以一种新型Gemini表面活性剂作为介孔模板剂通过转晶过程合成介孔ZSM-5分子筛

将一种新型Gemini表面活性剂,丙撑基双(十八烷基二甲基氯化铵)[C18H37(CH3)2–N+–(CH2)3–N+–(CH3)2C18H37]Cl2(C18-3-18),作为介孔模板剂用于水热法合成介孔ZSM-5分子筛.结果表明,在130 oC低温晶化即可高效合成介孔ZSM-5分子刷.C18-3-18的加入量可影响到所合成介孔ZSM-5分子筛的相对结晶度和织构性质,它的形成遵从一个转晶过程.在合成初期,凝胶中介孔模板剂C18-3-18的使用导向了介孔材料的生成;随后在TPABr的模板作用下,介孔材料慢慢转晶生成具有MFI结构的介孔ZSM-5;然后所合成的介孔ZSM-5晶粒进一步长大并聚集形成块状颗粒,同时产生晶间介孔.C18-3-18作为介孔导向剂不仅可用于合成介孔ZSM-5分子筛,也可用于其它介孔分子筛的合成中.     

KCl对Cu-K-La/γ-Al2O3催化剂上HCl氧化反应性能的影响

采用等体积浸渍法制备了Cu-K-La/γ-Al₂O₃催化剂,考察了KCl对该催化剂催化HCl氧化制Cl₂反应性能的影响. 当KCl的负载量为5 wt%时,Cu-K-La/γ-Al₂O₃催化剂表现出较好的催化活性和稳定性,可在较大的原料气空速变化范围内使用. 在0.1 MPa,360 ℃,空速450 L/（kg-cat·h）和HCl/O₂摩尔比为2：1的反应条件下,Cu-K-La/γ-Al₂O₃催化剂上HCl转化率在100 h内保持85%以上. 表征结果表明,Cu,K和La物种均高度分散于γ-Al₂O₃载体表面;一定量KCl的加入可降低Cu²⁺ → Cu⁺的还原温度,从而提高Cu²⁺活性中心的催化活性.     

改性ZSM-5分子筛催化裂解湛江等鞭金藻制取低碳烯烃(英)

研究了湛江等鞭金藻(Isochrysis zhanjiangensis)在改性ZSM-5分子筛上催化裂解制取低碳烯烃的过程.与热裂解过程相比,湛江等鞭金藻催化裂解可以得到更高的低碳烯烃选择性和收率.同时还研究了湛江等鞭金藻中不同油脂和藻渣的催化裂解.结果表明,微藻中的油脂能有效转化为烯烃,其中中性脂的烯烃收率最高,可达36.7%.不同溶剂抽提后得到的藻渣也可转化为低碳烯烃,但收率远低于微藻中的油脂.微藻中的油脂,特别是中性脂,是烯烃的主要贡献者,提高微藻中的中性脂含量能够得到更高的低碳烯烃收率.     

Syntheses,Crystal Structures and Antibacterial Activities of Two Heterocyclic Schiff Base Compounds

Two heterocyclic Schiff bases were synthesized via the condensation reactions of primary amines with carbonyl compounds. 2-[(4-pyridylmethylene)-amino] phenol(compound 1) was synthesized by the interaction of 4-pyridinecarboxaldehyde with o-aminophenol in ethanol solvent; N,N‘-bis(3-(furan-2-yl)allylidene)benzene-1,4-diamin(compound 2) was synthesized by the interaction of 3-(2-furyl)acrolein with p-phenylenediamine in ethanol medium. The compounds were characterized by elemental analysis, IR, MS and single-crystal X-ray diffraction. Compound 1(C12H10N2O) crystallizes in the monoclinic system, space group P21/c with a = 7.0771(7), b = 7.2820(7), c = 19.849(2),β= 96.3390(10)°, V = 1016.66(17) ?3, Z = 4, Mr = 198.22, Dc = 1.295 g/cm3, F(000) = 416, GOOF = 1.060, μ= 0.085 mm-1, the final R = 0.0371 and wR = 0.0929 for 1497 observed reflections with I 2σ(I). Compound 2(C20H16N2O2) crystallizes in the orthorhombic system, space group Fdd2 with a = 26.344(15), b = 48.50(3), c = 5.293(3), V = 6764(7) ?3, Z = 16, Mr = 316.35, Dc = 1.243 g/cm3, F(000) = 2656, GOOF = 1.043, = 0.081 mm-1, the final R = 0.0526 and wR = 0.1267 for 2059 observed reflections with I 2σ(I). 1 and 2 molecules are connected through hydrogen bonds to generate a 2D network and a 1D chain structure, respectively. The preliminary antibacterial activity results showed that the title compounds display excellent antibacterial activities to Escherichia coli, Staphylococcus aureus and Bacillus subtilis.     

Hydrolytic Degradation Behaviors of Poly（p-dioxanone） in Ambient Environments

The effects of temperature and relative humidity on the hydrolytic degradation of poly（p-dioxanone）（PPDO） were investigated. The hydrolytic degradation behaviors were monitored by tracing the changes of water absorption, mechanical and crystalline properties, molecular weight and its distribution, surface morphologies, as well as infrared absorption peaks and hydrogen chemical shifts during the degradation. It is found that the water absorption increases whilst the intrinsic viscosity, tensile strength and elongation at break decrease as the temperature or relative humidity increases. With degradation time growing, the molecular weight drops and its distribution broadens. The crystallinity of PPDO has a tendency to increase at first and then to decrease, while the crystalline structure is not significantly changed. At the same time, some cracks are observed on the surface and keep growing and deepening. All results show that temperature plays more significant roles than relative humidity during the degradation. The analyses of Fourier transform infrared spectroscopy and hydrogen nuclear magnetic resonance spectroscopy reveal that the degradation of PPDO is a predominant hydrolysis of ester linkages.     

Rapid Isolation of a Facultative Anaerobic Electrochemically Active Bacterium Capable of Oxidizing Acetate for Electrogenesis and Azo Dyes Reduction

In this study, 27 strains of electrochemically active bacteria (EAB) were rapidly isolated and their capabilities of extracellular electron transfer were identified using a photometric method based on WO₃ nanoclusters. These strains caused color change of WO₃ from white to blue in a 24-well agar plate within 40 h. Most of the isolated EAB strains belonged to the genera of Aeromonas and Shewanella. One isolate, Pantoea agglomerans S5-44, was identified as an EAB that can utilize acetate as the carbon source to produce electricity and reduce azo dyes under anaerobic conditions. The results confirmed the capability of P. agglomerans S5-44 for extracellular electron transfer. The isolation of this acetate-utilizing, facultative EBA reveals the metabolic diversity of environmental bacteria. Such strains have great potential for environmental applications, especially at interfaces of aerobic and anaerobic environments, where acetate is the main available carbon source.     

Fabrication of free-standing multilayer films by using pH-responsive microgels as sacrificial layers

A facile way to prepare free-standing polyelectrolyte multilayer films of poly(sodium 4-styrenesulfonate)(PSS)/poly(diallyldimethylammonium)(PDDA) was developed by applying a new pH-dependent sacrificial system based on cross-linked poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) microgels. The tertiary amine groups of PDMAEMA microgels can be protonated in acidic environment, and the protonated microgels were deposited by layer-by-layer (LbL) technique with PSS. PSS/PDDA multilayer films were constructed on the top of the PSS/microgels sacrificial layers. The LbL assembly process was investigated by UV–vis spectroscopy. Further study shows that the free-standing PSS/PDDA multilayer films can be obtained within 3 min by treating the as-prepared films in alkali aqueous solution with a pH of 12.0. The pH-triggered exfoliation of PSS/PDDA multilayer films provides a simple and facile way to prepare LbL assembled free-standing multilayer films.     

Fabrication of anisotropic silica hollow microspheres using polymeric protrusion particles as templates

Anisotropic polystyrene/poly(styrene-co-divinylbenzene) (PS/P(S-DVB)) protrusion particles with various morphologies such as eyeball-like, snowman-like, and raspberry-like were synthesized using a modified seeded polymerization method by dynamically controlling and stabilizing the phase separation. The effects of swelling agent, crosslinker, and monomer concentrations on the particle morphologies were studied. Using the PS/P(S-DVB) protrusion particles as templates, anisotropic silica (SiO₂) hollow microspheres were fabricated facilely. The obtained anisotropic silica hollow spheres had a potential application in rapid waste removal and detoxification extraction with a very simple procedure.     

Hydrogen bond induced chiral symmetry breaking in the crystallization of nickel(II) complexes

A pair of enantiomers formulated as {Δ-cis-[Ni(en)₂OAc][ClO₄]} _n (Δ-1) and {Λ-cis-[Ni(en)₂OAc][ClO₄]} _n (Λ-1) (en = diaminoethane, OAc^? = acetate anion) were obtained when nickel acetate was reacted with diaminoethane and sodium perchlorate in the absence of any chiral source, whereas the reactions of nickel acetate with 1,3-propanediamine and sodium perchlorate only gave a centrosymmetric complex [Ni(1,3-pn)₂OAc][ClO₄] (2) (1,3-pn = 1,3-propanediamine). Single-crystal X-ray diffraction analyses of all three complexes indicated that the central Ni(II) atoms all have a distorted octahedral coordination geometry, being coordinated by four nitrogen atoms of the diamine ligands, plus two oxygen atoms of OAc^?. In complexes Δ-1 and Λ-1, the monomers of {Δ-cis-[Ni(en)₂OAc]}⁺ and {Λ-cis-[Ni(en)₂OAc]}⁺ are connected through intermolecular hydrogen bonds to generate one-dimensional right- and left-handed homochiral helical chains, respectively, while the monomers of [Ni(1,3-pn)₂OAc]⁺ are linked by similar intermolecular hydrogen bonds to form one-dimensional zigzag chains instead of helical chains. The chiral natures of complexes Δ-1 and Λ-1 have been confirmed by circular dichroism spectroscopy.     

Fe~(3+)诱导全氟羧酸的光化学降解:pH值及链长的影响

以全氟辛酸(PFOA)为代表的全氟化合物是环境水体中新出现的一类持久性有机污染物,Fe3+的存在促进了其在254 nm紫外光下的有效降解.在此基础上,主要考察了溶液初始pH值对Fe3+诱导PFOA光化学降解的影响,并以全氟丁酸(PFBA)、全氟戊酸(PFPeA)、全氟己酸(PFHxA)和全氟庚酸(PFHpA)为对象,研究了Fe3+诱导短链全氟羧酸(PFCAs)的降解,通过对降解中间产物的分析,进而推断了其降解机理.结果表明,强酸性条件有利于PFOA的降解,弱酸性或中性反应条件下,PFOA的降解和脱氟均受到明显地抑制,进一步证实PFOA的降解主要是溶解性铁作用的结果,此时Fe(OH)2+则是铁(III)-羟基配合物的主要分配形态.Fe3+诱导PFCAs的降解表明:当碳原子数大于5,长链的PFCAs更易于降解,但对于碳原子数小于6的PFCAs,其降解没有明显的规律.降解中间产物主要是链更短的PFCAs,由此推断,PFCAs的降解遵循逐级降解的规律.