Efficient oxidation of benzyl alcohol with heteropolytungstate as reaction-controlled phase-transfer catalyst

A series of heteropolytungstates has been synthesized and utilized as catalysts to catalyze oxidation of benzyl alcohol with aqueous hydrogen peroxide. The results indicated that three of these catalysts showed the properties of reaction-controlled phasetransfer catalysis, and they had excellent catalytic ability to the oxidation of benzyl alcohol. No other by-products were detected by gas chromatography. Once the hydrogen peroxide was consumed completely, the catalyst precipitated from solvent, and the results of the catalyst recycle showed that the catalyst had high stability.

Nuclephilic ring opening of epoxides promoted by multi-site phase-transfer catalyst:An efficient and eco-friendly route to synthesis of β-hydroxythiocyanate

A highly effective and mild protocol for ring opening of epoxides with NH4SCN in the presence of catalytic amount of a multi- site phase-transfer catalyst, α,α＇,α＂-N-hexakis（triethylammoniummethylene chloride）-melamine, is developed. A variety of ^-hydroxy thiocyanates as important intermediates in agricultural and pharmaceutical chemistry were obtained in high yields with excellent regioselectivity and in short reaction times. 2009 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

A New Reaction-controlled Phase-transfer Catalyst System

A new reaction-controlled phase-transfer catalyst system was designed and synthesized. In this system, heteropolytungstate [C7H7N(CH3)3]9PW9O34 was used for catalytic epoxidation of cyclohexene with H2O2 as the oxidant. The conversion of H2O2 was 100% and the yield of cyclohexene oxide was 87.1% based on cyclohexene. Infrared spectra showed that both fresh catalyst and the recovered catalyst do have completely same absorption peak, indicating the structure of catalyst is very stability and can be recycled.

Ionic liquids as efficient phase-transfer catalysts for the solid base-promoted monoalkylation of diethyl malonate

Ionic liquids （ILs） based on 1,3-dialkylimidazolium and tetraalkylammonium cations were employed as a series of efficient, environmentally benign phase-transfer catalysts （PTCs） for the base-promoted monoalkylation of diethyl malonate. The influence of various heterogeneous bases on yields was studied. Good yields and high selectivity were obtained. Solvent-free, mild reaction condition, short reaction time, and easy purification were the merits of this method. The catalytic system （IL-hase） could also be recycled after the extraction of products with ether.

Asymmetric Phase-transfer Mediated Epoxidation of α, β-Enones Using Dendritic Catalysts Derived from Cinchona Alkaloids

Chiral phase-transfer catalysts, derived from cinchona alkaloids and Fréchet dendritic wedges up to generation two, have been synthesized. These chiral dendritic molecules have been used as PTCs in the epoxidation of α, β-enones, showing a moderate level of asymmetric induction.

Heteropolymolybdate as a New Reaction-controlled Phase-transfer Catalyst for Efficient Alcohol Oxidation with Hydrogen Peroxide

A new catalytic process for the synthesis of aldehyde from alcohol by oxidation with H202 with high selectivity, was studied. In this system, heteropolymolybdate [C7H7N（CH3）3]3 {PO4[MoO（O2）2]4} was utilized as the reaction-controlled phase-transfer catalyst to catalyze oxidation of benzyl and aliphatic alcohols. The molar ratio of H2O2 and alcohol was 0.75, no other by-products were detected by gas chromatography, the results of oxidation reaction indicated that the catalyst has high activity and stability.

A Convenient Synthesis of Aromatic Fluoride by Thermal Stable Pyridinium Phase-transfer Catalyst

Using 4-Dialkylaminopyridinium salt as a thermal stable phase-transfer catalyst (PTC), the excellent results were obtained in the halogen-exchange fluorination.

Characterization and Synthesis through Fast Phase-Transfer of Oil-Soluble Double-Coordinated Tea-Polyphenols Arsenic

Fast phase-transferring was adopted in ethanol solution at the condition of n (oil-soluble tea pol-yphenol): N (As3﹢) = 2:1, 4:1, 6:1, pH = 4.0, temperature 40°C - 45°C, action period of 15 h to compose the target, of which the productivity was 59%, UV was 267.50, 218.00, 220.50 nm, FTIR was 6291, 34158.6, 2850.2, 1708.2;1457.3;1370.4, 1224.2, 1144.0, 760.5 cm﹣1, fluorescence value λmax = 257, 591.1, 593.7, 590.3, 591.0, 591.5, XRD λ/nm is 3.6974, 4.186, 12.0762, 15.4747, 1H-NMRδ = 0.782, 1.193, 1.483 - 1.586, 1.959 - 2.184, 2.479, 3.116, 3.970 - 3.981, 5.231 - 5.753, 6.537 - 7.300. Finally it was ascertained through XRD as double-coordinated polycrystal compound.

Novel Catalytic Method for Synthesis of Glycosyl Esters by Combining PTC with DMAP

This article presents a novel catalytic method by combining phase-transfer catalyst, benzyltriethylammonium chloride, with 4-dimethylaminopyridine for the syntheses of glycosyl esters from substituted phenoxyaeetie acids and the peracetate of α-D-l-bromosugars to produee eight novel β-glyeosyl esters in high yields. The struetures of the syn-thesized eompounds were established by IR, MS, ^1H NMR, and ^13C NMR speetra and elemental analyses.

A New Indicator Reaction and Its Application-Catalytic Determination of Ultratrace Amounts of Rhodium with Linear Sweep Voltammetry

Introduction Sensitive linear sweep voltammetry to have been applied to the catalytic kinetic analysis may be helpful for the application of some organic reagents to the analysis of inorganic ones by voltammetry, The catalytic reaction-linear sweep voltammetric method for the determination of noble metals, such as Ag, Os, Ru and Ir has been developed, but no report about the method for the determination of rhodium has been published so far.

催化裂化汽油加氢后博士试验不合格原因分析及应对

中国石化青岛石油化工有限责任公司(青岛石化)汽油选择性加氢脱硫(RSDS)装置加氢原料汽油中烯烃含量较上周期增加,催化裂化稳定汽油在加氢脱硫的同时,产生了二次大分子硫醇,影响了博士试验通过率。优化操作使混合汽油总硫低于8μg/g后仍会发生博士试验不通过的情况,对于青岛石化汽油产品的顺利出厂产生了较大影响。因此,青岛石化以化验分析数据为基础,分析发现博士试验不通过的主要是原料烯烃含量、硫含量的增加以及催化剂烯烃饱和活性的下降导致大分子硫醇产生造成的。总结提出通过调整轻重汽油切割比例、使用低硫组分调合和采用串联氧化脱臭单元解决博士试验通过率低的问题。目前RSDS装置混合汽油中硫醇硫质量分数低于1μg/g,混合汽油博士试验全部通过。

Lacunary Keggin Polyoxotungstate as Reaction-controlled Phase-transfer Catalyst for Catalytic Epoxidation of Olefins

A new reaction-controlled phase-transfer catalyst system, lacunary Keggin polyoxotungstate [C7H7N(CH3)3]9PW9O34 has been synthesized and used for catalytic epoxidation of olefins with H2O2 as the oxidant. Infrared spectra were used to analyze the behavior of the phase transfer of catalyst. In this system, the catalyst not only can act as homogeneous catalyst but also as heterogeneous catalyst to be easily filtered and reused. The epoxi- dation reaction is clean and exhibits high conversion and selectivity as well as excellent catalyst stability.

Styrene epoxidation catalyzed by polyoxometalate/quaternary ammonium phase transfer catalysts: The effect of cation size and catalyst deactivation mechanism

Catalytic epoxidation of alkenes is an important type of organic reaction in chemical industry,and the deep insight into catalyst deactivation will help to develop new epoxidation process.In this work,series of quaternary ammoniums bearing different cationic sizes,i.e.MTOA+(methyltrioctylammonium,[(C_(8)H_(17))_(3)CH_(3)N]+),HTMA+(hexadecyltrimethylammonium,[(C_(16)H_(33))(CH_(3))_(3)N]+) and DMDOA+(dimethyldioctadecylammonium,[(C_(18)H_(37))_(2)(CH_(3))_(2)N]+) were incorporated with polyoxometalate (POM) anions to prepare phase transfer catalysts (PTCs),which were used in the styrene epoxidations.Among them,(MTOA)_(3)PW_(4)O_(24)exhibits the best catalytic performance judged from the highest styrene conversion rate(52%) and styrene oxide selectivity (93%),during which the styrene epoxidation conditions were optimized.Meanwhile,the deactivation mechanism of this kind of PTCs was proposed firstly,i.e.in the case of low H_(2)O_(2) content,the oxidant can only be used in the styrene epoxidation,in which the catalyst can transform into stable Keggin-type POM.But when the content of H_(2)O_(2) is higher,the excess H_(2)O_(2) can reactivate the Keggin-type POM into active (PW_(4)O_(24))_(3)-anions,which can trigger the ring-opening polymerization of styrene oxide.Consequently,the catalyst is deactivated by adhered poly(styrene oxide)irreversibly,which was determined by NMR spectra.In this situation,the active moiety{PO_(4)[WO(O_(2))_(2)]_(4)}_(3)-in phase-transfer catalytic system can break into some unidentified species with low W/P ratio with the presence of epoxides.This work will be beneficial for the design of new PTCs in alkene epoxidation in fine chemical industry.

双戊烯加工利用的研究（Ⅱ）──双戊烯氢化反应的中试研究

研究了我国合成樟脑副产品双戊烯的主要化学组成，双戊烯在催化剂金属镍或钯的作用下，氢化反应的条件、反应产物对烷的立体异构体。对烷存在顺式、反式两种异构体，以ＧＣ、ＩＲ和ＮＭＲ分析鉴定。中试氢化装置为φ２７３×２６×３０００ｍｍ固定催化床层的连续反应器，材质为ＩＣｒ１８Ｎｉ９Ｔｉ。反应条件在压力５～７ＭＰａ、温度１５０～１６０℃进行，处理过为６５ｋｇ／ｈ，粗对烷收率约为９６％。

CoPc/Al_2O_3催化分子氧环氧化环己烯的研究

CoPc complexes were supported on the acid alumina using in-situ method.The resulting compounds were characterized by DTA-TGA thermal analysis,ICP,solid-state infrared,and Ultraviolet/visible spectroscopy,and tested as catalysts for the eposidation of cyclohexene under ambient conditions using molecular dioxygen as oxidant and isobutyraldehyde as sacrificial reagent.The optimums for the reaction have been obtained.Under the conditions of time:9h,temperature:35℃,isobutyraldehyde to cyclohexene ratio:4,the weight of catalyst: 0.05g,the volume of solvent:20mL,the conversion of cyclohexene attained 73.5% and the selectivity of cyclohexene epoxide,84.1%

微波消解催化光度法测定食品中的痕量镍

建立微波消解-阻抑动力学光度法测定食品中痕量镍的新方法。通过微波消解试剂和消解仪器条件优化,确定最佳消解条件,即以70%HNO3-30%H2O2(4:1,V/V)为消解液、消解压力1.5MPa、消解时间15min。在硼砂介质中,镍对过氧化氢氧化溴甲酚紫褪色反应具有阻抑作用,聚乙二醇-200(PEG-200)对此反应体系有活化作用;通过对反应介质和活化剂的种类、用量、反应温度、反应时间、共存组分的考察,确定最佳分析条件,并测定一些动力学参数。该方法的测定波长为590nm,水溶条件为沸水浴,反应时间为14min,线性范围为1.7×10-3～0.14mg/L,检出限为1.7×10-3mg/L。所建方法用于食品中痕量镍的测定,最大相对标准偏差为5.2%,加标回收率为94.4%～107.1%;所建方法与GB/T 5009.138—2003《食品中镍的测定》进行对比,方法相对误差小于6.3%。

Selenium-catalyzed oxidative carbonylation of 2-aminobenzyl alcohol to give 1,4-dihydro-2H-3,1-benzoxazin-2-one

An efficient,economical,and phosgene-free approach was developed for the preparation of l,4-dihydro-2H-3,l-benzoxazin-2-one from 2-aminobenzyl alcohol.In terms of its key features,this reaction uses the cheap and recyclable non-metal selenium as a catalyst instead of the noble metal palladium;carbon monoxide as a carbonylation agent instead of virulent phosgene or one of its derivatives;and oxygen as an oxidant.The selenium-catalyzed oxidative carbonylation reaction of2-aminobenzyl alcohol proceeded efficiently in a single pot in the presence of triethylamine to afford l,4-dihydro-2H-3,l-benzoxazin-2-one in 87%yield.Furthermore,the selenium catalyst was readily recovered and recycled,affording a product yield of 80%after five cycles.

十二水合硫酸铁铵催化合成氯乙酸异戊酯的研究

以十二水合硫酸铁铵为催化剂、正己烷为带水剂,以氯乙酸与异戊醇为原料合成氯乙酸异戊酯。考察了醇酸摩尔比、催化剂用量、带水剂用量、反应时间、不同的带水剂及催化剂的重复使用对酯收率的影响。结果表明,在氯乙酸用量为0.1mol、醇酸摩尔比为1.2∶1、催化剂十二水合硫酸铁铵用量为1.5g、带水剂正己烷用量为15mL、反应时间为1.5h、反应温度为78～98℃的优化合成条件下,氯乙酸异戊酯收率达到89.6%。

固载杂多酸盐催化合成苯甲酸正戊酯

首次报道了以固载杂多酸盐TiSiW12 O4 0 /TiO2 为多相催化剂 ,对以苯甲酸和正戊醇为原料合成苯甲酸正戊酯的反应条件进行了研究 .实验表明 :TiSiW12 O4 0 /TiO2 是合成苯甲酸正戊酯的良好催化剂 .最佳反应条件为 :醇酸物质量比为 4∶1,催化剂用量为反应物料总量的 1.5 % ,反应时间为 2 .5h .上述条件下 ,苯甲酸正戊酯的产率可达 96 .7% .

非小细胞肺癌端粒酶催化亚单位的表达及其与c-myc基因的相关性

目的 研究端粒酶催化亚单位 (hTERT)在非小细胞肺癌的表达及其与c -myc基因的相关性 ,并探讨肺癌hTERT激活的可能调节机制。方法 应用荧光半定量逆转录聚合酶链反应方法 (RT -PCR)检测非小细胞肺癌组织hTERT及c-mycmRNA表达水平 ,对两者进行统计学相关分析。结果 5 1例非小细胞肺癌hTERT表达阳性率为 86 .3% ,明显高于癌旁正常肺组织和良性病变组织 (分别为 14 .3%和 2 7.3% )。hTERT的表达和肿瘤组织病理类型、分化程度、临床分期、肿块大小及淋巴结转移指标间未见明显相关性。相关分析显示hTERT与c-mycmRNA表达存在显著相关性 ,相关系数r =0 .6 33(P <0 .0 0 1)。结论hTERT对肺癌诊断具有潜在临床价值 ,hTERT的表达与c -myc表达存在显著相关性 ,进一步支持c -myc的过度表达可能是肺癌端粒酶激活和调节的机制之一。