用色谱-质谱法测定由 CO+H_2制取低碳混合醇产物的组成

一氧化碳加氢制取低碳混合醇的反应产物以水相为主,带有少量油相,两相主要组分相同,而油相的杂质多,含量大,故选择油相为检测对象,用同样的方法测定了水相组成。由于产物沸程宽,组成复杂,化合物类型多,而且其极性和含量相差较大,因而已发表的文献都采取先予处理或衍生化后再检测的方法,这不仅操作复杂,而且对含量低的组分检测不利。本文采用色-质法、选择色谱分离柱、特征碎片离子的质量色谱及关联碎片离子的出现时间和组分碳数等多种手段,测定出油相产物中123个组分,水相中60个组分。     

高温气相色谱和高温气相色谱-质谱法对费托合成蜡的分离和鉴定

费托合成蜡是费托合成反应中的重要产物之一。采用高温气相色谱与冷柱头进样相结合的方式,建立了一种分离分析费托合成蜡的气相色谱方法。该方法无需对费托合成蜡进行预处理,使用氦气为载气,选用更长的高温色谱柱,具有平稳的色谱基线,对费托合成蜡中正构烷烃和其他未知组分有很好的分离效果,能够洗脱费托合成蜡中碳数大于C₉₀的重组分。用高温气相色谱-质谱法对费托合成蜡馏分进行定性分析,其组分有烷烃、烯烃和含氧化合物。该方法对了解费托合成蜡组分的详细信息和费托合成工艺的开发有重要意义。     

固相萃取-气相色谱法测定甲醇制烯烃副产汽油及甲醇制汽油产物中的含氧化合物

采用纯硅胶柱固相萃取技术对甲醇制烯烃副产汽油或甲醇制汽油产物进行预处理,将产物中的含氧化合物与烃类进行色谱分离,采用质谱鉴定产物中的含氧化合物。使用标准溶液优化纯硅胶小柱的洗脱条件,比较预处理方法的回收率,考察预处理方法的重复性。结果表明,标准溶液的各含氧化合物组分回收率为87.7%~95.3%。采用气相色谱-火焰离子化检测器(GC-FID)通过内标法对实际样品中除甲醇和乙醇外的含氧化合物进行定量分析,使用丁酮、叔戊醇、戊酮和己酮的响应因子作为同碳数醛、酮、醇的FID响应因子,定量甲醇制烯烃副产汽油和甲醇制汽油产物中的含氧化合物。对于甲醇和乙醇,采用GC-MS分析提取特征离子用外标法定量。结果表明,甲醇制烯烃副产汽油和甲醇制汽油产物中的含氧化合物以酮类、醛类为主,并有少量的醇类。     

水相催化3,5-二烷基-4-硝基异噁唑与三氟甲基酮的亲核加成反应（英文）

研究了水相三乙胺催化3,5-二烷基-4-硝基异噁唑与三氟甲基酮的亲核加成反应,以66%~99%的产率合成了一系列三氟甲基叔醇衍生物.通过脱水或氧化反应可有效的将目标产物转化为烯烃或羧酸类化合物.     

高温气相色谱和高温气相色谱-质谱法对费托合成蜡的分离和鉴定（英文）

费托合成蜡是费托合成反应中的重要产物之一。采用高温气相色谱与冷柱头进样相结合的方式,建立了一种分离分析费托合成蜡的气相色谱方法。该方法无需对费托合成蜡进行预处理,使用氦气为载气,选用更长的高温色谱柱,具有平稳的色谱基线,对费托合成蜡中正构烷烃和其他未知组分有很好的分离效果,能够洗脱费托合成蜡中碳数大于C_(90)的重组分。用高温气相色谱-质谱法对费托合成蜡馏分进行定性分析,其组分有烷烃、烯烃和含氧化合物。该方法对了解费托合成蜡组分的详细信息和费托合成工艺的开发有重要意义。     

钾和钴对微波法制备钼基催化剂的改性作用

在微波辐射下制备了Co_x-MoS₃-K_y/γ-Al₂O₃催化剂,考察了催化剂中K和Co的含量对其催化CO加氢合成低碳醇性能的影响。结果表明,添加适量的K和Co可以形成K-Mo-S相和Co-Mo-S相,改善催化剂性能的同时还可以避免活性组分的集聚及载体孔道的堵塞;K/Mo物质的量比为1.0,Co/Mo物质的量比为0.2时,有利于生成低碳混合醇,尤其是C₂₊醇。CO转化率为38.4%,总醇的收率为5.65%,C₂₊OH的选择性为80.5%。     

二氧化钛光解水过程中乙醇选择性光催化氧化反应研究

光催化分解水的产氢体系往往采用小分子醇作为电子供体,本工作以纯金红石相与混晶结构P25 （80%锐钛矿与20%金红石相）二氧化钛为光催化剂,研究光解水过程中牺牲剂乙醇的氧化路径与反应机理.研究结果表明,无论是金红石相还是锐钛矿相为主的P25二氧化钛,其无氧条件下光催化氧化乙醇的主要终端产物均为乙醛,而不是2,3-丁二醇,2,3-丁二醇产物主要由醇醛特定波长范围内的有机光化学反应偶联产生.另外,不同晶相二氧化钛氧化乙醇至2,3-丁二醇的选择性差异可能主要由非均相固-液界面所产生羟基自由基迁移至溶液体系的距离不同所致,进而与有机光化学反应产生的·CH（OH）CH₃自由基发生不同路径与频率的猝灭反应.本研究对乙醇无氧光催化反应步骤的探索与解析可为小分子醇参与的醇类重整反应提供机理借鉴与设计思路.     

低碳烷烃的多相光催化选择氧化

许多含氧有机物如醇、醛、酮等 ,是化学工业的重要原料 .利用分子氧氧化烷烃生产含氧有机物 ,是化学工业的一个重要过程 .低碳烷烃催化部分氧化的过程往往伴随着初级产物的自氧化 ,从而导致选择性降低 .为了减少反应初级产物的自氧化 ,反应必须维持在烷烃低转化的条件下进行[1] .设计并合成直接将低碳烷烃中的 C- H键有效地选择活化的催化剂 ,是目前催化学科面临的一个艰巨任务 [2 ,3 ] .对于光催化来说 ,一度被寄于厚望的、以金属有机复合物及盐类 [4～ 6]催化低碳烷烃选择氧化为含氧有机物的需氧氧化过程也面临许多困难[7] ,作为研究克服…     

Fe@Si/S-34催化剂的制备及其合成气制烯烃性能

合成气经费托合成反应直接制低碳烯烃是极具开发前景的合成气直接制烯烃技术,其关键是通过产物分布的调控提高低碳烯烃的选择性.本工作将疏水性Fe基费托合成催化剂与SAPO-34分子筛进行复合,制备了一系列不同SAPO-34分子筛含量的Fe@Si/S-34复合催化剂.采用X射线衍射、扫描电子显微镜、N₂吸附-脱附、NH₃程序升温脱附和水接触角测量仪考察了SAPO-34分子筛含量对催化剂物化性质的影响.结果表明SAPO-34分子筛的含量对催化剂的表面积、孔体积、酸性和疏水性具有显著的影响.随着SAPO-34分子筛含量的增加,催化剂的比表面积和总孔体积增加,弱酸和中强酸位点增加,疏水性减弱.催化性能评价结果表明,Fe@Si/S-34复合催化剂明显降低了C₅₊产物选择性,增加了C₂～C₄烃类的选择性,适量的SAPO-34分子筛能够显著提高C₂～C₄烯烃的选择性.本研究将Fe@Si催化剂的疏水性和SAPO-34分子筛对C₅₊烃的...     

Fe、Co组成对Cu-Fe-Co基混合醇催化剂合成性能的影响

采用共浸渍法制备了一系列不同Fe、Co组成的Cu-Fe-Co基混合醇催化剂,对其CO加氢合成混合醇反应性能进行了考察,并采用BET比表面积分析、X射线衍射（XRD）、X射线光电子能谱（XPS）、场发射扫描电子显微镜（FE-SEM）及H₂程序升温还原（H₂-TPR）等手段对其进行了表征.结果表明:Cu-Fe二元催化剂添加适量的Co可以明显提高催化剂醇的明空收率（STY）、CO转化率,而总醇选择性不变.当活性组分Cu、Fe及助剂Co的质量分数分别为25%、22%、3%时,催化剂醇的时空收率高达205.6 g·kg^-1·h^-1,CO转化率为56.6%.XRD、XPS和TPR结果表明:在Cu组分含量不变时,少量Co组分的引入使催化剂表面形成微量的CuFe₂O₄相,促进了Cu-Fe组分间相互作用的增强,改善了催化剂活性组分的分散度,有利于提高催化剂活性及醇的时空收率;随Co含量的增大,催化剂中金属组分间的相互作用发生转变,形成了Cu-Co尖晶石相,导致催化剂的醇选择性有所下降.     

Analysis of Fischer-Tropsch by-product waters by gas chromatography

This paper describes a quantitative technique for the determination of organic constituents in Fischer-Tropsch by-product waters. Temperature-programmed gas chromatography on derivatized bonded polar capillary columns provides the required separation that permits reliable quantitation of individual compounds. A preliminary combined gas chromatographic–mass spectrometric survey to identify the components present in Fischer-Tropsch by-product waters is presented. The elution order of 58 identified components is tabulated. Components identified in a typical Fischer-Tropsch by-product water include C₁–C₉ linear and branched alcohols, C₃? C₈ ketones, C₂? C₆ carboxylic acids, and C₂? C₄ linear aldehydes.     

A TEMPO-like nitroxide combined with an alkyl-substituted pyridine: An efficient catalytic system for the selective oxidation of alcohols with iodine

An efficient method for the oxidation of alcohols to aldehydes or ketones in a two-phase CH₂Cl₂/NaHCO₃ (aq.) system, using iodine and catalytic amounts of 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxyl and 2,4,6-trimethylpyridine, was developed. The performance of the method was demonstrated by the selective oxidation of 37 variously substituted alcohols in ≥90% yield, including the gram-scale synthesis of the important chemical 2,5-diformylfuran from biomass-derived 5-hydroxylmethylfurfural.     

Efficient and convenient oxidation of alcohols to aldehydes and ketones with molecular oxygen mediated by In(NO3)3 in ionic liquid [C12mim][FeBr4]

A simple, efficient, and ecofriendly procedure for the aerobic oxidation of alcohols to aldehydes and ketones in the presence of In(NO₃)₃/[C₁₂mim][FeBr₄] in aqueous media has been developed. The oxidation reactions afford the target products in good to high yields and no over-oxidation was observed. The products can be separated by a simple extraction with dichloromethane, and the system can be recycled and reused without loss of activity.     

Single-Pot Synthesis of Alkyl-Substituted Quinolines and Indoles via Photoinduced Oxidation of Primary Alcohols

Single-pot synthesis of alkyl-substituted quinolines and indoles has been performed via photoinduced oxidation of primary aliphatic alcohols (C₂–C₅) and condensation of the aldehydes (products of the alcohols oxidation) with aniline under the action of iron-containing catalysts and inorganic oxidants. The synthesis was the most efficient in the presence of FeCl₃·6H₂O as catalyst and 10% aqueous solution of NaOCl as oxidant with irradiation by Hg lamp. The synthesis mechanism through photoinduced oxidation of primary aliphatic alcohol has been suggested.     

The Economic Synthesis of Pyridinium Fluorochromate(VI), C5H5NH[CrO3F] (PFC), and Solvent‐Free Oxidation of Organic Substrates with PFC

Abstract

A 1:1:1 stoichiometric reaction among CrO₃, aqueous HF and pyridine affords orange crystalline pyridinium fluorochromate(VI), C₅H₅NH[CrO₃F] (PFC), in 99.2% isolated yield. The reagent under solvent‐free conditions readily converts benzylic, secondary, and allylic alcohols to the corresponding carbonyls and selectively oxidizes secondary alcohols in the presence of primary alcohols, polycyclic hydrocarbons to cyclic ketones, benzoin to benzil, PPh₃ to O?PPh₃, methylphenyl sulfide to sulfoxide, cyclohexanone oxime to cyclohexanone, an allylic Δ⁵‐steroid to the corresponding α,β‐unsaturated ketone and deprotects dioxolanes and dithiolanes to aldehydes; the economic synthesis of PFC, its ease of reaction without solvent, versatility, and high isolated yields of the products are the significant features of the protocol.     

A hierarchically zeolite Y for the N-heterocyclic compounds synthesis

High activity and selectivity of the hierarchical H-Ymmm zeolite in the synthesis of practically important pyridines (by interaction of C₂–C₄ alcohols with formaldehyde and ammonia, cyclocondensation of acetaldehyde and propanal with ammonia), dialkyl quinolines (by reaction of aniline with aldehydes) and alkyl dihydroquinolines (by reaction of aniline with ketones- acetone, acetophenone) were revealed in the research.The advantages of the micro-meso-macroporous H-Ymmm zeolite over the microporous H-Y zeolite in the synthesis of pyridines and quinolines were demonstrated. In the products formed by the reaction of ethanol with formaldehyde and ammonia, picolines (up to 63%) and lutidine are predominant in H-Ymmm, Pb-H-Ymmm and Fe-H-Ymmm zeolites. The interaction of n-propanol (n-butanol) with formaldehyde and ammonia in the presence of H-Ymmm zeolite with high selectivity produced 3,5-lutidine (up to 90%) or 3,5-diethylpyridine (85%). H-Ymmm zeolite makes it possible to prepare 2-methyl-5-ethylpyridine with 87% selectivity (reaction of acetaldehyde with ammonia) and 2-ethyl-3,5-dimethylpyridine with 58% selectivity (reaction of propanal with ammonia).The synthesis of dialkylquinolines and dialkyltetrahydroquinolines with a total selectivity of 65–73% by the interaction of aniline with C₃–C₅ aldehydes has been carried out. The dihydroquinoline derivatives with the selectivity of up to 70% have been synthesized by the reaction of aniline with ketones (acetone, acetophenone).     

AlCl3.6H2O as a catalyst for simple and efficient synthesis of gem-dihydroperoxides from ketones and aldehydes using aqueous H2O2

AlCl₃.6H₂O was explored as an efficient catalyst for the synthesis of ingem-dihydroperoxides (DHPs) from ketones and aldehydes. The reactions took place within a short period of time using (30%) aqueous H₂O₂ as a ??green?? oxidant in acetonitrile under neutral conditions at room temperature to afford the products in high yields.     

Self-assembly of an organocatalyst for the enantioselective synthesis of Michael adducts and α-aminoxy alcohols in a nonpolar medium

A proline–thiourea host–guest complex is described as a self-assembled organocatalyst for the enantioselective Michael addition of aldehydes to nitroolefins and for the asymmetric α-aminoxylation of both aldehydes and ketones. The Michael adducts were obtained in good yields of up to 80%, high diastereoselectivities of up to 5:95, and high enantiomeric excesses of up to 98%. The optically active aminoxy alcohols were synthesized in 60–85% yields with 94–99% enantiomeric excesses after reduction of the α-oxidation products using NaBH₄.     

Generation of alkyl hypochlorites in oxidation of alcohols with carbon tetrachloride catalyzed by vanadium and manganese compounds

Primary alcohols and diols with various structures were subjected to transformations into esters, aldehydes, ketones, and lactones under the action of carbon tetrachloride in the presence of manganese compounds (MnCl₂, MnO₂, Mn(OAc)₂, Mn(acac)₃) and vanadium compounds (VCl₅, V₂O₅, VO(acac)₂) as catalysts. These transformation proceeded with the involvement of alkyl hypochlorites, which were generated in the course of oxidation of alcohols with carbon tetrachloride catalyzed by manganese or vanadium compounds. The optimum molar ratios between the catalyst and reagents were determined, and the reaction conditions for the highly selective synthesis of esters, aldehydes, ketones, and lactones from alcohols were found.     

Cobalt-Catalyzed Aerobic Oxidative Cleavage of Alkyl Aldehydes: Synthesis of Ketones,Esters, Amides,and α-Ketoamides

A widely applicable approach was developed to synthesize ketones, esters, amides via the oxidative C−C bond cleavage of readily available alkyl aldehydes. Green and abundant molecular oxygen (O₂) was used as the oxidant, and base metals (cobalt and copper) were used as the catalysts. This strategy can be extended to the one-pot synthesis of ketones from primary alcohols and α-ketoamides from aldehydes.