Synthesis of Aromatic Polythioethers Containing 1,3,5-Triazine Ring by Aromatic Nucleophilic Substitution Polymerization

Abstract

Reaction of 2,4-dichloro-6-phenyl-1,3,5-triazines with bis(4-mercaptophenyl) sulfide in the presence of a base in THF afforded the corresponding condensation polymer as a whole aromatic polythioether in moderate yield. The polymerization of several 2,4-dichloro-1,3,5-triazine derivatives with this dithiols also proceeded in the o-dichlorobenzene-water two-phase system by using phase transfer catalysts. The resulting polymers consisted of THF-soluble and -insoluble fractions. The x-ray diffraction pattern indicated that these THF-insoluble polymers have a highly crystalline nature. Further, the polymers obtained here showed high thermal stability.     

Phase transfer catalysis in dehydrofluorination of poly(vinylidene fluoride) by aqueous sodium hydroxide solutions

The reaction of poly(vinylidene fluoride) (PVDF) powder with aqueous sodium hydroxide solutions in the presence of quaternary ammonium or phosphonium halides as phase transfer catalysts afforded dehydrofluorinated polymers. The structure of the products was investigated by infrared spetroscopy, and a fluorine-substituted conjugated polyene structure was suggested which was found to be stable against air oxidation. Tetrabutylammonium bromide and tetrabutylphosphonium bromide were the most active among the catalysts used. The effects of the reaction conditions on the conversion are described. The treatment of PVDF films under phase transfer conditions increased the wettability of the surface and electric conductivity. The reaction of PVDF with potassium hydroxide in 2-propanol proceeded not only by elimination but also by substitution of hydroxide ions.     

Dehydrochlorination of vinylidene chloride-vinyl chloride copolymer by aqueous sodium or potassium hydroxide solutions under two-phase conditions

The reaction of solid copolymer of vinylidene chloride and vinyl chloride with aqueous sodium or potassium hydroxide solutions in the presence of quaternary ammonium or phosphonium salts as phase transfer catalysts gave dehydrochlorinated products with chlorine-substituted polyene structure. Among the catalysts used tetrapropylammonium bromide was the best and potassium hydroxide was more active than sodium hydroxide. The activity of quaternary ammonium salts was discussed in terms of hydrophile–lipophile balance. The effects of temperature and the concentration of the bases and catalysts were investigated to obtain the optimum reaction condition. Treatment of the polymer films and solutions in tetrahydrofuran with aqueous bases under two-phase conditions also produced dehydrochlorinated films and powders.     

Preparation of Polystyrenes Containing Sulfonamide Moieties and Their Use as Phase Transfer Catalysts

Styrenes containing sulfonamide moieties such as N-methyl-N-(P-vinylbenzyl)methanesulfonamide and N,N-dimethyl-p-styrene-sulfonamide were prepared. The copolymerization parameters of these monomers were obtained from copolymerization with styrene under free radical conditions. Crosslinked polymers prepared by free radical terpolymerization of the sulfonamide monomer, styrene, and divinylbenzene served as phase transfer catalysts for the reaction of n-octyl bromide with sodium thiophenoxide in the toluene-water system. However, the corresponding monomeric sulfonamides were practically inactive. These polymer catalysts were stable even under strongly alkaline conditions, and the recovered catalysts were used without a significant loss in activity.     

Insoluble polystyrenes containing amide moieties and N-alkylated nylon-66 as phase transfer catalysts

Insoluble polystrenes containing formamide and acetamide moieties were prepared by free radical terpolymerization of the corresponding vinyl monomers, styrene, and divinylbenzene. These polymers served as phase transfer catalysts for the reaction of n-octyl bromide with potassium thiocyanate in toluene–water system. The activity of these catalysts was affected by some factors such as stirring speed particle size, and degree of crosslinking. The activity also depended strongly on the structure of active site, copolymer composition, and spacer length which cause the difference in the adsorption of potassium ion and in the microenvironment around the active site. Furthermore, nylon-66 was found to display the activity for phase transfer reactions, and the activity was remarkably increased by replacing the amide hydrogen with an alkyl group.     

Synthesis, characterization and properties of poly(methylenetetrasulfide) using interfacial catalysis

A new polysulfide polymer was synthesized from methylene dichloride and sodium tetrasulfide by an interfacial polycondensation technique using two quarternary ammonium salts as phase transfer catalysts. The synthesized polymers were characterized by FT-IR, X-ray and elemental analysis. Thermal properties were evaluated by thermogravimetric analysis and differential scanning calorimetry. The solvent resistance of the polymer was investigated by the swelling method.     

Novel synthesis of polymeric phase transfer catalyst containing polar unit

Soluble polymeric phase transfer catalysts (PTCs) containing benzyltributylphosphonium chloride moieties and p-nitrophenoxy group or N,N-dimethylacrylamide as a polar unit were prepared via two-step reactions from polymers with chloromethyl group and polar units. These polymers were synthesized by copolymerization of p-chloromethylstyrene and the corresponding monomer or substitution of some parts of chloromethyl group with potassium p-nitrophenoxide. When the obtained polymers were added, the phase transfer catalyzed reaction of benzylchloride with solid potassium acetate to proceed smoothly. The catalytic activity was strongly affected by the content of phosphonium chloride and the varieties of comonomer unit in the polymeric PTC. The polymeric PTC containing N,N-dimethylacrylamide unit showed much higher catalytic activity than the corresponding low molecular weight PTC when the phase transfer catalyzed reaction was carried out in low polar solvent. © 1994 John Wiley & Sons, Inc.     

相转移催化合成药物有机中间体乙氧基苯的研究

乙氧基苯是一种重要的有机合成中间体,应用于农药、染料、化学试剂,药品如非那西丁、氢化可的松、醋酸泼尼松等的合成,本文研究了利用相转移催化反应在不同的催化剂反应条件下,合成中间体乙氧基苯,在氢氧化钠存在下,苯酚与硫酸二乙酯于60-65℃反应3h条件下合成乙氧基苯,产品产率达90%以上。对不同的催化剂的使用和反应时间进行了条件优化,对产品乙氧基苯的IR谱图、NMR谱图进行了确认和详细的分析.     

采用相转移催化法制备苯二甲酰亚胺基甲基聚苯乙烯

以邻苯二甲酰亚胺钾盐为亲核取代试剂, 采用相转移催化体系通过Gabriel反应, 将氯甲基聚苯乙烯转变为苯二甲酰亚胺基甲基聚苯乙烯, 考察了各种因素对相转移催化反应的影响规律, 探讨了相转移催化机理. 结果表明, 采用相转移催化体系, 相转移催化剂将邻苯二甲酰亚胺负离子从水相中转移至油相, 与氯甲基聚苯乙烯发生亲核取代, 顺利地将氯甲基聚苯乙烯大分子链上的氯甲基转变成了甲基化的苯二甲酰亚胺基, 成功地实现了高分子的功能化转变. 影响相转移催化反应的主要因素有催化剂种类与用量、溶剂的极性、油相与水相比例及温度等. 当以十六烷基三甲基溴化铵为催化剂且以甲苯为有机相时, 反应效果最佳, 反应温度为50 ℃时, 反应8 h氯甲基的转化率可达到87%.     

XiDehalogenation of Aryl Halides Catalyzed by MontK10 Immobilized PVP-Pd-Sn Catalyst in Aqueous System

Catalytic dehalogenation of organic halides is of great value to the organic synthesis and for the preventing of environmental pollution. Although, in recent years, there are many reports describing dehalogenation of organic halides in the literature1,2,3, most of them were carried out in the organic system,only few examples4,5 of dehalogenation were carried out in aqueous system. The toxic aryl halides may contaminate and harm human being seriously through food chain. Therefore, it is of utmo…     

Epoxidation of styrene catalyzed by manganese (III) porphyrins supported on chloromethylated polystyrene resin bearing crown ether groups,

Metalloporphyrins and crown ether groups were simultaneously supported on chloromethylated polystyrene resin to produce a series of polymer-supported catalysts. The synthesis of these catalysts has been studied. The influence of pH, concentrations of NaOCl and phase transfer catalysts on the epoxidation of styrene catalyzed by these catalysts has also been investigated. The experimental results show that manganese(III) porphyrin bound to chloromethylated polystyrene which bears crown ether groups is effective catalysts for the epoxidation of styrene by sodium hypochlorite. The introduction of crown ether groups increases the catalytic efficiency of supported metalloporphyrins. The kinetics of epoxidation catalyzed by supported manganese(III) porphyrins obeys Michaelis-Menten equation—the characteristic of enzyme-driven reaction.     

Dehydrochlorination of poly(vinyl chloride) by aqueous sodium hydroxide solution under two-phase conditions

The reaction of poly(vinyl chloride) powder with aqueous sodium hydroxide solution in the presence of quaternary ammonium or phosphonium halides yielded dehydrochlorinated products of conjugated polyene structure. The reaction was discussed in terms of a phase transfer catalytic mechanism between aqueous and polymer phases. Among the catalysts used tetrabutylammonium bromide was the best. To obtain the optimum conditions the effects of reaction temperature, the concentration of NaOH and the catalyst, and the molecular weight of poly(vinyl chloride) were investigated. Treatment of PVC films and solutions in tetrahydrofuran with aqueous NaOH solutions under two-phase conditions also produced dehydrochlorinated films and powders.     

Preparation of poly(2,4-dichloro-6-vinyl-1,3,5-triazine-co-styrene)s as polymer supports containing two replaceable groups in monomer unit

Poly(2,4-dichloro-6-vinyl-1,3,5-triazine-co-styrene)s were prepared by the reaction of poly(2,4-diamino-6-vinyl-1,3,5-triazine-co-styrene)s with hydrochloric acid, and followed by treatment with thionyl chloride and N,N-dimethylformamide. The chlorine atoms in the resulted polymers were replaced readily by several nucleophiles such as amide, alkoxide, and mercaptide to afford the corresponding polymers in moderate yields. Among these, polymers containing oligo (oxyethylene) groups at both 2 and 4 positions of 1,3,5-triazine ring worked effectively as phase transfer catalysts for the reaction of n-octyl bromide with alkali metal thiocyanates in toluene–water systems. However, polystyrenes containing only one oligo (oxyethylene) group in monomer unit scarcely exhibited the activity under these conditions although the degree of loading of the functional group was almost the same. The activity depended on the number of oxyethylene units, and the selectivity to alkali metal ions was also observed. © 1992 John Wiley & Sons, Inc.     

Synthesis of metal-containing carbohydrate polymers employing crown ether phase transfer catalyzed interfacial condensation

Phase transfer catalyzed interfacial reaction of the polysaccharide dextran (C₆H₁₀O₅)_n with organotitanium and organotin dichlorides to form metal-containing carbohydrate polymers has been carried out in the presence of two bases, sodium hydroxide and triethylamine. Interfacial systems employing sodium hydroxide with a crown ether phase transfer catalyst (PTC) gave generally greater yields compared with the analogous systems without a PTC. The trend of maximum yield for triethylamine systems with organotin dichloride not containing a PTC was different from that observed for the sodium hydroxide systems without a PTC, probably because of the ability of triethylamine to act as a PTC.     

Phase-Transfer Reactions Catalyzed by Polymer-Supported Imidazoles

Abstract

Polymer-supported imidazoles were prepared by copolymerization of vinyl monomers containing imidazole moiety, styrene, and divinylbenzene with AIBN. The resulting polymers accelerated the reaction of octyl bromide with potassium thiocyanate, and the alkylation of an active methylene compound, benzyl cyanide, under phase-transfer conditions. The latter catalytic reaction afforded monoalkylated compound exclusively, although dialkylated compound was also obtained in monomeric alkylimidazole catalyzed reaction. Further, these polymers served as phase-transfer catalysts for the reduction of acetophenone by sodium borohydride. The relationship between the structure and catalytic activity, and the factors governing these catalytic reactions were examined.     

Interfacial polycondensation and characterization of polyphosphates and polyphosphonates

The synthesis of four bisphenol A-based polyphosphates and phosphonates was accomplished. The polymerization involved a condensation between bisphenol A and a phosphorodichloridate. The heterophasic polycondensation technique was used with the aid of a phase transfer catalyst to yield molecular weights in the range of 20,000–40,000. The polymers were characterized by FT-IR, FT-NMR, and DSC. Systematic studies on the interfacial polymerization indicated that a more concentrated organic phase and a slight excess of diol favored the production of high molecular weight polymers. An optimum concentration of 5–10 mol % was observed for three different phase transfer catalysts. Kinetic studies showed that the polymerization was complete within the first 10 min. The degree of agitation was shown to be important, as the overhead mechanical stirrer was not as effective as the blender. In addition, crosslinking with pentaerythritol yielded significant increases in the molecular weights of these polymers.     

聚合物固载的聚乙二醇季铵盐型相转移催化剂的合成、表征及相转移催化作用

合成了一系列含有聚乙二醇链和季铵盐两种活性中心的高分子相转移催化剂，并考察了它们在正溴辛烷与固体碘化钠的亲核取代反应中的相转移催化性能。结果表明，催化反应对ｎ—Ｃ８Ｈ１７Ｂｒ浓度为表观一级。温度、溶剂和微量水等反应条件对催化反应有较大影响，从反应动力学、本征反应性和内扩散等方面讨论了实验结果。     

Crown-Ether Phase-Transfer Catalysts for Reduction of Ketones,Oxidation of Olefins and Polymerization of p-Xylenedibromide

Various homogeneous and heterogeneous crown ether catalysts were prepared and applied as phase transfer catalysts for some reductions, oxidations and polymerizations. Among various crown ethers, 15-crown-5 seems the best to catalyze the reduction of ketones and aldehydes with sodium borohydride in nonpolar aprotic solvents. A granular entrapped 15-crown-5-polyacrylamide catalysts was also prepared and applied as a heterogeneous catalyst for these reductions which seem to obey pseudo-first-order kinetics with rate constant 10^?4–10⁵ s^?1. The steric effects of ketones and the effects of temperature and concentration of crown ethers, sodium borohydride and carbonyl compounds were also investigated. Among various crown ethers, 18-crown-6 is the best to catalyze the oxidation of olefins such as styrene, xylene and stilbene with potassium permanganate. Crown ethers were successfully applied as catalysts for anionic polymerization of p-xylenedibromide with sodium dithionite as an initiator.     

超声在有机反应中的应用

介绍了超声化学的原理和实验室常用的超声设备。评述了超声在均、多相有机 反应中的应用。超声在均、多相反应中除可以提高反应速率，有时也可以改变反应 路线。在相转移催化反应体系中，超声能够取代相转移催化剂，使反应顺利进行。     

Preparation and Characterization of Dichlorocarbene Modified Multiple-walled Carbon Nanotubes

Multiple-walled carbon nanotubes were functionalized by cycloaddition of dichlorocarbene.The chemical modification was performed by using chloroform and sodium hydroxide.Various phase transfer catalysts were used to increase the efficiency of the reaction.Benzyltriethylammonium chloride used as phase transfer catalyst could highly enhance the effect of functionalization.Elemental analysis was used to evaluate the degree of functionalization.Characterization was performed using scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Fourier transform infrared spectroscopy(FTIR)and energy-dispersive X-ray spectroscopy(EDS)were used to confirm the resulting material.