裂解气相色谱-质谱法分析裂解气压缩机垢样的组成

采用裂解气相色谱-质谱联用技术对大庆石化公司裂解气压缩机EC301不同压缩段的垢样进行分析。实验使用了RJ-1型管炉式裂解器,在500℃下对垢样进行裂解,色谱柱为60 m DB-1型毛细管色谱柱,质谱采用电子轰击电离源,电离能70 eV。研究表明,垢样的形成与环戊二烯密切相关。裂解气相色谱-质谱法可以作为分析该垢样成因的有效手段。     

裂解同时烷基化气相色谱/质谱鉴定醇酸树脂

 用裂解同时烷基化气相色谱-质谱联用技术（SPM-GC-MS）对不同类型的醇酸树脂进行分析研究,将衍生化试剂四甲基氢氧化胺与样品同时裂解,经高效毛细管气相色谱分离,质谱鉴定,可区分醇酸树脂中的多元醇、多元酸、植物油类型,由此对改性醇酸树脂作结构鉴定。与直接裂解-气相色谱-质谱联用技术比较,具有样品前处理快速、简单,用量少,灵敏度高,定性准确,谱图直观等特点。     

废弃印刷电路板材料裂解产物的高分辨裂解气相色谱-质谱分析

采用高分辨裂解气相色谱-质谱法(PyGC-MS)分析了FR-4型印刷电路板粉末样品的裂解产物。在氦气氛围中,分别在350,450,550,650和750 ℃下对印刷电路板粉末样品进行热裂解,并通过毛细管气相色谱-质谱对裂解产物进行分析,研究了不同裂解温度下裂解产物分布以及主要裂解产物的产率与裂解温度的关系,根据热分解产物的组成,探讨了热分解反应机理。     

低分子有机物的裂解色谱定性

裂解色谱多用于不挥发的合成、天然和生物高分子的分析和鉴别,裂解色谱-质谱联用也有用于气相分子裂解反应的研究,裂解色谱作为低分子有机物的定性方法则尚未见报道。 本文用气相色谱将混合物分离,再用裂解色谱将分离的组分逐个得出裂解反应产物的色谱图,与标准物裂解色谱指纹图比较,可以得到混合物各组分的定性结果。本法设     

新书《高分辨气相色谱及高分辨裂解气相色谱》评介

高分辨气相色谱(即毛细管气相色谱)是八十年代得到充分发展的一种分离分析技术,把它与裂解设备结合起来形成的高分辨裂解气相色谱也是近年发展起来的具有广阔应用前景的新技术,它们广泛应用于科研、生产各个领域。由北京理工大学傅若农教授和北京大学刘虎威博士编著的《高分辨气相色谱及高分辨裂解气相色谱》一书,最近已由北京理工大学出版社正式出版发行。该书反映了作者多年来从事这一领域教学、科研工作的经验和成果。与已出版的同类型图书相比,该书具有以下几个特点:     

气相色谱一四温裂解气相色谱联用仪

本文用四个并联的蒸气相裂解器在气相色谱—裂解气相色谱联用装置,四个裂解器的温度为406.554,658及768℃,解决了实用的气相色谱—裂解气相色谱联用分析要求有普遍适用的裂解温度的问题,同时得到较多较大的裂解色谱峰,使定性更加准确。     

一种香精的气相色谱—裂解气相色谱联用分析方法

讨论了裂解二次反应对气相色谱—裂解气相色谱联用定性分析起的作用,改进了气相色谱—裂解气相色谱联用装置,对7组分的香精作定性分析,研究了多种实验条件与定性参数的关系,提出可用一组裂解色谱参数作为实用的主要定性依据,另一组参数作为辅助依据。     

热裂解气相色谱质谱法分析聚合物中红磷

采用单击热裂解(PY)模式和逸出气体分析(EGA)程序升温两种热裂解模式对红磷样品进行定性分析,利用气相色谱分离技术对红磷进行分离,根据红磷的特征质谱31,62,93,124及特征丰度比,质谱法分析不同材料中的红磷含量。单击热裂解模式下,材质和添加剂有可能对红磷造成干扰,改进后的EGA热裂解模式能排除红磷检测中材质和添加剂的干扰,并采用改进后的EGA裂解程序测定自制阳性样品中红磷的含量。结果表明:通过优化裂解温度和气相色谱条件可以有效改善红磷的分析结果,红磷质量浓度在100~500 mg/kg范围内具有良好线性,加标回收率在90.7%~97.7%,相对标准偏差(RSD)为1.6%~2.3%,定量限为81.27 mg/kg。     

裂解气相色谱-质谱联用法分析聚醚酰亚胺的裂解产物

应用裂解气相色谱及质谱联用法研究了3种聚醚酰亚胺(PEIM′s)的裂解行为,并根据裂解产物的结构及其相对产率推断了裂解的机理。取3种PEIM样品置于石英裂解管中,分别在550℃,650℃,750℃条件下裂解,所得产物用气相色谱-质谱联用法分析。分析中采用DB-5毛细管色谱柱,电子轰击离子源(200℃,70eV)及在m/z 29～500范围内全扫描方式,并用NIST谱库进行检索和用归一化法计算峰面积进行定量。由试验结果可知:选择在750℃进行裂解较好,在此条件下获得主要裂解产物存在的更明显的信息,有利于对产物进行详细分析和鉴定。     

纸张上光油关键物质的成分分析

利用色相色谱／质谱联用技术，傅立叶红外及裂解－气相色谱／质谱联用技术，对印刷用上光油的关键成分进行了分析，共鉴定出７种挥发性组分，２种高分子聚合物。     

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%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

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.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.