推荐一个无机合成综合实验——基于废弃大豆油的微乳液法制备纳米氧化锌

纳米氧化锌是一类多功能纳米材料,由于其优秀的物理化学性质而被广泛应用于多个领域。传统的合成方法存在成本过高、过程复杂、产物不稳定等问题。微乳合成法具有操作简单,成本低廉,产物尺寸可控等优点,可以有效避免传统合成方法的缺陷。特别是将废弃大豆油合成的乳化剂应用在合成的过程中,可以实现废物的回收再利用,又能满足绿色化学和可持续发展的要求。使用X射线衍射(XRD)、扫描电镜(SEM)、化学分析等多种方法对产物纳米氧化锌的形貌和性质进行了表征,实现了无机合成-化学分析-仪器分析的综合偶联,从而达到提升大学生进行综合实验能力的目的。

教育数字化背景下国家级化学实验教学示范中心建设与实践

大连理工大学化学国家级实验教学示范中心秉承“注重基础、培养能力、塑造人格”的育人宗旨、以学生发展为中心的育人理念,充分发挥人才培养的主战场作用,在实验教学体系构建、教学资源建设、实验室管理与师资队伍建设等方面进行了深层次的探索与研究。经过5年的建设实践,构建了“四位一体”的实验教学体系和“一体化”的安全教育新范式,打造了“系列化、数字化、多模态”的实验教学资源,建成了一流的实验室环境和制度保障,形成了“名师化”引领的实验教学团队,促进了学生自主探究、创新实践、防护应急处理等方面能力的提升。

希托夫法测定离子迁移数的影响因素探究

离子迁移数作为物理化学课程中电化学部分的一个重要概念,其测定实验被设置在多所高校的物理化学实验课程中。文献调研及过往教学实践表明,使用希托夫(Hittorf)法测定的离子迁移数,结果与文献值有较大出入。为了降低测定误差,以及探究测试结果的影响因素,本实验从溶液装液量控制、断液断电顺序、计算电量的数据来源三个方面进行改进,尽可能降低实验操作和浓度测定导致的误差,从而分析真正影响测试结果的因素。实验表明,当采用电流乘以时间作为电量的数据来源,且采用阴极区溶液计算离子迁移数时,所得结果更接近实验参考值。

高等学校化学类专业物理化学实验教学内容与教学要求建议

为了推进化学类专业本科教学质量国家标准和教育部化学类专业教学指导委员会相关要求的全面落实,推进物理化学实验的改革与建设,本建议明确了化学类专业物理化学实验的教学目标和相关教学要求,通过示例明确了物理化学参数或者性质的测量原理和仪器设备,明确相关教学实验所应达到的知识、能力与素质目标。对物理化学实验改革与建设具有指导意义。

基础化学实验课程思政建设的探索

在基础化学实验课程中以"统筹规划、共建共享"为原则,在实验教学过程中深入挖掘各实验课程和实验项目中蕴含的思政教育资源,凝练成涵盖"家国情怀""科学家/大国工匠""科技创新(理论/技术和方法创新)""安全环保""社会责任/职业素养""朋辈榜样"六大主题的化学实验课程思政案例库,并结合多形态呈现的"智能+教学"实验教学模式,多途径强化教师"育德"能力,充分发挥化学实验课程育人功能。

Adsorptive desulfurization over hierarchical beta zeolite by alkaline treatment

Hierarchical beta zeolites with SiO2/Al2O3 molar ratios of 16 to 25 were obtained by alkaline treatment in NaOH solution. The effects of treatment temperature on crystallinity, textural properties and chemical composites were studied by XRD, N2 sorption, FT-IR and XRF techniques. The desulfurization performance of parent and alkaline-treated beta zeolites was investigated by static absorption in four model fuels, containing four sulfur compounds of different molecular sizes like thiophene （TP）, 3-methylthiophene （3-MT）, benzothiophene （BT） and dibenzothiophene （DBT）, respectively. The crystallinity was observed to be successfully maintained when the treatment temperature was below 50 ℃. Mesoporosity of beta zeolite was evidently developed with alkaline treatment. The formation of mesopore remarkably improved the desulfurization performance for TP, 3-MT, BT and DBT, especially for DBT with larger molecular diameter. Though the addition of toluene in the model fuels resulted in a significant drop of the desulfurization performance of mesoporous beta zeolite, the introduction of cerium ions to some extent mitigated the effect of toluene, which means that both the adsorbent’s porous structure and the adsorption mode are responsible for the desulfurization performance. The adsorbent of cerium ion-exchanged mesoporous beta showed about 80% recovery of desulfurization after the first regeneration.

Effects of toluene on thiophene adsorption over NaY and Ce(IV)Y zeolites

Zeolites NaY and Ce（IV）Y were employed as adsorbents to remove organic sulfur compounds from model gasoline （MG） solutions with and without toluene in static adsorption experiments at room temperature （RT） and atmospheric pressure. The adsorbents were characterized by XRD, XRF and pyridine infrared spectrum （IR）. The adsorption experiments show that the desulfurization performance of Ce（IV）Y is much better than that of NaY. The sulfur removal over both NaY and Ce（IV）Y decreases with the increase of toluene concentration in MG, however, the decline tendency on Ce（IV）Y is smooth, and it is steep on NaY. FT-IR spectra of thiophene adsorption indicate that thiophene molecules are mainly adsorbed on NaY via π electron interaction, but on Ce（IV）Y, in addition to the π electron interaction, both Ce^4＋-S direct interaction and protonation of thiophene also play important roles. Toluene molecules are adsorbed on NaY also via π electron interaction. Although the amount of Bronsted acid sites is increased due to the introduction of Ce^4＋ ions into NaY zeolite, it is not found to influence the adsorption mode of toluene over Ce（IV）Y. Compared with NaY zeolite, the improved desulfurization performance over Ce（IV）Y for removing organic sulfur compounds from MG solution, especially those containing large amount of aromatics, may be ascribed to the direct Ce（IV）-S interaction, which is much resistant to the influence resulted from toluene adsorption.

Effective adsorptive denitrogenation from model fuels over yttrium ion-exchanged Y zeolite

The adsorption removal of indole and quinoline in octane with and without toluene over zeolites NaY and Yttrium Ion-exchanged Y(YY)using batch adsorption experiments was studied at 25℃and 0.1 MPa.YY was prepared by treating NaY with Y(NO3)3 solution twice via liquid ion-exchange method.NaY and YY were both characterized by XRD,SEM,N2 adsorption,XRF,NH3-TPD,and pyridine-FTIR techniques.Adsorption isotherms of indole,quinoline and toluene in octane were conducted at 25.0℃to explain the influence of toluene on nitrogen removal over NaY and YY.The partial destruct of the crystalline structure of NaY was observed after the introduction of yttrium ion,which led to an evident decline in BET surface area and pore volume of YY.Strong Br?nsted acidity and medium Lewis acidity were introduced by yttrium ion-exchange.Though the specific surface area and pore volume of YY were much lower than those of NaY,YY exhibited equivalent adsorption capacities for indole and quinoline as NaY in model fuels without toluene.In the presence of 20 vol%toluene,however,YY exhibited much higher adsorption capacities for indole and quinoline than NaY,especially in the case of quinoline.The improved toluene-tolerant of YY was ascribed to the strong acid–base interaction between YY and quinoline and the decreased adsorption strength between YY and toluene.

Adsorption desulfurization of model gasoline by metal–organic framework Ni3（BTC）2

This work presented the synthesis of Ni-based metal-organic framework material with a paddle-wheel structure Ni3(BTC)2 (Ni-BTC) and its application in thiophene (TP) adsorption from gasoline distillate by batch method. Adsorption isotherms of TP, cyclohexene, and toluene in cyclohexane onto Ni-BTC were conducted at 298-308 K to interpret the different effect of cyclohexene and toluene on TP adsorption. The results showed that, compared w让h cyclohexene, toluene addition in model gasoline led to a more evident decline in sulfur capacity of Ni-BTC, which is opposite to isostructural HKUST-1. The adsorption isotherms of TP, cyclohexene and toluene fit Langmuir model, S-type model and Temkin model well, respectively, indicating that the adsorption mechanisms of TP and the two competitors are different from one another The adsorption capacities on Ni-BTC followed the order of cyclohexene < toluene < TP at the same equilibrium concentrations, implying the order of the adsorption affinities, which is in good agreement with the different extent of influence by the two competitors. The enthalpy of TP adsorption on Ni-BTC was estimated to be -80.01 kj/mol, almost twice that on HKUST-1. The poor reusability of Ni-BTC in batch experiment, which is owing to its sensitivity to the air, can be prevented from regenerating used Ni-BTC in fixed-bed reactor by N2 flow. The difference between Ni-BTC and HKUST-1 in maximum adsorption capacity (q0),△H of TP adsorption, and stability demonstrates that the central metal in isostructural MOFs plays a key role in adjusting the desulfurization performance, which may open up a potential avenue for the development of MOF-based adsorbents with superior desulfurization performance.

Weak base favoring the synthesis of highly ordered V-MCM-41 with well-dispersed vanadium and the catalytic performances on selective oxidation of benzyl alcohol

The key to improve the performance of heteroatom catalysts is to ensure the orderliness of catalysts and the good dispersion of heteroatoms.The alkalinity plays the indispensable role in synthetic process of V-MCM-41 catalyst.The excessive alkalinity of synthetic system will make the MCM-41 difficult to crystallize,even to dissolve.It is easy to accumulate for heteroatomic species in the system of low alkalinity.Herein,the highly ordered VMCM-41 with high vanadic content in framework is synthesized in the condition of excessive NH3·H2 O in this paper.A series of characterization results prove the good dispersion of vanadium species,and most of vanadium gets into the framework of MCM-41 with the states of tetravalence and pentavalence.Furthermore,the modified MCM-41 by other transition metals is successful synthesized by the method of V-MCM-41 in this paper.The VMCM-41 shows well catalytic activity for the selective oxidation of benzyl alcohol,which up to 74.83%for the conversion of benzyl alcohol and 96.20%for selectivity of benzaldehyde when initial V/Si=0.10.The paper provides the possibility for industrial application of V-MCM-41 in the oxidation of benzyl alcohol for benzaldehyde.Besides,the work provides a significant idea for the synthesis of modified MCM-41 by well-dispersed transition metals.

Research Advance on Carbon Storage of Artificial Grassland in China

As an essential part of the grassland ecological system,study on the carbon storage has great significances to the carbon reduction in grassland ecological system.The carbon storage in biomass,carbon storage in soil and soil respiration are summarized in this paper to provide scientific reference for the evaluation of carbon storage in artificial grassland.

β分子筛的酸性和孔道对α-蒎烯催化转化性能的影响

高等物理化学实验是我校理科化学专业学生的必修课,催化剂的制备与表征是其中不可或缺的部分。本实验是对高等物理化学教学实验“NH3-TPD法分析材料的酸性质”及“催化剂活性及选择性的测定”的改进,改进后方案将原实验方案中考察单一催化剂上反应物在不同反应温度和反应时间下的转化率和选择性,更改为具有不同孔道结构和酸量的三种催化剂在同一反应条件下的催化性能对照,同时结合仪器分析实验“N2物理吸附”等相关化学实验,使学生连贯地学习催化剂的制备、改性与表征技术,更清晰地认识影响催化剂催化性能的影响因素。旨在使学生将在多门课程中所学习到的理论知识融会贯通,深入了解β分子筛在较大尺寸反应物分子的转化反应中发挥催化作用的原理。

Metal-organic framework-derived Co-C catalyst for the selective hydrogenation of cinnamaldehyde to cinnamic alcohol

The liquid phase selective hydrogenation of cinnamaldehyde has been investigated over the catalysts Co-C-T(T=400-700℃),which were derived from the carbonization of the MOF precursor Co-BTC at different temperatures in inert atmosphere.Co-C-500 exhibited a higher conversion(85.3%)than those carbonized at other temperatures,with 51.5%selectivity to cinnamyl alcohol,under a mild condition(90℃,4 h,2 MPa H_(2),solvent:9 ml ethanol and 1 ml water).The high catalytic activity of Co-C-500 can be ascribed to the large specific surface area of the catalyst,the uniformly dispersed metallic cobalt nanoparticles,and the more defect sites on the carbon support.Moreover,Co-C-500 showed excellent reusability in 5 successive cycles,mainly related to the uniformly dispersed cobalt nanoparticles embedded in carbon support.

Conversion of phenol to cyclohexane in the aqueous phase over Ni/zeolite bi-functional catalysts

A series of Ni/HZSM-5 and Ni/HIM-5 bi-functional catalysts were synthesized and applied to the aqueous-phase hydrodeoxygenation(HDO)of phenol.The Ni dispersibility and particle sizes were shown to be directly related to the porosity and crystal sizes of the parent zeolites,which further influenced the catalytic performances.The large pores and small crystal sizes of the parent zeolites were beneficial for dispersing Ni and forming small Ni particles,and the corresponding Ni/zeolite catalyst exhibited a higher phenol conversion and selectivity towards hydrocarbons.Importantly,the Ni/HIM-5 bi-functional catalyst exhibited a high activity(98.3%)and high selectivity for hydrocarbons(98.8%)when heated at 220°C for 1 h and is thus a new potential catalyst for the HDO of phenolics to form hydrocarbons in the aqueous phase.