基于层状氢氧化物衍生复合氧载体的生物质化学链气化实验研究

通过低饱和共沉淀法合成了类水滑石结构的层状氢氧化物(Layered Double Hydroxide,LDH)前驱体,经煅烧获得衍生Cu/Al/Zn、Cu/Al/Ni、Cu/Al/Ni/Zn高分散复合氧载体。采用XRD、XRF、H2-TPR、SEM及BET等分析手段对氧载体的结构及反应性能进行了表征,并通过固定床反应器开展了氧载体与生物质化学链气化实验。结果表明,合成的三种前驱体都具有典型的水滑石特征衍射峰,且层板稳定。Cu/Al/Zn前驱体层间厚度为0.264 2 nm,Ni2+引入后,层间距减小。前驱体煅烧后形成的复合氧载体中元素含量与制备试剂基本一致。氧载体中Zn、Ni元素的引入可提升Cu O的反应活性,降低H2还原的反应温度,Zn元素与Cu具有更好的协同作用。Cu/Al/Ni/Zn氧载体在固定床化学链气化中具有较好的碳转化率和气体产率,其碳转化率为82.03%。反应后氧载体比表面积为5.995 m2/g,具有较好的可再生性与抗烧结性,是生物质化学链气化反应较为理想的氧载体。     

电感耦合等离子体原子发射光谱法(ICP-AES)测定铜磁铁矿中的Al,Ni,Cu,Mg,Pb,Zn 6种元素

建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定铜磁铁矿中Al,Ni,Cu,Mg,Pb,Zn6种元素的定量分析方法。通过实验选择396.152,216.555,324.754,285.213,220.353,213.857nm分别作为Al,Ni,Cu,Mg,Pb,Zn的分析谱线,方法的检出限均小于0.010μg/mL。与原子吸收光谱法进行对比,测定结果基本一致,方法的加标回收率在94%~105%,精密度实验结果表明,相对标准偏差(RSD,n=6)均小于5%,能满足日常对铜磁铁矿中杂质元素的检测要求。     

磷酸三丁酯色层分离-电感耦合等离子体原子发射光谱法测定U_3Si_2中22个微量杂质元素

本法对U_3Si_2中22个微量杂质元素的测定,进行了较系统的实验研究.取样100mg时,Al、Ca、Cd、Co、Cr、Cu、Fe、Hf、In、Mg、Mn、Mo、Nb、Ni、Pb、Sn、Ta、Ti、V、Y Zn和 Zr的测定范围5μg/g~800μg/g,回收率为94%~105%,RSD(n=8)为0.4%~1.2%.     

卷心菜和芹菜中的17种元素测定

采用微波消解法处理卷心菜和芹菜样品,并用ICP-AES法测定这两种蔬菜中的17种微量元素Ca,Mg,K,Na,P,Zn,Fe,Cu,Mn,Al,Se,Cr,Ni,Cd,As,Pb,Hg。结果表明,两种蔬菜中均含有丰富的矿物元素Ca,Mg,K,Na,P,芹菜中的矿物元素更高,也存在少量能调节人体生理机能的有益微量元素Zn、Fe、Mn、Al、Cu、Ni,除了卷心菜中Hg含量超标外,其它有害重金属元素均属国家食品安全卫生标准之内。     

Determination of Seven Metal Elements in Gannan Wild by AAS

为开发和利用赣南野生草菇提供科学依据,采用原子吸收光谱法测定了其中Zn、Co、Ni、Cu、Fe、Cr和Mg 7种金属元素的含量.结果表明,草菇中Zn、Co、Ni、Fe、Cr和Mg含量丰富,Cu含量较低,Zn与Cu值为7.4,与抗癌中药中微元素的含量有Zn高Cu低的关系相同,说明赣南野生草菇有较高的营养价值.     

小麦粉的ICP-AES多元素同时测定

本文报告了ICP-AES法同时测量小麦粉中Ca、Mg、Al、Fe、Cu、Zn、Mn、Ba、Y、Ni的含量。采用元素间干扰系数法校正主要基体元素对微量元素测定的光谱干扰。本法应用于湖南省粮食中重金属含量调查与评价,获得了令人满意的结果。     

微波辅助消解ICP-AES法测定小茴香中20种元素

采用微波消解法处理小茴香样品,电感耦合等离子体发射光谱(ICP-AES)测定其中Na、K、Sr、Ca、Mg、P、As、Zn、Pb、Co、Cd、Ni、Ba、Fe、Mn、Cr、Cu、Al、Ti和B 20种常量和微量元素的含量。20种元素的检出限为0.00002~0.00468μg·mL-1,回收率为89.50%~107.89%,相对标准偏差(RSD)均小6%。结果显示,小茴香果实及其嫩叶中除含有人体必需的常量元素K,Na,Ca,Mg,P外,还含有Fe、Zn、Mn、Cr、Co等必需的微量元素和其他元素Ti、B、Ni、Al、Sr、Ba等。     

电感耦合等离体原子发射光谱法测定高纯银中25种微量元素

应用银生成氯化银沉淀分离银,超声雾化,ICP-AES法测定分离液中Al、Au、Ba、Bi、Ca、Co、Cr、Cu、Fe、Li、Mg、Mn、Mo、Ni、Pb、Pd、Pt、Sb、Se、Sn、Te、Ti、V、Y及Zn 25种微量元素.选择了被测元素的分析线,考察了载气流量,HNO3浓度和Ag的沉淀对测定元素的影响.取样2.5 g时,测定范围为10～320μg/g,回收率在93%～108%之间,相对标准偏差((RSD n=6)在2.9%～11%之间.     

共沉积铝镍氢氧化物的结构及电化学特性

为了改善Ni(OH)2的电化学性质,提高锌镍电池的充放电性能,用化学共沉淀法合成了混合铝镍氢氧化物Ni/Al(OH)x.用XRD和FTIR表征了Ni/Al(OH)x样品的晶体结构及IR光谱特征;测试了用Ni/Al(OH)x为正极活性物质的Zn/Ni实验电池的充放电性能.研究结果表明:所合成的Ni/Al(OH)x具有α-Ni(OH)2的晶体结构;Ni/Al(OH)x活性物质在充放电过程中主要为γ/α循环,以Ni/Al(OH)x作为正极活性物质的Zn/Ni试验电池具有优良的循环性能,其最高放电比容量为379mA·h/g.     

基于全反射X射线荧光光谱测定污水痕量重金属元素

以Ga为内标,探究全反射X射线荧光光谱（TXRF）快速测定多质量梯度浓度多元素重金属溶液Mn、Fe、Co、Ni、Cu、Zn、As、Cd、Sn、Sb和Pb的可行性,并以实际生活污水为研究对象,比较分析了离心、过滤和消解3种预处理方式对测定污水中重金属元素的影响。实验结果表明,Mn、Fe、Co、Ni、Cu、Zn、As和Pb,较适宜用TXRF直接进行定量分析;Pb的Lα与As的Kα谱线重叠,致使As的回收率略高于其它元素;Cd、Sn和Sb元素,仅可用于趋势分析。当质量浓度为40和4 mg/L时,Mn、Fe、Co、Ni、Cu、Zn和Pb元素呈现出较高的准确度和精密度,回收率在99%～117%之间,相对标准偏差（RSD）处于1%～14%。随着质量浓度的逐渐降低,各元素的准确度和精密度表现出不同程度的下降,当质量浓度处于本次试验的最低水平4μg/L时,大部分元素的回收率与RSD已超出定量分析的要求。通过对生活污水的3种预处理方式进行比较,发现污水悬浮颗粒同样携带部分金属元素,经消解后,Mn、Fe、Co、Ni、Cu和Zn这6种元素的准确度和精密度最好,质量浓度范围在36～152μg/L之间,回收率均...     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.