流动注射化学发光法测定甲氧氯普胺

在酸性条件下，甲醛对高锰酸钾氧化甲氧氯普胺的化学发光反应有很强的增敏作用，据此，建立了流动注射化学发光法测定甲氧氯普胺纳新方法。方法的线性范围为0．4-100μg/mL，检出限为0．2μg/mL，对10μg/mL的甲氧氯普胺标准溶液连续11次测定的相对标准偏差为1．8％。方法已用于药物中甲氧氯普胺含量的测定。     

Polymeric salen-Ti(IV) or V(V) complex catalyzed asymmetric synthesis of O-acetylcyanohydrins from KCN, Ac2O and aldehydes

Polymeric salen-Ti(IV) and V(V) complexes were employed in the enantioselective O-acetyl cyanation of aldehydes with potassium cyanide and acetic anhydride. The crosslinked polymeric salen-Ti(IV) catalyst exhibited good activities and enantioselectivities, up to 91% ee with 99% conversion was obtained at −20 °C with 1 mol% of catalyst (based on bimetallic catalytic unit). Moreover, six consecutive recyclings with the easily recovered crosslinked polymeric catalyst showed no obvious decrease in either activity or enantioselectivity. Linear polymeric salen-V(V) catalyst showed good catalytic efficiency too, up to 94% ee with 99% conversion was obtained at −42 °C with 5 mol% of catalyst.     

Kaliumhydrogensulfat-Dihydrogensulfat,K(HSO4)(H2SO4) – Synthese und Kristallstruktur

Potassium Hydrogensulfate Dihydrogensulfate, K(HSO₄)(H₂SO₄) – Synthesis and Crystal Structure Single crystals with the composition KH₃(SO₄)₂ have been synthesized from the system Potassium sulfate/sulfuric acid. The hitherto crystallographically not investigated compound crystallizes in the monoclinic space group P2₁/c (14) with the unit cell parameters a = 7.654(3), b = 11.473(5) and c = 8.643(3) Å, β = 112.43(3)°, V = 701.6 ų, Z = 4 and D_x = 2.22 g · cm^?3. The structure contains two types of tetrahedra, SO₃(OH) and SO₂(OH)₂. These tetrahedra form tetramers via hydrogen bonds consisting of both, two SO₃(OH) and two SO₂(OH)₂ tetrahedra. The tetramers are linked to each other via hydrogen bonds. Potassium is coordinated by 9 oxygen atoms which belong to both kinds of tetrahedra. These potassium oxygen polyhedra are connected by common faces forming chains running parallel z.     

H2O2的KMnO4-Luminol化学发光体系测定

在碱性介质中 ,H2O2 能极大地增强KMnO4-Luminol的化学发光强度 ,据此建立一种测定H2O2 的方法 ;该法的线性范围为5.0×10-8 ～5.0×10-5 mol/L,检出限为1.4×10-8 mol/L;利用该法测定了雨水中H2O2 的含量 ,并进行了回收率测定 ,回收率在95%～103% ,结果令人满意     

Standard Gibbs energies of transfer of potassium tetraphenylborate from water to straight-chain n-alkanols

Solubilities of potassium tetraphenylborate in water, methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, and 1-octanol at 15, 25, 35, 45, 55°C have been determined by spectrophotometry. The standard Gibbs energy of transfer of potassium tetraphenylborate form water to straightchain n-alkanols and the medium effect of potassium tetraphenylborate from 15 to 55°C have been calculated. Furthermore, the contribution of microscopic interactions to the standard Gibbs energy of transfer of potassium tetraphenylborate is calculated and discussed.     

The synthesis of indolo- and pyrrolo[2,1-a]isoquinolines

The synthesis of fused isoquinolines from N-benzyl protected indoles and pyrroles is described. For example, treatment of t-butyl-2-(2-formyl-3,4-dihydro-1-naphthalenyl)-3-methyl-1H-indole-1-carboxylate with KOBu^t in DMF provided 14-methyl-8-phenylbenzo[h]indolo[2,1-a]isoquinoline in good yield. Analogous N-benzylpyrrole precursors could similarly be cyclized to give pyrrolo[2,1-a]isoquinolines.     

Studies on the ageing of a magnesium-potassium nitrate pyrotechnic composition using isothermal heat flow calorimetry and thermal analysis techniques

The ageing behaviour of a pyrotechnic mixture of magnesium and potassium nitrate has been followed at 50 °C and 65% relative humidity by isothermal heat flow calorimetry. Measurements have been carried out with samples in air and in an inert atmosphere. The main reaction product was found to be magnesium hydroxide. This has been determined quantitatively by thermogravimetry and the amount formed correlated with the measured cumulative heat of ageing. The results have been compared with those obtained for magnesium powder studied under the same conditions. In addition the influence of the ageing process on the pyrotechnic reaction has been studied by high temperature differential scanning calorimetry under ignition conditions and modulated temperature differential scanning calorimetry.     

KNO3/Al2O3上强碱位的产生和表征

报导了碱性催化能力强于Ｋ２ＣＯ３／Ａｌ２Ｏ３或ＭｇＯ的新型固体碱ＫＮＯ３／Ａｌ２Ｏ３，并研究了ＫＮＯ３在Ａｌ２Ｏ３上的分解以及强碱位的产生．ＫＮＯ３负载在Ａｌ２Ｏ３上，活化过程中６７３Ｋ才开始分解并形成碱位．由于催化反应在原位情况下进行，活性位未受到污染而保持高效率．在２７３ＫＫＮＯ３／Ａｌ２Ｏ３对顺－丁烯－２的异构化反应的碱性催化能力高于Ｋ２ＣＯ３／Ａｌ２Ｏ３或ＭｇＯ     

苯并-18-冠醚-6和溴百里香酚蓝离子对萃取光度法测定钾

报道了以苯并 18 冠醚 6 K+ 与溴百里香酚蓝显色体系光度法测定钾的研究。一定条件下 ,苯并 18 冠醚 6与钾离子形成络合阳离子 ,与阴离子溴百里香酚蓝形成离子对缔合物 ,被萃入氯仿中。该离子对缔合物于 4 10nm处有最大吸收 ,测定钾的摩尔吸光系数为 1.6× 10 4 L·mol- 1·cm- 1,钾含量在 0 .0 5～ 2 .5 μg·ml- 1范围内呈线性关系 ,相对标准偏差为 2 .2 %。应用于土壤、植物和血清中痕量钾的测定 ,与原子吸收光谱法相比 ,结果满意     

Design and properties of a flow-injection analysis cell using potassium-selective ion-sensitive field-effect transistors as detection elements

The combination of flow-injection analysis (FIA) and chemically modified ion-sensitive field-effect transistors (CHEMFETs) is described. In a wall-jet cell, two identical potassium-selective CHEMFETs were used for a differential measurement using a platinum (pseudo-)reference electrode. Silicone-rubber membrane materials, chemically bound to the SiO₂ gate oxide, were used with valinomycin as the ionophore. The optimized FIA system showed a linear response of 56 mV per decade for potassium concentrations above 5 × 10^?5 M. Preliminary results of potassium determinations in human serum and urine samples are presented.