合成CFC-12替代物HFC-134a的CrF_3/AlF_3催化剂研究(Ⅴ)──CrF_3与AlF_3的相互作用

由于氟氯烃（ＣＦＣｓ）对大气臭氧层的破坏作用，使得开发ＣＦＣｓ无污染替代品的研究成为热门课题［１～４］．氢氟烃（ＨＦＣｓ，如ＨＦＣ－１３４ａ）是ＣＦＣｓ的理想替代物．在氟氯交换合成ＨＦＣ－１３４ａ的反应中，ＡｌＦ３基催化剂的活性、稳定性明显优于ＣｒＦ...     

THE PROMOTING EFFECT OF FLUORIDE TO OCM OCTALYST ZrO_2-BaF_2

ＴＨＥ　ＰＲＯＭＯＴＩＮＧ　ＥＦＦＥＣＴ　ＯＦ　ＦＬＵＯＲＩＤＥ　ＴＯ　ＯＣＭ　ＯＣＴＡＬＹＳＴ　ＺｒＯ_２－ＢａＦ_２ＴＨＥＰＲＯＭＯＴＩＮＧＥＦＦＥＣＴＯＦＦＬＵＯＲＩＤＥＴＯＯＣＭＯＣＴＡＬＹＳＴＺｒＯ_２－ＢａＦ_２￥ＺｉＳｈｅｎｇＣＨＡＯ；Ｘｉ...     

氟化烃会破坏高空臭氧层吗？

氟化烃会破坏高空臭氧层吗？自从氯氟烷（ＣＦＣ）因破坏自氧层而在全球范围逐渐停产以后，出现了各种各样的代替品，氟化烃（ＨＦＣ）是主要的一大类。目前所用的氟化烃主要有ＣＦ３ＣＦ２Ｈ，ＣＦ３ＣＦＨ２，ＣＦ３Ｈ，ＣＦ３ＣＨ３和ＣＦ２ＨＣＨ３，大多含ＣＦ３基团...     

合成CFC-12替代物HFC-134a的CrF3/AlF3催化剂的研究

考察了不同反应条件下ＨＣＦＣ－１３３ａ与ＨＦ在ＣｒＦ３／ＡｌＦ３催化剂作用下生成ＨＦＣ－１３４ａ的反应性能。需用ＧＣ－ＦＴＩＲ方法鉴定了产物的组成，探讨了副产物形成的原因，并进行了催化剂的稳定性试验。结果表明在ＨＦ／ＨＣＦＣ－１３３ａ流量比为１０和３５０℃和条件下，得到了较高的转化率和选择性。     

BASIC FUNCTION OF PARALLY HYDRATED FLUORIDE SPECIES ON SUPPORTED KF

ＢＡＳＩＣ　ＦＵＮＣＴＩＯＮ　ＯＦ　ＰＡＲＡＬＬＹ　ＨＹＤＲＡＴＥＤ　ＦＬＵＯＲＩＤＥ　ＳＰＥＣＩＥＳ　ＯＮ　ＳＵＰＰＯＲＴＥＤ　ＫＦＢＡＳＩＣＦＵＮＣＴＩＯＮＯＦＰＡＲＡＬＬＹＨＹＤＲＡＴＥＤＦＬＵＯＲＩＤＥＳＰＥＣＩＥＳＯＮＳＵＰＰＯＲＴＥＤＫＦ...     

关于二氟乙炔的异构化反应的量子化学研究

用ａｂ ｉｎｉｔｉｏｎ方法讨论了Ｆ２Ｃ２的异构化反应机理，用ＨＦ／６－３１Ｇ和ＭＰ２／６－３１Ｇ优化Ｆ２ＣＣ和二氟乙炔（ＦＣ＝ＣＦ）的几何构型，并得到反庆Ｆ２ＣＣ＿ＦＣＣＦ的过渡态（ＦＣ（Ｆ）Ｃ）。文中用内禀反应坐方法做反应路径解析，二氟乙炔是二氟丙二烯酮分解反应的产物，用从头算方法优化二氟丙二烯酮并在Ｍｕｌｌｉｋｅｎ集居分析中，发现Ｆ２Ｃ＝Ｃ＝Ｃ＝Ｏ在分解反庆中先产生中间产Ｆ２ＣＣ，之后经过过渡     

KAIF_4化合物的合成

ＫＦ－ＡＩＦ_３体系中介于ＫＡＩＦ_４和Ｋ_３ＡＩＦ_６之间的共晶点组成的熔盐作为钎剂大量用于各类铝散热器的钎焊,工业上称为Ｎｏｃｏｌｏｋ方法［１,２］。以ＫＡＩＦ_４为主体的Ｎｏｃｏｌｏｋ钎剂［１］合成方法虽有多种并已见诸文献报道［２－８］,但为深入研究Ｎｏｃｏｌｏｋ钎剂的特征,研究纯ＫＡＩＦ_４的制备非常必要。Ｅｉｔｅｌ等人报道用熔融ＫＦ和ＡＩＦ_３的方法,制得了纯ＫＡＩＦ_４［９］。Ｂｒｏｓｓｅｔ［４］则认为熔融ＫＦ和ＡＩＦ_３得不到纯的ＫＡＩＦ_４,他在水溶液中以定比例混合ＨＦ,ＡＩＦ_３和ＫＨＦ_…     

铁硅酸盐分子筛乙苯氧化脱氢催化性能研究Ⅱ．FeZSM－5的酸碱性质和积炭对反应活性的影响

本文应用碱性气体吸附的红外光谱和ＴＰＤ技术研究了ＦｅＺＳＭ－５（Ｆ＿４）的酸性，酸性顺序为：Ｈ－Ｆ＿４＞Ｆｅ＿２Ｏ＿３／Ｆ＿４＞Ｆ＿４原粉＞水热处理的Ｋ－Ｆ＿４＞Ｌｉ－Ｆ＿４＞ＮａＦ＿４＞Ｋ－Ｆ＿４＞ＮａＯＨ／Ｆ＿４，比较了酸强度和积炭对乙苯氧化脱氢性能的影响，以及催化剂酸碱性质与积炭的关系．结果表明，乙苯氧化脱氢反应是在酸碱协同作用下进行的，积炭也参与了氧化脱氢反应，催化剂表面上Ｌ酸中心产生的具有一定Ｃ、Ｈ、Ｏ比的积炭具有高的氧化脱氢活性．碱金属阳离子改性的具有Ｌ酸中心的ＦｅＺＳＭ－５是乙苯氧化脱氢的高活性催化剂。     

BaFClxGBr1—X：Sm体系的热释发光及其归属讨论

通过对ＢａＦＣｌｘＢｒ１－ｘ：Ｓｍ（０≤ｘ≤１）体系热释发光的研究，发现前人对ＢａＦＸ（Ｘ＝Ｃｌ，Ｂｒ）晶体热释发光的归属有误。结合多种技术的研究给出了正确的归属：ＢａＦＣｌｘＢｒ１－ｘ：Ｓｍ的第一、二、三个热释峰分别归属于Ｆ（Ｆ＾－），Ｆ（Ｃｌ＾－）和Ｆ（Ｂｒ＾－）心；ＢａＦＸ晶体的第一、二个热释峰分别归于Ｆ（Ｆ＾－）和Ｆ（Ｘ＾－）心。论证了结果的正确性，并分析了前人归属错误的可能原因。     

碳纤维增强聚砜颅骨修补材料的物理力学性能研究

对碳纤维增强聚砜（ＣＦ／ＰＳＵ）颅骨修补材料的物理力学性能进行了研究。结果表明，ＣＦ含量的增加，ＣＦ／ＰＳＵ复合材料的密度ρｃ及ρｖ的变化分别符合公式：ρｃ＝１．２４３＋０．４０５ＷＣＦ及ｌｇρｖ＝１６．７１７－２０．１８８ＷＣＦ（ＷＣＦ为ＣＦ的重量百分数）。当ＣＴ含量在０￣２５（ｗｔ．％）范围内，ＣＦ／ＰＳＵ复合材料的力学性能均随ＣＴ含量的增加而增加。对于ＣＦ含量为３０（ｗｔ．％）的ＣＦ／ＰＳＵ     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.