非晶态Ni-S合金在碱液中析氢反应(HER)机理的研究

本文研究了非晶态 Ni- S合金的析氢反应机理。用稳态极化曲线研究非晶态 Ni- S合金的极化行为 ,得到其反应的动力学参数塔菲尔斜率和表观反应活化能。用断电流法和循环伏安法研究氢原子的吸附和中间态粒子。考察电极表面粗糙度、活性粒子表面吸附浓度等因素 ,综合分析得出 Ni- S合金电极具有高催化活性的原因及其 HER电催化机理     

脂溶性壳多糖的制备

提出通过甲烷磺酸／酰氯体系低温均相制备乙酰化甲壳质（ＡＣＣ）、己酰化甲壳质（ＨＣＣ）、十二酰化甲壳质（ＤＣＣ）及已酰化Ｎ－苄基甲壳胺（ＮＢＣ），从而获得脂溶性Ｎ－苄基己酰甲壳胺（ＮＢＨＣ）的反应条件，并对各酰化产物在不同溶剂中的溶解性能进行试验。指出：产物ＡＣＣ溶于甲酸中；ＨＣＣ、ＤＣＣ溶于甲酸及乙醇中；ＮＢＨＣ溶于甲酸、乙醇、乙醚、苯及乙酸乙酯中。     

双(三氟甲基磺酰)亚胺锂的合成与表征

以三氟甲基磺酰氯为原料,经胺化、成盐、酸碱中和、复分解置换反应合成了无水双(三氟甲基磺酰)亚胺锂。通过研究温度、溶剂、反应时间、氨气通入速率等对反应产率的影响,优化了三氟甲基磺酰胺与双(三氟甲基磺酰)亚胺钾的合成条件。得到三氟甲基磺酰胺的最优合成条件为以乙腈为溶剂,氨气通入速度为0.8 m L/min,反应时间为1 h,反应温度为-10~-5℃;双(三氟甲基磺酰)亚胺钾的最优合成条件为反应时间3 h,反应温度-10~-5℃。利用FT-IR、13C-NMR和ICP对中间产物与最终产物进行了表征。双(三氟甲基磺酰)亚胺锂的产率为72.65%。     

白云石的微化反应与有序度

试验证实白云石的微化反应特征明显受有序度的影响，白云石粉末在稀盐酸中的起泡程度随有序度的降低而加剧，在茜素红溶液中的染色程度和速度随有序度的降低而增强。低有序度白云石或完全无序的原白云石，其微化反应与方解石极为相似，反之，高有序度白云石与菱镁矿相似。另外还讨论白云石微化反应的机理。     

Uptake of the NO <Subscript>3</Subscript> Radical on Aqueous Surfaces

Using a single drop experiment, the uptake of NO₃ radicals on aqueous solutions of the dye Alizarin Red S and NaCl was measured at 293 K. Uptake coefficients in the range (1.7–3.1) ⋅ 10^{− 3} were measured on Alizarin Red S solutions. The uptake coefficients measured on NaCl solutions were in the range of (1.1–2.0) ⋅ 10⁻³ depending on the salt concentration. Both experiments lead to a consistent result for the mass accommodation coefficient of α_NO3 = (4.2_{− 1.7}^+2.2)⋅ 10⁻³. The product H(D_l k_Cl−^II)^0.5 for the NO₃ radical was determined to be (1.9 ± 0.2) M atm^{− 1} cm s^−0.5 M^−0.5 s^−0.5 by fitting the uptake data for the NaCl solutions to the so-called resistance model. The yield of the chemical NO₃ radical source was characterized using UV-VIS and FT-IR spectroscopy. The amount of gas-phase NO₃ radicals measured at elevated humidities was less than expected. Instead, a rise of the gas-phase HNO₃ concentration was found indicating a conversion of gas-phase NO₃ radicals to gas-phase HNO₃ on the moist reactor walls.     

岱海近400年以来的环境变化:高分辨率XRF岩芯扫描结果的研究

岱海是东亚夏季风边缘地带的闭流型半咸水湖泊,其汇水流域降水量的变化易于引发湖泊水位和水化学变动。选用DH11-1岩芯进行1 mm分辨率XRF元素扫描分析,并对测试结果进行多元数理统计分析,旨在查明这些元素与外源碎屑、自生碳酸盐沉积以及岱海水位、水化学变化的关联。结果显示,Si、Al、Ti、K、Fe、Rb等元素相关性好,并呈现相似的变化趋势,其含量变化与主要河流带入的碎屑物的多寡有关;Ca元素主要反映沉积物中自生碳酸盐即文石和方解石矿物含量的增减。研究发现,在人类活动严重影响之前,岱海在过去~400年期间的环境特征总体可划分为4个阶段,各阶段的水位、水化学特征及水量平衡有所不同,总体受汇水盆地降水量变化的控制。此外,沉积物中Cu、Zn、Cr可能与人类活动影响有关。     

利用钾长石粉体合成雪硅钙石的实验研究

以氧化钙为反应物料,在200～250℃的水热反应条件下分解钾长石。实验研究了在不同的Ca/(Si Al)摩尔比、水固比、反应温度和反应时间条件下,钾长石中K2O的溶出率和固相的物相变化。结果表明,液相中K2O的溶出率为40%～87%,固相反应产物为结晶良好雪硅钙石晶体。采用化学分析、XRD、SEM、DSC_TG和BET等方法对合成的雪硅钙石粉体进行了表征,结果表明,合成的雪硅钙石粉体是由长5～10μm、宽100～200nm、厚度为49～50nm的薄片纤维晶体交织成的直径为30～40μm的空心球形团聚体,耐火温度高于650℃,是制备硅酸钙保温材料的良好原料。     

补偿式量热计在热化学中的应用

简要介绍了 Ｄ Ｄ Ｃ Ⅱ型补偿式数字精密量热系统及原理和对系统的标定。报道了用该量热计对无限稀的酸和碱反应过程的微反应热的自动测定,为热化学反应过程中微热效应的测定和该量热计的拓展提供了一条新途径。     

Diffusion-controlled corona reaction and overstepping of equilibrium in a garnet granulite, Yenisey Ridge, Siberia

Diffusion modelling is applied to layered garnet–pyroxene–quartz coronas, formed by a pressure-induced reaction between plagioclase and primary pyroxene in a metabasic granulite. The reconstructed reaction involves some change in composition of reactant minerals. The distribution of minerals between layers is satisfactorily explained by diffusion-controlled reaction with local equilibrium, in which the diffusion coefficient for Al was smaller than those for Fe, Mg and Ca by a factor of approximately four. Diffusion of Mg towards plagioclase implies a chemical-potential gradient for MgO component in a direction opposite to the changing Mg content of garnet; this is explained by the influence of Al₂O₃ on the chemical potential of the pyrope end-member. Grain-boundary diffusion is suggested to have operated, possibly with composition gradients different from those in the bulk minerals. Chemical-potential differences across the corona are estimated from the variation in garnet composition, enabling affinity (the free energy change driving the reaction) to be estimated as 6.9±1.8  kJ per 24-oxygen mole of garnet produced. This implies that the pressure for equilibrium among the minerals was overstepped by 1.4±0.4  kbar. The probable P–T conditions of reaction were in the range 650–790  °C, 8–10  kbar. Assuming a timescale of reaction between 10⁶ and 10⁸ years, estimated diffusion coefficients for Fe, Mg and Ca are in the range 9×10⁻²³ to 5×10⁻²⁰ m² s⁻¹. These are consistent with experimental values in the literature for solid-state diffusion, including grain-boundary diffusion.