风化中焦煤结构的变化

用低温氧化模拟焦煤在自然界的风化过程,借助付里叶变换红外发射光谱法,原位观察了过程中煤结构的变化,并和其成焦性质的下降相关联。所得谱图表明,脂肪族基减少、醚桥键的增多以及羧酸基的出现是氧化焦煤的结构特征。由于脂肪族基的损失以及含氧链的增多,导致用氧化焦煤炼焦时产生的液体产物减少和所形成的胶质体热稳定性降低,以致难以使芳核颗粒间产生良好的熔融缩聚反应,结果使得到的焦饼松散不均一     

低阶煤两段化学降解产物的组成性质

用硝酸对低阶煤在常压、加压条件下进行处理 ,可获取高收率的煤基水溶酸 (40～ 50 % ) ;氧化残渣中加入助剂在中性条件下进行二次降解 ,进一步提高水溶酸的收率。考察了对水溶酸在组成、性质、结构方面的特性并与晋城煤的黄腐酸 (FA)作比较 ,可知水溶酸在性能方面优于FA。实验发现 ,煤氧化降解过程中其结构变化主要发生在氧化阶段 ,降解过程对水溶酸中活性基团的增加贡献不大 ;一次氧解产物中含有大量的脂肪结构 ,而风化煤二次降解产物中稠环化程度高 ,与FA相似。     

不同形态水分对煤自燃过程微观作用机制研究

制备不同外在水分和原始赋存水分含量的煤体,通过模拟煤自燃升温氧化过程得到不同温度下的氧化煤样;利用原位傅里叶红外变换光谱仪测定不同氧化煤样中活性官能团的含量,研究形态水分对煤自燃过程微观官能团生成和转化的影响;利用氮吸附仪表征不同氧化煤样中比表面积大小,研究形态水分对煤自燃过程微观孔结构变化的影响;同时结合官能团与比表面积的变化规律,探讨形态水分对煤自燃过程的微观作用机制。形态水分对煤自燃过程的作用机制随着煤自燃状态发展而发生变化,表现出阶段性特征。外来水分含量和原始赋存水分都会促进酚、醇类羟基及含羧基类化合物的生成。外来水分和原始赋存水分的含量对煤自燃过程中微观比表面积、脂肪族C-H组分、含羟基化合物以及含羰基类化合物的生成和转化影响具有差异性;水分形态对微观比表面积和脂肪族C-H组分含量的变化影响具有差异性,而对含羟基化合物以及羧基化合物的生成和转化具有相似性。     

一些我国煤的裂解反应活化能统计分布模型研究

煤是一种很复杂的网状结构。据文献报道,煤中大致含有的基团是:芳核、氢化芳核、类似烷基链基团、烷基桥结构、含氧基团、含硫基团及含氮基团等。一般在700℃以前芳核中的键难于断裂,最易断裂的是与芳核联接的烷基链、脂肪链桥、氧桥及其它含氧化合物。这些键的断裂除与自身特性有关外,还与该键连接的邻接基团有关。因此煤的化学结构不同对煤的裂解有很大影响。而对煤裂解活化能的研究将有助于深入了解煤的裂解和燃烧过程。同时由于煤结构的复杂性,可以预期煤中键的断裂能量是连续分布,因而煤的裂解活化能也存在一个统计分布。据文献报道并结合我们的实验,对河北峰峰瘦煤和肥煤进行了研究,并得出了这两种煤活化能的统计分布模型。     

叠氮化物及其苯并衍生物的研究概况

本文对叠氮化物及其衍生物的研究进展作了阐述，对叠氮基团的结构进行了探讨，指出脂肪族叠氮化物的性能和芳香族叠氮化物脱氮环化生成苯并氧化呋咱这种叠氮衍生物的特征。     

典型沥青热解过程早期阶段的在位红外光谱研究 1.A-240石油沥青在惰性气流及空气中之热解

本文用在位红外光谱考察了A-240石油沥青在空气和氮气气氛下的热解反应机理。发现该试样在空气下加热时发生了激烈的氧化作用:随着反应温度升高氧化反应依次生成烷芳酮的羰基、羧基、芳香醚及脂肪醚,进一步的氧化生成小量酚羟基。此外,还发生脱氢、缩聚和交联反应。在氮气气氛下仅发生脱烷基、环烷脱氢、芳环脱氢、缩聚反应,且脱氢速率低于空气条件下的脱氢速率。在空气条件下芳香分子缩聚反应之剧烈进行归因于氧的诱导作用。根据芳香族和脂肪族C—H 键的吸收强度和氢的总含量,近似地计算了芳香族氢和脂肪族氢二者含量之比,进一步表征出石油沥青在热处理过程中芳香度的改变。     

腐植酸和硝基腐植酸的结构研究

本文通过物化分析和统计结构分析方法,考察了风化烟煤、褐煤和亚炭稀硝酸轻度氧解前后HA 和NHA 的官能团与分子结构特征的变化。结果表明,硝酸氧解均使煤结构中羧基和醒基明显增加。对于风化烟煤只发生脂肪侧链和部分芳碳的氧化脱氢反应,而对褐煤则氧解程度较深,以至芳核开环。前者生成的NHA 弱羧基较多,pK 值较低,后者的NHA 则与土壤中HA 的结构特征相似。对不同煤种的氧化-硝化反应过程也作了初步探讨。     

柴里煤人工氧化过程中性质和化学结构的变化

对鲁南柴里矿山西组三号煤层煤样进行了氧化模拟实验，对氧化系列煤样进行了元素分析、腐植酸含量和傅里叶变换红外光谱分析，讨论了氧化过程中元素成分和腐植酸含量的变化规律。以高岭石谱带为内标，利用差谱技术测定了氧化过程中柴里煤结构中含氧官能团、脂肪烃和芳烃的变化。结果表明，在煤氧化过程中，含氧官能团明显增加，主要是碳基；脂肪烃含量明显降低，但甲基、亚甲基之间没有发现优先攻击现象；而芳烃在氧化过程中基本上没有发生变化。     

Separation and analysis of the degradation products of two coals in aqueous NaOC1 solution

两种煤于温和条件下在次氯酸钠水溶液中进行降解,所得水溶液经酸化后,水溶物依次用乙醚、CS2、石油醚、乙酸乙酯和苯进行分级萃取,萃取物经重氮甲烷酯化后用GC/MS分析.结果发现氯代物、脂肪酸和芳酸是煤的NaOCl水溶液降解的典型化合物,不同极性溶剂分级萃取可以实现产物的初步族组分分离.通过该研究建立煤的次氯酸钠氧化反应混合物有效分离和分析的方法,为煤的高附加值利用提供有效的途径.     

两种煤的次氯酸钠水溶液降解产物的分离与分析

两种煤于温和条件下在次氯酸钠水溶液中进行降解,所得水溶液经酸化后,水溶物依次用乙醚、CS2、石油醚、乙酸乙酯和苯进行分级萃取,萃取物经重氮甲烷酯化后用GC/MS分析。结果发现氯代物、脂肪酸和芳酸是煤的NaOCl水溶液降解的典型化合物,不同极性溶剂分级萃取可以实现产物的初步族组分分离。通过该研究建立煤的次氯酸钠氧化反应混合物有效分离和分析的方法,为煤的高附加值利用提供有效的途径。     

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.     

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.     

Copper-catalyzed multicomponent reactions of 2-iodoanilines,benzylamines, and elemental sulfur toward 2-arylbenzothiazoles

A relatively cheap copper salt-catalyzed, three-component approach providing 2-arylbenzothiazoles in good to excellent yields from readily available 2-iodoanilines, benzylamines, and sulfur powder is reported. This methodology allows preparation of various classes of 2-arylbenzothiazoles and provides a general, reliable approach.