硝酸处理的活性碳催化苯一步合成苯酚

将市售的煤质活性炭用不同浓度的硝酸处理后,在乙腈体系下催化苯一步羟化成苯酚. 并对处理过的活性炭进行Boehm滴定、XPS/EDX、BET等方法表征,发现活性炭表面羧基的数量是影响其催化活性的主要因素. 得到苯酚的最高收率为15.7%,选择性为87.2%.     

高分辨连续光源石墨炉原子吸收光谱法测定面制食品中的铝

使用微波消解-高分辨连续光源石墨炉原子吸收光谱法测定四种面制食品(挂面、饺子皮、油条和梳打饼干)中铝的含量.样品置于密闭聚四氟乙烯消解罐中经HNO3和H2O2混合溶液完全消解.对微波消解条件、灰化温度和原子化温度进行了优化.确定最佳实验条件为:消解液HNO3和H2O2体积比7∶1,微波功率1 000 W,190℃消解4...     

Al-pillared clays supported rare earths and palladium catalysts for deep oxidation of low concentration of benzene

Al-pillared clays supported rare earths (RE/Al-PILC) are prepared and used as supports of palladium catalysts for deep oxidation of low concentrations of benzene (130-160 ppm). The supports and catalysts are characterized by X-ray powder diffraction (XRD), FT-IR, BET, transmission electron microscopy (TEM) and temperature-programmed reduction (H₂-TPR). The results show that Al-pillaring results in a strong increase in the basal spacing (d_0 0 1) from about 1.2 to 1.8 nm, and an increase in the BET surface area from 63.6 (±3.2) to 238.8 (±11.9) m²/g. Activity tests of deep oxidation of low concentration benzene show catalysts supported on Al-PILC and RE/Al-PILC are obviously more active than that on raw clay. Pd/6% Ce/Al-PILC, in particular, can catalyze the complete oxidation of low concentration benzene at a temperature as low as about 290 °C.     

微波消解ICP-AES法分析九种补血类中药元素

采用微波消解法处理样品,以电感耦合等离子体发射光谱法(ICP-AES)测定并分析九种补血类中药中Zn,Mn,Na,K,Ca,Mg,Ni,Pb,Se,Fe,Cu,Al,B,Ti,Sn,Hg和Li元素的含量。结果显示,九种补血类中药富含有益于人体健康的主要及微量元素,其中众所周知补血类元素Fe,Se,Ni,Mn,Zn含量较高。九种补血中药按各大元素分类(大量元素,必需元素,非必需元素,有害元素)分布于柱形直方图。应用主成分分析和聚类分析于数据矩阵去评价元素分析结果。聚类分析的结果显示九种补血类中药中十七种元素的含量所形成的树状系统图主要分为三个集群。通过优化微波消解条件,各元素的回收率均在97.89%～103.25%之间,相对标准偏差均小于3.0%。ICP-AES结合微波消解法可以精确和准确地测定九种补血类中药中的元素。     

含氧有机物催化重整制备纯氢

研究了一种新的利用含氧化合物制备纯氢的催化变换过程,该过程耦合了含氧化合物的催化重整、水煤气变换反应和CO₂去除步骤. 详细研究了重整催化剂的筛选、反应条件以及不同的含氧化合物催化重整行为. 利用所述集成方法获得的最高氢气浓度为99.96vol%和最大转化率为97.1mol%. 此外,通过含氧化合物的解离、催化重整和水煤气变换反应研究,探讨了含氧化合物制备纯氢的相关反应路径.     

催化荧光法测定痕量草酸

在硫酸介质中 ,草酸能催化重铬酸钾氧化罗丹明B褪色 ,使体系荧光猝灭 ,建立了催化荧光法测定草酸的新方法。催化反应在 50℃水浴中进行 1 0min ,为假零级反应。测定草酸的线性范围为 0 4～ 1 2 0mg·L- 1 ,其回归方程为ΔF =8 42c(mg·L- 1 ) 3 81 ,r=0 9983 ,检出限为 0 1 6mg·L- 1 。试验了 30种共存物质的干扰情况。此法用于生物样品中草酸含量的测定 ,结果满意。     

催化动力学光度法测定水中痕量铁

本文研究了ｐｈ５．０的ＨＡｃ－ＮａＡｃ介质中，痕量铁催化过氧化氢氧化紫脲酸的褪色反应，建立了催化动力学光度法测定痕量铁的新方法，方法的线性范围０－０．４０，０．４０－２．０μｇ／２５ｍＬ，检出限为８×１０＾－１１ｇ／ｍＬ，用于水样中痕量铁的测定，结果满意。     

ZnO/MoO3 mixed oxide nanotube: A highly efficient and stable catalyst for degradation of dye by air under room conditions

As a continuation of our work to develop catalysts with high activity for catalytic air wet oxidation process under mild conditions, degradation of wastewater containing 0.3 g/L Safranin-T (ST) by air oxidation over ZnO/MoO₃ nanotube catalyst was studied. It was found the decolorization efficiency and the chemical oxygen demand (COD) removal of ST reached above 98% and 95%, respectively, within 18 min at room temperature and atmospheric pressure. And the organic pollutants were totally mineralized to simple inorganic species such as HCO₃⁻, Cl⁻ and NO₃⁻, while the total organic carbon (TOC) decreased 99.3%. The structure and morphology of the catalyst after ten cycling runs showed that the catalyst was stable under such operating condition and the leaching test showed negligible leaching effect. This ZnO/MoO₃ nanotube is proved to be an active and stable heterogeneous catalyst in CWAO of ST under extremely mild conditions.     

Morphological effect of MoS2 nanoparticles on catalytic oxidation and vacuum lubrication

The closed layered MoS₂ nano-balls and the opened layered MoS₂ nano-slices were prepared by decomposing MoS₃ in hydrogen atmosphere. The obtained MoS₂ nanoparticles were respectively used as catalysts for S²⁻ oxidation into SO₄²⁻ and lubricating fillers in polyoxymethylene (POM) plastic. Only basal surface could be found in the closed layered MoS₂ nano-balls, which represented very low catalytic efficiency for S²⁻ oxidation into SO₄²⁻. However, the opened layered MoS₂ nano-slices were of both basal surface and rim-edge surface and showed excellent catalytic properties. Moreover, it was shown that MoS₂ nano-balls could improve the self-lubrication of POM plastic in vacuum. However, MoS₂ nano-slices led to the obvious degradation of POM, implying it is not a proper additive for POM. The high activity of MoS₂ nano-slices for catalyzing S²⁻oxidation and degrading POM was ascribed to their small sizes and partly wedge-like shapes, which led to a considerable increase in the rim sites. The weak catalysis and excellent lubrication of MoS₂ nano-balls were resulted from its closed structure and chemical inertness.     

木质素催化转化制备异丙苯

Cumene is an important intermediate and chemical in chemical industry.In this work,directional preparation of cumene using lignin was achieved by a three-step cascade process.The mixture aromatics were first produced by the catalytic pyrolysis of lignin at 450℃ over 1% Zn/HZSM-5 catalyst,monocyclic aromatics with the selectivity of 85.7 wt% were obtained.Then,the catalytic dealkylation of heavier aromatics resulted in benzene-rich aromatics with 93.6 wt% benzene at 600℃ over Hβ catalyst.Finally,the cumene synthesis was performed by the aromatic alkylation,giving cumene selectivity of 91.6 C-mol% using the[bmim]Cl-2AlCl₁₃ ionic liquid at room temperature for 15 min.Besides,adding a small amount of methanol to the feed can efficiently suppress the coke yield and enhance the aromatics yield.The proposed transformation potentially provides a useful route for production of cumene using renewable lignin.