聚苯乙烯固载化聚乙二醇苄醚的合成、相转移催化及机理研究

改进了聚苯乙烯固载化聚乙二醇苄醚的合成方法,并在正溴辛烷与固体NaI的亲核取代反应中考察了它们的相转移催化性能。结果表明,催化反应对n-C₈H₁₇Br浓度为表观1级。催化剂交联度越低,粒度越小,反应速率越大。大孔催化剂活性比凝胶催化剂高;聚乙二醇固载化后的活性比固载化前高,体系中水含量对反应速率也有影响。     

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.     

离子液体相转移催化环己醇氧化制备环己酮

以不同种类的离子液体作为相转移催化剂,用双氧水作为氧化剂,Na2WO4·2H2O为催化剂,在适当的反应条件下,能有效进行相转移催化环己醇氧化制备环己酮.实验结果表明,采用酸性离子液体[C16mim]HSO4和[C14mim]HSO4相转移催化合成环己酮,可提高环己酮的产率,具有反应条件温和、操作简便、需用时间短、相转移催化剂可以循环使用等优点.在反应温度为90℃,反应时间为50min条件下,环己醇的转化率高达100%,选择性99%以上.     

Ruthenacycles and Iridacycles as Transfer Hydrogenation Catalysts

In this review, we describe the synthesis and use in hydrogen transfer reactions of ruthenacycles and iridacycles. The review limits itself to metallacycles where a ligand is bound in bidentate fashion to either ruthenium or iridium via a carbon–metal sigma bond, as well as a dative bond from a heteroatom or an N-heterocyclic carbene. Pincer complexes fall outside the scope. Described are applications in (asymmetric) transfer hydrogenation of aldehydes, ketones, and imines, as well as reductive aminations. Oxidation reactions, i.e., classical Oppenauer oxidation, which is the reverse of transfer hydrogenation, as well as dehydrogenations and oxidations with oxygen, are described. Racemizations of alcohols and secondary amines are also catalyzed by ruthenacycles and iridacycles.     

The Reaction Between Sodium Hydrogen Telluride and Phase Transfer Catalysts

Phase transfer catalysts reacted with sodium hydrogen telluride with yields ranging from 79% to 94%.     

相转移催化法合成新型偶氮化合物

由β－苯丙烯酰氯与取代苯肼的综合反应合成了芳基取代的α,β－不饱和酰肼化合物,进而利用相转移催化剂４－羟基－２,２,６,６－四甲基－１－哌啶基氧自由基以及Ｇａｌｖｉｎｏｘｙｌ自由基对基进行了相转移催化脱氢,合成了８种芳基取代的α,β－不饱和酰基偶氮新型化合物,其结构经元素分析、ＩＲ和＾１ＨＮＭＲ证实,并讨论了可能的反应机理。     

Trialkyl Acyl Ammonium Halides-A New Series of Phase Transfer Catalysts

Trialkyl acyl ammonium halides have found to be superior phase transfer catalysts. They were easy to prepare and afford the reactions to be carried out at elevated temperature, owing to their stability.     

Macrocyclic Polyether Phase Transfer Catalysts for Free Radical Polymerization of Acrolein

Macrocyclic polyethers, e.g., crown ethers and cryptands, were prepared and employed as phase transfer catalysts for free radical polymerization of acrolein, a vinyl monomer, with persulfates (S₂O₈^2–) as initiators. The catalytic abilities of various macrocyclic polyethers as catalysts for the free radical polymerization of acrolein were found to be in the order: benzo‐15‐crown‐5 > dibenzo‐18‐crown‐6 > 12‐crown‐4 > 15‐crown‐5 > 18‐crown‐6 > cryptand‐22 with sodium persulfate (Na₂S₂O₈) as initiator. Sodium persulfate proved to be a better initiator than ammonium persulfate or potassium persulfate with benzo‐15‐crown‐5 as a catalyst. Effects of solvents and temperature on the catalytic polymerization were also investigated. The polymerization rates in various solvents were in the order: dioxane > benzene > acetonitrile > acetone > dichloromethane > hexane > water. Comparison between bulk polymerization and solution polymerization was also made. Higher polymerization rate was observed at higher temperature. The molecular weights of polyacrolein and the conversion of monomer in reaction period were determined with gel permeation chromatography and ultra‐violet spectrophotometry, respectively. Concentration effects of crown ether and initiator were also investigated and discussed.     

新型金鸡纳生物碱季铵盐类手性相转移催化剂的合成及其催化活性

通过在金鸡纳衍生物的9-OH上引入苄基,合成了四种新型的手性相转移催化剂--金鸡纳生物碱季铵盐(1a～1d),其结构经1H NMR和IR表征.以N-二苯亚甲基甘氨酸叔丁酯为底物考察了1的催化活性和对映选择性,最高产率69%,最佳立体选择性90%ee.     

Ethoxylation of o,p-Nitrochlorobenzene Using Phase Transfer Catalysts by Microwave Irradiation

Microwave irradiation is very efficient to accelerate the rate of ethoxylation of o, p-nitrochlorobenzene. The enhancement of reaction rate is 144–240fold.     

新型手性相转移催化剂的合成及其催化作用研究

以金鸡纳生物碱和2-氯甲基苯并咪唑为原料方便地合成了四种新型的手性相转移催化剂. 该类催化剂在相转移催化的二苯亚胺甘氨酸叔丁酯的对映选择性烷基化反应中, 可有效地催化多种卤代烃的不对称烷基化反应, 化学产率最高达85%, 对映体过量值最高达95% ee.     

手性季铵盐类相转移催化剂的新进展

叙述了手性季铵盐类相转移催化剂在不对称催化反应（包括活性亚甲基的烷基 化、Michael加成、双键的环氧化、Darzens缩合、氮杂环丙烷的合成、羟醛缩合以 及Horner-Wadsworth-Emmons反应）中应用的新进展。     

Application of Cryptand/Polystyrene Drift-Type Phase Transfer Catalysts for Reduction of Ketones

A drift-type phase transfer catalyst, cryptand-22, adsorbed on poly(styrene/diviny benzene)-sulfonic resin was prepared and applied to catalyze the reduction of ketones, e.g., acetophenone, benzophenone and benzaldehyde with NaBH₄ as a reducing agent. Before the reaction, cryptand-22 was adsorbed on the sulfonic resin with ion-pairing, resin-SO₃^{? +}NH-cryptand-22. The ion-pairs can be destroyed by adjusting the basicity of the reaction solution with NaOH and the cryptand can be released from the resin into the reaction solution as a homogeneous catalyst during the reaction period. After the reaction, the cryptand catalyst can be readsorbed on the resin by adjusting the acidity of the solution with HCl and can be readily recovered by filtration like a heterogeneous catalyst. The draft-type cryptand catalyst exhibited better catalytic ability than some common crown ethers, e.g., 15-crown-5, benzo-15-crown-5, 12-crown-4 and dibenzo-18-crown-6 for the reduction of acetophenone with NaBH₄. Effects of solvents, pH of solutions, concentration of the catalyst, reducing agents and resin property on the reduction of ketones were investigated and discussed. The reaction mechanism of the cryptand catalyzed reduction was also studied.     

多壁碳纳米管固载金鸡纳生物碱季铵盐类手性相转移催化剂的制备及其催化烷基化反应性能

制备了多壁碳纳米管(MWCNTs)固载的金鸡纳生物碱季铵盐类手性相转移催化剂PTC-1/MWCNTs,并用于催化N-二苯亚甲基-甘氨酸叔丁酯的不对称烷基化反应中.采用紫外-可见光谱系统研究了五种有机溶剂对PTC-1在MWCNTs上吸附和脱附的影响.结果表明,在甲苯中,MWCNTs对PTC-1的吸附率最高(53%),而在三氯甲烷中PTC-1的脱附率最低(仅为0.75%).PTC-1/MWCNTs催化剂在催化N-二苯亚甲基-甘氨酸叔丁酯和不同卤代烃的不对称烷基化反应中,所得产物的收率和对映体选择性都较高,而且该催化剂可回收循环使用,说明PTC-1经MWCNTs固载后,仍能够有效地催化多种卤代烃的不对称烷基化反应.     

用β沸石分子筛作催化剂液-固相合成丁酸戊酯的研究

用β沸石分子筛作催化剂，对正丁酸与正戊醇的液-固相酯化反应进行了研究，考察了催化剂用量、β沸石中阳离子的类型、醇酸摩尔比、反应时间、带水剂环己烷的用量和催化剂活化时间对正丁酸转化率及丁酸戊酯产率的影响，提出了无催化剂及以Al-β沸石分子筛为催化剂时的酯化反应动力学模型。     

Two‐Phase Reactions in Microdroplets without the Use of Phase‐Transfer Catalysts

Many important chemical transformations occur in two‐phase reactions, which are widely used in chemical, pharmaceutical, and polymer manufacturing. We present an efficient method for performing two‐phase reactions in microdroplets sheared by sheath gas without using a phase‐transfer catalyst. This avoids disadvantages such as thermal instability, high cost, and, especially, the need to separate and recycle the catalysts. We show that various alcohols can be oxidized to the corresponding aldehydes and ketones within milliseconds in moderate to good yields (50–75 %). The scale‐up of the present method was achieved at an isolated rate of 1.2 mg min⁻¹ for the synthesis of 4‐nitrobenzylaldehyde from 4‐nitrobenzyl alcohol in the presence of sodium hypochlorite. The biphasic nature of this process, which avoids use of a phase‐transfer catalyst, greatly enhances synthetic effectiveness.     

手性（恶）唑啉催化醛的不对称苯基转移反应

以3-羟基金刚烷羧酸和手性氨基醇为原料,合成了4个嘿唑啉金刚烷醇催化剂,并将其应用于醛的不对称苯基转移反应,得到了较好产率(62%～85%),e.e.值最高为54%.