附，得到了有关吸附平衡常数、吸附热、吸附等温线以及平均势能等。结果表明，在373 K，2－甲基丁烷的饱和吸附量高于其他两种异构体；473 K，环戊烷的饱和吸附量高于其他两种异构体；573 K，在所测试的压力范围内，环戊烷的吸附量都高于其他两种异构体，2－甲基丁烷的吸附量高于正戊烷。C5烷烃分子在AlPO4-5中吸附量的不同是由于他们在分子筛中的排列方式不同而引起的。低吸附量时C5烷烃分子平均势能不随吸附量变化；高吸附量时平均势能随着吸附量的增加而降低；而2－甲基丁烷和环戊烷分子的平均势能变化更加明显。     

ETS-10 synthesized from gels with dodecyltrimethylammonium bromide

The aim of this paper is to define the characteristics of crystalline phase ETS-10 obtained from gel with dodecyltrimethylammonium bromide, as an organic template. ETS-10 zeolites has been synthesised under hydrothermal conditions from gels of composition 5Na₂O–3KF–TiO₂–6.4HCl– xC₁₂TMAB –7.45SiO₂–197.5H₂O (where x=0.0, 0.25, 0.55, 1.0 and 1.5) with dodecyltrimethylammonium bromide. The crystalline phases synthesised with organic salt have an exothermal peak at ca. 360°C, due to the degradation of organic entrapped in the porous structure. Physical-chemical properties of C₁₂TMAB -ETS-10 are studied by XRD, SEM and thermal analyses.     

Molecular sieves supported recyclable catalyst for atom transfer radical polymerization using hydration approach

Molecular Sieves (MS) were used as a recyclable support for atom transfer radical polymerization. The catalyst complex, CuBr₂/ligand was supported on hydrated MS and used for the polymerization of benzyl methacrylate at room temperature in anisole. The polymerization using CuBr₂/PMDETA (pentamethyl diethyltetraamine) catalyst that is physically held by the hydration of MS exhibited moderate control and produced catalyst free polymers (<0.1 ppm) with narrow molecular weight distribution (M_w/M_n ≤ 1.33). The polymerization occurred at the interface between the hydrated support and the solution containing initiator and monomer. The hydrated MS supported catalyst was recycled efficiently without a significant loss in activity. The polymerization proceeded in a “living”/controlled manner as was evident from first‐order time conversion plots. The split kinetics experiment affirmed that there was no propagation in the solution in the absence of the supported catalyst. The reaction order plot showed zero‐order dependence on the bulk initiator concentration in solution. The results of MS supported catalyst were compared to Na‐clay supported catalyst system and the improved results were attributed to high self‐diffusion coefficient and low diffusion activation energy of water on its surface. Published 2017.^§ J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3875–3883     

Synthesis of Mesoporous Silica Molecular Sieves via a NovelTemplating Scheme

ThediscoveryofM41SfamilyofmesoporousmolecularsievesbyMobilresearchersI'2hasstimulatedconsiderableinterestintheuseofthesematerialsascatalysts,catalystsupports,aswellasadsorbents3'#.Intheoriginalreport"=,MCM-41waspreparedfromaself-assemblyprocesswhichinvolveselectrostaticinteractionsbetweenpositivelychargedquaternaryammoniummicelles(S )andinorganicanions(l-)usedasframeworkprecursors.Huoetal5extendedtheelectrostaticassemblyapproachesbyproposingfourcomplementarysynthesisschemes(S l-,S-I ,S X-…     

Molecular sieves-supported palladium(II) catalyst: Suzuki coupling of chloroarenes and an easy access to useful intermediates for the synthesis of irbesartan, losartan and boscalid

Palladium(II) chloride supported on 4 Å molecular sieves efficiently catalyzes the Suzuki coupling reactions of chlorobenzenes in presence of tetrabutylammonium bromide without any ligand. The useful intermediates for the synthesis of bioactive compounds such as irbesartan, and losartan have been prepared in one step following this reaction. The preparation of this catalyst is very simple. The FE-SEM image shows a cube shape ordered structure. The catalyst does not exhibit any nanoparticles as indicated by TEM. EDS and XPS demonstrate anchoring of Pd on molecular sieves in +2 oxidation state. This heterogeneous catalyst is stable, non-air sensitive and recyclable.     

MCM-41固载Co席夫碱配合物的制备及其催化烯烃环氧化的研究

环氧化合物作为有机合成中间体具有广泛应用,催化烯烃环氧化一直是催化化学中的一个重要课题[1～2].尽管已经报道了以过酸、过氧化氢、烷基过氧化物、或分子氧为氧化剂,以金属配合物(通常为钌、钼、钛的配合物)为催化剂的反应体系,但对环氧化物的选择性却很低[3].另外,除了需探索具有高选择性的催化体系外,应用分子氧或空气作为氧化剂更适宜于经济和安全的要求.目前,在以分子氧作为氧化剂,均相催化烯烃环氧化的研究中,应用醛类化合物作为氧转移试剂是一种有效的和方便的促进烯烃环氧化的方法[4].但是,均相催化剂难于分离和重复使用,因此…     

Features of Functionalization of MCM-41 Silica Mesoporous Molecular Sieves during Their Template Synthesis

We have shown that functionalization of MCM-41 mesoporous molecular sieves during their template synthesis using the effect of solubilization of organic hydrophobic co-condensing compounds makes it possible to obtain highly ordered mesoporous molecular sieves, with concentrations of vinyl or allyl groups covalently bonded to the surface of the silica matrix of about 3.5 mmol/g, which after sulfonation have acidic properties and exhibit catalytic activity in the process of ethyl tert-butyl ether synthesis.