气相毛细管柱切割-反吹技术及归一化法分析汽油中的芳烃(英文)

 发展了一种采用毛细管气相柱切割 反吹技术分析汽油中芳烃的方法。利用强极性毛细管预柱将芳烃保留至n C10 的脂肪族化合物之后 ,并将其反吹到非极性毛细管柱中按沸点详细分离分析。该方法使预柱先流出的组分和分析柱流出的组分通过一个微型三通进入同一检测器中 ,因此可用归一化方法定量分析汽油中的芳烃。该方法可在 15min内完成汽油中苯至C10 芳烃的分析 ,结果的相对标准偏差 (RSD)≤ 3% ,切割误差为± 5s时分析结果的RSD≤ 4 %。     

毛细管色谱切割-反吹法归一化分析汽油中芳烃

发展了一种毛细管色谱切割 反吹方法分析汽油中的芳烃。利用OV 2 3 3 0强极性毛细管预柱将芳烃保留至n C1 0 之后 ,并反吹到非极性毛细管柱中按沸点详细分离分析。从预柱先流出的组分和从分析柱流出的组分都先后进入同一检测器中 ,因此可用响应因子校正的归一化方法定量分析汽油中的芳烃。该方法在15min内完成汽油中苯至C1 0 芳烃的分析 ,结果的重复精度误差≤ 3 % (RSD) ,切割误差± 5s时对分析结果的影响≤ 4% (RSD)。对该方法的装置和部分应用进行了讨论     

二维中心切割气相色谱法测定汽油中芳烃含量

利用二维中心切割气相色谱的原理和切换、反吹技术,将预柱(TCEP)中的待测组分切换到毛细管柱(SE-30)中,建立了汽油中苯、甲苯、C8和C8以上芳烃含量的检测方法。在第一次分析的进样状态下,在待测物质苯从预柱中流出之前,将六通阀切换到反吹状态,这样待测物质苯,甲苯等极性组分被切换至非极性的SE-30毛细管色谱柱中进行分析。在第二次分析的进样状态下,在乙苯流出之前立即将六通阀切换到反吹状态,TCEP柱中的保留组分进入分析柱中进行分析。采用氢火焰离子化检测器(FID),内标法定量,在检测范围内苯,甲苯,邻二甲苯,1,2,4-三甲苯线性关系良好,相关系数(r2)分别为0.9964,0.9981,0.9988和0.9989,对标样进行6次重复实验,相对标准偏差(RSD)都小于2%。     

气相色谱法测定汽油馏分中的单体芳烃

采用三柱一阀气相色谱系统单次进样、归一化法定量分析初馏至200 ℃的汽油(包括含有醇类、醚类的成品汽油)中的芳烃含量。具体操作:样品进入系统后分为两路,一路经过分析柱1(Col.2)后直接到检测器;另一路进入预切柱(Col.1),烷烃和烯烃先于芳烃流出,待烷烃和烯烃放空后将阀切换到反吹状态,Col.1中的芳烃被反吹出来,进入分析柱2(Col.3),经过分离后到检测器,经计算得到样品分析结果。该法简便、快速、样品用量少、测试范围宽,避免了汽油中其他组分对芳烃测定的干扰。     

油品族组成的详细分析和燃油中芳烃的分析

用毛细管液相色谱-毛细管气相色谱联用方法详细分析了航空煤油、各种柴油、润滑油、抽出油和塔底油的族组成。在毛细管液相色谱上分离得到的单环、双环、三环、四环和稠环芳烃族,经过多位存储接口后,顺序进入毛细管气相色谱,通过毛细管气相色谱对每个族组分作详细分析及定量。用单检测器的二维毛细管气相色谱切割-反吹方法定性定量分析汽油、航空煤油中的各种芳烃,从第一维柱流出的组分和第二维柱流出的组分都先后进入同一氢火焰离子化检测器中,因此能用质量校正响应因子归一化方法准确定量分析而不需要标准样。用上述技术分析实际样品,证明了     

高效可逆吸附测定含烯汽油族组成的气相色谱法研究

在研制成功高效烯烃可逆吸附剂ＡＤ－１的基础上,开发了一套适于日常分析的高稳定性专用ＳＯＡ分析系统和相应的分析方法。分析样品时,样品先进入极性分析柱（ＣＯＬ．１）,芳烃留在柱中,烯烃与烷烃继续进入可逆吸附柱（ＣＯＬ．２）。烯烃被吸附,烷烃进入检测器,待饱和烃全部流出后,切换十通阀反吹芳烃,待芳烃完全流出后再将十通阀切换回进样状态,同时将吸附柱升温至２００℃,使烯烃脱附出来,利用积分仪以面积归一法计算出样品中的饱和烃（Ｓ）、芳烃（Ａ）及烯烃（Ｏ）的含量。至此完成一次样品分析。     

气相色谱法测定黑色PMMA燃烧产物中的一氧化碳和二氧化碳含量

利用气相色谱法检测黑色PMMA完全燃烧烟气中的常量二氧化碳和微量一氧化碳,建立了双气路双检测器的检测方法。恒定色谱柱温度,通过定量管进样,Poropak T色谱柱预分离后,采用阀切换及柱反吹技术使不同组分分别流入5A分子筛色谱柱和Poropak N色谱柱中。5A分子筛色谱柱用于分离一氧化碳,经Ni催化甲烷化转化后用FID检测器测定;Poropak N色谱柱分离二氧化碳后进入电导检测器测定。采用峰面积法建立标准曲线,一氧化碳和二氧化碳的线性相关系数分别为0.999 9和0.999 6。用该法测定标准气体,其测定值与标准值的相对误差小于2%,测定结果的相对标准偏差小于1%。该方法可用于烟气毒性的分析。     

气相色谱法测定车用汽油中含氧化合物和苯胺类化合物

利用中心切割技术和双毛细管色谱柱系统,采用两次进样的方式,建立了气相色谱测定车用汽油中含氧化合物和苯胺类化合物的分析方法。第一次进样分析,组分首先进入非极性DB-1色谱柱(30 m×0.32 mm×1.0μm),按沸点由低到高的顺序分离,通过电磁阀切换将沸点小于2-己酮的组分切割至强极性GS-OxyPLOT色谱柱(10 m×0.53 mm×10μm)或CP-Lowox色谱柱(10 m×0.53 mm×10μm),其余重烃组分通过阻尼柱进入FID检测器。在GS-OxyPLOT或CP-Lowox色谱柱上,烃类组分与含氧化合物分离并进入检测器检测,消除了大量的烃类组分对含氧化合物测定的影响。第二次进样分析,设定电磁阀切换时间为间-甲基苯胺从非极性色谱柱流出的时间,苯胺类化合物在GS-OxyPLOT或CP-Lowox色谱柱上与烃类和含氧化合物分离并进入检测器检测。以乙二醇二甲基醚为内标化合物进行内标法定量。实现了在一套系统上同时测定车用汽油中添加的甲基叔丁基醚(MTBE)、甲醇、甲缩醛、乙酸仲丁酯、乙酸乙酯、苯胺、邻/间/对-甲基苯胺和N-甲基苯胺的含量,各组分的检测范围为0.01%~10%(质量分数),回收率为86.0%~102.6%。该法可以为车用汽油的质量控制提供有效的检测手段。     

高温正相色谱/反相色谱(HTNPLC/RPLC)二维联用系统的构建与应用

为解决含水正相色谱与反相色谱联用过程中的谱带展宽问题,以高温正相色谱(HTNPLC)为第一维,室温反相色谱(RPLC)为第二维,分别建立了切割模式的二维液相色谱(HTNPLC-μRPLC)和全二维液相色谱(HTNPLC×RPLC)系统.样品首先在第一维(CN色谱柱)进行正相分离,第一维洗脱产物选择性地或者交替存储在十通阀上的定量环中,然后切换十通阀将定量环内存储的样品组分转移到第二维(C18色谱柱)进行反相分离.该系统降低了第一维切割组分在第二维柱头的扩散,提高了分离度以及分离效率.采用多环芳烃混合物和天然植物甘草提取液对该二维液相色谱系统进行了评价.     

氨基酸光学异构体的气相色谱分离——光学活性毛细管柱与无阀柱切换技术的应用

应用双炉、双柱带无阀切换系统的气相色谱仪,建立了氨基酸光学异构体的分析方法。预柱是涂渍OV-101的玻璃毛细管柱,主柱是涂渍手性固定液——chiyasil-val的玻璃毛细管柱。具有溶剂切割、中心切割和反吹功能的二维无阀切换技术的应用,不仅能保护主柱。而且能缩短分析时间,同时大大提高柱分离能力,使更有利于体液中氨基酸的定性定量分析。     

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%.     

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.