Brønsted Acid‐Catalyzed Dihydroxylation of Olefins in Aqueous Medium

The trans‐dihydroxylation of olefins occurs efficiently by aqueous hydrogen peroxide catalyzed by p‐toluenesulfonic acid at 50 °C, allowing the catalyst reuse and an outstanding substrate functional group tolerance such as tert‐butoxycarbonylamino (BocNH), benzyloxycarbonylamino (CbzNH), benzyloxy (OBn), tosyloxy (OTs), hindered ketal, (2‐trimethylsilyl)ethoxymethoxy (OSEM), benzylamino (NBz), benzyloxy (OBz) and free amino acid.     

过渡金属多相催化剂催化的分子氧选择性氧化邻二醇研究进展

邻二醇选择性氧化断键生成醛、酮和羧酸是重要和基本的有机反应,氧化剂通常采用化学计量的高碘酸盐或四乙酸铅,无论从经济还是环保的角度考虑,这些传统方法都有违绿色化工的发展理念。理论上以分子氧为氧化剂选择性氧化邻二醇断键的副产物只有水,而且分子氧廉价易得,因而具有环境友好和经济可行的双重优势。经过多年探索,人们已发展了多个基于不同过渡金属为活性组分的多相催化剂或催化体系用于分子氧选择性氧化邻二醇断键反应,如钌、金、锰、钴,为未来广泛应用奠定了基础。本文将按贵金属和非贵金属分类综述此类催化剂及相关反应工艺的研究进展,并指出该领域的发展方向     

三乙烯二胺催化合成聚(碳酸1,6-己二醇)酯二醇

采用碳酸二甲酯(DMC)和1,6-己二醇(HD)为原料,三乙烯二胺为催化剂,通过酯交换反应合成了聚(碳酸1,6-己二醇)酯二醇(PHCDL)。考察了反应条件对该过程的影响,得到了最优合成工艺条件:当三乙烯二胺的用量为1,6-己二醇(HD)的0.026%,常压下160℃反应3 h,然后180℃减压反应8h,得到目的产物PHCDL。三乙烯二胺为Lewis碱,该缩聚反应被推断为通过碱催化的醇解反应来完成的。     

Novel Long‐Chain Diol Phospholipids from Some Bacteria Belonging to the Class Thermomicrobia

Polar lipids of bacteria from the class Thermomicrobia are known to contain long‐chain 1,2‐diols instead of glycerol, although the nature of polar head groups has not been investigated. We have studied phospholipid classes of two species from the class Thermomicrobia—Sphaerobacter thermophilus and Thermomicrobia sp. WKT50.2. TLC and ³¹P‐NMR analysis of polar lipids revealed that both S. thermophilus and Thermomicrobia sp. WKT50.2 contain the same set of four major phospholipid classes. Structures of the novel phospholipids in S.thermophilus were established as 2‐acylalkyldiol‐1‐O‐phosphoinositol, 2‐acylalkyldiol‐1‐O‐phosphoinositol mannoside, 2‐acylalkyldiol‐1‐O‐phospho‐acylmannoside, and 2‐acylalkyldiol‐1‐O‐phosphoinositol acylmannoside. To our knowledge, this is the first report of a phospholipid with a mannose directly bound to the phosphate. We also analyzed fatty acids and long‐chain 1,2‐diols of S. thermophilus and Thermomicrobia sp. WKT50.2 and compared our data with available information for T. roseum. All species share a similar set of fatty acids, with 12‐Me 18:0 being the major fatty acid. The major diol in S. thermophilus was identified as 13‐Me 19:0 (66.2 %). The 21:0 diol was the major component both in Thermomicrobia sp. WKT50.2 (50.6 %) and in T. roseum (56.6 %).     

酯溶型聚氨酯的合成研究

甲苯型聚氨酯由于其残存的溶剂会随着包装渗透至食品里,因此,尽快寻找一种新型的油墨来代替已经迫在眉捷。水性聚氨酯虽然以水为溶剂,但是其性能还远远不能达到实际生产的要求,目前,很多工作者都在研究以乙酸乙酯来代替甲苯,制备酯溶型聚氨酯。很多文献均以单种聚酯二元醇来原料来制备聚氨酯,但是性能对于塑料包装欠佳,因此,文章以分子量为500的二元醇pol-1和分子量为2000的二元醇pol-2制备了酯溶性聚氨酯,并利用红外光谱对聚氨酯进行了定性表征。由测定T-型剥离强度结果可知,当pol-1与pol-2的质量比为1∶3时最好。     

Synthesis and characterization of polyurethanes containing arylene sulfone ether linkages

Polyurethanes containing arylene sulfone ether linkages were synthesized by solution polymerization of 4,4′-bis(4-isocyanatophenoxy)diphenylsulfone (SPI) and 4,4′-bis(3-isocyanatophenoxy)diphenylsulfone (SMI) with various aliphatic glycols such as ethylene glycol (EG), 1,2-propylene glycol (PG), 1,4-butylene glycol (BG), polyethylene glycol (PEG 300 and 1000), polypropylene glycol (PPG 300 and 1000) and polytetramethylene glycol (PTMG 1000. TERACOL) in dimethylacetamide (DMAC) at 120°C. The diisocyanates SPI and SMI were prepared from the corresponding diacid chlorides via Curtius rearrangement. The polyurethanes were obtained in high yields. The effect of structures of diisocyanate and aliphatic diols on the molecular weight and thermal properties of polyurethanes was also investigated. The polyurethanes prepared were characterized by infrared spectroscopy, solution viscosity, elemental analysis, thermogravimetric analysis and X-ray diffraction. Physical and thermal properties of polyurethanes prepared from SPI and various aliphatic glycols were compared with the polyurethanes from SMI and various aliphatic glycols.     

Synthesis and properties of new polyurethane ionomers. I. Photosensitive cationomers with triazene units

New bifunctional triazene compounds 1‐(m‐ hydroxymethyl)phenyl‐3‐(2‐hydroxyethyl)‐3‐methyltriaz(1)ene and l‐p‐nitrophenyl‐3,3‐di(2‐hydroxyethyl)triaz(1)ene as intermediates in polyurethane synthesis were prepared. Photosensitive polyetherurethane cationomers based on poly(tetramethylene oxide) diol of 2,000 average molecular weight, tolylene‐2,4‐diisocyanate, and N‐methyldiethanolamine/triazene diols, as cochain extender, followed by a quaternization with benzyl chloride, were synthesized and characterized. Upon UV irradiation, feniltriazene chromophore in monomer and both polymers (ionomeric or nonionomeric type) is irreversibly cleaved, as evidenced in photolytic and kinetic studies. The rate constant of photolysis in ionomer film was lower than for the corresponding nonionic film. A positive pattern can then be developed by treatment with CHCl₃ that dissolves the exposed zone, while the unexposed area remains resistant and insoluble. By incorporating side nitrofeniltriazene groups, photostable polyurethanes were obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1203–1210, 2003     

Synthesis of L-Lactide-Based Segmented Polyurethanes

A series of segmented polyurethanes with polylactidediols soft segments and methylene-diphenyl-diisocyanate/1,4-butanediol hard segments with molecular weights in the range of 6.18 × 10³ to 9.36 × 10³ Da were synthesized. Stannous octoate was the catalyst for the reactions. These polymers were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, gel permeation chromatography, and thermogravimetric analyzer. Fourier transform infrared analyses revealed the formation of urethane groups and complete curing of polyurethane. The thermal degradation temperatures were in the range of 248.55–257.09°C. X-ray diffraction studies confirmed the segmented structure of polyurethanes.     

Absolute Stereochemistry of 1,2-Diols from Lipids of Thermomicrobia

1,2‐Diol based phospholipids are a well‐known feature of bacteria from the class Thermomicrobia. Since these bacteria contain only lipids with an alkyldiol‐1 ‐phosphate backbone instead of sn‐glycero‐3‐phosphate, it is important to elucidate the stereochemistry of the 1,2‐diols. We have studied the absolute stereochemistry of long‐chain 1,2‐diols isolated from Thermorudis pharmacophila (formerly known as Thermomicrobia sp. WKT50.2) by nuclear magnetic resonance (NMR) using α‐methoxyphenylacetic acid (MPA). Low‐temperature (?60 °C) NMR of bis‐(R)‐MPA ester showed (R) stereochemistry of the 1,2‐diols. This is the first report concerning the stereochemistry of natural 1,2‐diols, which replace the glyceride moiety in phospholipids. The (R) stereochemistry of the diols is expected as it is the same configuration as for the common bacterial lipid backbone—sn‐glycero‐3‐phosphate. This is the first application of low‐temperature NMR of a single MPA derivative for assignment of stereochemistry of natural 1,2‐diols. The results were confirmed by the comparison of NMR data with bis‐(R)‐MPA ester of (R) and rac‐1,2‐octanediol.     

新型二元醇生产应用及技术研究进展

新型二元醇是生产差别化聚酯高分子材料的重要单体原料,产品具有较高附加值,市场增值空间和发展潜力大。介绍了几种重要新型二元醇的性能用途、市场现状、国内外技术应用进展。