苯部分加氢制环己烯的非晶态Ru-M-B/ZrO2催化剂的表征

采用化学还原法，制备了高活性，高选择性非晶态RU-M-B/ZRO2催化剂，并将其用于催化苯部分加氢制环己烯，在140℃、5.0Mpa氢压下，苯转化40%时，环己烯选择性达到85%左右。环己烯最高收率达到52.1%，用XRD、SEM、BET比表面积测定等手段对摧化剂进行表征，XRD和SEM测试表明，RU-U-B/ZRO2属于非晶态，活性组分高度分散，XRD结果证实，在加氢过程中，非晶分解，RU晶化；温度愈高，RU晶化愈快，催化剂的活性、选择性与RU微晶的粒径有关，RU微晶粒径应控制在5nm左右，BET比表面积测定表明，ZRO2的负载提高了催化剂的比表面积，从而有利于活性组分的高度分散，并可阻止RU微晶的长大，讨论了B和ZRO2对提高选择性的作用。     

Covalent attachment of phospholipid analogous polymers to modify a polymeric membrane surface: a novel approach

A novel method for the surface modification of a microporous polypropylene membrane by tethering phospholipid analogous polymers (PAPs) is given, which includes the photoinduced graft polymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA) and the ring-opening reaction of grafted poly-(DMAEMA) with 2-alkyloxy-2-oxo-1,3,2-dioxaphospholanes. Five 2-alkyloxy-2-oxo-1,3,2-dioxaphospholanes, containing octyloxy, dodecyloxy, tetradecyloxy, hexadecyloxy, and octadecyloxy groups in the molecular structure, were used to fabricate the PAP-modified polypropylene membranes. The attenuated total reflectance FT-IR spectra of the original, poly(DMAEMA)-grafted, and PAP-modified membranes confirmed the chemical changes on the membrane surface. Scanning electron microscope pictures showed that, compared with the original membrane, the surface porosities ofpoly(DMAEMA)-grafted and PAP-modified membranes were somewhat reduced. Water contact angles measured by the sessile drop method on PAP-modified membranes were slightly lower than that on the original polypropylene membrane, but higher than those on poly(DMAEMA)-grafted membranes with the exception of octyloxy-containing PAP-modified membranes. However, BSA adsorption experiments indicated that the five PAP-modified membranes had a much better protein-resistant property than the original polypropylene membrane and the poly(DMAEMA)-grafted membranes. For hexadecyloxy- and octadecyloxy-containing PAP-modified membranes, almost no protein adsorption was observed when the grafting degree was above 6 wt %. It was also found that the platelet adhesion was remarkably suppressed on the PAP-modified membranes. All these results demonstrate that the described approach is an effective way to improve the surface biocompatibility for polymeric membranes.     

过渡金属钼钒砷杂多化合物的合成与TPR,TPD研究

Seven transition metal molybdovanadoarsenic heteropoly compounds have been synthesized and characterized using IR, UV, TG-DTA, pH potential titration techniques. The molecular formulae of these compounds are pro-posed to be H_xM_yAsMO₁₀V₂O₄₀·zH₂O(x=1～3, y=1,2, M=Cr, Mn, Fe, Co, Ni, Cu, Zn).They are all keggin structure. Surface nature of these compounds have been investigated by temperature programmed desorption and temperature programmed reduction techniques. NH₃-TPD results show that in TPD profiles of the compounds there are two desorption peaks corresponding to weak acid sites of desorption, respectively. Desorbing activativon energy and preexponential factor of weak acid site of desorption for compounds have been calculated. H₂-TPR re-sults show that introducting transtion metal to molybdovanarsenic acid, the reduction peak temperatures of H₂-TPR shift regularly with increasing d electron numbers of transition metals. In addition, Zn and Cu heteropoly com-pounds have yet apparent effect of hydrogen spill over.     

ZrO_2对CuO-ZnO-ZrO_2催化剂低压合成甲醇的促进作用

我们曾报道CO_2/H_2在CuO-ZnO及CuO-ZnO-ZrO_2催化剂上低压合成甲醇的反应,指出CuO-ZnO-ZrO_2对CO_2/H_2制甲醇具有较高的活性和选择性。本文通过TPD-MS测试研究了第3组分ZrO_2的加入对CO_2/H_2在CuO-ZnO-ZrO_2催化剂上低压合成甲醇的促进作用。 1 实验部分 催化剂的评价在恒压流动反应系统内进行。用色谱仪分析产物(Porapak Q柱,4 mm×3m,柱温120℃,CO、CO_2、CH_3OH、H_2O的保留时间分别为0.55、0.84、4.72、6.6 min),热     

有机钛氢化物的化学

本文综述了有机钛氢化物化学的最近进展,包括:合成方法,反应及其在有机合成中的应用。     

Spectroscopic evidence for triplet excitation energy transfer among carotenoids in the LH2 complex from photosynthetic bacterium <Emphasis Type="Italic">Rhodopseudomonas palustris</Emphasis>

The LH2 complex from Rhodopsudomonas (Rps.) palustris is unique in the heterogeneous carotenoid compositions. The dynamics of triplet excited state Carotenoids (³Car* has been investigated by means of sub-microsecond time-resolved absorption spectroscopy both at physiological temperature (295 K) and at cryogenic temperature (77K). Broad and asymmetric T _n ←T ₁ transient absorption was observed at room temperature following the photo-excitation of Car at 532 nm, which suggests the contribution from various carotenoid compositions having different numbers of conjugated C=C double bonds (N_c=c). The triplet absorption bands of different carotenoids, which superimposed at room temperature, could be clearly distinguished upon decreasing the temperature down to 77 K. At room temperature the shorter-wavelength side of the main T_n04T₁ absorption band decayed rapidly to reach a spectral equilibration with a characteristic time constant of ∽1 μs, the same spectral dynamics, however, was not observed at 77 K. The aforementioned spectral dynamics can be explained in terms of the triplet-excitation transfer among heterogeneous carotenoid compositions. Global spectral analysis was applied to the time-resolved spectra at room temperature, which revealed two spectral components peaked at 545 and 565 nm, and assignable to the T_n04 T₁ absorption of Cars with Nc=c=11 and Nc=c=13, respectively. Surprisingly, the decay time constant of a shorter-conjugated Car, i.e. 0.72 ώs (aerobic) and 1.36 ώs (anaerobic), is smaller than that of a longer-conjugated Car, i.e. 2.12 us (aerobic) and 3.75 ώs (anaerobic), which is contradictory to the general rule of carotenoids and relative polyenes. The results are explained in terms of triplet-excitation transfer among different types of Cars. It is postulated that two Cars with different conjugation lengths coexist in an α, β-subunit in the LH2 complex.     

丙环唑配合物的合成、缓释性能及生物活性研究

Five propiconazole(L) complexes (ML₂Cl₂, M=Zn(Ⅱ), Cu(Ⅱ), Co(Ⅱ); ML₄Cl₂, M=Ni(Ⅱ), Mn(Ⅱ)) were prepared and characterized by elemental analysis and IR. These complexes exhibited favorable controlled release property, it took 40 to 120 hours to release 85% amount of ligand in the water. The toxicity determination to Botrytis cinera, Rhizoctonia cerealis, Gibberella zeae, Fussrium moniliforme and Colletotrichum orbiculare indicated that the fungicidal activities of the complexes were better than that of the ligand except Mn-complex to Rhizoctonia cereali. The EC50 of Zn-propiconazole were 0.045 2～0.144 1 μg·mL^-1, Co- and Ni-propiconazole were 0.066 3～0.210 4 μg·mL^-1 and 0.183 9～0.340 7 μg·mL^-1, respectively, and Mn-propiconazole were only 0.353 6～0.538 0 μg·mL^-1. The growth regulation experiment to wheat seeding by dressing treating indicated that inhibiting activities of the complexes to root length and stem height were weaker than that of the ligand.     

Cyanex 923-H2SO4体系萃取第3相的形成和应用

三相体系;Cyanex 923-H2SO4体系萃取第3相的形成和应用     

Crystal Structure and Characterization of a Large Polyoxotungstate (NH4)21{La(H2O)5[Ni(H2O)]2As4W40O140}·53H2O

The heteropolytungstate (NH4)₂₁{La(H₂O)₅[Ni(H₂O)]₂As₄W₄₀O₁₄₀}·53H₂O is obtained by the reaction of Na₂₇[NaAs₄W₄₀O₁₄₀]· 60H₂O with NiCl₂·6H₂O, La(NO₃)₃·6H₂O and NH₄Cl at pH‐4.5. The structure and chemical composition are determined by X‐ray diffraction analysis and elemental analysis. The crystal data and main structure refinement are a = 1.9551(3) nm, b = 2.4156(4) nm, c= 3.7068(6) nm, β = 91.505(3)°, V = 17.500 (5) nm³, monoclinic crystal system with space group P2₁/n, Z = 4, R₁ = 0.0573, wR₂ = 0.0717 [I >2<s?(I)], R₁, = 0.2463 and wR₂ = 0.1199 (all data). [La(H₂O)₅] {Ni(H₂O)}₂AS₄W₄₀O₁₄₀ has C₂, symmetry. IR spectra of the ligand [NaAs₄W₄₀O₁₄₀]^27‐ and its three complexes were discussed.