用环境友好催化剂俣成丙酸苄酯的研究

应用环境友好催化剂H－β沸石催化苯甲醇与丙酸的酯化反应,合成了丙酯苄酯。研究结果表明,H－β沸石 具有较高的催化活性。考察了苯甲醇／丙酸摩尔比、催化剂用量、反应温度、反应时间和带水剂环己烷用量对酯产率的影响。在典型反应条件（苯甲醇／丙酸摩尔比＝1.15:1、10.5gH－β沸石/摩尔丙酸、反应温度160℃ 、反应时间3.5h和20mL环己烷／摩尔丙酸）下,所得丙酸苄酯的产率为77％,该催化剂易于回收且可重复使用,具有良好的活性稳定性,并研究了用某些金属阳离子改性的β沸石的催化活性。     

三丁胺胺化强碱性阴离子交换树脂催化合成羧酸苄酯

用组合化学方法筛选出的对无外加碱条件下的亲核取代催化活性最高的聚合物季铵盐-三丁胺胺化强碱性阴离子交换树脂为相转移催化剂,催化合成了乙酸苄酯、丙酸苄酯、丁酸苄酯、戊酸苄酯等羧酸苄酯。讨论了各种反应条件对合成丙酸苄酯的产率的影响,并对传统合成方法进行了改进。在优化反应条件下,反应产率接近100%。     

接枝型三相相转移催化剂的制备及其催化作用

将苯乙烯（St）接枝聚合在微米级硅胶表面,制备了接枝微粒PSt／SiO2;使用新型氯甲基化试剂1,4-二氯甲氧基丁烷,对接枝在硅胶表面的聚苯乙烯进行了氯甲基化（CM）反应,制得了氯甲基聚苯乙烯／硅胶（CMPS／SiO2）接枝微粒;使三乙胺与CMPS分子链上的苄氯基团发生季铵化反应,制得了固载有季铵盐（Quaternary salt）的接枝微粒QPSt／SiO2,即制得了接枝型三相相转移催化剂．将此相转移催化剂用于氯化苄与乙酸钠合成乙酸苄酯的相转移催化反应,考察了催化活性、各种因素对相转移催化反应的影响及催化剂的重复使用性能．实验结果表明,接枝型三相相转移催化剂QPSt／SiO2对乙酸苄酯的合成具有较高的催化活性,在液-固-液之间即可有效地实现反应物种乙酸根的转移,在60℃的较低温度下反应7h,氯化苄的转化率可达66．1％;研究发现,固体催化剂QPSt／SiO2表面接枝聚合物PSt的季铵化程度对其催化活性有很大的影响,季铵化程度过大与过小催化活性都较低,当季铵化程度为20％左右时,催化剂的活性最高．     

活性炭固载磷钨酸催化合成丙酸丙酯

用活性碳固载磷钨酸催化剂合成了丙酸丙酯,考察了磷钨酸固载量、催化剂用量、醇酸摩尔比、反应温度、反应时间、带水剂用量对酯化反应的影响。在优化条件(催化固载量30．0％、催化剂用量2．5g/0．2mol丙酸、醇酸摩尔比1．2：1、反应温度110--116℃、反应时问2．51h、带水剂环己烷用量10mL下反应,丙酸丙酯收率为95．8％,催化剂可重复使用。     

四氯化锡催化合成己二酸二丁酯

应用五水四氯化锡催化己二酸和正丁酯的酯化反应，合成了己二酸二丁酯。研究结果表明，五水四氯化锡具有较高的催化活性。考察了己二酸／正丁醇摩尔比和催化剂用量对酯产率的影响，在适宜反应条件[n(己二酸)：n(正丁醇)：n(四氯化锡)＝1：8：0．114，回流反应60min]下，己二酸二丁酯的产率为96．9％。     

高分子固载化螯合钛酸酯的合成及酯化催化性能研究

将高分子载体聚苯乙烯二乙醇胺树脂与乙二胺钛酸二丁酯反应，制得高分子固载化螯合钛酸酯催化剂，并对其在高沸点酯的合成反应中的催化性能进行了研究，结果表明它具有良好的催化活性，易与产品酯分离，可以回收及重复使用。     

聚苯乙烯支载N-苄基-N-甲基氨基吡啶催化合成乙酸芳樟酯的研究

以大孔聚苯乙烯氯球为原料,在氮气保护及氢化钠存在下,将其与４ 氨基吡啶及硫酸二甲酯反应,制成聚苯乙烯支载Ｎ 苄基 Ｎ 甲基氨基吡啶（ＢＭＡＰ）催化剂．与文献相比,该法具有反应时间短,价格低,制备的ＢＭＡＰ活性高等特点．经过元素分析、ＦＴＩＲ及ＭＡＳ１Ｈ ＮＭＲ对其结构进行表征．利用该催化剂进行了芳樟醇的乙酰化反应,对影响反应的诸因素如反应物料比,反应时间,反应温度等进行了讨论,芳樟醇的转化率为９９％以上,总酯率为９５％左右,其中芳樟酯的产率为６０％以上（目前工业上使用Ｈ３ＰＯ４催化剂芳樟酯产率为５０％左右）．催化剂通过再生连续使用五次,活性无明显下降．     

硫酸高铈催化合成丙酸苄酯

以结晶硫酸高铈为催化剂对丙酸苄酯的合成进行了研究，考察了反应时间、催化剂用量、醇酸摩尔比和带水剂等因素对反应的影响，结果表明，在最佳反应条件下，酯化率在85％以上。     

2—聚苯乙烯磺酰基乙醇树脂的合成及其在海因和脲固相合成中的应用

合成了一种新型的聚合物载体－－2－聚苯乙烯磺酰基乙醇，并研究其在固相有机合成中的应用。聚苯乙烯亚磺酸钠树脂（1）在相转移催化剂Bu4NI和助催化剂KI的作用下，与氯乙醇进行砜化反应，得到含羟基功能基的2－聚苯乙烯磺酰基乙醇树脂2。树脂2用Boc保护的氨基酸酯化，封闭树脂上未反应的羟基，用酸脱保护并用三乙胺中和，再与异（硫）氰酸苯酯反应生成聚合物支载的脲树脂6。树脂6用酸解脱得到了海因和硫代海因化合物。用碱处理树脂6时得到取代的脲和硫脲。优化了合成反应的全过程，探讨了树脂在酸性条件下的解脱方法。结果表明，2－聚苯乙烯磺酸基乙醇树脂易与羧工形成含酯键的连接桥，连接桥在强酸性和碱性条件下均可解脱得到产物。     

蔗糖酯合成新方法的研究

本法以苛性钾与脂肪酸甲（乙）酯首先反应生成的部分中性皂作为乳化分散剂，使蔗糖和脂肪酸甲（乙）酯在熔融状态下直接发生酯交换反应合成蔗糖酯．适宜的反应条件为：蔗糖／硬脂酸甲酯／苛性钾／催化剂的摩尔比１：（１～２）：（０．４～０．６）：０．００３６；１３５～１４０℃、２６６６～６６６５Ｐａ负压下反应３～３．５ｈ。所得粗产物含蔗糖酯５５％，其中单酯６２％。     

Efficient and Mild Iron-Catalyzed Direct Allylation of Benzyl Alcohols and Benzyl Halides with Allyltrimethylsilane

An efficient and mild iron-catalyzed direct allylation of benzyl alcohols and benzyl halides with allyltrimethylsilane has been developed. The present reaction would provide an excellent alternative to published methods because of its excellent yields, sustainable catalyst, and mild conditions.     

烷基苄基醚的简易合成

本文利用醇、氢氧化钠和氯苄反应合成了五种烷基苄基醚。     

Thiourea-Catalyzed C−F Bond Activation: Amination of Benzylic Fluorides

We describe the first thiourea-catalyzed C−F bond activation. The use of a thiourea catalyst and Ti(OiPr)₄ as a fluoride scavenger allows the amination of benzylic fluorides to proceed in moderate to excellent yields. Preliminary results with S- and O-based nucleophiles are also presented. DFT calculations reveal the importance of hydrogen bonds between the catalyst and the fluorine atom of the substrate to lower the activation energy during the transition state.     

New convergent one pot synthesis of amino benzyl ethers bearing a nitrogen-containing bicycle

We report herein a new convergent one pot method for the synthesis of amino benzyl ethers containing a bicyclic amine, derived from different substituted benzyl alcohols and bicyclic amino alcohols such as tropine, pseudotropine, and 3-quinuclidinol, using chlorotrimethylsilane and sodium iodide. In order to avoid the competitive reaction with the nitrogen atom, a solution of the separately prepared alkoxide of tropine, pseudotropine, and 3-quinuclidinol was added to the preformed substituted benzyl iodides and allowed to reflux at 90?°C for 15?h under nitrogen atmosphere. This method provides an efficient alternative of the preparation of amino benzyl ethers in organic synthesis with good yields in comparison with existed methods.     

Electronic spectra of paramethoxy benzyl alcohol and parachloro benzyl cyanide

The electronic absorption spectra of paramethoxy benzyl alcohol (pmba) and parachloro benzyl cyanide (pcbc) are described. The broad features of the spectra of the molecules are consistent with allowed transition forC _2v symmetry. However, the solid state and glass matrix spectra of pmba at 77K indicate possible deviation from planarity in the structure of the molecule. In pcbc, it is pointed out that intensity borrowing may be responsible for the large intensity of the vibrationally-induced part of the spectra, in which non-totally symmetric vibrations are excited.     

Kinetics of phase-transfer-catalyzed oxidations ofp-substituted benzyl alcohols with aqueous hypochlorite

A series ofp-substituted benzyl alcohols have been oxidized to their corresponding aldehydes using aqueous hypochlorite and phase-transfer catalyst (PTC) conditions. The reaction constant, p, has been determined to be +1.03. Possible mechanisms are suggested.     

KINETIC STUDIES OF LEWIS BASE ADDITION TO CpFe(CO)(η3-CH2C6H4-p-X); X = OMe,Me, H,F, Cl,Br

Abstract

Kinetic studies illuminate details of the reaction of photoproduced CpFe(CO)(η³-CH₂C₆H₅) with two electron Lewis bases. Rate constants of 151(10)M^?1s^?1 for CO back reaction and between 440 and 3200 M^?1s^?1 for reaction with various phosphine nucleophiles were recorded. Linear free energy analysis quantifies the stereoelectronic effect of the nucleophile. Variation of the para-substituent on the benzyl group demonstrates that an electron rich benzyl group impedes reaction. The effect of ancillary ligands was seen by substitution of C₅Me₅ for C₅H₅. The large, electron rich C₅Me₅ speeds up CO substitution but slows down PPh₃ substitution. Mechanistic clues were obtained from Eyring plots for reaction of CpFe(CO)(η³-CH₂C₆H₅) with 4 different phosphines. Examination of the measured enthalpy and entropy barriers suggests a stepwise reaction mechanism.     

New Method for the Synthesis of Benzyl Alkyl Ethers Mediated by FeSO4

The synthesis of benzyl alkyl ethers from benzyl bromides and alcohols using FeSO₄ as a recoverable and reusable mediator has been described without use of base and cosolvent under mild conditions.