煤热解过程中含氮气相产物转化规律的实验研究

为了研究煤在热解过程中含氮气相产物的生成规律,在滴管炉反应系统中对四种原煤以及两种脱除矿物质煤样分别在500℃、700℃、900℃和1100℃进行了实验研究。结果表明,随着温度的升高,作为NO前驱物的HCN和NH3的收率随之增加,N2的收率也增加。煤种对含氮气相产物的生成规律也有着较大的影响,煤化程度比较低的煤在热解过程中,燃料氮向气相含氮产物的转化率较高;煤化程度比较高的煤转化率则偏低,大部分的氮缩聚在多环芳香结构中,成为焦炭氮。煤中的矿物质对燃料氮向N2的转化起到了促进作用,而对燃料氮向HCN和NH3的转化起到了抑制作用。     

三种高变质程度煤热解过程中H2的逸出特征研究

氢气是煤热解的主要气体产物之一。近年来,随着氢能源研究热潮的兴起,煤制氢成为煤转化技术新的研究热点。由于煤的热解是煤热转化过程的初次阶段,深入分析煤热解过程中氢的析出特征不仅可以深入理解煤的热解机理,而且也可以为煤热转化的后续工艺设计提供基础。同时,也是理解地     

QDTA/T/EGD/GC在线联同技术 Ⅸ.煤的热解、碳化度应历程及其机理的研究

应用QDTA/T/EGD/GC在线联同技术及其装置测定了在N_2气下五种不同煤化程度的煤种之DTA/EGD/GC热解特性曲线。实验结果可提供如下三方面的信息和数据:(1)唯有中等煤化程度的煤,才在一次碳化反应阶段的曲线上呈现出台阶状的放热效应,由这种煤可获得性能良好的焦炭;(2)取得了在碳化过程中的各项表征温度和碳化气特征;(3)提出了焦煤的热解、碳化反应历程及其机理。     

红外发射光谱法用于煤化学研究

提出了一套可用于煤化学研究的红外发射光谱测试系统 ,设计了一个结构简单 ,使用方便的样品槽 ,讨论了操作中影响光谱质量的有关因素 ,并以观察煤在低温氧化过程中结构变化为例 ,展示了这一方法在煤化学领域中的应用前景。     

高硫煤热解过程活性氢/氧对有机硫变迁行为影响研究述评

随着优质煤资源的消耗,高硫煤的清洁高效转化备受关注,尤其是高硫炼焦煤中有机硫的调控至关重要。煤热解过程中,有机硫的变迁始于煤大分子结构中C–S键的断裂和含硫自由基的稳定,活性氢/氧是影响其转化赋存形态的重要因素。研究表明,煤在富氢/氧氛围下热解或与生物质、含氧有机物共热解的体系中,含有的活性氢/氧可弱化有机硫的C–S键,促进其断裂并及时结合生成的含硫自由基,促进煤中硫分向气相变迁,减少了含硫自由基与煤基质的二次反应。同时,高挥发分煤与高硫煤共热解过程中,相对丰富的挥发分中的活性氢/氧也会影响高硫煤中有机硫的变迁,降低焦炭中的硫含量,这为煤中硫分定向调控提供了理论基础。     

煤热解过程焦中硫的残留及煤中硅、铝、碳的影响

用HCl和HNO3对不同煤阶(褐煤、烟煤、无烟煤)的七种煤进行了部分矿物质的脱除处理,获得的样品主要含硅铝矿物质。通过程序升温热解和程序升温氧化两个过程,结合含碳量的差别,对煤热解过程中煤中硅铝对硫在焦中的残留状况的影响进行了研究。结果表明,脱除了其他矿物质的煤其煤化程度和硅铝比共同影响热解过程中焦中硫的残留率。焦中硫的残留率随样品含碳量增加而增加,但在煤的含碳量90%左右发生转折。这与煤的其他物理性质(如孔隙率、可磨性、质量热容、介电常数、溶剂溶胀率)类似,与煤结构在这点附近的较大变化有关。对应于各自煤阶,由于硅对气相含硫产物与半焦二次反应的抑制作用,焦中硫的残留率随着Si/Al质量比的增加而减少。     

一种测算煤弹性模量的方法——全微硬度法

在采煤工艺和煤化学研究中,都要测知煤的弹性模量。它既是采煤工艺、矿山压力研究中所必要的参数,又可以作为固体中键强度的量度,为进行煤化学研究提供煤质结构单元间化学键的特性。进而研究煤的微细结构。关于弹性模量的测定方法,大致分动态法和静态法两类。国内主要应用电阻应变仪法,共振频率法等几种方法为国外普遍应用,其它很少为人们所采用。电阻应变仪法要求煤样制成规则形状,这对有些煤来说,颇难办到。本文介绍一种利用全微硬度测算煤弹性模量的方法。     

两种煤在热解过程中汞的析出和形态分布实验研究

在程序升温热解反应系统上,研究了大同煤和宝日希勒煤在N2气氛下热解过程中汞析出及形态分布规律。实验结果表明,温度是影响煤热解过程中汞释放的主要因素。煤中汞释放率随着温度的升高而明显升高,当热解温度为600℃时,煤中汞已基本逸出,汞释放率在92%以上。元素汞(Hg0)是气态汞释放的主要形态,随着热解温度的升高,大同煤释放的元素汞在气态汞中的质量分数先增加后减小,而宝日希勒煤中元素汞的质量分数逐渐降低。随着停留时间的延长,煤中汞释放率和元素汞的质量分数都呈增加趋势,宝日希勒煤的增幅较大同煤更为显著。较高的加热速率促进了煤中汞的释放,同时也在一定程度上提高了氧化汞的质量分数,其中宝日希勒煤的氧化汞增幅明显大于大同煤,达19.5%。     

低煤化度煤低温热解脱氧后结构的变化

采用低温热解脱氧方法对低煤化度煤中含氧官能团化学活性进行了系列研究,测定了ＦＴＩＲ、１Ｈ－ＮＭＲ、１３Ｃ－ＮＭＲ及比表面积和孔径分布。得出了煤中含氧官能团的化学活性顺序,并发现低温热解脱氧的同时,煤分子中的Ｏ重新分布,Ｈ分布、Ｃ分布及孔径分布的变化,是低温热解导致煤分子改性的原因所在     

低煤级煤热解H2生成动力学及其与第一次煤化作用跃变的关系

用开放体系的热重-质谱联用仪(TG/MS)研究了7种低煤级煤的热解特征、H2的生成动力学特征以及它们与第一次煤化作用跃变的关系. 结果显示, 煤热解失重率在碳含量(Cdaf)为80%(质量分数)和镜质组最大反射率(R0max)为0.60%附近发生转折; 氢气生成的特征温度参数以及动力学参数均在Cdaf为80%(R0max为0.60%)左右表现为最低; 氢气的总产率在此处最大. 这些特征参数的极值点刚好与第一次煤化作用跃变点一致, 说明这些参数可以反映第一次煤化作用跃变的发生. 结合傅立叶变换红外(FTIR)光谱法获得的煤结构特征, 对影响机制进行了分析解释, 认为是由以下3个方面的原因导致的: (1)煤中脂肪类含氧官能团的演化特征; (2)可溶有机质的低温热缩聚作用; (3)有机质的“两极分化”作用.     

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%).     

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.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.