(±)-反式菊酸拆分研究

本文叙述了用光学活性拆分剂D(-)-苯甘氨酸乙酯盐酸盐对(±)-反式菊酸进行拆分,从而分别得到富( )-反式菊酸和富(-)-反式菊酸的方法。     

(±)-反式菊酸经差向异构化制备(1R)顺式谱醛酸酯的研究

本文报道由(±)-反式菊酸经差向导构化制备(1R)-顺式蒈醛酸酯的研究,(±)-反式菊酸由Martel路线合成,或由顺反菊酸酯混合物(顺:反=37:63)皂化后分离制得。     

毛细管气相色谱法分离检测合成菊酯产物中光学异构体

将合成产品菊酸乙酯和菊酸冰片酯水解后,重新酯化成菊酸－１薄荷酯,利用毛细管柱色谱分离检测其光学异构体的含量,可得到ｄ－反式菊酸、１－反式菊酸、顺式外消旋菊酸的相对含量,并由此计算出菊酸不对称催化合成反应中顺、反菊酸的比例、菊酸乙酯、菊酸冰片酯的反式的对映体超量为：７．７９％和１５．８４％。     

菊酸乙酯的合成工艺

研究了菊酸乙酯合成的工艺条件，采用了自制的催化剂，在优化条件下，菊酸乙酯的收率超过８０％。     

反体二氯菊酸的立体选择合成

以贲亭酸甲酯为原料,经自由基加成、立体有择环化合成了富反式二氯菊酸甲酯,收率高达95%,反顺比为88∶12。还以顺反混合体 (trans/cis=60/40) 二氯菊酸酰氯为原料,立体选择性转化合成富反式二氯菊酸酯,对催化剂、反应时间、溶剂进行条件实验,以4-二甲氨基吡啶催化立体转化效果最好,收率95%,反顺比达93/7。     

顺式二氯菊酸的合成

本文从3,3-二甲基-4-戊烯酸乙酯(4)出发,经调聚加成、立体选择性分子内环化及皂化三步反应合成顺式二氯菊酸(1)。重点研究了反应条件对分子内环化甲顺式选择性的影响,筛选出有利的反应条件。同时,本文提出了顺式有择环化的机理。     

二溴菊酸制备工艺的研究

本文以第一菊酸乙酯为原料,对二溴菊酸的制备工艺进行了研究,通过四步反应,最终得到二溴菊酸产品,反应收率为72%。     

光学活性拟除虫菊酯的合成

<正> 天然除虫菊素的主要成分之一菊酸,是右旋反式(1R:3R)的立体构型。人工合成的除虫菊酸,若采用重氮乙酸乙酯对烯烃的加成环化反应,则产物是顺反异构体和外消旋体的四个异构体的混合物。用合成的方法获得与天然除虫菊素具有相同构型的菊酸,乃是近年来合成除虫菊研究的一个重要方向。马特塞(Ma-     

氯甲酸三氯甲酯法合成DV－菊酰氯

本文报道了由ＤＶ－菊酸甲酯经皂化、酸化制得ＤＶ－菊酸，然后用氯甲酸三氯甲酯酰氯化合成ＤＶ－菊酰氯，含量达到９４．５％，酰氯化收率达到９６％。     

氯甲酸三氯甲酯法合成DV—菊酰氯

本文了报道了由ＤＶ－菊酸甲酯经皂化、酸化制得ＤＶ－菊酸，然后用氯甲酸三氯甲酯酰氯化合成ＤＶ－菊酰氯，含量达到９４．５％，酰氯化收率达到９６％。     

Omega−3 fatty acid ethyl ester from a simple catalytic non-oxidative dehydrogenation of a biobased oleochemical

Essential fatty acids and derivatives, such as ethyl esters, have acquired an important interest, lately. The reactivity of ethyl linoleate (di-unsaturated fatty acid ethyl ester, FAEE), specially the catalytic reactions of non-oxidative dehydrogenation and isomerization, in a fixed bed reactor using active carbon as a catalyst has been studied. Active carbon presented dehydrogenation properties under non-oxidative conditions and in a temperature range of 70–120 °C. Omega−3 tri-unsaturated FAEE and aromatic FAEE were the detected dehydrogenation compounds. Mono-unsaturated FAEE and isomers of ethyl linoleate were the products of hydrogenation and isomerization reactions, respectively. The dehydrogenation activity of active carbon remained stable with time. The non-oxidative dehydrogenation to omega−3 tri-unsaturated FAEE becomes more important than the isomerization and hydrogenation reactions at lower temperatures such as 70 °C. Up to a 7.2% of omega−3 tri-unsaturated FAEE has been obtained synthetically for the first time.     

Highly unsaturated fatty acids. III. Isolation of methyl eicosapentaenoate,ethyl docosapentaenoate,and ethyl docosahexaenoate from cod liver oil esters by chromatography

a) Displacement chromatography using a charcoal-isopropanol-methyl behenate system has been successfully applied to the isolation of docosahexaenoic acid and ethyl docosahexaenoate from cod liver oil concentrates. b) Methyl eicosapentaenoate was isolated from cod liver oil methyl esters by combined elution chromatography on silicic acid and displacement chromatography. c) Using silicic acid as adsorbent and petroleum ether-chloroform as solvent, ethyl docosapentaenoate was isolated from cod liver oil ethyl esters. d) With a spinning band fractionation column it was found that fractional distillation of methyl esters of cod liver oil at 0.5 mm. Hg. resulted in increasing conjugation in the distillate as the fractionation proceeded. Fractional distillation is to be avoided as a final step in purification of polyunsaturated esters. e) The end absorption of conjugated pentaenoic acids is so large at the characteristic maximum for hexaene (3,750 Å) that simultaneous equations are required for the calculation of hexaenoic and pentaenoic acids. f) Fifteen minutes of treatment with 21% KOH-ethylene glycol at 180° is not optimum for isomerization of ethyl docosapentaenoate from cod liver oil. The optimum isomerization times for hexaenoic acids of various sources are 4 to 6 minutes, considerably different from the 15 minutes established for arachidonate.     

Gold‐ and Silver‐Catalyzed Intramolecular Hydroamination of Terminal Alkynes: Water‐Triggered Chemo‐ and Regioselective Synthesis of Fused Tricyclic Xanthines

A simple, convenient and green synthetic approach to diverse fused tricyclic xanthines has been developed via gold(I) complex‐catalyzed intramolecular hydroamination or silver(I)‐catalyzed isomerization‐hydroamination of terminal alkynes under microwave irradiation in water. The first synthesis of N9‐annelated xanthines has also been reported.     

Equilibrium of the simultaneous etherification of isobutene and isoamylenes with ethanol in liquid-phase

The simultaneous etherification of isobutene and isoamylenes with ethanol has been studied using macroreticular acid ion-exchange resins as catalyst. Most of the experiments were carried out over Amberlyst-35. In addition, Amberlyst-15 and Purolite CT-275 were also tested. Chemical equilibrium of four chemical reactions was studied: ethyl tert-butyl ether formation, tert-amyl ethyl ether formation from isoamylenes (2-methyl-1-butene and 2-methyl-2-butene) and isomerization reaction between both isoamylenes. Equilibrium data were obtained in a batchwise stirred tank reactor operated at 2.0 MPa and within the temperature range from 323 to 353 K. Experimental molar standard enthalpy and entropy changes of reaction were determined for each reaction. From these data, the molar enthalpy change of formation of ethyl tert-butyl ether and tert-amyl ethyl ether were estimated. Besides, the chemical equilibrium between both diisobutene dimers, 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene, was evaluated. A good agreement between thermodynamic results for the simultaneous etherification carried out in this work and those obtained for the isolated ethyl tert-butyl ether and tert-amyl ethyl ether systems was obtained.     

活性炭负载硅钨酸催化α-蒎烯的异构化研究

以活性炭负载硅钨酸为催化剂 ,研究了 α-蒎烯的异构化反应 ;考察了反应温度、反应时间、配料比和溶剂等因素对异构化反应的转化率和选择性的影响。实验结果表明 ,反应温度升高 ,反应时间增加 ,配料比减小 ,蒎烯的转化率增大。在乙醇介质中 ,α-蒎烯能发生异构化和乙氧基化反应。主要产物是莰烯、苎烯和 α-松油基乙醚 ,总醚选择性约 5 0 %     

Isomerization of aromatic azo chromophores in poly(ethyl acrylate) networks and photomechanical effect

The photochemical and thermal cis-trans isomerization of azo chromophores which were either dissolved, a pendant group or part of a crosslink in rubbery poly(ethyl acrylate) networks has been investigated. The thermal relaxation behaviour of the azo compound in the networks depends on the crosslinking density and can be described by a WLF-equation with the same parameters as found for non-crosslinked polymers. For stretched polymer films with azo-aromatic crosslinks, a photomechanical effect, i.e., a reversible contraction and expansion was observed, which is mainly ascribed to conformational change of the azo chromophore.     

Isomerization of 3-methyl(3-13C)pentane over platinum supported sulphated zirconias: reaction mechanisms

This paper studies the isomerization mechanisms of 3-methyl(3-¹³C)pentane over Pt supported sulphated zirconias (SZs). Pt hydrogenates the reaction intermediates that desorbs, hinders successive isomerizations from occurring and reduces the isomerization steps to two (three with Pt-free SZs). The isomerization is a monomolecular process to which Pt does not participate. Lastly, it is suggested that the ratio between the proportions of methyl migration and ethyl migration could be appreciated as a catalyst intrinsic characteristic.     

SKI-400型二甲苯异构化催化剂的工业应用

介绍了镇海炼化芳烃PX装置异构化单元所采用的SKI- 4 0 0型催化剂的技术指标、反应性能、首次装填、预处理、投料试车及六个月来的运行情况 ,并对该催化剂的应用进行特性分析 ,指出了SKI - 4 0 0型催化剂完全适用于缺少歧化的芳烃联合装置 ,具有高活性、高乙苯转化率的特点。     

Cis–trans isomerization of olefinic alcohols promoted by Rh(I) complexes

Homogeneous hydrogenation and isomerization reaction of cis-2-butene-1,4-diol has been investigated in ethanol by using tris(triphenylphosphine)chlororhodium(I), RhCl(PPh₃)₃, and triethylamine at 303 K and 0.01–0.1 MPa partial hydrogen pressure. Under reduced H₂ pressure, the geometric isomerization reaction occurs, to a high extent, leading to trans-2-butene-1,4-diol up to 93% selectivity at 90% conversion of the cis analogous. Effects of H₂ partial pressure as well as triethylamine, added phosphine and olefin concentrations on the rate of reaction and on the products distribution were also investigated. The results obtained can be interpreted on the basis of a proposed mechanism in which RhH(PPh₃)₃ is the active species. The high selectivity towards cis-trans isomerization of cis-2-butene-1,4-diol is attributed to steric factors of the Rh(I) coordinated triphenylphosphine groups.     

碳五叔碳烯烃乙醇醚化研究进展

FCC轻汽油中的叔碳烯烃和乙醇醚化,不仅可以降低油品中的烯烃含量,而且可获得优良的汽油增辛剂乙基叔烷基醚。本文全面回顾了碳五（C₅）叔碳烯烃与乙醇醚化合成乙基叔戊基醚（TAEE）的研究进展,分析了所涉及的醚化、异构化、烯烃聚合以及水合等各类反应,并通过对反应体系的热力学分析,考察了各反应进行的难易程度。同时对醚化催化剂、反应机理及动力学等方面的研究成果进行了综合分析,并对今后该领域的发展方向进行了展望。