聚对二氧六环酮及其共聚物的合成与性能

给出了新型功能化单体5-苄氧甲基-1，4-二氧六环-2-酮（BDON）的合成方法，并将其中间体5-羟甲基-1，4-二氧六环-2-酮（HDON）的产率由文献值的35％提高到48％，同时还研究了BDON在不同催化剂Sn（Oct）2、Al（O^i Pr）3和Al（O^iBu）3的存在下的本体开环聚合，得到分子量为19200的聚合物，研究了聚合温度、时间、催化剂以及催化剂浓度对单体转化率和分子量的影响．通过催化氢化去除苄基保护基得到聚（5-羟甲基-1，4-二氧六环-2-酮）（PHDON），并用FTIR、^1 HNMR、^13 CNMR和GPC等方法对聚合物进行了表征．另外，研究了3种聚合物PHDON、PBDON和PDON在不同条件下的体外降解速率以及BDON和DON的共聚和聚合物的亲水性．     

戊二酸锌催化环氧丙烷与马来酸酐开环共聚反应

以戊二酸锌为催化剂,在无溶剂条件下催化环氧丙烷与马来酸酐的开环共聚反应;优化了聚合条件,利用红外光谱和核磁共振谱研究了共聚物的结构,利用凝胶渗透色谱测定了其分子量.结果表明,戊二酸锌可以有效地催化马来酸酐与环氧丙烷的开环共聚,从而以较高转化率得到交替度较高的共聚物.     

TRANSAMIDATION IN THE in situ BLENDING OF POLYAMIDE 1212 WITH POLYAMIDE 6 THROUGH ANIONIC POLYMERIZATION OF CAPROLACTAM

20 wt% polyamide 12(PA1212)pellets were dissolved in molten caprolactam.The caprolactam was then catalyzed at 180℃and polymerized by means of anionic ring-opening polymerization to produce in situ blends of the resultant polyamide 6(PA6)and PA1212.Mechanical blends with same ingredient were prepared through melt blending on a twin-screw extruder.Scanning electron microscopy(SEM)observation revealed that contrary to the mechanical blends with small spherulites embedded in the matrix,no phase-separation existed in the in situ blends.The results of thermal analysis by differential scanning calorimetry(DSC)showed that single melting peak and crystallization peak existed for the in situ blends,while two melting and crystallization peaks appeared for the mechanical blends.The in situ blend film and the mixed blend film,both cast from a dilute formic acid solution with a concentration of 0.5 g/L,remained similar crystallization and melting behavior as above.It is proved by solution ~(13)C-NMR analysis that transamidation took place during the in situ blending,and it is suggested that the combination of temperature increasing and the basic surrounding derived from NaOH during polymerization resulted in the occurrence of transamidation.Furthermore,it is proposed that the interchange reaction between PA1212 and PA6 also resulted from the degradative reaction during the anionic polymerization.     

含靶向和造影双功能基的PEO的合成

含靶向和造影双功能基的PEO的合成;泛影酸;磺胺嘧啶钠;靶向性;造影剂;聚环氧乙烷;开环聚合     

Synthesis and characterization of α-N,N-dihydroxyethylaminopropyl-ω-butylpolydimethylsiloxanes

A series of α-N,N-dihydroxyethylaminopropyl-ω-butylpolydimethylsiloxanes with different molecular weight were synthe-sized. The preparation included five steps which were hydroxyl protection, alkylation, anionic ring-opening polymerization,hydrosilylation and deprotection. The structure of reaction products was characterized by FF-IR, GC, 1H NMR.     

4-Toluenesulfonic acid: an environmentally benign catalyst for Nazarov cyclizations

An efficient metal-free catalytic protocol for the electrocyclization of α-alkoxydienones to cyclopentenones (Nazarov reaction) in near to quantitative yields is described. The key parameters are the use of inexpensive 4-toluenesulfonic acid in 5 mol % at room temperature in acetonitrile or under solvent-free conditions. The versatility of the transformation is demonstrated with unpolarized dienones with good regioselectivities and excellent yields.     

A new silane precursor with reduced polymerization shrinkage

There is a growing interest in precursor molecules for the sol-gel process which allow the formation of inorganic-organic copolymers, the so-called ORMOCER^®s, with no or only low shrinkage. A new silane type, the spiro ortho ester silanes, which can be polymerized by a ring opening reaction has been developed in order to overcome problems associated with loss of precise dimension and poor cohesion or stresses in coatings or in bulk materials caused by shrinkage during the curing step. In this paper, the synthesis of the new reactive silane precursor, the incorporation into the sol-gel process and the ring-opening reaction that can be UV-induced, for instance, will be described. First investigations show that the last reaction step is accompanied by a volume change of only <0.30 vol. -%.     

Synthesis and Unexpected Ring-opening Reaction of a New TADDOL Analogue with Chiral Cyclopropane Ring as Backbone

Optically active TADDOL (α, α, α′, α′-tetraaryl-1, 3-dioxolane-4, 5-dimethanol) and the related ligands have played a significant role in asymmetric reactions1. Although several hundreds of different TADDOLs and TADDOL analogues have already been de     

Chloro(η-dihydropentalenyl)bis(triphenylphosphine)ruthenium(II): synthesis, structural characterization and catalytic activity in the dimerization of phenylacetylene

Reactions between HRuCl(PPh₃)₃ and 1,3- or 1,5-cyclooctadiene yield the 1,2-dihydropentalenyl complex (η⁵-C₈H₉)Ru(PPh₃)₂Cl through a series of steps including olefin insertion and electrocyclization. The reaction is accompanied by the loss of two equivalents of hydrogen. The product crystallizes in the monoclinic space group (No. 2). (η⁵-C₈H₉)Ru(PPh₃)₂Cl catalyzes the dimerization of phenylacetylene to a ≈2:1 mixture of Z:E 1,4-diphenyl-1-buten-3-yne. Comparison of the catalytic activity of (η⁵-C₈H₉)Ru(PPh₃)₂Cl with (η⁵-C₅H₅)Ru(PPh₃)₂Cl, (η⁵-C₅Me₅)Ru(PPh₃)H₃ and {η⁵-HB(pz)₃}Ru(PPh₃)₂Cl suggests that the more electron-rich η⁵ ligands favor formation of the Z isomer.