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题名:
钯膦络合物催化烯烃氢羧基化及氢酯基化反应
作者: 何珍红
答辩日期: 2014-05-22
导师: 侯震山、吾满江·艾力
专业: 有机化学
授予单位: 中国科学院大学
授予地点: 北京
学位: 博士
关键词: 烯烃 ; 氢羧基化反应 ; 氢酯基化反应 ; 水油两相催化 ; 多相催化体系
摘要:

羧酸与羧酸酯在精细化工以及医药合成中有着非常重要的地位,烯烃氢羧基化反应以及氢酯基化反应能够从烯烃一步反应直接得到羧酸或羧酸酯类产物,其为双键的功能化提供了一条绿色高效的原子经济性合成路线而备受关注。这两种类型的反应的传统催化剂为钯膦络合催化剂,其中油溶性膦配体因其高效的催化活性而广为使用,然而,油溶性膦配体的使用难以分离贵金属钯催化剂与有机产物,这限制了该类反应的进一步发展。为了解决钯催化剂的回收和重复利用问题,水油两相催化体系和多相催化体系应运而生,通常由于传质问题,水油两相催化体系和多相催化体系较均相体系活性差,本论文主要致力于提升水相钯膦络合催化体系和多相催化体系的催化活性以及开发出新的高效的多相催化剂体系。论文研究的主要内容和结果如下:
1.研究了水溶性膦配体TPPTS 与Pd 络合催化1-辛烯氢羧基化反应制壬酸长链烯烃如1-辛烯等在水相中溶解性很差,其在水-油两相催化体系中反应活性较低,为了提高1-辛烯的溶解度,通常添加表面活性剂具有非常好的效果,本论文中系统考察了Pd-TPPTS 络合催化体系中各种反应条件对该反应的影响,在适宜的反应条件下(H2O =16 mL, c(Pd)=2.0 mmol/L, c(TPPTS)/c(Pd) = 25,c(p-TsOH) = 33.8 mmol/L,c(CTAB) = 79.4 mmol/L,反应时间5.5 h,CO 压力为4 MPa,反应温度150 oC 时), 1-辛烯的转化率能够达到90.8%,壬酸的选择性接近80%,生成壬酸中n/i 比为4 左右。另外,通过31P NMR 表征水相中膦配体的变化推测反应过程中Pd-P 的变化规律并出了反应机理。
2.研究了Pd-TPPTS 络合物催化体系中碱金属卤化物的促进作用之前研究发现碱金属卤盐能够促进Pd-TPPTS 络合催化体系的催化活性,然而对这种促进作用的机理却鲜有报道,为此,本论文研究了在Pd-TPPTS 络合催化剂催化苯乙烯氢羧基化反应中添加不同种类,不同质量的碱金属卤盐对反应中产物收率与选择性的影响以考察碱金属卤盐的促进作用,并在水溶性底物烯烃的氢羧基化反应中用1H NMR 验证这种促进作用,同时采用31P NMR 表征检测反应过程中膦配体的变化推测反应过程中Pd 物种的变化。研究发现,碱金属卤化物能够提高羧酸的总收率以及直链产物的选择性,并且直链产物选择性选择性的提高随MCl < MBr < MI 的顺序依次升高。 从31P NMR 和 1H NMR 结果中得出,碱金属卤化物能够稳定Pd(II),同时发现在室温下苯乙烯中碳碳双键能够跟Pd-TPPTS 络合物有较强的配位作用。另外,从添加的碱金属卤化物对反应活性以及选择性方面的影响出发,推测出了Pd(II) 和 Pd(0)催化苯乙烯氢羧基化反应的机理。
3. 研究了Pd-TPPTS-OTPPTS/LSI-600 类型多相催化剂催化苯乙烯及其衍生物氢酯基化反应钯催化烯烃氢酯基化反应与氢羧基化反应中都需要添加一定量的Brönsted酸作为助剂,传统均相酸如p-TsOH 等的使用对反应设备有着较强的腐蚀作用,本论文中开发出用固体酸负载Pd-TPPTS 络合催化剂催化苯乙烯及其衍生物氢酯基化反应,研究发现通过添加适量的OTPPTS 能够显著提高催化剂的催化活性以及支链产物的区域选择性,OTPPTS 与Pd 中心金属的配位能力很弱,也正因此而为烯烃,CO 等与Pd 的配位提供了更多的空位,进而大幅提高催化活性以及区域选择性,另外对比实验发现树脂的孔道对反应产物的区域选择性也有着非常重要的影响;进一步对催化剂进行中毒实验以及热过滤实验研究发现Pd(0)物种是该催化体系中的催化活性中心,通过31P NMR 表征发现OTPPTS 的加入能够促进Pd(II)成Pd(0)且提出了反应可能的机理。
4. 制备了SiO2 负载的TPPTS 稳定的纳米Pd 催化剂催化苯乙烯氢酯基化反应由于之前的研究发现Pd(0)是苯乙烯氢酯基化反应的活性组分,因此在本论文中将Pd(II)在反应前还原成Pd 纳米颗粒制成催化剂,在制备的过程中为了使得Pd 纳米颗粒粒径分布比较集中,使用了聚乙烯吡咯烷酮(PVP)作为稳定剂,然而PVP 在催化体系中能够因其与Pd 配位较强而抑制了反应的进行,因而在制备了纳米Pd 催化剂之后还需去除PVP,本文中采用在ScCO2 体系中用乙醇萃取的方法去除PVP,表征发现大部分PVP 已经被萃取。另外,该催化剂采用TPPTS作为配体,该配体在有机体系中溶解度很低进而有利于催化剂的循环,该催化剂在催化苯乙烯氢酯基化反应时分离简单且能够重复循环7 次上。
5. 开发出酸性离子液体修饰的高分子材料负载Pd-TPPTS 络合催化剂催化苯乙烯氢酯基化反应在钯催化烯烃氢酯基化反应时需要添加Br_nsted 酸作为助剂,通常p-TsOH因其阴离子很弱的配位能力而被广泛应用于该类反应。近年来研究发现酸性离子液体对该类反应具有很高的促进作用,负载型酸性离子液体不仅保留着离子液体的优良特性,同时还兼顾固体催化剂易于分离回收等特点。基于此本论文中设计并合成了酸性离子液体修饰的高分子材料负载的Pd-TPPTS 络合催化剂Pd-TPPTS/Polymer-BAILs 催化苯乙烯氢酯基化反应。研究发现,该类催化剂在催化过程中发生在高分子材料表面的离子液体膜中,类似于SAPC 催化体系。该类催化剂在催化苯乙烯氢酯基化反应时表现出较高的催化活性,在CO 压力为3 MPa,100 oC,5 h 以及P/Pd 摩尔比例为20 时,苯乙烯的转化率可达98.9%,生成的酯类产物的选择性可达到99.9%,产物中b/l 值为4.91。

 

英文摘要:

Carboxylic acid and its ester are important intermediates in fine chemicals and pharmaceuticals. Carbonylation of olefins provide an atom-economical route for C=C double bond functionalization, and for this reason, the reactions attract more attention. Palladium-phosphine complexes, especially for the oil-soluble phosphine ligands are the conventional catalysts in these reactions for their high activities. However, the problem of difficulty in separation of catalyst from the reaction mixture was posed in utilization of these oil-soluble phosphine ligands. To solve this problem, aqueous-organic biphasic catalytic system and heterogeneous catalytic system are developed. Generally, the catalytic activities of these two systems are lower than the homogeneous catalytic system for the problem in mass-transfer resistance. In this paper, the main objective was focus on increasing the catalytic activities of aqueous organic biphasic and heterogeneous catalysts. The main works and conclusions are as follows: 1. Hydrocarboxylation of 1-octene catalyzed by Pd-TPPTS complexes    Generally, Pd-TPPTS complexes catalyzed hydrocarboxylation of 1-octene in aqueous organic biphasic system with low activity for the low solubility of 1-octene. To improve the activity, surfactants are always used to enhance the mass-transfer. In this paper, different reaction conditions were studied in the reaction, and under the optimum conditions (H2O 16 mL, c(Pd) 2.0 mmol/L, c(TPPTS)/c(Pd) 25, c(p-TsOH) 33.8 mmol/L,c(CTAB) 79.4 mmol/L,5.5 h,4 MPa and 150 oC), the conversion of 1-octene was up to 90.8%, the selectivity of total acids was near to 80% and n/i molar ratio was about 4. Additional, the possible reaction mechanism was proposed. 2. The effect of alkali metal halides on the hydrocarboxylation of styrene catalyzed by Pd-TPPTS complexes.    The former studies have found the addition of alkali metal halides could improve the catalytic activity of Pd-TPPTS complexes, but the main reason for this effect was not clear. So, to study this effect, different kinds and amounts of alkali metal halides were investigated, and the results were further confirmed by 1H NMR in hydrocarboxylation of water-soluble olefins in D2O. The changes of the phosphine ligand were monitored by 31P NMR and then the reaction mechanisms were proposed. It was found that the alkali metal halides could improve the total yield of acids and the selectivity of linear product, and the promote effect in selectivity of linear product agreed to the order of MCl < MBr < MI. From the results of 31P NMR and 1H NMR, it was also found that the alkali metal halide could stabilize the Pd(II) species and the C=C double bond could coordinate with Pd strongly even in the room temperature. 3. Hydroesterification of styrene and its derivatives catalyzed by a heterogeneous Pd-TPPTS-OTPPTS/LSI-600 catalyst    Br?nsted acid is always needed in hydroesterification of olefins. The weak coordinated homogeneous acid such as p-TsOH is most commonly used in the reaction. However, corrosion problem is posed from the utilization of homogeneous acid. In this paper, some solid acidic resins supporting Pd-TPPTS complexes were prepared as heterogeneous catalysts for hydroesterification of olefins, and the OTPPTS was found to improve the catalytic activity and the selectivity of branched product for its weak coordination ability to Pd atom. In the following study, it was found the pore size had a great effect on the regioselectivity of branched ester. Pd(II) was acceleratively reduced to Pd(0) by adding OTPPTS, and the Pd(0) was found to be as activity species from the results of poisoning and hot filtration tests then the reaction mechanism was proposed. 4. Hydroesterification of styrene catalyzed by Nano-Pd(0)-TPPTS/SiO2 heterogeneous catalyst    Pd(0) was found to be catalytic active species in the former studies. In this paper, Pd(II) was initially reduced to Pd NPs before uses. PVP was used as stabilizer in the preparation of Pd NPs, however, the PVP was found to decrease the catalytic activity in the reaction. So the PVP should be removed before the hydroesterification. PVP was extracted by ethanol in the ScCO2 system and then the Nano-Pd(0)-TPPTS/SiO2 catalyst was obtained. From the results of catalyst characterizations, it was found that most of the PVP was removed after the extraction. Additionally, the water-soluble phosphine ligands TPPTS with poorly soluble in organic liquids was used in the reaction, and the catalyst can be reused for at least 7 times without loss in activity. 5. Hydroesterification of styrene catalyzed by Pd-TPPTS/Polymer-BAILs    Recently, the Br?nsted acid ionic liquids (BAILs) were found to be acid promoters in hydroesterification of olefins. Supported BAILs combines the advantages of both ionic liquids and heterogeneous catalyst. In this paper, BAILs supported on polymer was prepared and used as a carrier in the Pd-TPPTS/Polymer-BAILs catalyst for hydroesterification of olefins. It was found that the catalytic process was carried out in the ionic liquids film on the surface of polymer, which was similar to the SAPC catalyst system. High activity was found in hydroesterification of styrene catalyzed by this heterogeneous catalyst. Under the optimum conditions (3 MPa,100 oC,5 h and the molar ratio of P/Pd was 20), the conversion of styrene, selectivity of total esters and b/l molar ratio were up to 98.9%, 99.9% and 4.91, respectively.

内容类型: 学位论文
URI标识: http://ir.xjipc.cas.cn/handle/365002/3424
Appears in Collections:新疆维吾尔自治区精细化工工程技术研究中心_学位论文

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作者单位: 中国科学院新疆理化技术研究所

Recommended Citation:
何珍红. 钯膦络合物催化烯烃氢羧基化及氢酯基化反应[D]. 北京. 中国科学院大学. 2014-05-22.
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