A simple one-step synthesis of unsaturated copolyesters

Copolyesters containing pendent vinylidine groups were prepared in a one-step synthesis by reacting either chloro- or bromoacetic acid with 2-(bromomethyl)acrylic acid and triethylamine in diethyl ether. Polymers were characterized by IR, ¹H- and ¹³C-NMR, DSC, and TGA. Copolymer formation supports a mechanism involving a triethylammonium carboxylate salt acting as an active nucleophilic species in a manner analogous to that seen in phase transfer catalysis involving carboxylate anions. Comparison of ¹³C-NMR spectra intensities indicates that 2-(bromomethyl)acrylic acid is much more reactive than the haloacetic acids leading to higher copolymer incorporation than in the monomer feed. Unsaturation in the copolymers provides a site for crosslinking during radical polymerization with an added vinyl monomer, similar to the way unsaturated polyesters function in commercial fiberglass formulations. This was confirmed by polymerization of both styrene and methyl methacrylate in the presence of an unsaturated copolymer giving insoluble semi-interpenetrating networks. These unsaturated copolymers are the first examples of soluble biodegradable glycolic acid polyesters containing such reactive functionality.     

L-焦谷氨酰胺的无溶剂一步反应合成新方法

以L-谷氨酸和尿素为原料,采用无溶剂的一步反应新方法合成了标题化合物;利用高效液相色谱(蒸发光散射检测器)对不同反应条件下合成的产品进行分析,结果表明,当L-谷氨酸与尿素的物质的量比为1:1.3时,让反应混合物在145℃下反应2 h后,再在180℃下反应20 min,产品收率达96.3%,产物纯度为99.67%.     

A convenient,one-step synthesis of 1,4-dithiin

A practical, high-yielding, one-step synthesis of 1,4-dithiin is described starting from commercially available 1,4-dithiane-2,5-diol.     

一步法合成烯丙基缩水甘油醚的研究

烯丙基缩水甘油醚是一种脂肪族缩水甘油醚,可以用作聚合单体和有机合成中间体,是合成硅烷偶联剂KH560的主要原料。实验研究了以环氧氯丙烷和烯丙醇为原料,在一定的相转移催化剂条件下,直接合成烯丙基缩水甘油醚。考察了反应温度、反应时间、物料物质的量比、催化剂体系、带水剂体系对反应产率的影响,确定了最佳的合成工艺条件。     

Use of functionalised silica in catalysis and organic synthesis

Uses of silica in the immobilisation of enzymes and functionalized reagents for resolution of racemic mixtures and synthesis of peptides, oligonucleotide and other compounds are discussed. Silica is superior over organic polymers in its high chemical stability, and being virtually nonswellable. This inhibits the influence of the solvent on physical and chemical behaviour of attached moeties and permits automisation of batch processes.     

A one-step electrochemical synthesis of polyaniline-polypyrrole composite coatings on carbon fibers

Polyaniline-polypyrrole composite coatings were formed on carbon fibers by potentiostatic electrochemical polymerization. Electropolymerization was done by varying the applied potential and molar feed ratio of monomers. The dual nature of the composite coatings was deduced from the current-time (I-t) curves traced during polymerization. I-t curves were also used to predict the mechanism of the formation of composite coatings. UV-vis absorption spectroscopy was used to study the electronic structure of the composite coatings.     

一步合成锡酸钠实验研究

介绍了一步合成锡酸钠的工艺方法,详细考察了碱锡质量比、液固比、反应时间等技术参数对锡反应率的影响,并选用优化条件参数进行了工业试验.工业试验结果表明,使用金属锡和工业氢氧化钠水溶液,加入氧化剂,在加温、加压条件下,可一步直接合成锡酸钠溶液,产出的锡酸钠产品质量达到了企业标准,操作人员劳动强度小,生产过程无三废排放.     

New one-step synthesis of polyimides in salicylic acid

A new polymerization in the melt of salicylic acid has been developed for the one-step synthesis of polyimides from various diamines and dianhydrides. The polymerization is carried out in high solid content up to 40-50 wt/v% at 200 °C and affords the completely cyclized polyimides with high molecular weights in 1-2 h. The preliminary studies on some of the polymerization variables (e.g., concentration and time) suggest that the imidization is very fast and the chain growth is likely to proceed via the addition of the growing imide segments.     

保护的3,6位支化葡萄三糖选择性合成

以2,3,4,6-四-O-苯甲酰-α-D-吡喃葡萄糖三氯乙酰亚胺酸酯为糖基供体,与不保护的烯丙基-α-D-吡喃葡萄糖苷为糖基受体进行一锅糖苷化法反应制得标题化合物.同时,对反应溶剂及配比进行了考察,目标产物及重要中间体的结构经MS、1HNMR、13CNMR及1H-1H COSY表征.     

一步法合成聚酯酰亚胺漆包线漆工艺的研究

本文主要叙述了用一步法合成聚酯酰亚胺漆包线漆的配方的工艺研究及应用.一步法相对多步法对配方和工艺的要求更为细致,同时用一步法合成的产品有更优的综合性能,更高的经济效益.     

Bioconjugated silicon quantum dots from one-step green synthesis

Biofunctionalized silicon quantum dots were prepared through a one step strategy avoiding the use of chemical precursors. UV-Vis spectroscopy, Raman spectroscopy and HAADF-STEM prove oligonucleotide conjugation to the surface of silicon nanoparticle with an average size of 4 nm. The nanoparticle size results from the size-quenching effect during in situ conjugation. Photoemissive properties, conjugation efficiency and stability of these pure colloids were studied and demonstrate the bio-application potential, e.g. for nucleic acid vector delivery with semiconducting, biocompatible nanoparticles.     

2-噻唑硫酮的两种一步合成法

2噻唑硫酮是合成农药、杀菌防霉剂、射线防护剂和冷式卷发剂的中间体,也是制备某些杂环或非杂环化合物的合成试剂[1]。一般的合成方法是以一乙醇胺和二硫化碳为原料,经酯化和环化的2个反应来进行[2]:Ｈ2ＮＣＨ2ＣＨ2ＯＨＨ2ＳＯ4250℃Ｈ2ＮＣＨ2ＣＨ2ＯＳＯ3ＨＣＳ2ＮａＯＨＮＳＨＳ在以往的方法中,酯化是在250℃进行的。由于升温时间较长(约需1ｈ),造成硫酸对乙醇胺产生严重的炭化副反应,故在酯化反应后要加入溶剂(如60%乙醇溶液等)对反应产物进行研磨清洗,再经过滤、洗涤、干燥才能得到较纯的乙醇胺硫酸氢酯,方可进行下一步的环化反应。此…     

一步法合成氨基磺酸镍工艺的研究

采用适宜的活化剂,可实现氨基磺酸与镍的直接、快速反应,通过一步法合成氨基磺酸镍,避免了多步法对产品的污染。研究了预活化时间、活化剂、反应温度、pH、反应时间对反应的影响。结果表明,活化预处理4 h,使用自行研制的氧化性活化剂,在30～50 ℃、pH为3.0～4.0、反应时间为72 h的条件下,能够完成合成反应,并有效控制氨基磺酸水解的发生。产品满足GB/T 23847-2009《电镀用氨基磺酸镍》优等品指标要求,硫酸根和游离氨仅为优等品指标的1/6。该产品已顺利实现产业化。     

合成气一步法制二甲醚工艺及催化剂研究进展

二甲醚在车用燃料和民用燃料方面具有良好发展前景。合成气一步法制二甲醚工艺分气相法和浆态床法。综述了合成气一步法制取二甲醚的工艺和催化剂的研究进展以及工业化前景。     

一步法合成二甲醚反应器的研究进展

综述了合成气一步法合成二甲醚反应器的发展近况,着重介绍了固定床、浆态床及组合床的研究进展,并根据国内外的研究对几种反应器进行了工艺比较。     

The synthesis,characterisation and thermal behaviour of functionalised aryl cyanate ester monomers

The syntheses of several functionalised aryl cyanate esters bearing reactive allyl groups are presented. The monomers were purified (to c. 98%) using preparative HPLC and a range of techniques, including heteronuclear nuclear magnetic resonance (NMR) spectroscopy, was employed in their characterisation. A model functionalised aryl cyanate ester was doped with a variety of additives and the resulting thermal behaviour examined using dynamic differential scanning calorimetry (DSC). Furthermore, the postulated co-reaction of the model functionalised cyanate ester with bis-maleimides was investigated using heteronuclear NMR and dynamic mechanical techniques.     

新型皮革的绿色合成方法

以制革固体废弃物铬鞣革屑为原料,将其溶解再进行化学交联与修饰合成新型皮革。此过程充分利用制革固体废弃物,对环境实现“零排放”,没有带来二次污染。本文考察了温度、时间、以及助溶剂、交联剂用量对反应的影响。结果表明:溶解过程最佳条件为60℃下搅拌溶解3h,废革屑∶助溶剂(质量比)为1∶0.2;交联反应过程最佳条件为60℃下搅拌反应24h,废革屑∶交联剂(质量比)为1∶0.35。     

合成气一步法制汽油馏分烃费托合成催化剂研究进展

围绕对费托合成产物分布的有效调控,综述了近年来有关合成气一步法制汽油馏分烃(C5^C11烷烃)费托合成催化剂的研究进展。重点分析了铁、钴、钌基分子筛催化剂对C5C11烷烃)费托合成催化剂的研究进展。重点分析了铁、钴、钌基分子筛催化剂对C5^C11烃选择性的影响,并对费托合成一步法制汽油馏分烃催化剂的未来发展方向进行了展望。     

合成气一步法制汽油馏分烃费托合成催化剂研究进展

围绕对费托合成产物分布的有效调控,综述了近年来有关合成气一步法制汽油馏分烃(C5~C11烷烃)费托合成催化剂的研究进展。重点分析了铁、钴、钌基分子筛催化剂对C5~C11烃选择性的影响,并对费托合成一步法制汽油馏分烃催化剂的未来发展方向进行了展望。     

生物质合成气一步法合成二甲醚的研究

用共沉淀沉积法制备了生物质合成气直接合成二甲醚(DME)的催化剂,考察了固定床中温度、压力、空速等工艺条件对二甲醚合成性能的影响,同时基于Gibbs自由能最小法对合成DIME反应的化学平衡进行模拟计算,并与实际测试结果相比较.结果表明,模拟结果与测试结果吻合较好.