1,6-六亚甲基二异氰酸酯自聚产物的结构表征

用IR与NMR表征了用醋酸钾为催化剂时 1,6 六亚甲基二异氰酸酯 (HDI)自聚产物的结构 .结果表明 ,自聚主产物是三聚体异氰脲酸酯 ,主要含有三聚体异氰脲基、异氰酸根 ,同时含有由杂质带来的微量氨基甲酸酯、脲基甲酸酯基、取代脲基、缩二脲基 .一维核磁谱及二维化学位移相关谱分辨出 7种羰基 ,一种NCO基 ,确定了氮上 8种不同取代结构的分子链连接情况 .通过建立理论模型 ,定量地描述了自聚产物的结构 .     

Investigations providing a plausible mechanism in the hexamethyldisilazane-catalyzed trimerization of alkyl isocyanates

Using HMDS as catalyst for the trimerization of isocyanates presents many advantages as the expected isocyanurate is not contaminated by the catalyst or other side-products resulting from its degradation. In addition, HMDS presents a low toxicity, and is compatible with industrial applications. This article describes the hexamethyldisilazane (HMDS)-catalyzed trimerization of octylisocyanate. Experimental investigations and mechanistic considerations indicate that the true catalyst of the trimerization is trimethylsilyloctylamine, which results from the preliminary condensation of HMDS with octylisocyanate.     

Attempt to Synthesize Hindered 2,4,6‐Tri‐Aryloxy‐s‐Triazines: Bis(2,4‐di‐tert‐Butylphenyl) Carbonate – Crystal Structure

Some less hindered 2,4,6‐tri‐aryloxy‐s‐triazines were synthesized through the reaction of the corresponding phenols as a starting materials with cyanogen bromide (BrCN) to obtain the corresponding arylcyanates and then trimerized. Unexpectedly, 2,4‐di‐tert‐butyl‐1‐cyanatobenzene derived from 2,4‐di‐tert‐butylphenol did not trimerize but, indeed, yielded bis(2,4‐di‐tert‐butylphenyl) carbonate. The structures of 2,4,6‐tri‐aryloxy‐s‐triazines and bis(2,4‐di‐tert‐butylphenyl) carbonate were characterized by means of IR, ¹H, and ¹³C NMR spectroscopies. Also the structure of the latter compound was studied by X‐ray crystallography.     

Linear trimerization of 1-ethynylcyclohexan-1-ol catalysed by nickel(II) complexes

The catalytic reaction of 1-ethynylcyclohexan-1-ol (EC) in the presence of bisphosphine nickel(II) complexes yields a linear trimer. The trimer could be isolated and characterized by means of MS, IR and NMR spectroscopies. The reaction mechanism is also discussed.     

新型含环己烯结构的氮杂环聚醚聚合物的合成

用新型聚合单体 1 甲基 4,5 二 (4 氯代苯甲酰基 )环己烯与 4 (4 羟基苯基 ) 2 ,3 二氮杂萘 1 酮、4,4′ 二氯二苯砜单体经亲核共缩聚反应 ,成功地合成了含环己烯结构的杂环联苯型聚醚系列聚合物 .用FT IR、1 H NMR、DSC、X 射线衍射等方法对聚合物进行了表征 ,并研究了聚合物的溶解性能 .结果表明 ,这系列聚合物是具有较高的玻璃化温度的可溶性无规共聚物 .聚合物含有不饱和双键结构 ,可作为交联聚合物、接枝聚合物及其它特种高分子材料的中间体 .而且通过二元或三元聚合 ,来改变交联点和接枝点的密度 ,为进一步得到结构更加多样化与性能各异的聚芳醚的交联聚合物、接枝聚合物及其它特种高分子材料 ,提供一个良好的基础     

Trimerisierung von Dicyanamid-Ionen C2N3– im Festkörper – Synthesen,Kristallstrukturen und Eigenschaften von NaCs2(C2N3)3 und Na3C6N9 · 3 H2O

Trimerization of Dicyanamide Ions C₂N₃^– in the Solid – Syntheses, Crystal Structures, and Properties of NaCs₂(C₂N₃)₃ und Na₃C₆N₉ · 3 H₂O The Tricyanomelaminate Na₃C₆N₉ · 3 H₂O is obtained by heating NaC₂N₃ to 500 °C and subsequent crystallization from water. According to the single-crystal structure determination (Na₃C₆N₉ · 3 H₂O: P62c; a = 1023.53(8), c = 650.85(15) pm, Z = 2, R1 = 0.0276, wR2 = 0.0710) in the solid cyclic C₆N₉^3– ions occur. Partial ion exchange and crystallization from water yields anhydrous NaCs₂(C₂N₃)₃. The X-ray structure determination (NaCs₂(C₂N₃)₃: P6₃/m, a = 700.01(4), c = 1449.29(7) pm, Z = 2, R1 = 0.0173, wR2 = 0.0432) reveals C₂N₃^– ions in the solid. Calorimetric investigations and detailed IR spectroscopy of NaC₂N₃, Na₃C₆N₉, Na₃C₆N₉ · 3 H₂O, as well as NaCs₂(C₂N₃)₃ reveal in combination with the structure analyses that NaC₂N₃ transforms to Na₃C₆N₉ above 380 °C by trimerization of the C₂N₃^– ions in the solid. Above 180 °C the hydrate Na₃C₆N₉ · 3 H₂O reversibly dehydrates.     

Heat-resistant aromatic S-triazine-containing ring-chain polymers based on bis(ether nitrile)s: Synthesis and properties

A novel series of aromatic s-triazine-containing ring-chain polymers, which typically require high pressures to produce, were prepared by the bulk polymerization of low-melting bis(ether nitrile)s (BENs) with or without the presence of terephthalonitrile (TPH) in the catalysis of ZnCl₂ under normal pressure. Four kinds of BENs were readily synthesized by the nucleophilic displacement reaction of 4-chlorobenzonitrile with commercially available aromatic bisphenols or bisphenol-like monomers. Chemical structure of the obtained BENs and their polymers was characterized by FT-IR, WAXD and elemental analysis. Conversion studies indicate that cyano concentration, mobility and reactivity are all important factors for the polymerization, while among of them the cyano reactivity plays a dominant role. The addition of a small mount of TPH is found to be effective in promoting s-triazine forming reaction of the BENs. The synthesized polymers are insoluble, and exhibit good chemical-resistant property towards strong acids and bases together with good hydrolysis-resistant property. No detectable endothermic inflection for glass transitions is observed in the DSC traces of all polymers up to 450 °C, and the polymers exhibit excellent thermal stability with decomposition temperatures for 5% mass-loss ranging from 493-540 °C. All these attracting properties make the s-triazine-containing ring-chain polymers good candidates as matrixes for high performance polymeric materials.     

异佛尔酮二异氰酸酯自聚产物的~(13)C-NMR研究

研究了用季铵盐N,N,N-三甲基-N-(2-羟基乙基)-氢氧化铵为催化剂时异佛尔酮二异氰酸酯(IPDI)自聚产物的合成,用13C-NMR1、H-NMR、不失真地极化转移增强(DEPT)1、3C-1H异核远程相关(HMBC)实验表征了产物结构.结果表明,自聚产物是三聚异氰酸酯,主要含有三聚体异氰脲基、异氰酸根.一维核磁谱及二维化学位移相关谱分辨出两种羰基,确定了氮上4种不同取代结构的分子链连接情况.对自聚产物的碳谱图进行了全归属.     

Trimerization of isobutene over cation exchange resins: Effect of physical properties of the resins and reaction conditions

Oligomerization of isobutene has been investigated using several cation exchange resins in order to produce triisobutenes that are useful feedstock for heavy alkylates and neo-acids. Trimers selectivity increases with increasing isobutene conversion. High isobutene conversion is obtained at high temperature and low space velocity by using macroporous cation exchange resins that have high concentration of sulfonic acid groups. Under selected conditions (viz., isobutene WHSV: 10 h⁻¹; temperature: 70 °C; catalyst: Amberlyst-35), the isobutene is quantitatively oligomerized with higher than or equal to 70% selectivity for trimers. The wet resin catalysts containing water or ethanol are very stable for the oligomerization up to about 70 h contrary to the gradual decrease in the conversion with dehydrated catalysts.     

Synthesis of star-shaped pyrrole-based C3-symmetric molecules via ring-closing metathesis,Buchwald–Hartwig cross-coupling and Clauson–Kaas pyrrole synthesis as key steps

We have demonstrated three contrasting synthetic strategies to assemble pyrrole-based C₃-symmetric molecule. Here, ring-closing metathesis (RCM), Buchwald–Hartwig cross-coupling and Clauson–Kaas pyrrole synthesis have been used as key steps. Interestingly, readily available starting materials such as 4-aminoacetophenone, 4-bromo acetophenone and 4-nitro acetophenone have been used as starting materials. Grubbs’ first generation catalyst (G-I) is useful for one-pot RCM and aromatization sequence without the involvement of additional reagents. We also report photophysical properties of these star-shaped molecules.