电感耦合等离子体原子发射光谱法测定钨钢中硅、锰、磷、铬、镍、铜、钼、钒和钨

采用电感耦合等离子体原子发射光谱法测定钨钢中硅、锰、磷、铬、镍、铜、钼、钒和钨的含量。试样用盐酸、柠檬酸铵、硝酸溶解。基体效应采用基体匹配法消除。硅、锰、磷、铬、镍、铜、钼、钒、钨的分析谱线依次为288.158,257.610,177.495,267.716,213.604,327.396,204.598,310.230,239.709nm。9种元素的质量分数在一定的范围内与其发射强度呈线性关系,方法的检出限(3s)在0.000 3%~0.004 8%之间。方法用于两种标准物质的测定,测定结果与认定值相符,测定值的相对标准偏差(n=5)在0.74%~2.1%之间。方法的回收率在95.0%~107%之间。     

ICP–AES法测定铬镍不锈钢中锰、铬、镍、硅、磷、铜、钼的含量

建立电感耦合等离子体原子发射光谱(ICP–AES)法测定铬镍不锈钢中锰、铬、镍、硅、磷、铜、钼7种元素含量的方法。试样用盐酸与硝酸混合酸溶液溶解,采用溶解国家标准样品的方法制备校准曲线溶液,确定了元素最佳分析谱线。各元素的含量在其测试范围内与原子发射强度呈良好的线性关系,线性相关系数不小于0.999,7种元素的检出限在0.000 3%~0.003 0%之间。该方法应用于铬镍不锈钢标准样品的测定,测定值与认定值相符,测定值的相对标准偏差在0.12%~1.15%之间(n=8)。应用于铬镍不锈钢样品测定时,加标回收率在90%~110%之间。该方法操作简便、迅速,可满足日常铬镍不锈钢中多元素含量的检测需要。     

区域地球化学样品中磷、钒、铬、镍、硒等13元素的高效测定方法研究

本文采用硝酸、氢氟酸、高氯酸等三种混合酸预消解,再用王水、盐酸分两次复溶提取,电感耦合等离子体质谱仪（ICP-MS）测定钴、铜、钼、铅、镉,电感耦合等离子体发射光谱仪（ICP-OES）测定磷、钒、铬、锌、钾、镍、锰,原子荧光发射光谱仪（AFS）测定硒,最终实现区域地球化学样品中磷、钒、铬等13元素的准确、高效、组合测定。在选定的实验条件下,各元素的检出限分别为：磷8.42μg·g-1、钒2.55μg·g-1、铬2.00μg·g-1、镍0.50μg·g-1、锌2.00μg·g-1、氧化钾0.05μg·g-1、锰8.00μg·g-1、钴0.20μg·g-1、铜0.80μg·g-1、钼0.10μg·g-1、镉0.01μg·g-1、铅1.70μg·g-1、硒0.01μg·g-1;准确度分别为：砷0.000~0.011、钒0.001~0.002、铬0.001~0.002、镍0.002~0.012、锌-0.008~0.009、氧化钾-0.001~0.005、锰0.003~0.006、钴0.005~0.008、铜0.001~0.006、钼-0.003~0.002、镉0.002~0.020、铅0.003~0.007、硒-0.007~0.008;精密度分别为：磷1.11%~2.95%、钒1.91%~2.52%、铬1.02%~3.41%、镍1.89%~5.56%、锌1.37%~3.05%、氧化钾1.99%~3.47%、锰0.51%~1.98%、钴3.01%~3.28%、铜2.31%~2.77%、钼2.01%~7.20%、镉5.81%~7.76%、铅2.01%~3.65%、硒3.98~7.43%;均满足或优于《多目标区域地球化学调查规范（1：250000）》要求,该方法具有操作简单、多元素同时测定、方法检出限低、测定线性范围宽、准确度高、精密度好等优点,尤其是协同高效,大大节约水、电、试剂等特点,适合实验室广泛推广应用。     

多谱拟合(MSF)电感耦合等离子体发射光谱法测定钼精矿中磷

受钼精矿基体中铜、钼元素的干扰,ICP-OES法无法直接用于磷(213.617nm)的检测。本文考察了钼和铜谱线对磷(213.617nm)测定的影响,应用ICP-OES 多谱拟合(MSF)法消除铜(213.599nm)、钼(213.606nm)的光谱干扰,建立了适合钼精矿中磷的检测方法。对方法的准确度和精密度进行试验,钼精矿中磷的加标回收率为96.2%~103.7%,RSD为2.60%~6.02%。试验证明,本方法是一种较为理想的分析方法,适合钼精矿中磷的测量范围为0.0010%~1%。     

电感耦合等离子体发射光谱(ICP-OES)法测定不锈钢中的硅、锰、磷、铬、镍、钼、铜

用HCl-HNO3混和酸溶解不锈钢样品,用钇为内标物质,使用标准样品绘制工作曲线,用电感耦合等离子体发射光谱(ICP-OES)法测定了不锈钢中的硅、锰、磷、铬、镍、钼、铜。在选定的操作条件下,对不锈钢标准样品按实验方法进行测定,标准样品的测定值与标准值基本吻合。元素质量分数在0.01%～0.10%时,相对标准偏差(n=11)RSD5%;质量分数大于0.10%,RSD 1%。同时测定不锈钢中的硅、锰、磷、铬、镍、钼、铜元素的含量,操作简单、快速、灵敏度高,结果令人满意。     

多谱拟合(MSF)-电感耦合等离子体原子发射光谱法(ICP-OES)测定钼精矿中的磷

受钼精矿基体中铜、钼元素的干扰,电感耦合等离子体原子发射光谱法(ICP-OES)无法直接用于磷(213.617nm)的检测。考察了钼和铜谱线对磷(213.617nm)测定的影响,应用ICP-OES多谱拟合(MSF)法消除铜(213.599nm)、钼(213.606nm)的光谱干扰,建立了适合钼精矿中磷的检测方法。对方法的准确度和精密度进行实验,钼精矿中磷的加标回收率为96.2%~103.7%,RSD为2.6%~6.0%。实验证明,多谱拟合(MSF)电感耦合等离子体原子发射光谱法测定钼精矿中磷的方法是一种较为理想的分析方法,适合钼精矿中磷的测量范围为0.0010%~1%。     

电感耦合等离子体原子发射光谱法测定不锈钢中8种合金元素

采用硝酸-盐酸-水(1+3+6)混合酸溶液溶解不锈钢样品,用电感耦合等离子体原子发射光谱法同时测定试样溶液中铬、镍、铜、锰、磷、硅、钼和钛等8种合金元素。选择钇元素作为内标元素,选择波长为357.869,231.604,327.396,257.610,178.284,251.611,202.030,337.280 nm8条谱线依次作为铬、镍、铜、锰、磷、硅、钼和钛的分析线。方法用于分析了12种标准物质,测定值同证书值一致,各元素的相对标准偏差(n=7)均小于5.5%。     

微波消解–电感耦合等离子体发射光谱法测定DD6单晶合金中铝、铬、钴

建立电感耦合等离子体发射光谱法测定DD6单晶高温合金中铝、铬、钴元素含量的方法。采用密闭微波消解法对样品进行前处理,利用模拟溶液分别考察基体元素和共存元素的光谱干扰及非光谱干扰对测定结果的影响,确定了铝、铬、钴的分析谱线分别为394.401,267.716,228.616 nm,通过基体匹配法对非光谱干扰进行补偿。待测元素在各自的质量浓度范围内与光谱强度呈良好的线性关系,相关系数均为0.9999,铝、铬、钴的检出限分别为0.110,0.018,0.003 μg/mL。测定结果的相对标准偏差为0.99%~1.21%(n=11),铝、铬、钴的加标回收率在分别为96.45%~103.69%,98.20%~99.40%,100.22%~102.85%。该方法简便、快速,具有较高的准确度,适用于镍基单晶高温合金中铝、铬、钴元素的测定。     

GBS-307C型硅、锰、磷、铬、镍、铜等多元素自动分析仪的研制

为解决黑色金属材料中硅、锰、磷、铬、镍、铜、钼、钛、稀土、镁等元素含量（质量分数）的自动分析,设计了GBS-307C型多元素自动分析仪。该仪器根据流体力学原理自动定量加入和分取试液,常温显色法进行被测元素的化学反应,计算机完成仪器程序控制及工作曲线建立和数据处理等。用研制的分析仪对标准样品进行测定,测定结果与标准值相符合。     

微波消解-电感耦合等离子体原子发射光谱法(ICP-AES)测定高速工具钢中锰、磷、镍、铜、铬、钒

高速工具钢为高碳高合金工具钢,常温下样品酸溶分解较为困难,因此建立了微波消解电感耦合等离子体原子发射光谱法(ICP-AES)测定高速工具钢中锰、磷、镍、铜、铬、钒的方法,利用微波消解提高溶样的温度和压力,在王水、氢氟酸和硫酸介质中使样品充分消解,再用饱和硼酸溶液络合过量的氢氟酸,基体匹配消除铁基体的影响,ICP-AES法同时测定锰、磷、镍、铜、铬、钒的含量。测定高速工具钢标准样品,测定值与标样值相吻合,方法的相对标准偏差在0.55%~4.1%。加标回收率在95.6%~114.8%,满足测定要求。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.