高效液相色谱-二极管阵列检测法测定L-丙氨酸与L-氨基丙醇

建立了柱前衍生同时测定L丙-氨酸、L氨-基丙醇的高效液相色谱方法。色谱条件为:Shim-pack VP-ODS柱(150 mm×4.6 mm.ID.,5μm);二极管阵列检测器;流动相为甲醇-磷酸盐缓冲溶液(NaH2PO4浓度为0.02 mol/L,pH 4.00 H3PO4调节)(体积比为30∶70),流速为0.5 mL/m in,检测波长为222 nm,柱温为30℃。L丙-氨酸与L氨-基丙醇的线性范围分别为2.30~178 mg/L和9.3~8690 mg/L;检出限分别为1.1 mg/L和1.6 mg/L;日内、日间测定的相对标准偏差(RSD)分别为0.22%、0.46%和0.02%、0.03%。     

全自动红外测油仪的研制

研制新型全自动红外测油仪。通过对进样系统、萃取系统、吸附过滤系统和检测系统自动化和集成化设计,实现了对水中油分的全自动检测。仪器的测量范围为0～200 mg/L。自动进样器取样体积误差在1%以内,仪器示值误差在样品浓度不大于10 mg/L时为0.1 mg/L,样品浓度大于10 mg/L时为0.9%,仪器重复性为0.2%(n=6),零点漂移为–0.1 mg/L,示值漂移为0.6%,最小检出浓度为0.1 mg/L,两种水样测量结果的相对标准偏差分别为1.28%和0.91%(n=11),加标回收率分别为96.8%和96.1%,检出限为0.006 mg/L。该仪器测量准确,性能稳定,能够降低工作强度,提高工作效率,减少有机物危害,为环境监测提供有效保障。     

一种同时测定桂油中肉桂醛和苯甲醛双组分的新方法

建立了一种双波长分光光度法同时测定桂油中肉桂醛和苯甲醛的分析方法。苯甲醛的线性方程为A=0.1089x-0.0014,线性范围为1~12 mg/L,检出限为0.1047 mg/L;肉桂醛的线性方程为A=0.1442x-0.0006,线性范围为0.8~8 mg/L,检出限为0.0735 mg/L。     

硝普钠和盐酸二甲双胍分光光度法相互测定

建立了硝普钠(SNP)和盐酸二甲双胍(MET)分光光度法相互测定的新方法。在碱性条件下,MET与SNP以1:1的化学计量比生成了一种酒红色的物质,其最大吸收波长为524 nm。当固定SNP(6.0×10-3mol/L)为5.00 m L时,吸光度和MET的浓度呈现良好的线性关系,线性回归方程为A=0.008+0.449cM ET(mmol/L),相关系数为0.9997,检出限(3σ/k)为0.02 mmol/L。当固定MET(6.0×10-3mol/L)为5 m L时,吸光度与SNP的浓度呈现良好的线性关系,线性回归方程为A=0.005+0.436cSNP(mmol/L),相关系数为0.9992,检出限(3σ/k)为0.01 mmol/L。方法可用于分别测定药物样品中MET和SNP含量。     

离子交换色谱-氢化物发生双道原子荧光法同时测定砷和硒形态

建立了离子交换色谱-氢化物发生双道原子荧光联用同时测定4种As形态和3种Se形态的方法,并优化了各种实验参数。采用PRP-X100阴离子交换分析柱可以在10min内同时分离、检测As和Se形态。在8%HCl和1.5%(m/V)KBH4的氢化物反应条件下,进样量100μL,各形态的检出限为:As(Ⅲ)0.2μg/L、DMA0.3μg/L、MMA0.2μg/L、As(Ⅴ)0.3μg/L、SeCys0.6μg/L、Se(Ⅳ)0.5μg/L、SeMet3μg/L。当各As形态浓度为100μg/L、各Se形态浓度为200μg/L,各形态的精密度RSD(n=7)均小于5%。当各As形态浓度范围为5～100μg/L、SeCys和Se(Ⅳ)浓度范围为10～200μg/L、SeMet浓度范围为50～200μg/L时,各形态均可得到良好的线性关系,线性相关系数均大于0.9992。用建立的方法测定了富硒营养品中的As和Se形态,加标回收率在91%～115%之间。     

桥头碳上氮杂芳基功能化的双吡唑甲烷与羰基钨反应

研究了(氮甲基咪唑-2-基)双(3,5-二甲基吡唑)甲烷(L1),2-吡啶基双(3,5-二甲基吡唑)甲烷(L2)及4-吡啶基双(3,5-二甲基吡唑)甲烷(L3)与羰基钨的反应,合成了一系列以单齿,双齿及三齿氮配位的羰基金属衍生物LW(CO)5(L=L1或L3),LW(CO)4(L=L1,L2或L3)和LW(CO)3(L=L1或L2)。核磁,红外及X-射线单晶衍射分析表明这3种配体表现出了可变的配位方式。在LW(CO)5中,当配体为L1时,其倾向于通过咪唑氮与金属配位,而为L3则倾向于利用吡啶氮与金属作用;在LW(CO)4中,配体L1表现为通过咪唑氮和吡唑氮原子配位的[N,N′]双齿配体,而L2和L3表现为通过吡唑氮原子配位的[N,N]双齿配体;在LW(CO)3中,L1和L2起着[N,N,N′]三齿螯合配体的作用。     

分散液液微萃取-反萃取-接受相固化-高效液相色谱法测定减肥茶中的西布曲明

建立了分散液液微萃取-反萃取-接受相固化与高效液相色谱联用测定减肥茶中西布曲明的方法。优化的条件为:400"L石油醚为萃取剂、120"L甲醇为分散剂、14"L 0.2 mol/L HCl溶液和1"L甲醇的混合溶液为接受相,萃取2 min。在优化条件下西布曲明的富集因子可达130倍。方法的线性范围为0.6～200"g/L,检测出限为0.2"g/L,定量限为0.6"g/L。样品加标回收率介于91.9%～108.4%,日间相对标准偏差小于14%。     

亲水作用色谱-串联质谱测定尿液中尼古丁和可替宁

建立了测定人尿液中尼古丁和可替宁含量的亲水作用色谱-串联质谱(HILIC-MS/MS)方法。尿样加入尼古丁-d4和可替宁-d3同位素内标后,用水稀释10倍,经过滤后的滤液由超高效液相色谱-串联质谱(UPLC-MS/MS)进行分离分析。采用ACQUITY UPLC~BEH HILIC色谱柱(50 mm×3.0 mm,1.7μm),以甲醇和体积分数为0.1%的氨水为流动相,流速为0.2 mL/min,在电喷雾电离源正离子模式下测定尿液中尼古丁和可替宁的含量,用标准曲线法定量。尼古丁和可替宁在1.0~1 000μg/L范围内线性关系良好,相关系数分别为0.994 9和0.995 8;检出限分别为0.082μg/L和0.077μg/L;定量限分别为0.27μg/L和0.26μg/L;加标回收率分别为90.4%~103.5%和93.0%~104.6%;相对标准偏差分别为4.80%~6.21%和4.22%~7.15%。应用所建立的方法测定了200份尿样,结果表明,吸烟人群尿中尼古丁含量为26.68~854.30μg/L,可替宁含量为36.66~1 191.18μg/L(n=86,M_(nicotine)=76.00μg/L,M_(nicotine)=83.52μg/L,M为中位数);非吸烟人群尿中尼古丁含量为5.08~69.66μg/L,可替宁含量为3.16~28.21μg/L(n=114,Mnicotine=7.53μg/L,M_(nicotine)=3.79μg/L)。该方法快速灵敏,操作简单,适用于尿样中尼古丁和可替宁的批量测定,能满足烟草暴露评价的需要。     

游离和膜固定化脂肪酶在双液相介质中催化二肽合成的研究

以N－乙酰－L－苯丙氨酸乙酯和L－亮氨酰胺、L－丙氨酰胺、L－苯丙氨酰胺 、L－缬氨酰胺等L－氨基酰胺为底物，以游离或膜固定化脂肪酶为催化剂，在水、 有机溶剂单相和水－有机相双相体系反应介质中，合成了N－乙酰－L－苯丙氨酰基 －L－亮氨酰胺、N－乙酰－L－苯丙氨酰基－L－丙氨酰胺、N－乙酰－L－苯丙氨酰 基－L－苯丙氨酰胺、N－乙酰－L－苯丙氨酰基－L－缬氨酰胺等二肽。研究证明， 由于反应和纯化的同步进行，二肽可以在双液相酶膜反应器中达到高纯度和高收率 合成。     

基于中空纤维液相微萃取的麻黄碱和伪麻黄碱优势构象的确定及含量测定

利用中空纤维液相微萃取方法(HF-LPME)分析麻黄碱和伪麻黄碱在不同基质中的优势构象,阐明了麻黄碱和伪麻黄碱的萃取机理;结合高效液相色谱(HPLC)建立了微量麻黄碱和伪麻黄碱的分离测定方法。以聚偏氟乙烯中空纤维为有机溶剂载体,正己醇为萃取溶剂,麻黄碱和伪麻黄碱的NaOH(5 mol/L)溶液为样品相,0.01 mol/L H2SO4溶液为接收相,在1200 r/min转速下萃取35 min,收集萃取液直接进行HPLC分析。麻黄碱和伪麻黄碱在水溶液中的线性范围为5～100 μg/L,检出限分别为1.9 μg/L和1.2 μg/L,富集倍数分别为38和61倍,平均回收率分别为100.6%±1.2%和103.2%±3.5%;在鼠尿液中的线性范围为100～5×104 μg/L,检出限分别为30 μg/L和42 μg/L,富集倍数分别为20和17倍,平均回收率分别为108.4%±4.4%和106.1%±5.4%。研究表明该方法操作简单,选择性高,适用于微量麻黄碱的含量测定和分析。     

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%.     

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.     

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.     

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.     

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.     

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.     

关于"对‘燃料电池物理及化学性能的有限时间热力学分析方法'的讨论”答复

把有限时间热力学理论用于化学过程的研究,将会得到一系列新的结论,开展这方面的研究是很有意义的.文献[1]以燃料电池为例,在同时考虑化学反应及传热不可逆性的情况下,研究了燃料电池的性能界限,文献[2]指出了文献[1]计算化学反应及传热不可逆性而引起系统与有关环境的总熵产生率的错误以及由此而导致的结论所存在的问题,并进行了富有启发性的分析与讨论.但文献[2]对于系统与有关环境的总熵产生率的计算也是不正确的,由此得到的其它结论自然不能成立.本文将就此情况下系统与有关环境的总熵产生率的计算再次进行讨论,并给出电池功率和效率的有限时间热力学性能界限.